[blender.git] / source / blender / blenkernel / intern / constraint.c

/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): 2007, Joshua Leung, major recode
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenkernel/intern/constraint.c
 *  \ingroup bke
 */


#include <stdio.h> 
#include <stddef.h>
#include <string.h>
#include <math.h>
#include <float.h>

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_kdopbvh.h"
#include "BLI_utildefines.h"

#include "DNA_armature_types.h"
#include "DNA_camera_types.h"
#include "DNA_constraint_types.h"
#include "DNA_modifier_types.h"
#include "DNA_object_types.h"
#include "DNA_action_types.h"
#include "DNA_curve_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"

#include "DNA_lattice_types.h"
#include "DNA_scene_types.h"
#include "DNA_text_types.h"
#include "DNA_tracking_types.h"
#include "DNA_movieclip_types.h"


#include "BKE_action.h"
#include "BKE_anim.h" /* for the curve calculation part */
#include "BKE_armature.h"
#include "BKE_blender.h"
#include "BKE_bvhutils.h"
#include "BKE_camera.h"
#include "BKE_constraint.h"
#include "BKE_displist.h"
#include "BKE_deform.h"
#include "BKE_DerivedMesh.h"    /* for geometry targets */
#include "BKE_cdderivedmesh.h" /* for geometry targets */
#include "BKE_object.h"
#include "BKE_ipo.h"
#include "BKE_global.h"
#include "BKE_library.h"
#include "BKE_idprop.h"
#include "BKE_mesh.h"
#include "BKE_shrinkwrap.h"
#include "BKE_mesh.h"
#include "BKE_tessmesh.h"
#include "BKE_tracking.h"
#include "BKE_movieclip.h"

#ifdef WITH_PYTHON
#include "BPY_extern.h"
#endif

#ifndef M_PI
#define M_PI        3.14159265358979323846
#endif



/* ************************ Constraints - General Utilities *************************** */
/* These functions here don't act on any specific constraints, and are therefore should/will
 * not require any of the special function-pointers afforded by the relevant constraint 
 * type-info structs.
 */

/* -------------- Naming -------------- */

/* Find the first available, non-duplicate name for a given constraint */
void unique_constraint_name(bConstraint *con, ListBase *list)
{
        BLI_uniquename(list, con, "Const", '.', offsetof(bConstraint, name), sizeof(con->name));
}

/* ----------------- Evaluation Loop Preparation --------------- */

/* package an object/bone for use in constraint evaluation */
/* This function MEM_calloc's a bConstraintOb struct, that will need to be freed after evaluation */
bConstraintOb *constraints_make_evalob(Scene *scene, Object *ob, void *subdata, short datatype)
{
        bConstraintOb *cob;
        
        /* create regardless of whether we have any data! */
        cob = MEM_callocN(sizeof(bConstraintOb), "bConstraintOb");
        
        /* for system time, part of deglobalization, code nicer later with local time (ton) */
        cob->scene = scene;
        
        /* based on type of available data */
        switch (datatype) {
                case CONSTRAINT_OBTYPE_OBJECT:
                {
                        /* disregard subdata... calloc should set other values right */
                        if (ob) {
                                cob->ob = ob;
                                cob->type = datatype;
                                cob->rotOrder = EULER_ORDER_DEFAULT; // TODO: when objects have rotation order too, use that
                                copy_m4_m4(cob->matrix, ob->obmat);
                        }
                        else
                                unit_m4(cob->matrix);
                        
                        copy_m4_m4(cob->startmat, cob->matrix);
                }
                break;
                case CONSTRAINT_OBTYPE_BONE:
                {
                        /* only set if we have valid bone, otherwise default */
                        if (ob && subdata) {
                                cob->ob = ob;
                                cob->pchan = (bPoseChannel *)subdata;
                                cob->type = datatype;
                                
                                if (cob->pchan->rotmode > 0) {
                                        /* should be some type of Euler order */
                                        cob->rotOrder = cob->pchan->rotmode;
                                }
                                else {
                                        /* Quats, so eulers should just use default order */
                                        cob->rotOrder = EULER_ORDER_DEFAULT;
                                }
                                
                                /* matrix in world-space */
                                mult_m4_m4m4(cob->matrix, ob->obmat, cob->pchan->pose_mat);
                        }
                        else
                                unit_m4(cob->matrix);
                                
                        copy_m4_m4(cob->startmat, cob->matrix);
                }
                break;
                        
                default: /* other types not yet handled */
                        unit_m4(cob->matrix);
                        unit_m4(cob->startmat);
                        break;
        }
        
        return cob;
}

/* cleanup after constraint evaluation */
void constraints_clear_evalob(bConstraintOb *cob)
{
        float delta[4][4], imat[4][4];
        
        /* prevent crashes */
        if (cob == NULL) 
                return;
        
        /* calculate delta of constraints evaluation */
        invert_m4_m4(imat, cob->startmat);
        mult_m4_m4m4(delta, cob->matrix, imat);
        
        /* copy matrices back to source */
        switch (cob->type) {
                case CONSTRAINT_OBTYPE_OBJECT:
                {
                        /* cob->ob might not exist! */
                        if (cob->ob) {
                                /* copy new ob-matrix back to owner */
                                copy_m4_m4(cob->ob->obmat, cob->matrix);
                                
                                /* copy inverse of delta back to owner */
                                invert_m4_m4(cob->ob->constinv, delta);
                        }
                }
                break;
                case CONSTRAINT_OBTYPE_BONE:
                {
                        /* cob->ob or cob->pchan might not exist */
                        if (cob->ob && cob->pchan) {
                                /* copy new pose-matrix back to owner */
                                mult_m4_m4m4(cob->pchan->pose_mat, cob->ob->imat, cob->matrix);
                                
                                /* copy inverse of delta back to owner */
                                invert_m4_m4(cob->pchan->constinv, delta);
                        }
                }
                break;
        }
        
        /* free tempolary struct */
        MEM_freeN(cob);
}

/* -------------- Space-Conversion API -------------- */

#if 0 /* XXX Old code, does the same as one in armature.c, will remove it later. */
static void constraint_pchan_diff_mat(bPoseChannel *pchan, float diff_mat[4][4])
{
        if (pchan->parent) {
                float offs_bone[4][4];

                /* construct offs_bone the same way it is done in armature.c */
                copy_m4_m3(offs_bone, pchan->bone->bone_mat);
                copy_v3_v3(offs_bone[3], pchan->bone->head);
                offs_bone[3][1] += pchan->bone->parent->length;

                if (pchan->bone->flag & BONE_HINGE) {
                        /* pose_mat = par_pose-space_location * chan_mat */
                        float tmat[4][4];

                        /* the rotation of the parent restposition */
                        copy_m4_m4(tmat, pchan->bone->parent->arm_mat);

                        /* the location of actual parent transform */
                        copy_v3_v3(tmat[3], offs_bone[3]);
                        zero_v3(offs_bone[3]);
                        mul_m4_v3(pchan->parent->pose_mat, tmat[3]);

                        mult_m4_m4m4(diff_mat, tmat, offs_bone);
                }
                else {
                        /* pose_mat = par_pose_mat * bone_mat * chan_mat */
                        if (pchan->bone->flag & BONE_NO_SCALE) {
                                float tmat[4][4];
                                copy_m4_m4(tmat, pchan->parent->pose_mat);
                                normalize_m4(tmat);
                                mult_m4_m4m4(diff_mat, tmat, offs_bone);
                        }
                        else {
                                mult_m4_m4m4(diff_mat, pchan->parent->pose_mat, offs_bone);
                        }
                }
        }
        else {
                /* pose_mat = chan_mat * arm_mat */
                copy_m4_m4(diff_mat, pchan->bone->arm_mat);
        }
}
#endif

/* This function is responsible for the correct transformations/conversions 
 * of a matrix from one space to another for constraint evaluation.
 * For now, this is only implemented for Objects and PoseChannels.
 */
void constraint_mat_convertspace(Object *ob, bPoseChannel *pchan, float mat[][4], short from, short to)
{
        float diff_mat[4][4];
        float imat[4][4];
        
        /* prevent crashes in these unlikely events  */
        if (ob == NULL || mat == NULL) return;
        /* optimize trick - check if need to do anything */
        if (from == to) return;
        
        /* are we dealing with pose-channels or objects */
        if (pchan) {
                /* pose channels */
                switch (from) {
                        case CONSTRAINT_SPACE_WORLD: /* ---------- FROM WORLDSPACE ---------- */
                        {
                                /* world to pose */
                                invert_m4_m4(imat, ob->obmat);
                                mult_m4_m4m4(mat, imat, mat);
                                
                                /* use pose-space as stepping stone for other spaces... */
                                if (ELEM(to, CONSTRAINT_SPACE_LOCAL, CONSTRAINT_SPACE_PARLOCAL)) {
                                        /* call self with slightly different values */
                                        constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                                }
                        }
                        break;
                        case CONSTRAINT_SPACE_POSE: /* ---------- FROM POSESPACE ---------- */
                        {
                                /* pose to world */
                                if (to == CONSTRAINT_SPACE_WORLD) {
                                        mult_m4_m4m4(mat, ob->obmat, mat);
                                }
                                /* pose to local */
                                else if (to == CONSTRAINT_SPACE_LOCAL) {
                                        if (pchan->bone) {
                                                BKE_armature_mat_pose_to_bone(pchan, mat, mat);
#if 0  /* XXX Old code, will remove it later. */
                                                constraint_pchan_diff_mat(pchan, diff_mat);

                                                invert_m4_m4(imat, diff_mat);
                                                mult_m4_m4m4(mat, imat, mat);

                                                /* override with local location */
                                                if ((pchan->parent) && (pchan->bone->flag & BONE_NO_LOCAL_LOCATION)) {
                                                        BKE_armature_mat_pose_to_bone_ex(ob, pchan, pchan->pose_mat, tempmat);
                                                        copy_v3_v3(mat[3], tempmat[3]);
                                                }
#endif
                                        }
                                }
                                /* pose to local with parent */
                                else if (to == CONSTRAINT_SPACE_PARLOCAL) {
                                        if (pchan->bone) {
                                                invert_m4_m4(imat, pchan->bone->arm_mat);
                                                mult_m4_m4m4(mat, imat, mat);
                                        }
                                }
                        }
                        break;
                        case CONSTRAINT_SPACE_LOCAL: /* ------------ FROM LOCALSPACE --------- */
                        {
                                /* local to pose - do inverse procedure that was done for pose to local */
                                if (pchan->bone) {
                                        /* we need the posespace_matrix = local_matrix + (parent_posespace_matrix + restpos) */
                                        BKE_armature_mat_bone_to_pose(pchan, mat, mat);
#if 0
                                        constraint_pchan_diff_mat(pchan, diff_mat);

                                        mult_m4_m4m4(mat, diff_mat, mat);
#endif
                                }
                                
                                /* use pose-space as stepping stone for other spaces */
                                if (ELEM(to, CONSTRAINT_SPACE_WORLD, CONSTRAINT_SPACE_PARLOCAL)) {
                                        /* call self with slightly different values */
                                        constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                                }
                        }
                        break;
                        case CONSTRAINT_SPACE_PARLOCAL: /* -------------- FROM LOCAL WITH PARENT ---------- */
                        {
                                /* local + parent to pose */
                                if (pchan->bone) {
                                        copy_m4_m4(diff_mat, pchan->bone->arm_mat);
                                        mult_m4_m4m4(mat, mat, diff_mat);
                                }
                                
                                /* use pose-space as stepping stone for other spaces */
                                if (ELEM(to, CONSTRAINT_SPACE_WORLD, CONSTRAINT_SPACE_LOCAL)) {
                                        /* call self with slightly different values */
                                        constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                                }
                        }
                        break;
                }
        }
        else {
                /* objects */
                if (from == CONSTRAINT_SPACE_WORLD && to == CONSTRAINT_SPACE_LOCAL) {
                        /* check if object has a parent */
                        if (ob->parent) {
                                /* 'subtract' parent's effects from owner */
                                mult_m4_m4m4(diff_mat, ob->parent->obmat, ob->parentinv);
                                invert_m4_m4(imat, diff_mat);
                                mult_m4_m4m4(mat, imat, mat);
                        }
                        else {
                                /* Local space in this case will have to be defined as local to the owner's 
                                 * transform-property-rotated axes. So subtract this rotation component.
                                 */
                                BKE_object_to_mat4(ob, diff_mat);
                                normalize_m4(diff_mat);
                                zero_v3(diff_mat[3]);
                                
                                invert_m4_m4(imat, diff_mat);
                                mult_m4_m4m4(mat, imat, mat);
                        }
                }
                else if (from == CONSTRAINT_SPACE_LOCAL && to == CONSTRAINT_SPACE_WORLD) {
                        /* check that object has a parent - otherwise this won't work */
                        if (ob->parent) {
                                /* 'add' parent's effect back to owner */
                                mult_m4_m4m4(diff_mat, ob->parent->obmat, ob->parentinv);
                                mult_m4_m4m4(mat, diff_mat, mat);
                        }
                        else {
                                /* Local space in this case will have to be defined as local to the owner's 
                                 * transform-property-rotated axes. So add back this rotation component.
                                 */
                                BKE_object_to_mat4(ob, diff_mat);
                                normalize_m4(diff_mat);
                                zero_v3(diff_mat[3]);
                                
                                mult_m4_m4m4(mat, diff_mat, mat);
                        }
                }
        }
}

/* ------------ General Target Matrix Tools ---------- */

/* function that sets the given matrix based on given vertex group in mesh */
static void contarget_get_mesh_mat(Object *ob, const char *substring, float mat[][4])
{
        DerivedMesh *dm = NULL;
        BMEditMesh *em = BMEdit_FromObject(ob);
        float vec[3] = {0.0f, 0.0f, 0.0f};
        float normal[3] = {0.0f, 0.0f, 0.0f}, plane[3];
        float imat[3][3], tmat[3][3];
        const int defgroup = defgroup_name_index(ob, substring);
        short freeDM = 0;
        
        /* initialize target matrix using target matrix */
        copy_m4_m4(mat, ob->obmat);
        
        /* get index of vertex group */
        if (defgroup == -1) return;

        /* get DerivedMesh */
        if (em) {
                /* target is in editmode, so get a special derived mesh */
                dm = CDDM_from_editbmesh(em, FALSE, FALSE);
                freeDM = 1;
        }
        else {
                /* when not in EditMode, use the 'final' derived mesh, depsgraph
                 * ensures we build with CD_MDEFORMVERT layer 
                 */
                dm = (DerivedMesh *)ob->derivedFinal;
        }
        
        /* only continue if there's a valid DerivedMesh */
        if (dm) {
                MDeformVert *dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
                int numVerts = dm->getNumVerts(dm);
                int i, count = 0;
                float co[3], nor[3];
                
                /* check that dvert is a valid pointers (just in case) */
                if (dvert) {
                        MDeformVert *dv = dvert;
                        /* get the average of all verts with that are in the vertex-group */
                        for (i = 0; i < numVerts; i++, dv++) {
                                MDeformWeight *dw = defvert_find_index(dv, defgroup);
                                if (dw && dw->weight != 0.0f) {
                                        dm->getVertCo(dm, i, co);
                                        dm->getVertNo(dm, i, nor);
                                        add_v3_v3(vec, co);
                                        add_v3_v3(normal, nor);
                                        count++;
                                        
                                }
                        }

                        /* calculate averages of normal and coordinates */
                        if (count > 0) {
                                mul_v3_fl(vec, 1.0f / count);
                                mul_v3_fl(normal, 1.0f / count);
                        }
                        
                        
                        /* derive the rotation from the average normal: 
                         *              - code taken from transform_manipulator.c, 
                         *                      calc_manipulator_stats, V3D_MANIP_NORMAL case
                         */
                        /*      we need the transpose of the inverse for a normal... */
                        copy_m3_m4(imat, ob->obmat);
                        
                        invert_m3_m3(tmat, imat);
                        transpose_m3(tmat);
                        mul_m3_v3(tmat, normal);
                        
                        normalize_v3(normal);
                        copy_v3_v3(plane, tmat[1]);
                        
                        cross_v3_v3v3(mat[0], normal, plane);
                        if (len_v3(mat[0]) < 1e-3f) {
                                copy_v3_v3(plane, tmat[0]);
                                cross_v3_v3v3(mat[0], normal, plane);
                        }

                        copy_v3_v3(mat[2], normal);
                        cross_v3_v3v3(mat[1], mat[2], mat[0]);

                        normalize_m4(mat);

                        
                        /* apply the average coordinate as the new location */
                        mul_v3_m4v3(mat[3], ob->obmat, vec);
                }
        }
        
        /* free temporary DerivedMesh created (in EditMode case) */
        if (dm && freeDM)
                dm->release(dm);
}

/* function that sets the given matrix based on given vertex group in lattice */
static void contarget_get_lattice_mat(Object *ob, const char *substring, float mat[][4])
{
        Lattice *lt = (Lattice *)ob->data;
        
        DispList *dl = BKE_displist_find(&ob->disp, DL_VERTS);
        float *co = dl ? dl->verts : NULL;
        BPoint *bp = lt->def;
        
        MDeformVert *dv = lt->dvert;
        int tot_verts = lt->pntsu * lt->pntsv * lt->pntsw;
        float vec[3] = {0.0f, 0.0f, 0.0f}, tvec[3];
        int grouped = 0;
        int i, n;
        const int defgroup = defgroup_name_index(ob, substring);
        
        /* initialize target matrix using target matrix */
        copy_m4_m4(mat, ob->obmat);

        /* get index of vertex group */
        if (defgroup == -1) return;
        if (dv == NULL) return;
        
        /* 1. Loop through control-points checking if in nominated vertex-group.
         * 2. If it is, add it to vec to find the average point.
         */
        for (i = 0; i < tot_verts; i++, dv++) {
                for (n = 0; n < dv->totweight; n++) {
                        MDeformWeight *dw = defvert_find_index(dv, defgroup);
                        if (dw && dw->weight > 0.0f) {
                                /* copy coordinates of point to temporary vector, then add to find average */
                                memcpy(tvec, co ? co : bp->vec, 3 * sizeof(float));

                                add_v3_v3(vec, tvec);
                                grouped++;
                        }
                }
                
                /* advance pointer to coordinate data */
                if (co) co += 3;
                else bp++;
        }
        
        /* find average location, then multiply by ob->obmat to find world-space location */
        if (grouped)
                mul_v3_fl(vec, 1.0f / grouped);
        mul_v3_m4v3(tvec, ob->obmat, vec);
        
        /* copy new location to matrix */
        copy_v3_v3(mat[3], tvec);
}

/* generic function to get the appropriate matrix for most target cases */
/* The cases where the target can be object data have not been implemented */
static void constraint_target_to_mat4(Object *ob, const char *substring, float mat[][4], short from, short to, float headtail)
{
        /*      Case OBJECT */
        if (!strlen(substring)) {
                copy_m4_m4(mat, ob->obmat);
                constraint_mat_convertspace(ob, NULL, mat, from, to);
        }
        /*  Case VERTEXGROUP */
        /* Current method just takes the average location of all the points in the
         * VertexGroup, and uses that as the location value of the targets. Where 
         * possible, the orientation will also be calculated, by calculating an
         * 'average' vertex normal, and deriving the rotation from that.
         *
         * NOTE: EditMode is not currently supported, and will most likely remain that
         *              way as constraints can only really affect things on object/bone level.
         */
        else if (ob->type == OB_MESH) {
                contarget_get_mesh_mat(ob, substring, mat);
                constraint_mat_convertspace(ob, NULL, mat, from, to);
        }
        else if (ob->type == OB_LATTICE) {
                contarget_get_lattice_mat(ob, substring, mat);
                constraint_mat_convertspace(ob, NULL, mat, from, to);
        }
        /*      Case BONE */
        else {
                bPoseChannel *pchan;
                
                pchan = BKE_pose_channel_find_name(ob->pose, substring);
                if (pchan) {
                        /* Multiply the PoseSpace accumulation/final matrix for this
                         * PoseChannel by the Armature Object's Matrix to get a worldspace
                         * matrix.
                         */
                        if (headtail < 0.000001f) {
                                /* skip length interpolation if set to head */
                                mult_m4_m4m4(mat, ob->obmat, pchan->pose_mat);
                        }
                        else {
                                float tempmat[4][4], loc[3];
                                
                                /* interpolate along length of bone */
                                interp_v3_v3v3(loc, pchan->pose_head, pchan->pose_tail, headtail);
                                
                                /* use interpolated distance for subtarget */
                                copy_m4_m4(tempmat, pchan->pose_mat);
                                copy_v3_v3(tempmat[3], loc);
                                
                                mult_m4_m4m4(mat, ob->obmat, tempmat);
                        }
                }
                else
                        copy_m4_m4(mat, ob->obmat);
                        
                /* convert matrix space as required */
                constraint_mat_convertspace(ob, pchan, mat, from, to);
        }
}

/* ************************* Specific Constraints ***************************** */
/* Each constraint defines a set of functions, which will be called at the appropriate
 * times. In addition to this, each constraint should have a type-info struct, where
 * its functions are attached for use. 
 */
 
/* Template for type-info data:
 *  - make a copy of this when creating new constraints, and just change the functions
 *    pointed to as necessary
 *  - although the naming of functions doesn't matter, it would help for code
 *    readability, to follow the same naming convention as is presented here
 *  - any functions that a constraint doesn't need to define, don't define
 *    for such cases, just use NULL 
 *  - these should be defined after all the functions have been defined, so that
 *    forward-definitions/prototypes don't need to be used!
 *      - keep this copy #if-def'd so that future constraints can get based off this
 */
#if 0
static bConstraintTypeInfo CTI_CONSTRNAME = {
        CONSTRAINT_TYPE_CONSTRNAME, /* type */
        sizeof(bConstrNameConstraint), /* size */
        "ConstrName", /* name */
        "bConstrNameConstraint", /* struct name */
        constrname_free, /* free data */
        constrname_id_looper, /* id looper */
        constrname_copy, /* copy data */
        constrname_new_data, /* new data */
        constrname_get_tars, /* get constraint targets */
        constrname_flush_tars, /* flush constraint targets */
        constrname_get_tarmat, /* get target matrix */
        constrname_evaluate /* evaluate */
};
#endif

/* This function should be used for the get_target_matrix member of all 
 * constraints that are not picky about what happens to their target matrix.
 */
static void default_get_tarmat(bConstraint *con, bConstraintOb *UNUSED(cob), bConstraintTarget *ct, float UNUSED(ctime))
{
        if (VALID_CONS_TARGET(ct))
                constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
        else if (ct)
                unit_m4(ct->matrix);
}

/* This following macro should be used for all standard single-target *_get_tars functions 
 * to save typing and reduce maintenance woes.
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
// TODO: cope with getting rotation order...
#define SINGLETARGET_GET_TARS(con, datatar, datasubtarget, ct, list) \
        { \
                ct = MEM_callocN(sizeof(bConstraintTarget), "tempConstraintTarget"); \
                 \
                ct->tar = datatar; \
                BLI_strncpy(ct->subtarget, datasubtarget, sizeof(ct->subtarget)); \
                ct->space = con->tarspace; \
                ct->flag = CONSTRAINT_TAR_TEMP; \
                 \
                if (ct->tar) { \
                        if ((ct->tar->type == OB_ARMATURE) && (ct->subtarget[0])) { \
                                bPoseChannel *pchan = BKE_pose_channel_find_name(ct->tar->pose, ct->subtarget); \
                                ct->type = CONSTRAINT_OBTYPE_BONE; \
                                ct->rotOrder = (pchan) ? (pchan->rotmode) : EULER_ORDER_DEFAULT; \
                        } \
                        else if (OB_TYPE_SUPPORT_VGROUP(ct->tar->type) && (ct->subtarget[0])) { \
                                ct->type = CONSTRAINT_OBTYPE_VERT; \
                                ct->rotOrder = EULER_ORDER_DEFAULT; \
                        } \
                        else { \
                                ct->type = CONSTRAINT_OBTYPE_OBJECT; \
                                ct->rotOrder = ct->tar->rotmode; \
                        } \
                } \
                 \
                BLI_addtail(list, ct); \
        } (void)0
        
/* This following macro should be used for all standard single-target *_get_tars functions 
 * to save typing and reduce maintenance woes. It does not do the subtarget related operations
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
// TODO: cope with getting rotation order...
#define SINGLETARGETNS_GET_TARS(con, datatar, ct, list) \
        { \
                ct = MEM_callocN(sizeof(bConstraintTarget), "tempConstraintTarget"); \
                 \
                ct->tar = datatar; \
                ct->space = con->tarspace; \
                ct->flag = CONSTRAINT_TAR_TEMP; \
                 \
                if (ct->tar) ct->type = CONSTRAINT_OBTYPE_OBJECT; \
                 \
                BLI_addtail(list, ct); \
        } (void)0

/* This following macro should be used for all standard single-target *_flush_tars functions
 * to save typing and reduce maintenance woes.
 * Note: the pointer to ct will be changed to point to the next in the list (as it gets removed)
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
#define SINGLETARGET_FLUSH_TARS(con, datatar, datasubtarget, ct, list, nocopy) \
        { \
                if (ct) { \
                        bConstraintTarget *ctn = ct->next; \
                        if (nocopy == 0) { \
                                datatar = ct->tar; \
                                BLI_strncpy(datasubtarget, ct->subtarget, sizeof(datasubtarget)); \
                                con->tarspace = (char)ct->space; \
                        } \
                         \
                        BLI_freelinkN(list, ct); \
                        ct = ctn; \
                } \
        } (void)0
        
/* This following macro should be used for all standard single-target *_flush_tars functions
 * to save typing and reduce maintenance woes. It does not do the subtarget related operations.
 * Note: the pointer to ct will be changed to point to the next in the list (as it gets removed)
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
#define SINGLETARGETNS_FLUSH_TARS(con, datatar, ct, list, nocopy) \
        { \
                if (ct) { \
                        bConstraintTarget *ctn = ct->next; \
                        if (nocopy == 0) { \
                                datatar = ct->tar; \
                                con->tarspace = (char)ct->space; \
                        } \
                         \
                        BLI_freelinkN(list, ct); \
                        ct = ctn; \
                } \
        } (void)0
 
/* --------- ChildOf Constraint ------------ */

static void childof_new_data(void *cdata)
{
        bChildOfConstraint *data = (bChildOfConstraint *)cdata;
        
        data->flag = (CHILDOF_LOCX | CHILDOF_LOCY | CHILDOF_LOCZ |
                      CHILDOF_ROTX | CHILDOF_ROTY | CHILDOF_ROTZ |
                      CHILDOF_SIZEX | CHILDOF_SIZEY | CHILDOF_SIZEZ);
        unit_m4(data->invmat);
}

static void childof_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bChildOfConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int childof_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bChildOfConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void childof_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bChildOfConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void childof_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bChildOfConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;

        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float parmat[4][4];
                
                /* simple matrix parenting */
                if (data->flag == CHILDOF_ALL) {
                        
                        /* multiply target (parent matrix) by offset (parent inverse) to get 
                         * the effect of the parent that will be exerted on the owner
                         */
                        mult_m4_m4m4(parmat, ct->matrix, data->invmat);
                        
                        /* now multiply the parent matrix by the owner matrix to get the 
                         * the effect of this constraint (i.e. owner is 'parented' to parent)
                         */
                        mult_m4_m4m4(cob->matrix, parmat, cob->matrix);
                }
                else {
                        float invmat[4][4], tempmat[4][4];
                        float loc[3], eul[3], size[3];
                        float loco[3], eulo[3], sizo[3];
                        
                        /* get offset (parent-inverse) matrix */
                        copy_m4_m4(invmat, data->invmat);
                        
                        /* extract components of both matrices */
                        copy_v3_v3(loc, ct->matrix[3]);
                        mat4_to_eulO(eul, ct->rotOrder, ct->matrix);
                        mat4_to_size(size, ct->matrix);
                        
                        copy_v3_v3(loco, invmat[3]);
                        mat4_to_eulO(eulo, cob->rotOrder, invmat);
                        mat4_to_size(sizo, invmat);
                        
                        /* disable channels not enabled */
                        if (!(data->flag & CHILDOF_LOCX)) loc[0] = loco[0] = 0.0f;
                        if (!(data->flag & CHILDOF_LOCY)) loc[1] = loco[1] = 0.0f;
                        if (!(data->flag & CHILDOF_LOCZ)) loc[2] = loco[2] = 0.0f;
                        if (!(data->flag & CHILDOF_ROTX)) eul[0] = eulo[0] = 0.0f;
                        if (!(data->flag & CHILDOF_ROTY)) eul[1] = eulo[1] = 0.0f;
                        if (!(data->flag & CHILDOF_ROTZ)) eul[2] = eulo[2] = 0.0f;
                        if (!(data->flag & CHILDOF_SIZEX)) size[0] = sizo[0] = 1.0f;
                        if (!(data->flag & CHILDOF_SIZEY)) size[1] = sizo[1] = 1.0f;
                        if (!(data->flag & CHILDOF_SIZEZ)) size[2] = sizo[2] = 1.0f;
                        
                        /* make new target mat and offset mat */
                        loc_eulO_size_to_mat4(ct->matrix, loc, eul, size, ct->rotOrder);
                        loc_eulO_size_to_mat4(invmat, loco, eulo, sizo, cob->rotOrder);
                        
                        /* multiply target (parent matrix) by offset (parent inverse) to get 
                         * the effect of the parent that will be exerted on the owner
                         */
                        mult_m4_m4m4(parmat, ct->matrix, invmat);
                        
                        /* now multiply the parent matrix by the owner matrix to get the 
                         * the effect of this constraint (i.e.  owner is 'parented' to parent)
                         */
                        copy_m4_m4(tempmat, cob->matrix);
                        mult_m4_m4m4(cob->matrix, parmat, tempmat);
                        
                        /* without this, changes to scale and rotation can change location
                         * of a parentless bone or a disconnected bone. Even though its set
                         * to zero above. */
                        if (!(data->flag & CHILDOF_LOCX)) cob->matrix[3][0] = tempmat[3][0];
                        if (!(data->flag & CHILDOF_LOCY)) cob->matrix[3][1] = tempmat[3][1];
                        if (!(data->flag & CHILDOF_LOCZ)) cob->matrix[3][2] = tempmat[3][2];
                }
        }
}

/* XXX note, con->flag should be CONSTRAINT_SPACEONCE for bone-childof, patched in readfile.c */
static bConstraintTypeInfo CTI_CHILDOF = {
        CONSTRAINT_TYPE_CHILDOF, /* type */
        sizeof(bChildOfConstraint), /* size */
        "ChildOf", /* name */
        "bChildOfConstraint", /* struct name */
        NULL, /* free data */
        childof_id_looper, /* id looper */
        NULL, /* copy data */
        childof_new_data, /* new data */
        childof_get_tars, /* get constraint targets */
        childof_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get a target matrix */
        childof_evaluate /* evaluate */
};

/* -------- TrackTo Constraint ------- */

static void trackto_new_data(void *cdata)
{
        bTrackToConstraint *data = (bTrackToConstraint *)cdata;
        
        data->reserved1 = TRACK_Y;
        data->reserved2 = UP_Z;
}       

static void trackto_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bTrackToConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int trackto_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bTrackToConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void trackto_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bTrackToConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}


static int basis_cross(int n, int m)
{
        switch (n - m) {
                case 1: 
                case -2:
                        return 1;
                        
                case -1: 
                case 2:
                        return -1;
                        
                default:
                        return 0;
        }
}

static void vectomat(const float vec[3], const float target_up[3], short axis, short upflag, short flags, float m[][3])
{
        float n[3];
        float u[3]; /* vector specifying the up axis */
        float proj[3];
        float right[3];
        float neg = -1;
        int right_index;

        if (normalize_v3_v3(n, vec) == 0.0f) {
                n[0] = 0.0f;
                n[1] = 0.0f;
                n[2] = 1.0f;
        }
        if (axis > 2) axis -= 3;
        else negate_v3(n);

        /* n specifies the transformation of the track axis */
        if (flags & TARGET_Z_UP) {
                /* target Z axis is the global up axis */
                copy_v3_v3(u, target_up);
        }
        else {
                /* world Z axis is the global up axis */
                u[0] = 0;
                u[1] = 0;
                u[2] = 1;
        }

        /* project the up vector onto the plane specified by n */
        project_v3_v3v3(proj, u, n); /* first u onto n... */
        sub_v3_v3v3(proj, u, proj); /* then onto the plane */
        /* proj specifies the transformation of the up axis */

        if (normalize_v3(proj) == 0.0f) { /* degenerate projection */
                proj[0] = 0.0f;
                proj[1] = 1.0f;
                proj[2] = 0.0f;
        }

        /* Normalized cross product of n and proj specifies transformation of the right axis */
        cross_v3_v3v3(right, proj, n);
        normalize_v3(right);

        if (axis != upflag) {
                right_index = 3 - axis - upflag;
                neg = (float)basis_cross(axis, upflag);
                
                /* account for up direction, track direction */
                m[right_index][0] = neg * right[0];
                m[right_index][1] = neg * right[1];
                m[right_index][2] = neg * right[2];
                
                copy_v3_v3(m[upflag], proj);
                
                copy_v3_v3(m[axis], n);
        }
        /* identity matrix - don't do anything if the two axes are the same */
        else {
                unit_m3(m);
        }
}


static void trackto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bTrackToConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float size[3], vec[3];
                float totmat[3][3];
                
                /* Get size property, since ob->size is only the object's own relative size, not its global one */
                mat4_to_size(size, cob->matrix);
                
                /* Clear the object's rotation */
                cob->matrix[0][0] = size[0];
                cob->matrix[0][1] = 0;
                cob->matrix[0][2] = 0;
                cob->matrix[1][0] = 0;
                cob->matrix[1][1] = size[1];
                cob->matrix[1][2] = 0;
                cob->matrix[2][0] = 0;
                cob->matrix[2][1] = 0;
                cob->matrix[2][2] = size[2];
                
                /* targetmat[2] instead of ownermat[2] is passed to vectomat
                 * for backwards compatibility it seems... (Aligorith)
                 */
                sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
                vectomat(vec, ct->matrix[2], 
                         (short)data->reserved1, (short)data->reserved2,
                         data->flags, totmat);

                mul_m4_m3m4(cob->matrix, totmat, cob->matrix);
        }
}

static bConstraintTypeInfo CTI_TRACKTO = {
        CONSTRAINT_TYPE_TRACKTO, /* type */
        sizeof(bTrackToConstraint), /* size */
        "TrackTo", /* name */
        "bTrackToConstraint", /* struct name */
        NULL, /* free data */
        trackto_id_looper, /* id looper */
        NULL, /* copy data */
        trackto_new_data, /* new data */
        trackto_get_tars, /* get constraint targets */
        trackto_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        trackto_evaluate /* evaluate */
};

/* --------- Inverse-Kinemetics --------- */

static void kinematic_new_data(void *cdata)
{
        bKinematicConstraint *data = (bKinematicConstraint *)cdata;
        
        data->weight = 1.0f;
        data->orientweight = 1.0f;
        data->iterations = 500;
        data->dist = 1.0f;
        data->flag = CONSTRAINT_IK_TIP | CONSTRAINT_IK_STRETCH | CONSTRAINT_IK_POS;
}

static void kinematic_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bKinematicConstraint *data = con->data;
        
        /* chain target */
        func(con, (ID **)&data->tar, FALSE, userdata);
        
        /* poletarget */
        func(con, (ID **)&data->poletar, FALSE, userdata);
}

static int kinematic_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bKinematicConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints is used twice here */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                SINGLETARGET_GET_TARS(con, data->poletar, data->polesubtarget, ct, list);
                
                return 2;
        }
        
        return 0;
}

static void kinematic_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bKinematicConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
                SINGLETARGET_FLUSH_TARS(con, data->poletar, data->polesubtarget, ct, list, nocopy);
        }
}

static void kinematic_get_tarmat(bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bKinematicConstraint *data = con->data;
        
        if (VALID_CONS_TARGET(ct)) 
                constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
        else if (ct) {
                if (data->flag & CONSTRAINT_IK_AUTO) {
                        Object *ob = cob->ob;
                        
                        if (ob == NULL) {
                                unit_m4(ct->matrix);
                        }
                        else {
                                float vec[3];
                                /* move grabtarget into world space */
                                mul_v3_m4v3(vec, ob->obmat, data->grabtarget);
                                copy_m4_m4(ct->matrix, ob->obmat);
                                copy_v3_v3(ct->matrix[3], vec);
                        }
                }
                else
                        unit_m4(ct->matrix);
        }
}

static bConstraintTypeInfo CTI_KINEMATIC = {
        CONSTRAINT_TYPE_KINEMATIC, /* type */
        sizeof(bKinematicConstraint), /* size */
        "IK", /* name */
        "bKinematicConstraint", /* struct name */
        NULL, /* free data */
        kinematic_id_looper, /* id looper */
        NULL, /* copy data */
        kinematic_new_data, /* new data */
        kinematic_get_tars, /* get constraint targets */
        kinematic_flush_tars, /* flush constraint targets */
        kinematic_get_tarmat, /* get target matrix */
        NULL /* evaluate - solved as separate loop */
};

/* -------- Follow-Path Constraint ---------- */

static void followpath_new_data(void *cdata)
{
        bFollowPathConstraint *data = (bFollowPathConstraint *)cdata;
        
        data->trackflag = TRACK_Y;
        data->upflag = UP_Z;
        data->offset = 0;
        data->followflag = 0;
}

static void followpath_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bFollowPathConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int followpath_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bFollowPathConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints without subtargets */
                SINGLETARGETNS_GET_TARS(con, data->tar, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void followpath_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bFollowPathConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy);
        }
}

static void followpath_get_tarmat(bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bFollowPathConstraint *data = con->data;
        
        if (VALID_CONS_TARGET(ct)) {
                Curve *cu = ct->tar->data;
                float vec[4], dir[3], radius;
                float totmat[4][4] = MAT4_UNITY;
                float curvetime;

                unit_m4(ct->matrix);

                /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
                 *              currently for paths to work it needs to go through the bevlist/displist system (ton) 
                 */
                
                /* only happens on reload file, but violates depsgraph still... fix! */
                if (cu->path == NULL || cu->path->data == NULL)
                        BKE_displist_make_curveTypes(cob->scene, ct->tar, 0);
                
                if (cu->path && cu->path->data) {
                        float quat[4];
                        if ((data->followflag & FOLLOWPATH_STATIC) == 0) {
                                /* animated position along curve depending on time */
                                Nurb *nu = cu->nurb.first;
                                curvetime = cu->ctime - data->offset;
                                
                                /* ctime is now a proper var setting of Curve which gets set by Animato like any other var that's animated,
                                 * but this will only work if it actually is animated... 
                                 *
                                 * we divide the curvetime calculated in the previous step by the length of the path, to get a time
                                 * factor, which then gets clamped to lie within 0.0 - 1.0 range
                                 */
                                curvetime /= cu->pathlen;

                                if (nu && nu->flagu & CU_NURB_CYCLIC) {
                                        /* If the curve is cyclic, enable looping around if the time is
                                         * outside the bounds 0..1 */
                                        if ((curvetime < 0.0f) || (curvetime > 1.0f)) {
                                                curvetime -= floorf(curvetime);
                                        }
                                }
                                else {
                                        /* The curve is not cyclic, so clamp to the begin/end points. */
                                        CLAMP(curvetime, 0.0f, 1.0f);
                                }
                        }
                        else {
                                /* fixed position along curve */
                                curvetime = data->offset_fac;
                        }
                        
                        if (where_on_path(ct->tar, curvetime, vec, dir, (data->followflag & FOLLOWPATH_FOLLOW) ? quat : NULL, &radius, NULL) ) {  /* quat_pt is quat or NULL*/
                                if (data->followflag & FOLLOWPATH_FOLLOW) {
#if 0
                                        float x1, q[4];
                                        vec_to_quat(quat, dir, (short)data->trackflag, (short)data->upflag);
                                        
                                        normalize_v3(dir);
                                        q[0] = (float)cos(0.5 * vec[3]);
                                        x1 = (float)sin(0.5 * vec[3]);
                                        q[1] = -x1 * dir[0];
                                        q[2] = -x1 * dir[1];
                                        q[3] = -x1 * dir[2];
                                        mul_qt_qtqt(quat, q, quat);
#else
                                        quat_apply_track(quat, data->trackflag, data->upflag);
#endif

                                        quat_to_mat4(totmat, quat);
                                }

                                if (data->followflag & FOLLOWPATH_RADIUS) {
                                        float tmat[4][4], rmat[4][4];
                                        scale_m4_fl(tmat, radius);
                                        mult_m4_m4m4(rmat, tmat, totmat);
                                        copy_m4_m4(totmat, rmat);
                                }
                                
                                copy_v3_v3(totmat[3], vec);
                                
                                mul_serie_m4(ct->matrix, ct->tar->obmat, totmat, NULL, NULL, NULL, NULL, NULL, NULL);
                        }
                }
        }
        else if (ct)
                unit_m4(ct->matrix);
}

static void followpath_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct = targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float obmat[4][4];
                float size[3];
                bFollowPathConstraint *data = con->data;
                
                /* get Object transform (loc/rot/size) to determine transformation from path */
                /* TODO: this used to be local at one point, but is probably more useful as-is */
                copy_m4_m4(obmat, cob->matrix);
                
                /* get scaling of object before applying constraint */
                mat4_to_size(size, cob->matrix);
                
                /* apply targetmat - containing location on path, and rotation */
                mul_serie_m4(cob->matrix, ct->matrix, obmat, NULL, NULL, NULL, NULL, NULL, NULL);
                
                /* un-apply scaling caused by path */
                if ((data->followflag & FOLLOWPATH_RADIUS) == 0) { /* XXX - assume that scale correction means that radius will have some scale error in it - Campbell */
                        float obsize[3];
                        
                        mat4_to_size(obsize, cob->matrix);
                        if (obsize[0])
                                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
                        if (obsize[1])
                                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
                        if (obsize[2])
                                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
                }
        }
}

static bConstraintTypeInfo CTI_FOLLOWPATH = {
        CONSTRAINT_TYPE_FOLLOWPATH, /* type */
        sizeof(bFollowPathConstraint), /* size */
        "Follow Path", /* name */
        "bFollowPathConstraint", /* struct name */
        NULL, /* free data */
        followpath_id_looper, /* id looper */
        NULL, /* copy data */
        followpath_new_data, /* new data */
        followpath_get_tars, /* get constraint targets */
        followpath_flush_tars, /* flush constraint targets */
        followpath_get_tarmat, /* get target matrix */
        followpath_evaluate /* evaluate */
};

/* --------- Limit Location --------- */


static void loclimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bLocLimitConstraint *data = con->data;
        
        if (data->flag & LIMIT_XMIN) {
                if (cob->matrix[3][0] < data->xmin)
                        cob->matrix[3][0] = data->xmin;
        }
        if (data->flag & LIMIT_XMAX) {
                if (cob->matrix[3][0] > data->xmax)
                        cob->matrix[3][0] = data->xmax;
        }
        if (data->flag & LIMIT_YMIN) {
                if (cob->matrix[3][1] < data->ymin)
                        cob->matrix[3][1] = data->ymin;
        }
        if (data->flag & LIMIT_YMAX) {
                if (cob->matrix[3][1] > data->ymax)
                        cob->matrix[3][1] = data->ymax;
        }
        if (data->flag & LIMIT_ZMIN) {
                if (cob->matrix[3][2] < data->zmin) 
                        cob->matrix[3][2] = data->zmin;
        }
        if (data->flag & LIMIT_ZMAX) {
                if (cob->matrix[3][2] > data->zmax)
                        cob->matrix[3][2] = data->zmax;
        }
}

static bConstraintTypeInfo CTI_LOCLIMIT = {
        CONSTRAINT_TYPE_LOCLIMIT, /* type */
        sizeof(bLocLimitConstraint), /* size */
        "Limit Location", /* name */
        "bLocLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        loclimit_evaluate /* evaluate */
};

/* -------- Limit Rotation --------- */

static void rotlimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bRotLimitConstraint *data = con->data;
        float loc[3];
        float eul[3];
        float size[3];
        
        copy_v3_v3(loc, cob->matrix[3]);
        mat4_to_size(size, cob->matrix);

        mat4_to_eulO(eul, cob->rotOrder, cob->matrix);

        /* constraint data uses radians internally */
        
        /* limiting of euler values... */
        if (data->flag & LIMIT_XROT) {
                if (eul[0] < data->xmin) 
                        eul[0] = data->xmin;
                        
                if (eul[0] > data->xmax)
                        eul[0] = data->xmax;
        }
        if (data->flag & LIMIT_YROT) {
                if (eul[1] < data->ymin)
                        eul[1] = data->ymin;
                        
                if (eul[1] > data->ymax)
                        eul[1] = data->ymax;
        }
        if (data->flag & LIMIT_ZROT) {
                if (eul[2] < data->zmin)
                        eul[2] = data->zmin;
                        
                if (eul[2] > data->zmax)
                        eul[2] = data->zmax;
        }
                
        loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
}

static bConstraintTypeInfo CTI_ROTLIMIT = {
        CONSTRAINT_TYPE_ROTLIMIT, /* type */
        sizeof(bRotLimitConstraint), /* size */
        "Limit Rotation", /* name */
        "bRotLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        rotlimit_evaluate /* evaluate */
};

/* --------- Limit Scale --------- */


static void sizelimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bSizeLimitConstraint *data = con->data;
        float obsize[3], size[3];
        
        mat4_to_size(size, cob->matrix);
        mat4_to_size(obsize, cob->matrix);
        
        if (data->flag & LIMIT_XMIN) {
                if (size[0] < data->xmin) 
                        size[0] = data->xmin;
        }
        if (data->flag & LIMIT_XMAX) {
                if (size[0] > data->xmax) 
                        size[0] = data->xmax;
        }
        if (data->flag & LIMIT_YMIN) {
                if (size[1] < data->ymin) 
                        size[1] = data->ymin;
        }
        if (data->flag & LIMIT_YMAX) {
                if (size[1] > data->ymax) 
                        size[1] = data->ymax;
        }
        if (data->flag & LIMIT_ZMIN) {
                if (size[2] < data->zmin) 
                        size[2] = data->zmin;
        }
        if (data->flag & LIMIT_ZMAX) {
                if (size[2] > data->zmax) 
                        size[2] = data->zmax;
        }
        
        if (obsize[0]) 
                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
        if (obsize[1]) 
                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
        if (obsize[2]) 
                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
}

static bConstraintTypeInfo CTI_SIZELIMIT = {
        CONSTRAINT_TYPE_SIZELIMIT, /* type */
        sizeof(bSizeLimitConstraint), /* size */
        "Limit Scale", /* name */
        "bSizeLimitConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        sizelimit_evaluate /* evaluate */
};

/* ----------- Copy Location ------------- */

static void loclike_new_data(void *cdata)
{
        bLocateLikeConstraint *data = (bLocateLikeConstraint *)cdata;
        
        data->flag = LOCLIKE_X | LOCLIKE_Y | LOCLIKE_Z;
}

static void loclike_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bLocateLikeConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int loclike_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bLocateLikeConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void loclike_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bLocateLikeConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void loclike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bLocateLikeConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float offset[3] = {0.0f, 0.0f, 0.0f};
                
                if (data->flag & LOCLIKE_OFFSET)
                        copy_v3_v3(offset, cob->matrix[3]);
                        
                if (data->flag & LOCLIKE_X) {
                        cob->matrix[3][0] = ct->matrix[3][0];
                        
                        if (data->flag & LOCLIKE_X_INVERT) cob->matrix[3][0] *= -1;
                        cob->matrix[3][0] += offset[0];
                }
                if (data->flag & LOCLIKE_Y) {
                        cob->matrix[3][1] = ct->matrix[3][1];
                        
                        if (data->flag & LOCLIKE_Y_INVERT) cob->matrix[3][1] *= -1;
                        cob->matrix[3][1] += offset[1];
                }
                if (data->flag & LOCLIKE_Z) {
                        cob->matrix[3][2] = ct->matrix[3][2];
                        
                        if (data->flag & LOCLIKE_Z_INVERT) cob->matrix[3][2] *= -1;
                        cob->matrix[3][2] += offset[2];
                }
        }
}

static bConstraintTypeInfo CTI_LOCLIKE = {
        CONSTRAINT_TYPE_LOCLIKE, /* type */
        sizeof(bLocateLikeConstraint), /* size */
        "Copy Location", /* name */
        "bLocateLikeConstraint", /* struct name */
        NULL, /* free data */
        loclike_id_looper, /* id looper */
        NULL, /* copy data */
        loclike_new_data, /* new data */
        loclike_get_tars, /* get constraint targets */
        loclike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        loclike_evaluate /* evaluate */
};

/* ----------- Copy Rotation ------------- */

static void rotlike_new_data(void *cdata)
{
        bRotateLikeConstraint *data = (bRotateLikeConstraint *)cdata;
        
        data->flag = ROTLIKE_X | ROTLIKE_Y | ROTLIKE_Z;
}

static void rotlike_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bRotateLikeConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int rotlike_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bRotateLikeConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void rotlike_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bRotateLikeConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void rotlike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bRotateLikeConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float loc[3];
                float eul[3], obeul[3];
                float size[3];
                
                copy_v3_v3(loc, cob->matrix[3]);
                mat4_to_size(size, cob->matrix);
                
                /* to allow compatible rotations, must get both rotations in the order of the owner... */
                mat4_to_eulO(obeul, cob->rotOrder, cob->matrix);
                /* we must get compatible eulers from the beginning because some of them can be modified below (see bug #21875) */
                mat4_to_compatible_eulO(eul, obeul, cob->rotOrder, ct->matrix);
                
                if ((data->flag & ROTLIKE_X) == 0)
                        eul[0] = obeul[0];
                else {
                        if (data->flag & ROTLIKE_OFFSET)
                                rotate_eulO(eul, cob->rotOrder, 'X', obeul[0]);
                        
                        if (data->flag & ROTLIKE_X_INVERT)
                                eul[0] *= -1;
                }
                
                if ((data->flag & ROTLIKE_Y) == 0)
                        eul[1] = obeul[1];
                else {
                        if (data->flag & ROTLIKE_OFFSET)
                                rotate_eulO(eul, cob->rotOrder, 'Y', obeul[1]);
                        
                        if (data->flag & ROTLIKE_Y_INVERT)
                                eul[1] *= -1;
                }
                
                if ((data->flag & ROTLIKE_Z) == 0)
                        eul[2] = obeul[2];
                else {
                        if (data->flag & ROTLIKE_OFFSET)
                                rotate_eulO(eul, cob->rotOrder, 'Z', obeul[2]);
                        
                        if (data->flag & ROTLIKE_Z_INVERT)
                                eul[2] *= -1;
                }
                
                /* good to make eulers compatible again, since we don't know how much they were changed above */
                compatible_eul(eul, obeul);
                loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
        }
}

static bConstraintTypeInfo CTI_ROTLIKE = {
        CONSTRAINT_TYPE_ROTLIKE, /* type */
        sizeof(bRotateLikeConstraint), /* size */
        "Copy Rotation", /* name */
        "bRotateLikeConstraint", /* struct name */
        NULL, /* free data */
        rotlike_id_looper, /* id looper */
        NULL, /* copy data */
        rotlike_new_data, /* new data */
        rotlike_get_tars, /* get constraint targets */
        rotlike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        rotlike_evaluate /* evaluate */
};

/* ---------- Copy Scale ---------- */

static void sizelike_new_data(void *cdata)
{
        bSizeLikeConstraint *data = (bSizeLikeConstraint *)cdata;
        
        data->flag = SIZELIKE_X | SIZELIKE_Y | SIZELIKE_Z;
}

static void sizelike_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bSizeLikeConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int sizelike_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bSizeLikeConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void sizelike_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bSizeLikeConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void sizelike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bSizeLikeConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float obsize[3], size[3];
                
                mat4_to_size(size, ct->matrix);
                mat4_to_size(obsize, cob->matrix);
                
                if ((data->flag & SIZELIKE_X) && (obsize[0] != 0)) {
                        if (data->flag & SIZELIKE_OFFSET) {
                                size[0] += (obsize[0] - 1.0f);
                                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
                        }
                        else
                                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
                }
                if ((data->flag & SIZELIKE_Y) && (obsize[1] != 0)) {
                        if (data->flag & SIZELIKE_OFFSET) {
                                size[1] += (obsize[1] - 1.0f);
                                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
                        }
                        else
                                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
                }
                if ((data->flag & SIZELIKE_Z) && (obsize[2] != 0)) {
                        if (data->flag & SIZELIKE_OFFSET) {
                                size[2] += (obsize[2] - 1.0f);
                                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
                        }
                        else
                                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
                }
        }
}

static bConstraintTypeInfo CTI_SIZELIKE = {
        CONSTRAINT_TYPE_SIZELIKE, /* type */
        sizeof(bSizeLikeConstraint), /* size */
        "Copy Scale", /* name */
        "bSizeLikeConstraint", /* struct name */
        NULL, /* free data */
        sizelike_id_looper, /* id looper */
        NULL, /* copy data */
        sizelike_new_data, /* new data */
        sizelike_get_tars, /* get constraint targets */
        sizelike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        sizelike_evaluate /* evaluate */
};

/* ----------- Copy Transforms ------------- */

static void translike_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bTransLikeConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int translike_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bTransLikeConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void translike_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bTransLikeConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void translike_evaluate(bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                /* just copy the entire transform matrix of the target */
                copy_m4_m4(cob->matrix, ct->matrix);
        }
}

static bConstraintTypeInfo CTI_TRANSLIKE = {
        CONSTRAINT_TYPE_TRANSLIKE, /* type */
        sizeof(bTransLikeConstraint), /* size */
        "Copy Transforms", /* name */
        "bTransLikeConstraint", /* struct name */
        NULL, /* free data */
        translike_id_looper, /* id looper */
        NULL, /* copy data */
        NULL, /* new data */
        translike_get_tars, /* get constraint targets */
        translike_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        translike_evaluate /* evaluate */
};

/* ---------- Maintain Volume ---------- */

static void samevolume_new_data(void *cdata)
{
        bSameVolumeConstraint *data = (bSameVolumeConstraint *)cdata;

        data->flag = SAMEVOL_Y;
        data->volume = 1.0f;
}

static void samevolume_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
        bSameVolumeConstraint *data = con->data;

        float volume = data->volume;
        float fac = 1.0f;
        float obsize[3];

        mat4_to_size(obsize, cob->matrix);
        
        /* calculate normalizing scale factor for non-essential values */
        if (obsize[data->flag] != 0) 
                fac = sqrtf(volume / obsize[data->flag]) / obsize[data->flag];
        
        /* apply scaling factor to the channels not being kept */
        switch (data->flag) {
                case SAMEVOL_X:
                        mul_v3_fl(cob->matrix[1], fac);
                        mul_v3_fl(cob->matrix[2], fac);
                        break;
                case SAMEVOL_Y:
                        mul_v3_fl(cob->matrix[0], fac);
                        mul_v3_fl(cob->matrix[2], fac);
                        break;
                case SAMEVOL_Z:
                        mul_v3_fl(cob->matrix[0], fac);
                        mul_v3_fl(cob->matrix[1], fac);
                        break;
        }
}

static bConstraintTypeInfo CTI_SAMEVOL = {
        CONSTRAINT_TYPE_SAMEVOL, /* type */
        sizeof(bSameVolumeConstraint), /* size */
        "Maintain Volume", /* name */
        "bSameVolumeConstraint", /* struct name */
        NULL, /* free data */
        NULL, /* id looper */
        NULL, /* copy data */
        samevolume_new_data, /* new data */
        NULL, /* get constraint targets */
        NULL, /* flush constraint targets */
        NULL, /* get target matrix */
        samevolume_evaluate /* evaluate */
};

/* ----------- Python Constraint -------------- */

static void pycon_free(bConstraint *con)
{
        bPythonConstraint *data = con->data;
        
        /* id-properties */
        IDP_FreeProperty(data->prop);
        MEM_freeN(data->prop);
        
        /* multiple targets */
        BLI_freelistN(&data->targets);
}       

static void pycon_copy(bConstraint *con, bConstraint *srccon)
{
        bPythonConstraint *pycon = (bPythonConstraint *)con->data;
        bPythonConstraint *opycon = (bPythonConstraint *)srccon->data;
        
        pycon->prop = IDP_CopyProperty(opycon->prop);
        BLI_duplicatelist(&pycon->targets, &opycon->targets);
}

static void pycon_new_data(void *cdata)
{
        bPythonConstraint *data = (bPythonConstraint *)cdata;
        
        /* everything should be set correctly by calloc, except for the prop->type constant.*/
        data->prop = MEM_callocN(sizeof(IDProperty), "PyConstraintProps");
        data->prop->type = IDP_GROUP;
}

static int pycon_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bPythonConstraint *data = con->data;
                
                list->first = data->targets.first;
                list->last = data->targets.last;
                
                return data->tarnum;
        }
        
        return 0;
}

static void pycon_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bPythonConstraint *data = con->data;
        bConstraintTarget *ct;
        
        /* targets */
        for (ct = data->targets.first; ct; ct = ct->next)
                func(con, (ID **)&ct->tar, FALSE, userdata);
                
        /* script */
        func(con, (ID **)&data->text, TRUE, userdata);
}

/* Whether this approach is maintained remains to be seen (aligorith) */
static void pycon_get_tarmat(bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
#ifdef WITH_PYTHON
        bPythonConstraint *data = con->data;
#endif

        if (VALID_CONS_TARGET(ct)) {
                /* special exception for curves - depsgraph issues */
                if (ct->tar->type == OB_CURVE) {
                        Curve *cu = ct->tar->data;
                        
                        /* this check is to make sure curve objects get updated on file load correctly.*/
                        if (cu->path == NULL || cu->path->data == NULL) /* only happens on reload file, but violates depsgraph still... fix! */
                                BKE_displist_make_curveTypes(cob->scene, ct->tar, 0);
                }
                
                /* firstly calculate the matrix the normal way, then let the py-function override
                 * this matrix if it needs to do so
                 */
                constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
                
                /* only execute target calculation if allowed */
#ifdef WITH_PYTHON
                if (G.f & G_SCRIPT_AUTOEXEC)
                        BPY_pyconstraint_target(data, ct);
#endif
        }
        else if (ct)
                unit_m4(ct->matrix);
}

static void pycon_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
#ifndef WITH_PYTHON
        (void)con; (void)cob; (void)targets; /* unused */
        return;
#else
        bPythonConstraint *data = con->data;
        
        /* only evaluate in python if we're allowed to do so */
        if ((G.f & G_SCRIPT_AUTOEXEC) == 0) return;
        
/* currently removed, until I this can be re-implemented for multiple targets */
#if 0
        /* Firstly, run the 'driver' function which has direct access to the objects involved 
         * Technically, this is potentially dangerous as users may abuse this and cause dependency-problems,
         * but it also allows certain 'clever' rigging hacks to work.
         */
        BPY_pyconstraint_driver(data, cob, targets);
#endif
        
        /* Now, run the actual 'constraint' function, which should only access the matrices */
        BPY_pyconstraint_exec(data, cob, targets);
#endif /* WITH_PYTHON */
}

static bConstraintTypeInfo CTI_PYTHON = {
        CONSTRAINT_TYPE_PYTHON, /* type */
        sizeof(bPythonConstraint), /* size */
        "Script", /* name */
        "bPythonConstraint", /* struct name */
        pycon_free, /* free data */
        pycon_id_looper, /* id looper */
        pycon_copy, /* copy data */
        pycon_new_data, /* new data */
        pycon_get_tars, /* get constraint targets */
        NULL, /* flush constraint targets */
        pycon_get_tarmat, /* get target matrix */
        pycon_evaluate /* evaluate */
};

/* -------- Action Constraint ----------- */

static void actcon_new_data(void *cdata)
{
        bActionConstraint *data = (bActionConstraint *)cdata;
        
        /* set type to 20 (Loc X), as 0 is Rot X for backwards compatibility */
        data->type = 20;
}

static void actcon_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bActionConstraint *data = con->data;
        
        /* target */
        func(con, (ID **)&data->tar, FALSE, userdata);
        
        /* action */
        func(con, (ID **)&data->act, TRUE, userdata);
}

static int actcon_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bActionConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void actcon_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bActionConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void actcon_get_tarmat(bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
        bActionConstraint *data = con->data;
        
        if (VALID_CONS_TARGET(ct)) {
                float tempmat[4][4], vec[3];
                float s, t;
                short axis;
                
                /* initialize return matrix */
                unit_m4(ct->matrix);
                
                /* get the transform matrix of the target */
                constraint_target_to_mat4(ct->tar, ct->subtarget, tempmat, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
                
                /* determine where in transform range target is */
                /* data->type is mapped as follows for backwards compatibility:
                 *      00,01,02        - rotation (it used to be like this)
                 *  10,11,12    - scaling
                 *      20,21,22        - location
                 */
                if (data->type < 10) {
                        /* extract rotation (is in whatever space target should be in) */
                        mat4_to_eul(vec, tempmat);
                        mul_v3_fl(vec, RAD2DEGF(1.0f)); /* rad -> deg */
                        axis = data->type;
                }
                else if (data->type < 20) {
                        /* extract scaling (is in whatever space target should be in) */
                        mat4_to_size(vec, tempmat);
                        axis = data->type - 10;
                }
                else {
                        /* extract location */
                        copy_v3_v3(vec, tempmat[3]);
                        axis = data->type - 20;
                }
                
                /* Target defines the animation */
                s = (vec[axis] - data->min) / (data->max - data->min);
                CLAMP(s, 0, 1);
                t = (s * (data->end - data->start)) + data->start;
                
                if (G.debug & G_DEBUG)
                        printf("do Action Constraint %s - Ob %s Pchan %s\n", con->name, cob->ob->id.name + 2, (cob->pchan) ? cob->pchan->name : NULL);
                
                /* Get the appropriate information from the action */
                if (cob->type == CONSTRAINT_OBTYPE_OBJECT || (data->flag & ACTCON_BONE_USE_OBJECT_ACTION)) {
                        Object workob;
                        
                        /* evaluate using workob */
                        /* FIXME: we don't have any consistent standards on limiting effects on object... */
                        what_does_obaction(cob->ob, &workob, NULL, data->act, NULL, t);
                        BKE_object_to_mat4(&workob, ct->matrix);
                }
                else if (cob->type == CONSTRAINT_OBTYPE_BONE) {
                        Object workob;
                        bPose *pose;
                        bPoseChannel *pchan, *tchan;
                        
                        /* make a temporary pose and evaluate using that */
                        pose = MEM_callocN(sizeof(bPose), "pose");
                        
                        /* make a copy of the bone of interest in the temp pose before evaluating action, so that it can get set 
                         *      - we need to manually copy over a few settings, including rotation order, otherwise this fails
                         */
                        pchan = cob->pchan;
                        
                        tchan = BKE_pose_channel_verify(pose, pchan->name);
                        tchan->rotmode = pchan->rotmode;
                        
                        /* evaluate action using workob (it will only set the PoseChannel in question) */
                        what_does_obaction(cob->ob, &workob, pose, data->act, pchan->name, t);
                        
                        /* convert animation to matrices for use here */
                        BKE_pchan_calc_mat(tchan);
                        copy_m4_m4(ct->matrix, tchan->chan_mat);
                        
                        /* Clean up */
                        BKE_pose_free(pose);
                }
                else {
                        /* behavior undefined... */
                        puts("Error: unknown owner type for Action Constraint");
                }
        }
}

static void actcon_evaluate(bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float temp[4][4];
                
                /* Nice and simple... we just need to multiply the matrices, as the get_target_matrix
                 * function has already taken care of everything else.
                 */
                copy_m4_m4(temp, cob->matrix);
                mult_m4_m4m4(cob->matrix, temp, ct->matrix);
        }
}

static bConstraintTypeInfo CTI_ACTION = {
        CONSTRAINT_TYPE_ACTION, /* type */
        sizeof(bActionConstraint), /* size */
        "Action", /* name */
        "bActionConstraint", /* struct name */
        NULL, /* free data */
        actcon_id_looper, /* id looper */
        NULL, /* copy data */
        actcon_new_data, /* new data */
        actcon_get_tars, /* get constraint targets */
        actcon_flush_tars, /* flush constraint targets */
        actcon_get_tarmat, /* get target matrix */
        actcon_evaluate /* evaluate */
};

/* --------- Locked Track ---------- */

static void locktrack_new_data(void *cdata)
{
        bLockTrackConstraint *data = (bLockTrackConstraint *)cdata;
        
        data->trackflag = TRACK_Y;
        data->lockflag = LOCK_Z;
}       

static void locktrack_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bLockTrackConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int locktrack_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bLockTrackConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void locktrack_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bLockTrackConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void locktrack_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bLockTrackConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        if (VALID_CONS_TARGET(ct)) {
                float vec[3], vec2[3];
                float totmat[3][3];
                float tmpmat[3][3];
                float invmat[3][3];
                float mdet;
                
                /* Vector object -> target */
                sub_v3_v3v3(vec, ct->matrix[3], cob->matrix[3]);
                switch (data->lockflag) {
                        case LOCK_X: /* LOCK X */
                        {
                                switch (data->trackflag) {
                                        case TRACK_Y: /* LOCK X TRACK Y */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                                sub_v3_v3v3(totmat[1], vec, vec2);
                                                normalize_v3(totmat[1]);
                                        
                                                /* the x axis is fixed */
                                                normalize_v3_v3(totmat[0], cob->matrix[0]);
                                        
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                        }
                                        break;
                                        case TRACK_Z: /* LOCK X TRACK Z */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                                sub_v3_v3v3(totmat[2], vec, vec2);
                                                normalize_v3(totmat[2]);
                                        
                                                /* the x axis is fixed */
                                                normalize_v3_v3(totmat[0], cob->matrix[0]);
                                        
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                        }
                                        break;
                                        case TRACK_nY: /* LOCK X TRACK -Y */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                                sub_v3_v3v3(totmat[1], vec, vec2);
                                                normalize_v3(totmat[1]);
                                                negate_v3(totmat[1]);
                                        
                                                /* the x axis is fixed */
                                                normalize_v3_v3(totmat[0], cob->matrix[0]);
                                        
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                        }
                                        break;
                                        case TRACK_nZ: /* LOCK X TRACK -Z */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[0]);
                                                sub_v3_v3v3(totmat[2], vec, vec2);
                                                normalize_v3(totmat[2]);
                                                negate_v3(totmat[2]);
                                                
                                                /* the x axis is fixed */
                                                normalize_v3_v3(totmat[0], cob->matrix[0]);
                                                
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                        }
                                        break;
                                        default:
                                        {
                                                unit_m3(totmat);
                                        }
                                        break;
                                }
                        }
                        break;
                        case LOCK_Y: /* LOCK Y */
                        {
                                switch (data->trackflag) {
                                        case TRACK_X: /* LOCK Y TRACK X */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                                sub_v3_v3v3(totmat[0], vec, vec2);
                                                normalize_v3(totmat[0]);
                                        
                                                /* the y axis is fixed */
                                                normalize_v3_v3(totmat[1], cob->matrix[1]);

                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                        }
                                        break;
                                        case TRACK_Z: /* LOCK Y TRACK Z */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                                sub_v3_v3v3(totmat[2], vec, vec2);
                                                normalize_v3(totmat[2]);
                                        
                                                /* the y axis is fixed */
                                                normalize_v3_v3(totmat[1], cob->matrix[1]);
                                        
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                        }
                                        break;
                                        case TRACK_nX: /* LOCK Y TRACK -X */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                                sub_v3_v3v3(totmat[0], vec, vec2);
                                                normalize_v3(totmat[0]);
                                                negate_v3(totmat[0]);
                                        
                                                /* the y axis is fixed */
                                                normalize_v3_v3(totmat[1], cob->matrix[1]);
                                        
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                                        }
                                        break;
                                        case TRACK_nZ: /* LOCK Y TRACK -Z */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[1]);
                                                sub_v3_v3v3(totmat[2], vec, vec2);
                                                normalize_v3(totmat[2]);
                                                negate_v3(totmat[2]);
                                        
                                                /* the y axis is fixed */
                                                normalize_v3_v3(totmat[1], cob->matrix[1]);
                                        
                                                /* the z axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                        }
                                        break;
                                        default:
                                        {
                                                unit_m3(totmat);
                                        }
                                        break;
                                }
                        }
                        break;
                        case LOCK_Z: /* LOCK Z */
                        {
                                switch (data->trackflag) {
                                        case TRACK_X: /* LOCK Z TRACK X */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                                sub_v3_v3v3(totmat[0], vec, vec2);
                                                normalize_v3(totmat[0]);
                                        
                                                /* the z axis is fixed */
                                                normalize_v3_v3(totmat[2], cob->matrix[2]);
                                        
                                                /* the x axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                        }
                                        break;
                                        case TRACK_Y: /* LOCK Z TRACK Y */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                                sub_v3_v3v3(totmat[1], vec, vec2);
                                                normalize_v3(totmat[1]);
                                        
                                                /* the z axis is fixed */
                                                normalize_v3_v3(totmat[2], cob->matrix[2]);
                                                
                                                /* the x axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                        }
                                        break;
                                        case TRACK_nX: /* LOCK Z TRACK -X */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                                sub_v3_v3v3(totmat[0], vec, vec2);
                                                normalize_v3(totmat[0]);
                                                negate_v3(totmat[0]);
                                        
                                                /* the z axis is fixed */
                                                normalize_v3_v3(totmat[2], cob->matrix[2]);
                                        
                                                /* the x axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                                        }
                                        break;
                                        case TRACK_nY: /* LOCK Z TRACK -Y */
                                        {
                                                /* Projection of Vector on the plane */
                                                project_v3_v3v3(vec2, vec, cob->matrix[2]);
                                                sub_v3_v3v3(totmat[1], vec, vec2);
                                                normalize_v3(totmat[1]);
                                                negate_v3(totmat[1]);
                                        
                                                /* the z axis is fixed */
                                                normalize_v3_v3(totmat[2], cob->matrix[2]);
                                                
                                                /* the x axis gets mapped onto a third orthogonal vector */
                                                cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                                        }
                                        break;
                                        default:
                                        {
                                                unit_m3(totmat);
                                        }
                                        break;
                                }
                        }
                        break;
                        default:
                        {
                                unit_m3(totmat);
                        }
                        break;
                }
                /* Block to keep matrix heading */
                copy_m3_m4(tmpmat, cob->matrix);
                normalize_m3(tmpmat);
                invert_m3_m3(invmat, tmpmat);
                mul_m3_m3m3(tmpmat, totmat, invmat);
                totmat[0][0] = tmpmat[0][0]; totmat[0][1] = tmpmat[0][1]; totmat[0][2] = tmpmat[0][2];
                totmat[1][0] = tmpmat[1][0]; totmat[1][1] = tmpmat[1][1]; totmat[1][2] = tmpmat[1][2];
                totmat[2][0] = tmpmat[2][0]; totmat[2][1] = tmpmat[2][1]; totmat[2][2] = tmpmat[2][2];
                
                mdet = determinant_m3(totmat[0][0], totmat[0][1], totmat[0][2],
                                      totmat[1][0], totmat[1][1], totmat[1][2],
                                      totmat[2][0], totmat[2][1], totmat[2][2]);
                if (mdet == 0) {
                        unit_m3(totmat);
                }
                
                /* apply out transformaton to the object */
                mul_m4_m3m4(cob->matrix, totmat, cob->matrix);
        }
}

static bConstraintTypeInfo CTI_LOCKTRACK = {
        CONSTRAINT_TYPE_LOCKTRACK, /* type */
        sizeof(bLockTrackConstraint), /* size */
        "Locked Track", /* name */
        "bLockTrackConstraint", /* struct name */
        NULL, /* free data */
        locktrack_id_looper, /* id looper */
        NULL, /* copy data */
        locktrack_new_data, /* new data */
        locktrack_get_tars, /* get constraint targets */
        locktrack_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        locktrack_evaluate /* evaluate */
};

/* ---------- Limit Distance Constraint ----------- */

static void distlimit_new_data(void *cdata)
{
        bDistLimitConstraint *data = (bDistLimitConstraint *)cdata;
        
        data->dist = 0.0f;
}

static void distlimit_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bDistLimitConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int distlimit_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bDistLimitConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void distlimit_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bDistLimitConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void distlimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bDistLimitConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float dvec[3], dist = 0.0f, sfac = 1.0f;
                short clamp_surf = 0;
                
                /* calculate our current distance from the target */
                dist = len_v3v3(cob->matrix[3], ct->matrix[3]);
                
                /* set distance (flag is only set when user demands it) */
                if (data->dist == 0)
                        data->dist = dist;
                
                /* check if we're which way to clamp from, and calculate interpolation factor (if needed) */
                if (data->mode == LIMITDIST_OUTSIDE) {
                        /* if inside, then move to surface */
                        if (dist <= data->dist) {
                                clamp_surf = 1;
                                if (dist != 0.0f) sfac = data->dist / dist;
                        }
                        /* if soft-distance is enabled, start fading once owner is dist+softdist from the target */
                        else if (data->flag & LIMITDIST_USESOFT) {
                                if (dist <= (data->dist + data->soft)) {
                                        
                                }
                        }
                }
                else if (data->mode == LIMITDIST_INSIDE) {
                        /* if outside, then move to surface */
                        if (dist >= data->dist) {
                                clamp_surf = 1;
                                if (dist != 0.0f) sfac = data->dist / dist;
                        }
                        /* if soft-distance is enabled, start fading once owner is dist-soft from the target */
                        else if (data->flag & LIMITDIST_USESOFT) {
                                /* FIXME: there's a problem with "jumping" when this kicks in */
                                if (dist >= (data->dist - data->soft)) {
                                        sfac = (float)(data->soft * (1.0f - expf(-(dist - data->dist) / data->soft)) + data->dist);
                                        if (dist != 0.0f) sfac /= dist;
                                        
                                        clamp_surf = 1;
                                }
                        }
                }
                else {
                        if (IS_EQF(dist, data->dist) == 0) {
                                clamp_surf = 1;
                                if (dist != 0.0f) sfac = data->dist / dist;
                        }
                }
                
                /* clamp to 'surface' (i.e. move owner so that dist == data->dist) */
                if (clamp_surf) {
                        /* simply interpolate along line formed by target -> owner */
                        interp_v3_v3v3(dvec, ct->matrix[3], cob->matrix[3], sfac);
                        
                        /* copy new vector onto owner */
                        copy_v3_v3(cob->matrix[3], dvec);
                }
        }
}

static bConstraintTypeInfo CTI_DISTLIMIT = {
        CONSTRAINT_TYPE_DISTLIMIT, /* type */
        sizeof(bDistLimitConstraint), /* size */
        "Limit Distance", /* name */
        "bDistLimitConstraint", /* struct name */
        NULL, /* free data */
        distlimit_id_looper, /* id looper */
        NULL, /* copy data */
        distlimit_new_data, /* new data */
        distlimit_get_tars, /* get constraint targets */
        distlimit_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get a target matrix */
        distlimit_evaluate /* evaluate */
};

/* ---------- Stretch To ------------ */

static void stretchto_new_data(void *cdata)
{
        bStretchToConstraint *data = (bStretchToConstraint *)cdata;
        
        data->volmode = 0;
        data->plane = 0;
        data->orglength = 0.0; 
        data->bulge = 1.0;
}

static void stretchto_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bStretchToConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int stretchto_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bStretchToConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void stretchto_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bStretchToConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void stretchto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bStretchToConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float size[3], scale[3], vec[3], xx[3], zz[3], orth[3];
                float totmat[3][3];
                float dist;
                
                /* store scaling before destroying obmat */
                mat4_to_size(size, cob->matrix);
                
                /* store X orientation before destroying obmat */
                normalize_v3_v3(xx, cob->matrix[0]);
                
                /* store Z orientation before destroying obmat */
                normalize_v3_v3(zz, cob->matrix[2]);
                
                /* XXX That makes the constraint buggy with asymmetrically scaled objects, see #29940. */
/*              sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);*/
/*              vec[0] /= size[0];*/
/*              vec[1] /= size[1];*/
/*              vec[2] /= size[2];*/
                
/*              dist = normalize_v3(vec);*/
                
                dist = len_v3v3(cob->matrix[3], ct->matrix[3]);
                /* Only Y constrained object axis scale should be used, to keep same length when scaling it. */
                dist /= size[1];
                
                /* data->orglength==0 occurs on first run, and after 'R' button is clicked */
                if (data->orglength == 0)
                        data->orglength = dist;
                if (data->bulge == 0)
                        data->bulge = 1.0;
                
                scale[1] = dist / data->orglength;
                switch (data->volmode) {
                        /* volume preserving scaling */
                        case VOLUME_XZ:
                                scale[0] = 1.0f - (float)sqrt(data->bulge) + (float)sqrt(data->bulge * (data->orglength / dist));
                                scale[2] = scale[0];
                                break;
                        case VOLUME_X:
                                scale[0] = 1.0f + data->bulge * (data->orglength / dist - 1);
                                scale[2] = 1.0;
                                break;
                        case VOLUME_Z:
                                scale[0] = 1.0;
                                scale[2] = 1.0f + data->bulge * (data->orglength / dist - 1);
                                break;
                        /* don't care for volume */
                        case NO_VOLUME:
                                scale[0] = 1.0;
                                scale[2] = 1.0;
                                break;
                        default: /* should not happen, but in case*/
                                return;
                } /* switch (data->volmode) */

                /* Clear the object's rotation and scale */
                cob->matrix[0][0] = size[0] * scale[0];
                cob->matrix[0][1] = 0;
                cob->matrix[0][2] = 0;
                cob->matrix[1][0] = 0;
                cob->matrix[1][1] = size[1] * scale[1];
                cob->matrix[1][2] = 0;
                cob->matrix[2][0] = 0;
                cob->matrix[2][1] = 0;
                cob->matrix[2][2] = size[2] * scale[2];
                
                sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
                normalize_v3(vec);
                
                /* new Y aligns  object target connection*/
                negate_v3_v3(totmat[1], vec);
                switch (data->plane) {
                        case PLANE_X:
                                /* build new Z vector */
                                /* othogonal to "new Y" "old X! plane */
                                cross_v3_v3v3(orth, vec, xx);
                                normalize_v3(orth);

                                /* new Z*/
                                copy_v3_v3(totmat[2], orth);

                                /* we decided to keep X plane*/
                                cross_v3_v3v3(xx, orth, vec);
                                normalize_v3_v3(totmat[0], xx);
                                break;
                        case PLANE_Z:
                                /* build new X vector */
                                /* othogonal to "new Y" "old Z! plane */
                                cross_v3_v3v3(orth, vec, zz);
                                normalize_v3(orth);

                                /* new X */
                                negate_v3_v3(totmat[0], orth);

                                /* we decided to keep Z */
                                cross_v3_v3v3(zz, orth, vec);
                                normalize_v3_v3(totmat[2], zz);
                                break;
                } /* switch (data->plane) */

                mul_m4_m3m4(cob->matrix, totmat, cob->matrix);
        }
}

static bConstraintTypeInfo CTI_STRETCHTO = {
        CONSTRAINT_TYPE_STRETCHTO, /* type */
        sizeof(bStretchToConstraint), /* size */
        "Stretch To", /* name */
        "bStretchToConstraint", /* struct name */
        NULL, /* free data */
        stretchto_id_looper, /* id looper */
        NULL, /* copy data */
        stretchto_new_data, /* new data */
        stretchto_get_tars, /* get constraint targets */
        stretchto_flush_tars, /* flush constraint targets */
        default_get_tarmat, /* get target matrix */
        stretchto_evaluate /* evaluate */
};

/* ---------- Floor ------------ */

static void minmax_new_data(void *cdata)
{
        bMinMaxConstraint *data = (bMinMaxConstraint *)cdata;
        
        data->minmaxflag = TRACK_Z;
        data->offset = 0.0f;
        zero_v3(data->cache);
        data->flag = 0;
}

static void minmax_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
{
        bMinMaxConstraint *data = con->data;
        
        /* target only */
        func(con, (ID **)&data->tar, FALSE, userdata);
}

static int minmax_get_tars(bConstraint *con, ListBase *list)
{
        if (con && list) {
                bMinMaxConstraint *data = con->data;
                bConstraintTarget *ct;
                
                /* standard target-getting macro for single-target constraints */
                SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list);
                
                return 1;
        }
        
        return 0;
}

static void minmax_flush_tars(bConstraint *con, ListBase *list, short nocopy)
{
        if (con && list) {
                bMinMaxConstraint *data = con->data;
                bConstraintTarget *ct = list->first;
                
                /* the following macro is used for all standard single-target constraints */
                SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy);
        }
}

static void minmax_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
        bMinMaxConstraint *data = con->data;
        bConstraintTarget *ct = targets->first;
        
        /* only evaluate if there is a target */
        if (VALID_CONS_TARGET(ct)) {
                float obmat[4][4], imat[4][4], tarmat[4][4], tmat[4][4];
                float val1, val2;
                int index;
                
                copy_m4_m4(obmat, cob->matrix);
                copy_m4_m4(tarmat, ct->matrix);
                
                if (data->flag & MINMAX_USEROT) {
                        /* take rotation of target into account by doing the transaction in target's localspace */
                        invert_m4_m4(imat, tarmat);
                        mult_m4_m4m4(tmat, imat, obmat);
                        copy_m4_m4(obmat, tmat);
                        unit_m4(tarmat);
                }
                
                switch (data->minmaxflag) {
                        case TRACK_Z:
                                val1 = tarmat[3][2];
                                val2 = obmat[3][2] - data->offset;
                                index = 2;
                                break;
                        case TRACK_Y:
                                val1 = tarmat[3][1];
                                val2 = obmat[3][1] - data->offset;
                                index = 1;
                                break;
                        case TRACK_X:
                                val1 = tarmat[3][0];
                                val2 = obmat[3][0] - data->offset;
                                index = 0;
                                break;
                        case TRACK_nZ:
                                val2 = tarmat[3][2];
                                val1 = obmat[3][2] - data->offset;
                                index = 2;
                                break;
                        case TRACK_nY:
                                val2 = tarmat[3][1];
                                val1 = obmat[3][1] - data->offset;
                                index = 1;
                                break;
                        case TRACK_nX:
                                val2 = tarmat[3][0];
                                val1 = obmat[3][0] - data->offset;
                                index = 0;
                                break;
                        default:
                                return;
                }
                
                if (val1 > val2) {
                        obmat[3][index] = tarmat[3][index] + data->offset;
                        if (data->flag & MINMAX_STICKY) {
                                if (data->flag & MINMAX_STUCK) {
                                        copy_v3_v3(obmat[3], data->cache);
                                }
                                else {
                                        copy_v3_v3(data->cache, obmat[3]);
                                        data->flag |= MINMAX_STUCK;
                                }
                        }
                        if (data->flag & MINMAX_USEROT) {