Sound clip NLA Strips for Nexyon

[blender-staging.git] / source / blender / blenkernel / intern / anim_sys.c

/*
 * $Id$
 *
 * ***** 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) 2009 Blender Foundation, Joshua Leung
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): Joshua Leung (full recode)
 *
 * ***** END GPL LICENSE BLOCK *****
 */

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


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

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_dynstr.h"
#include "BLI_utildefines.h"

#include "DNA_anim_types.h"
#include "DNA_material_types.h"
#include "DNA_scene_types.h"
#include "DNA_texture_types.h"

#include "BKE_animsys.h"
#include "BKE_action.h"
#include "BKE_fcurve.h"
#include "BKE_nla.h"
#include "BKE_global.h"
#include "BKE_main.h"
#include "BKE_library.h"
#include "BKE_report.h"
#include "BKE_utildefines.h"

#include "RNA_access.h"

#include "nla_private.h"

/* ***************************************** */
/* AnimData API */

/* Getter/Setter -------------------------------------------- */

/* Check if ID can have AnimData */
short id_type_can_have_animdata (ID *id)
{
        /* sanity check */
        if (id == NULL)
                return 0;
                
        /* Only some ID-blocks have this info for now */
        // TODO: finish adding this for the other blocktypes
        switch (GS(id->name)) {
                        /* has AnimData */
                case ID_OB:
                case ID_ME: case ID_MB: case ID_CU: case ID_AR: case ID_LT:
                case ID_KE:
                case ID_PA:
                case ID_MA: case ID_TE: case ID_NT:
                case ID_LA: case ID_CA: case ID_WO:
                case ID_SPK:
                case ID_SCE:
                {
                        return 1;
                }
                
                        /* no AnimData */
                default:
                        return 0;
        }
}


/* Get AnimData from the given ID-block. In order for this to work, we assume that 
 * the AnimData pointer is stored immediately after the given ID-block in the struct,
 * as per IdAdtTemplate.
 */
AnimData *BKE_animdata_from_id (ID *id)
{
        /* only some ID-blocks have this info for now, so we cast the 
         * types that do to be of type IdAdtTemplate, and extract the
         * AnimData that way
         */
        if (id_type_can_have_animdata(id)) {
                IdAdtTemplate *iat= (IdAdtTemplate *)id;
                return iat->adt;
        }
        else
                return NULL;
}

/* Add AnimData to the given ID-block. In order for this to work, we assume that 
 * the AnimData pointer is stored immediately after the given ID-block in the struct,
 * as per IdAdtTemplate. Also note that 
 */
AnimData *BKE_id_add_animdata (ID *id)
{
        /* Only some ID-blocks have this info for now, so we cast the 
         * types that do to be of type IdAdtTemplate, and add the AnimData
         * to it using the template
         */
        if (id_type_can_have_animdata(id)) {
                IdAdtTemplate *iat= (IdAdtTemplate *)id;
                
                /* check if there's already AnimData, in which case, don't add */
                if (iat->adt == NULL) {
                        AnimData *adt;
                        
                        /* add animdata */
                        adt= iat->adt= MEM_callocN(sizeof(AnimData), "AnimData");
                        
                        /* set default settings */
                        adt->act_influence= 1.0f;
                }
                
                return iat->adt;
        }
        else 
                return NULL;
}

/* Action Setter --------------------------------------- */

/* Called when user tries to change the active action of an AnimData block (via RNA, Outliner, etc.) */
short BKE_animdata_set_action (ReportList *reports, ID *id, bAction *act)
{
        AnimData *adt = BKE_animdata_from_id(id);
        short ok = 0;
        
        /* animdata validity check */
        if (adt == NULL) {
                BKE_report(reports, RPT_WARNING, "No AnimData to set action on");
                return ok;
        }
        
        /* active action is only editable when it is not a tweaking strip 
         * see rna_AnimData_action_editable() in rna_animation.c
         */
        if ((adt->flag & ADT_NLA_EDIT_ON) || (adt->actstrip) || (adt->tmpact)) {
                /* cannot remove, otherwise things turn to custard */
                BKE_report(reports, RPT_ERROR, "Cannot change action, as it is still being edited in NLA");
                return ok;
        }
        
        /* manage usercount for current action */
        if (adt->action)
                id_us_min((ID*)adt->action);
        
        /* assume that AnimData's action can in fact be edited... */
        if (act) {
                /* action must have same type as owner */
                if (ELEM(act->idroot, 0, GS(id->name))) {
                        /* can set */
                        adt->action = act;
                        id_us_plus((ID*)adt->action);
                        ok = 1;
                }
                else {
                        /* cannot set */
                        BKE_reportf(reports, RPT_ERROR,
                                        "Couldn't set Action '%s' onto ID '%s', as it doesn't have suitably rooted paths for this purpose", 
                                        act->id.name+2, id->name);
                        //ok = 0;
                }
        }
        else {
                /* just clearing the action... */
                adt->action = NULL;
                ok = 1;
        }
        
        return ok;
}

/* Freeing -------------------------------------------- */

/* Free AnimData used by the nominated ID-block, and clear ID-block's AnimData pointer */
void BKE_free_animdata (ID *id)
{
        /* Only some ID-blocks have this info for now, so we cast the 
         * types that do to be of type IdAdtTemplate
         */
        if (id_type_can_have_animdata(id)) {
                IdAdtTemplate *iat= (IdAdtTemplate *)id;
                AnimData *adt= iat->adt;
                
                /* check if there's any AnimData to start with */
                if (adt) {
                        /* unlink action (don't free, as it's in its own list) */
                        if (adt->action)
                                adt->action->id.us--;
                        /* same goes for the temporarily displaced action */
                        if (adt->tmpact)
                                adt->tmpact->id.us--;
                                
                        /* free nla data */
                        free_nladata(&adt->nla_tracks);
                        
                        /* free drivers - stored as a list of F-Curves */
                        free_fcurves(&adt->drivers);
                        
                        /* free overrides */
                        // TODO...
                        
                        /* free animdata now */
                        MEM_freeN(adt);
                        iat->adt= NULL;
                }
        }
}

/* Freeing -------------------------------------------- */

/* Make a copy of the given AnimData - to be used when copying datablocks */
AnimData *BKE_copy_animdata (AnimData *adt, const short do_action)
{
        AnimData *dadt;
        
        /* sanity check before duplicating struct */
        if (adt == NULL)
                return NULL;
        dadt= MEM_dupallocN(adt);
        
        /* make a copy of action - at worst, user has to delete copies... */
        if (do_action) {
                dadt->action= copy_action(adt->action);
                dadt->tmpact= copy_action(adt->tmpact);
        }
        else {
                id_us_plus((ID *)dadt->action);
                id_us_plus((ID *)dadt->tmpact);
        }

        /* duplicate NLA data */
        copy_nladata(&dadt->nla_tracks, &adt->nla_tracks);
        
        /* duplicate drivers (F-Curves) */
        copy_fcurves(&dadt->drivers, &adt->drivers);
        
        /* don't copy overrides */
        dadt->overrides.first= dadt->overrides.last= NULL;
        
        /* return */
        return dadt;
}

int BKE_copy_animdata_id (ID *id_to, ID *id_from, const short do_action)
{
        AnimData *adt;

        if ((id_to && id_from) && (GS(id_to->name) != GS(id_from->name)))
                return 0;

        BKE_free_animdata(id_to);

        adt = BKE_animdata_from_id(id_from);
        if (adt) {
                IdAdtTemplate *iat = (IdAdtTemplate *)id_to;
                iat->adt= BKE_copy_animdata(adt, do_action);
        }

        return 1;
}

void BKE_copy_animdata_id_action(struct ID *id)
{
        AnimData *adt= BKE_animdata_from_id(id);
        if (adt) {
                if (adt->action) {
                        id_us_min((ID *)adt->action);
                        adt->action= copy_action(adt->action);
                }
                if (adt->tmpact) {
                        id_us_min((ID *)adt->tmpact);
                        adt->tmpact= copy_action(adt->tmpact);
                }
        }
}

/* Make Local -------------------------------------------- */

static void make_local_strips(ListBase *strips)
{
        NlaStrip *strip;

        for (strip=strips->first; strip; strip=strip->next) {
                if (strip->act) make_local_action(strip->act);
                if (strip->remap && strip->remap->target) make_local_action(strip->remap->target);
                
                make_local_strips(&strip->strips);
        }
}

/* Use local copy instead of linked copy of various ID-blocks */
void BKE_animdata_make_local(AnimData *adt)
{
        NlaTrack *nlt;
        
        /* Actions - Active and Temp */
        if (adt->action) make_local_action(adt->action);
        if (adt->tmpact) make_local_action(adt->tmpact);
        /* Remaps */
        if (adt->remap && adt->remap->target) make_local_action(adt->remap->target);
        
        /* Drivers */
        // TODO: need to remap the ID-targets too?
        
        /* NLA Data */
        for (nlt=adt->nla_tracks.first; nlt; nlt=nlt->next) 
                make_local_strips(&nlt->strips);
}


/* When duplicating data (i.e. objects), drivers referring to the original data will 
 * get updated to point to the duplicated data (if drivers belong to the new data)
 */
void BKE_relink_animdata (AnimData *adt)
{
        /* sanity check */
        if (adt == NULL)
                return;
        
        /* drivers */
        if (adt->drivers.first) {
                FCurve *fcu;
                
                /* check each driver against all the base paths to see if any should go */
                for (fcu= adt->drivers.first; fcu; fcu=fcu->next) {
                        ChannelDriver *driver= fcu->driver;
                        DriverVar *dvar;
                        
                        /* driver variables */
                        for (dvar= driver->variables.first; dvar; dvar=dvar->next) {
                                /* only change the used targets, since the others will need fixing manually anyway */
                                DRIVER_TARGETS_USED_LOOPER(dvar)
                                {
                                        if (dtar->id && dtar->id->newid) {
                                                dtar->id= dtar->id->newid;
                                        }
                                }
                                DRIVER_TARGETS_LOOPER_END
                        }
                }
        }
}

/* Sub-ID Regrouping ------------------------------------------- */

/* helper heuristic for determining if a path is compatible with the basepath 
 * < path: (str) full RNA-path from some data (usually an F-Curve) to compare
 * < basepath: (str) shorter path fragment to look for
 * > returns (bool) whether there is a match
 */
static short animpath_matches_basepath (const char path[], const char basepath[])
{
        /* we need start of path to be basepath */
        return (path && basepath) && (strstr(path, basepath) == path);
}

/* Move F-Curves in src action to dst action, setting up all the necessary groups 
 * for this to happen, but only if the F-Curves being moved have the appropriate 
 * "base path". 
 *      - This is used when data moves from one datablock to another, causing the
 *        F-Curves to need to be moved over too
 */
void action_move_fcurves_by_basepath (bAction *srcAct, bAction *dstAct, const char basepath[])
{
        FCurve *fcu, *fcn=NULL;
        
        /* sanity checks */
        if ELEM3(NULL, srcAct, dstAct, basepath) {
                if (G.f & G_DEBUG) {
                        printf("ERROR: action_partition_fcurves_by_basepath(%p, %p, %p) has insufficient info to work with\n",
                                        (void *)srcAct, (void *)dstAct, (void *)basepath);
                }
                return;
        }
                
        /* clear 'temp' flags on all groups in src, as we'll be needing them later 
         * to identify groups that we've managed to empty out here
         */
        action_groups_clear_tempflags(srcAct);
        
        /* iterate over all src F-Curves, moving over the ones that need to be moved */
        for (fcu = srcAct->curves.first; fcu; fcu = fcn) {
                /* store next pointer in case we move stuff */
                fcn = fcu->next;
                
                /* should F-Curve be moved over?
                 *      - we only need the start of the path to match basepath
                 */
                if (animpath_matches_basepath(fcu->rna_path, basepath)) {                       
                        bActionGroup *agrp = NULL;
                        
                        /* if grouped... */
                        if (fcu->grp) {
                                /* make sure there will be a matching group on the other side for the migrants */
                                agrp = action_groups_find_named(dstAct, fcu->grp->name);
                                
                                if (agrp == NULL) {
                                        /* add a new one with a similar name (usually will be the same though) */
                                        agrp = action_groups_add_new(dstAct, fcu->grp->name);
                                }
                                
                                /* old groups should be tagged with 'temp' flags so they can be removed later
                                 * if we remove everything from them
                                 */
                                fcu->grp->flag |= AGRP_TEMP;
                        }
                        
                        /* perform the migration now */
                        action_groups_remove_channel(srcAct, fcu);
                        
                        if (agrp)
                                action_groups_add_channel(dstAct, agrp, fcu);
                        else
                                BLI_addtail(&dstAct->curves, fcu);
                }
        }
        
        /* cleanup groups (if present) */
        if (srcAct->groups.first) {
                bActionGroup *agrp, *grp=NULL;
                
                for (agrp = srcAct->groups.first; agrp; agrp = grp) {
                        grp = agrp->next;
                        
                        /* only tagged groups need to be considered - clearing these tags or removing them */
                        if (agrp->flag & AGRP_TEMP) {
                                /* if group is empty and tagged, then we can remove as this operation
                                 * moved out all the channels that were formerly here
                                 */
                                if (agrp->channels.first == NULL)
                                        BLI_freelinkN(&srcAct->groups, agrp);
                                else
                                        agrp->flag &= ~AGRP_TEMP;
                        }
                }
        }
}

/* Transfer the animation data from srcID to dstID where the srcID
 * animation data is based off "basepath", creating new AnimData and
 * associated data as necessary
 */
void BKE_animdata_separate_by_basepath (ID *srcID, ID *dstID, ListBase *basepaths)
{
        AnimData *srcAdt=NULL, *dstAdt=NULL;
        LinkData *ld;
        
        /* sanity checks */
        if ELEM(NULL, srcID, dstID) {
                if (G.f & G_DEBUG)
                        printf("ERROR: no source or destination ID to separate AnimData with\n");
                return;
        }
        
        /* get animdata from src, and create for destination (if needed) */
        srcAdt = BKE_animdata_from_id(srcID);
        dstAdt = BKE_id_add_animdata(dstID);
        
        if ELEM(NULL, srcAdt, dstAdt) {
                if (G.f & G_DEBUG)
                        printf("ERROR: no AnimData for this pair of ID's\n");
                return;
        }
        
        /* active action */
        if (srcAdt->action) {
                /* set up an action if necessary, and name it in a similar way so that it can be easily found again */
                if (dstAdt->action == NULL) {
                        dstAdt->action = add_empty_action(srcAdt->action->id.name+2);
                }
                else if (dstAdt->action == srcAdt->action) {
                        printf("Argh! Source and Destination share animation! ('%s' and '%s' both use '%s') Making new empty action\n",
                                srcID->name, dstID->name, srcAdt->action->id.name);
                        
                        // TODO: review this...
                        id_us_min(&dstAdt->action->id);
                        dstAdt->action = add_empty_action(dstAdt->action->id.name+2);
                }
                        
                /* loop over base paths, trying to fix for each one... */
                for (ld = basepaths->first; ld; ld = ld->next) {
                        const char *basepath = (const char *)ld->data;
                        action_move_fcurves_by_basepath(srcAdt->action, dstAdt->action, basepath);
                }
        }
        
        /* drivers */
        if (srcAdt->drivers.first) {
                FCurve *fcu, *fcn=NULL;
                
                /* check each driver against all the base paths to see if any should go */
                for (fcu = srcAdt->drivers.first; fcu; fcu = fcn) {
                        fcn = fcu->next;
                        
                        /* try each basepath in turn, but stop on the first one which works */
                        for (ld = basepaths->first; ld; ld = ld->next) {
                                const char *basepath = (const char *)ld->data;
                                
                                if (animpath_matches_basepath(fcu->rna_path, basepath)) {
                                        /* just need to change lists */
                                        BLI_remlink(&srcAdt->drivers, fcu);
                                        BLI_addtail(&dstAdt->drivers, fcu);
                                        
                                        // TODO: add depsgraph flushing calls?
                                        
                                        /* can stop now, as moved already */
                                        break;
                                }
                        }
                }
        }
}

/* Path Validation -------------------------------------------- */

/* Check if a given RNA Path is valid, by tracing it from the given ID, and seeing if we can resolve it */
static short check_rna_path_is_valid (ID *owner_id, char *path)
{
        PointerRNA id_ptr, ptr;
        PropertyRNA *prop=NULL;
        
        /* make initial RNA pointer to start resolving from */
        RNA_id_pointer_create(owner_id, &id_ptr);
        
        /* try to resolve */
        return RNA_path_resolve(&id_ptr, path, &ptr, &prop); 
}

/* Check if some given RNA Path needs fixing - free the given path and set a new one as appropriate 
 * NOTE: we assume that oldName and newName have [" "] padding around them
 */
static char *rna_path_rename_fix (ID *owner_id, const char *prefix, char *oldName, char *newName, char *oldpath, int verify_paths)
{
        char *prefixPtr= strstr(oldpath, prefix);
        char *oldNamePtr= strstr(oldpath, oldName);
        int prefixLen= strlen(prefix);
        int oldNameLen= strlen(oldName);
        
        /* only start fixing the path if the prefix and oldName feature in the path,
         * and prefix occurs immediately before oldName
         */
        if ( (prefixPtr && oldNamePtr) && (prefixPtr+prefixLen == oldNamePtr) ) {
                /* if we haven't aren't able to resolve the path now, try again after fixing it */
                if (!verify_paths || check_rna_path_is_valid(owner_id, oldpath) == 0) {         
                        DynStr *ds= BLI_dynstr_new();
                        char *postfixPtr= oldNamePtr+oldNameLen;
                        char *newPath = NULL;
                        char oldChar;
                        
                        /* add the part of the string that goes up to the start of the prefix */
                        if (prefixPtr > oldpath) {
                                oldChar= prefixPtr[0]; 
                                prefixPtr[0]= 0;
                                BLI_dynstr_append(ds, oldpath);
                                prefixPtr[0]= oldChar;
                        }
                        
                        /* add the prefix */
                        BLI_dynstr_append(ds, prefix);
                        
                        /* add the new name (complete with brackets) */
                        BLI_dynstr_append(ds, newName);
                        
                        /* add the postfix */
                        BLI_dynstr_append(ds, postfixPtr);
                        
                        /* create new path, and cleanup old data */
                        newPath= BLI_dynstr_get_cstring(ds);
                        BLI_dynstr_free(ds);
                        
                        /* check if the new path will solve our problems */
                        // TODO: will need to check whether this step really helps in practice
                        if (!verify_paths || check_rna_path_is_valid(owner_id, newPath)) {
                                /* free the old path, and return the new one, since we've solved the issues */
                                MEM_freeN(oldpath);
                                return newPath;
                        }
                        else {
                                /* still couldn't resolve the path... so, might as well just leave it alone */
                                MEM_freeN(newPath);
                        }
                }
        }
        
        /* the old path doesn't need to be changed */
        return oldpath;
}

/* Check RNA-Paths for a list of F-Curves */
static void fcurves_path_rename_fix (ID *owner_id, const char *prefix, char *oldName, char *newName, ListBase *curves, int verify_paths)
{
        FCurve *fcu;
        
        /* we need to check every curve... */
        for (fcu= curves->first; fcu; fcu= fcu->next) {
                /* firstly, handle the F-Curve's own path */
                if (fcu->rna_path)
                        fcu->rna_path= rna_path_rename_fix(owner_id, prefix, oldName, newName, fcu->rna_path, verify_paths);
        }
}

/* Check RNA-Paths for a list of Drivers */
static void drivers_path_rename_fix (ID *owner_id, const char *prefix, char *oldName, char *newName, char *oldKey, char *newKey, ListBase *curves, int verify_paths)
{
        FCurve *fcu;
        
        /* we need to check every curve - drivers are F-Curves too! */
        for (fcu= curves->first; fcu; fcu= fcu->next) {
                /* firstly, handle the F-Curve's own path */
                if (fcu->rna_path)
                        fcu->rna_path= rna_path_rename_fix(owner_id, prefix, oldKey, newKey, fcu->rna_path, verify_paths);
                
                /* driver? */
                if (fcu->driver) {
                        ChannelDriver *driver= fcu->driver;
                        DriverVar *dvar;
                        
                        /* driver variables */
                        for (dvar= driver->variables.first; dvar; dvar=dvar->next) {
                                /* only change the used targets, since the others will need fixing manually anyway */
                                DRIVER_TARGETS_USED_LOOPER(dvar) 
                                {
                                        /* rename RNA path */
                                        if (dtar->rna_path && dtar->id)
                                                dtar->rna_path= rna_path_rename_fix(dtar->id, prefix, oldKey, newKey, dtar->rna_path, verify_paths);
                                        
                                        /* also fix the bone-name (if applicable) */
                                        if (strstr(prefix, "bones")) {
                                                if ( ((dtar->id) && (GS(dtar->id->name) == ID_OB)) &&
                                                         (dtar->pchan_name[0]) && (strcmp(oldName, dtar->pchan_name)==0) )
                                                {
                                                        BLI_strncpy(dtar->pchan_name, newName, sizeof(dtar->pchan_name));
                                                }
                                        }
                                }
                                DRIVER_TARGETS_LOOPER_END
                        }
                }
        }
}

/* Fix all RNA-Paths for Actions linked to NLA Strips */
static void nlastrips_path_rename_fix (ID *owner_id, const char *prefix, char *oldName, char *newName, ListBase *strips, int verify_paths)
{
        NlaStrip *strip;
        
        /* recursively check strips, fixing only actions... */
        for (strip= strips->first; strip; strip= strip->next) {
                /* fix strip's action */
                if (strip->act)
                        fcurves_path_rename_fix(owner_id, prefix, oldName, newName, &strip->act->curves, verify_paths);
                /* ignore own F-Curves, since those are local...  */
                
                /* check sub-strips (if metas) */
                nlastrips_path_rename_fix(owner_id, prefix, oldName, newName, &strip->strips, verify_paths);
        }
}

/* Fix all RNA-Paths in the AnimData block used by the given ID block
 * NOTE: it is assumed that the structure we're replacing is <prefix><["><name><"]>
 *              i.e. pose.bones["Bone"]
 */
void BKE_animdata_fix_paths_rename (ID *owner_id, AnimData *adt, const char *prefix, char *oldName, char *newName, int oldSubscript, int newSubscript, int verify_paths)
{
        NlaTrack *nlt;
        char *oldN, *newN;
        
        /* if no AnimData, no need to proceed */
        if (ELEM(NULL, owner_id, adt))
                return;
        
        if ((oldName != NULL) && (newName != NULL)) {
                /* pad the names with [" "] so that only exact matches are made */
                oldN= BLI_sprintfN("[\"%s\"]", oldName);
                newN= BLI_sprintfN("[\"%s\"]", newName);
        } 
        else {
                oldN= BLI_sprintfN("[%d]", oldSubscript);
                newN= BLI_sprintfN("[%d]", newSubscript);
        }
        
        /* Active action and temp action */
        if (adt->action)
                fcurves_path_rename_fix(owner_id, prefix, oldN, newN, &adt->action->curves, verify_paths);
        if (adt->tmpact)
                fcurves_path_rename_fix(owner_id, prefix, oldN, newN, &adt->tmpact->curves, verify_paths);
                
        /* Drivers - Drivers are really F-Curves */
        drivers_path_rename_fix(owner_id, prefix, oldName, newName, oldN, newN, &adt->drivers, verify_paths);
        
        /* NLA Data - Animation Data for Strips */
        for (nlt= adt->nla_tracks.first; nlt; nlt= nlt->next)
                nlastrips_path_rename_fix(owner_id, prefix, oldN, newN, &nlt->strips, verify_paths);
                
        /* free the temp names */
        MEM_freeN(oldN);
        MEM_freeN(newN);
}

/* Whole Database Ops -------------------------------------------- */

/* apply the given callback function on all data in main database */
void BKE_animdata_main_cb (Main *mainptr, ID_AnimData_Edit_Callback func, void *user_data)
{
        ID *id;

        /* standard data version */
#define ANIMDATA_IDS_CB(first) \
        for (id= first; id; id= id->next) { \
                AnimData *adt= BKE_animdata_from_id(id); \
                if (adt) func(id, adt, user_data); \
        }
        
        /* "embedded" nodetree cases (i.e. scene/material/texture->nodetree) */
#define ANIMDATA_NODETREE_IDS_CB(first, NtId_Type) \
        for (id= first; id; id= id->next) { \
                AnimData *adt= BKE_animdata_from_id(id); \
                NtId_Type *ntp= (NtId_Type *)id; \
                if (ntp->nodetree) { \
                        AnimData *adt2= BKE_animdata_from_id((ID *)ntp); \
                        if (adt2) func(id, adt2, user_data); \
                } \
                if (adt) func(id, adt, user_data); \
        }
        
        /* nodes */
        ANIMDATA_IDS_CB(mainptr->nodetree.first);
        
        /* textures */
        ANIMDATA_NODETREE_IDS_CB(mainptr->tex.first, Tex);
        
        /* lamps */
        ANIMDATA_IDS_CB(mainptr->lamp.first);
        
        /* materials */
        ANIMDATA_NODETREE_IDS_CB(mainptr->mat.first, Material);
        
        /* cameras */
        ANIMDATA_IDS_CB(mainptr->camera.first);
        
        /* shapekeys */
        ANIMDATA_IDS_CB(mainptr->key.first);
        
        /* metaballs */
        ANIMDATA_IDS_CB(mainptr->mball.first);
        
        /* curves */
        ANIMDATA_IDS_CB(mainptr->curve.first);
        
        /* armatures */
        ANIMDATA_IDS_CB(mainptr->armature.first);
        
        /* lattices */
        ANIMDATA_IDS_CB(mainptr->latt.first);
        
        /* meshes */
        ANIMDATA_IDS_CB(mainptr->mesh.first);
        
        /* particles */
        ANIMDATA_IDS_CB(mainptr->particle.first);

        /* speakers */
        ANIMDATA_IDS_CB(mainptr->speaker.first);

        /* objects */
        ANIMDATA_IDS_CB(mainptr->object.first);
        
        /* worlds */
        ANIMDATA_IDS_CB(mainptr->world.first);
        
        /* scenes */
        ANIMDATA_NODETREE_IDS_CB(mainptr->scene.first, Scene);
}

/* Fix all RNA-Paths throughout the database (directly access the Global.main version)
 * NOTE: it is assumed that the structure we're replacing is <prefix><["><name><"]>
 *              i.e. pose.bones["Bone"]
 */
/* TODO: use BKE_animdata_main_cb for looping over all data  */
void BKE_all_animdata_fix_paths_rename (char *prefix, char *oldName, char *newName)
{
        Main *mainptr= G.main;
        ID *id;
        
        /* macro for less typing 
         *      - whether animdata exists is checked for by the main renaming callback, though taking 
         *        this outside of the function may make things slightly faster?
         */
#define RENAMEFIX_ANIM_IDS(first) \
        for (id= first; id; id= id->next) { \
                AnimData *adt= BKE_animdata_from_id(id); \
                BKE_animdata_fix_paths_rename(id, adt, prefix, oldName, newName, 0, 0, 1);\
        }
        
        /* another version of this macro for nodetrees */
#define RENAMEFIX_ANIM_NODETREE_IDS(first, NtId_Type) \
        for (id= first; id; id= id->next) { \
                AnimData *adt= BKE_animdata_from_id(id); \
                NtId_Type *ntp= (NtId_Type *)id; \
                if (ntp->nodetree) { \
                        AnimData *adt2= BKE_animdata_from_id((ID *)ntp); \
                        BKE_animdata_fix_paths_rename((ID *)ntp, adt2, prefix, oldName, newName, 0, 0, 1);\
                } \
                BKE_animdata_fix_paths_rename(id, adt, prefix, oldName, newName, 0, 0, 1);\
        }
        
        /* nodes */
        RENAMEFIX_ANIM_IDS(mainptr->nodetree.first);
        
        /* textures */
        RENAMEFIX_ANIM_NODETREE_IDS(mainptr->tex.first, Tex);
        
        /* lamps */
        RENAMEFIX_ANIM_IDS(mainptr->lamp.first);
        
        /* materials */
        RENAMEFIX_ANIM_NODETREE_IDS(mainptr->mat.first, Material);
        
        /* cameras */
        RENAMEFIX_ANIM_IDS(mainptr->camera.first);
        
        /* shapekeys */
        RENAMEFIX_ANIM_IDS(mainptr->key.first);
        
        /* metaballs */
        RENAMEFIX_ANIM_IDS(mainptr->mball.first);
        
        /* curves */
        RENAMEFIX_ANIM_IDS(mainptr->curve.first);
        
        /* armatures */
        RENAMEFIX_ANIM_IDS(mainptr->armature.first);
        
        /* lattices */
        RENAMEFIX_ANIM_IDS(mainptr->latt.first);
        
        /* meshes */
        RENAMEFIX_ANIM_IDS(mainptr->mesh.first);
        
        /* particles */
        RENAMEFIX_ANIM_IDS(mainptr->particle.first);

        /* speakers */
        RENAMEFIX_ANIM_IDS(mainptr->speaker.first);

        /* objects */
        RENAMEFIX_ANIM_IDS(mainptr->object.first); 
        
        /* worlds */
        RENAMEFIX_ANIM_IDS(mainptr->world.first);
        
        /* scenes */
        RENAMEFIX_ANIM_NODETREE_IDS(mainptr->scene.first, Scene);
}

/* *********************************** */ 
/* KeyingSet API */

/* Finding Tools --------------------------- */

/* Find the first path that matches the given criteria */
// TODO: do we want some method to perform partial matches too?
KS_Path *BKE_keyingset_find_path (KeyingSet *ks, ID *id, const char group_name[], const char rna_path[], int array_index, int UNUSED(group_mode))
{
        KS_Path *ksp;
        
        /* sanity checks */
        if ELEM3(NULL, ks, rna_path, id)
                return NULL;
        
        /* loop over paths in the current KeyingSet, finding the first one where all settings match 
         * (i.e. the first one where none of the checks fail and equal 0)
         */
        for (ksp= ks->paths.first; ksp; ksp= ksp->next) {
                short eq_id=1, eq_path=1, eq_index=1, eq_group=1;
                
                /* id */
                if (id != ksp->id)
                        eq_id= 0;
                
                /* path */
                if ((ksp->rna_path==NULL) || strcmp(rna_path, ksp->rna_path))
                        eq_path= 0;
                        
                /* index - need to compare whole-array setting too... */
                if (ksp->array_index != array_index)
                        eq_index= 0;
                        
                /* group */
                if (group_name) {
                        // FIXME: these checks need to be coded... for now, it's not too important though
                }
                        
                /* if all aspects are ok, return */
                if (eq_id && eq_path && eq_index && eq_group)
                        return ksp;
        }
        
        /* none found */
        return NULL;
}
 
/* Defining Tools --------------------------- */

/* Used to create a new 'custom' KeyingSet for the user, that will be automatically added to the stack */
KeyingSet *BKE_keyingset_add (ListBase *list, const char name[], short flag, short keyingflag)
{
        KeyingSet *ks;
        
        /* allocate new KeyingSet */
        ks= MEM_callocN(sizeof(KeyingSet), "KeyingSet");

        BLI_strncpy(ks->name, name ? name : "KeyingSet", sizeof(ks->name));

        ks->flag= flag;
        ks->keyingflag= keyingflag;
        
        /* add KeyingSet to list */
        BLI_addtail(list, ks);
        
        /* make sure KeyingSet has a unique name (this helps with identification) */
        BLI_uniquename(list, ks, "KeyingSet", '.', offsetof(KeyingSet, name), sizeof(ks->name));
        
        /* return new KeyingSet for further editing */
        return ks;
}

/* Add a path to a KeyingSet. Nothing is returned for now...
 * Checks are performed to ensure that destination is appropriate for the KeyingSet in question
 */
KS_Path *BKE_keyingset_add_path (KeyingSet *ks, ID *id, const char group_name[], const char rna_path[], int array_index, short flag, short groupmode)
{
        KS_Path *ksp;
        
        /* sanity checks */
        if ELEM(NULL, ks, rna_path) {
                printf("ERROR: no Keying Set and/or RNA Path to add path with \n");
                return NULL;
        }
        
        /* ID is required for all types of KeyingSets */
        if (id == NULL) {
                printf("ERROR: No ID provided for Keying Set Path. \n");
                return NULL;
        }
        
        /* don't add if there is already a matching KS_Path in the KeyingSet */
        if (BKE_keyingset_find_path(ks, id, group_name, rna_path, array_index, groupmode)) {
                if (G.f & G_DEBUG)
                        printf("ERROR: destination already exists in Keying Set \n");
                return NULL;
        }
        
        /* allocate a new KeyingSet Path */
        ksp= MEM_callocN(sizeof(KS_Path), "KeyingSet Path");
        
        /* just store absolute info */
        ksp->id= id;
        if (group_name)
                BLI_strncpy(ksp->group, group_name, sizeof(ksp->group));
        else
                ksp->group[0]= '\0';
        
        /* store additional info for relative paths (just in case user makes the set relative) */
        if (id)
                ksp->idtype= GS(id->name);
        
        /* just copy path info */
        // TODO: should array index be checked too?
        ksp->rna_path= BLI_strdupn(rna_path, strlen(rna_path));
        ksp->array_index= array_index;
        
        /* store flags */
        ksp->flag= flag;
        ksp->groupmode= groupmode;
        
        /* add KeyingSet path to KeyingSet */
        BLI_addtail(&ks->paths, ksp);
        
        /* return this path */
        return ksp;
}       

/* Free the given Keying Set path */
void BKE_keyingset_free_path (KeyingSet *ks, KS_Path *ksp)
{
        /* sanity check */
        if ELEM(NULL, ks, ksp)
                return;

        /* free RNA-path info */
        if(ksp->rna_path)
                MEM_freeN(ksp->rna_path);

        /* free path itself */
        BLI_freelinkN(&ks->paths, ksp);
}

/* Copy all KeyingSets in the given list */
void BKE_keyingsets_copy (ListBase *newlist, ListBase *list)
{
        KeyingSet *ksn;
        KS_Path *kspn;
        
        BLI_duplicatelist(newlist, list);

        for (ksn=newlist->first; ksn; ksn=ksn->next) {
                BLI_duplicatelist(&ksn->paths, &ksn->paths);
                
                for (kspn=ksn->paths.first; kspn; kspn=kspn->next)
                        kspn->rna_path= MEM_dupallocN(kspn->rna_path);
        }
}

/* Freeing Tools --------------------------- */

/* Free data for KeyingSet but not set itself */
void BKE_keyingset_free (KeyingSet *ks)
{
        KS_Path *ksp, *kspn;
        
        /* sanity check */
        if (ks == NULL)
                return;
        
        /* free each path as we go to avoid looping twice */
        for (ksp= ks->paths.first; ksp; ksp= kspn) {
                kspn= ksp->next;
                BKE_keyingset_free_path(ks, ksp);
        }
}

/* Free all the KeyingSets in the given list */
void BKE_keyingsets_free (ListBase *list)
{
        KeyingSet *ks, *ksn;
        
        /* sanity check */
        if (list == NULL)
                return;
        
        /* loop over KeyingSets freeing them 
         *      - BKE_keyingset_free() doesn't free the set itself, but it frees its sub-data
         */
        for (ks= list->first; ks; ks= ksn) {
                ksn= ks->next;
                BKE_keyingset_free(ks);
                BLI_freelinkN(list, ks);
        }
}

/* ***************************************** */
/* Evaluation Data-Setting Backend */

/* Retrieve string to act as RNA-path, adjusted using mapping-table if provided 
 * It returns whether the string needs to be freed (i.e. if it was a temp remapped one)
 * // FIXME: maybe it would be faster if we didn't have to alloc/free strings like this all the time, but for now it's safer
 *
 *      - remap: remapping table to use
 *      - path: original path string (as stored in F-Curve data)
 *      - dst: destination string to write data to
 */
static short animsys_remap_path (AnimMapper *UNUSED(remap), char *path, char **dst)
{
        /* is there a valid remapping table to use? */
        //if (remap) {
                /* find a matching entry... to use to remap */
                // ...TODO...
        //}
        
        /* nothing suitable found, so just set dst to look at path (i.e. no alloc/free needed) */
        *dst= path;
        return 0;
}


/* less then 1.0 evaluates to false, use epsilon to avoid float error */
#define ANIMSYS_FLOAT_AS_BOOL(value) ((value) > ((1.0f-FLT_EPSILON)))

/* Write the given value to a setting using RNA, and return success */
static short animsys_write_rna_setting (PointerRNA *ptr, char *path, int array_index, float value)
{
        PropertyRNA *prop;
        PointerRNA new_ptr;
        
        //printf("%p %s %i %f\n", ptr, path, array_index, value);
        
        /* get property to write to */
        if (RNA_path_resolve(ptr, path, &new_ptr, &prop)) 
        {
                /* set value - only for animatable numerical values */
                if (RNA_property_animateable(&new_ptr, prop)) 
                {
                        int array_len= RNA_property_array_length(&new_ptr, prop);
                        
                        if (array_len && array_index >= array_len)
                        {
                                if (G.f & G_DEBUG) {
                                        printf("Animato: Invalid array index. ID = '%s',  '%s[%d]', array length is %d \n",
                                                (ptr && ptr->id.data) ? (((ID *)ptr->id.data)->name+2) : "<No ID>",
                                                path, array_index, array_len-1);
                                }
                                
                                return 0;
                        }
                        
                        switch (RNA_property_type(prop)) 
                        {
                                case PROP_BOOLEAN:
                                        if (array_len)
                                                RNA_property_boolean_set_index(&new_ptr, prop, array_index, ANIMSYS_FLOAT_AS_BOOL(value));
                                        else
                                                RNA_property_boolean_set(&new_ptr, prop, ANIMSYS_FLOAT_AS_BOOL(value));
                                        break;
                                case PROP_INT:
                                        if (array_len)
                                                RNA_property_int_set_index(&new_ptr, prop, array_index, (int)value);
                                        else
                                                RNA_property_int_set(&new_ptr, prop, (int)value);
                                        break;
                                case PROP_FLOAT:
                                        if (array_len)
                                                RNA_property_float_set_index(&new_ptr, prop, array_index, value);
                                        else
                                                RNA_property_float_set(&new_ptr, prop, value);
                                        break;
                                case PROP_ENUM:
                                        RNA_property_enum_set(&new_ptr, prop, (int)value);
                                        break;
                                default:
                                        /* nothing can be done here... so it is unsuccessful? */
                                        return 0;
                        }
                        
                        /* buffer property update for later flushing */
                        if (RNA_property_update_check(prop)) {
                                short skip_updates_hack = 0;
                                
                                /* optimisation hacks: skip property updates for those properties
                                 * for we know that which the updates in RNA were really just for
                                 * flushing property editing via UI/Py
                                 */
                                if (RNA_struct_is_a(new_ptr.type, &RNA_PoseBone)) {
                                        /* bone transforms - update pose (i.e. tag depsgraph) */
                                        skip_updates_hack = 1;
                                }                               
                                
                                if (skip_updates_hack == 0)
                                        RNA_property_update_cache_add(&new_ptr, prop);
                        }
                }
                
                /* successful */
                return 1;
        }
        else {
                /* failed to get path */
                // XXX don't tag as failed yet though, as there are some legit situations (Action Constraint) 
                // where some channels will not exist, but shouldn't lock up Action
                if (G.f & G_DEBUG) {
                        printf("Animato: Invalid path. ID = '%s',  '%s[%d]' \n",
                                (ptr && ptr->id.data) ? (((ID *)ptr->id.data)->name+2) : "<No ID>", 
                                path, array_index);
                }
                return 0;
        }
}

/* Simple replacement based data-setting of the FCurve using RNA */
static short animsys_execute_fcurve (PointerRNA *ptr, AnimMapper *remap, FCurve *fcu)
{
        char *path = NULL;
        short free_path=0;
        short ok= 0;
        
        /* get path, remapped as appropriate to work in its new environment */
        free_path= animsys_remap_path(remap, fcu->rna_path, &path);
        
        /* write value to setting */
        if (path)
                ok= animsys_write_rna_setting(ptr, path, fcu->array_index, fcu->curval);
        
        /* free temp path-info */
        if (free_path)
                MEM_freeN(path);
                
        /* return whether we were successful */
        return ok;
}

/* Evaluate all the F-Curves in the given list 
 * This performs a set of standard checks. If extra checks are required, separate code should be used
 */
static void animsys_evaluate_fcurves (PointerRNA *ptr, ListBase *list, AnimMapper *remap, float ctime)
{
        FCurve *fcu;
        
        /* calculate then execute each curve */
        for (fcu= list->first; fcu; fcu= fcu->next) 
        {
                /* check if this F-Curve doesn't belong to a muted group */
                if ((fcu->grp == NULL) || (fcu->grp->flag & AGRP_MUTED)==0) {
                        /* check if this curve should be skipped */
                        if ((fcu->flag & (FCURVE_MUTED|FCURVE_DISABLED)) == 0) 
                        {
                                calculate_fcurve(fcu, ctime);
                                animsys_execute_fcurve(ptr, remap, fcu); 
                        }
                }
        }
}

/* ***************************************** */
/* Driver Evaluation */

/* Evaluate Drivers */
static void animsys_evaluate_drivers (PointerRNA *ptr, AnimData *adt, float ctime)
{
        FCurve *fcu;
        
        /* drivers are stored as F-Curves, but we cannot use the standard code, as we need to check if
         * the depsgraph requested that this driver be evaluated...
         */
        for (fcu= adt->drivers.first; fcu; fcu= fcu->next) 
        {
                ChannelDriver *driver= fcu->driver;
                short ok= 0;
                
                /* check if this driver's curve should be skipped */
                if ((fcu->flag & (FCURVE_MUTED|FCURVE_DISABLED)) == 0) 
                {
                        /* check if driver itself is tagged for recalculation */
                        if ((driver) && !(driver->flag & DRIVER_FLAG_INVALID)/*&& (driver->flag & DRIVER_FLAG_RECALC)*/) {      // XXX driver recalc flag is not set yet by depsgraph!
                                /* evaluate this using values set already in other places */
                                // NOTE: for 'layering' option later on, we should check if we should remove old value before adding new to only be done when drivers only changed
                                calculate_fcurve(fcu, ctime);
                                ok= animsys_execute_fcurve(ptr, NULL, fcu);
                                
                                /* clear recalc flag */
                                driver->flag &= ~DRIVER_FLAG_RECALC;
                                
                                /* set error-flag if evaluation failed */
                                if (ok == 0)
                                        driver->flag |= DRIVER_FLAG_INVALID; 
                        }
                }
        }
}

/* ***************************************** */
/* Actions Evaluation */

/* strictly not necessary for actual "evaluation", but it is a useful safety check
 * to reduce the amount of times that users end up having to "revive" wrongly-assigned
 * actions
 */
static void action_idcode_patch_check (ID *id, bAction *act)
{
        int idcode = 0;
        
        /* just in case */
        if (ELEM(NULL, id, act))
                return;
        else
                idcode = GS(id->name);
        
        /* the actual checks... hopefully not too much of a performance hit in the long run... */
        if (act->idroot == 0) {
                /* use the current root if not set already (i.e. newly created actions and actions from 2.50-2.57 builds)
                 *      - this has problems if there are 2 users, and the first one encountered is the invalid one
                 *        in which case, the user will need to manually fix this (?)
                 */
                act->idroot = idcode;
        }
        else if (act->idroot != idcode) {
                /* only report this error if debug mode is enabled (to save performance everywhere else) */
                if (G.f & G_DEBUG) {
                        printf("AnimSys Safety Check Failed: Action '%s' is not meant to be used from ID-Blocks of type %d such as '%s'\n",
                                act->id.name+2, idcode, id->name);
                }
        }
}

/* ----------------------------------------- */

/* Evaluate Action Group */
void animsys_evaluate_action_group (PointerRNA *ptr, bAction *act, bActionGroup *agrp, AnimMapper *remap, float ctime)
{
        FCurve *fcu;
        
        /* check if mapper is appropriate for use here (we set to NULL if it's inappropriate) */
        if ELEM(NULL, act, agrp) return;
        if ((remap) && (remap->target != act)) remap= NULL;
        
        action_idcode_patch_check(ptr->id.data, act);
        
        /* if group is muted, don't evaluated any of the F-Curve */
        if (agrp->flag & AGRP_MUTED)
                return;
        
        /* calculate then execute each curve */
        for (fcu= agrp->channels.first; (fcu) && (fcu->grp == agrp); fcu= fcu->next) 
        {
                /* check if this curve should be skipped */
                if ((fcu->flag & (FCURVE_MUTED|FCURVE_DISABLED)) == 0) 
                {
                        calculate_fcurve(fcu, ctime);
                        animsys_execute_fcurve(ptr, remap, fcu); 
                }
        }
}

/* Evaluate Action (F-Curve Bag) */
void animsys_evaluate_action (PointerRNA *ptr, bAction *act, AnimMapper *remap, float ctime)
{
        /* check if mapper is appropriate for use here (we set to NULL if it's inappropriate) */
        if (act == NULL) return;
        if ((remap) && (remap->target != act)) remap= NULL;
        
        action_idcode_patch_check(ptr->id.data, act);
        
        /* calculate then execute each curve */
        animsys_evaluate_fcurves(ptr, &act->curves, remap, ctime);
}

/* ***************************************** */
/* NLA System - Evaluation */

/* calculate influence of strip based for given frame based on blendin/out values */
static float nlastrip_get_influence (NlaStrip *strip, float cframe)
{
        /* sanity checks - normalise the blendin/out values? */
        strip->blendin= (float)fabs(strip->blendin);
        strip->blendout= (float)fabs(strip->blendout);
        
        /* result depends on where frame is in respect to blendin/out values */
        if (IS_EQ(strip->blendin, 0)==0 && (cframe <= (strip->start + strip->blendin))) {
                /* there is some blend-in */
                return (float)fabs(cframe - strip->start) / (strip->blendin);
        }
        else if (IS_EQ(strip->blendout, 0)==0 && (cframe >= (strip->end - strip->blendout))) {
                /* there is some blend-out */
                return (float)fabs(strip->end - cframe) / (strip->blendout);
        }
        else {
                /* in the middle of the strip, we should be full strength */
                return 1.0f;
        }
}

/* evaluate the evaluation time and influence for the strip, storing the results in the strip */
static void nlastrip_evaluate_controls (NlaStrip *strip, float ctime)
{
        /* firstly, analytically generate values for influence and time (if applicable) */
        if ((strip->flag & NLASTRIP_FLAG_USR_TIME) == 0)
                strip->strip_time= nlastrip_get_frame(strip, ctime, NLATIME_CONVERT_EVAL);
        if ((strip->flag & NLASTRIP_FLAG_USR_INFLUENCE) == 0)
                strip->influence= nlastrip_get_influence(strip, ctime);
        
        /* now strip's evaluate F-Curves for these settings (if applicable) */
        if (strip->fcurves.first) {
                PointerRNA strip_ptr;
                
                /* create RNA-pointer needed to set values */
                RNA_pointer_create(NULL, &RNA_NlaStrip, strip, &strip_ptr);
                
                /* execute these settings as per normal */
                animsys_evaluate_fcurves(&strip_ptr, &strip->fcurves, NULL, ctime);
        }

        /* if user can control the evaluation time (using F-Curves), consider the option which allows this time to be clamped 
         * to lie within extents of the action-clip, so that a steady changing rate of progress through several cycles of the clip
         * can be achieved easily
         */
        // NOTE: if we add any more of these special cases, we better group them up nicely...
        if ((strip->flag & NLASTRIP_FLAG_USR_TIME) && (strip->flag & NLASTRIP_FLAG_USR_TIME_CYCLIC))
                strip->strip_time= fmod(strip->strip_time - strip->actstart, strip->actend - strip->actstart);
}

/* gets the strip active at the current time for a list of strips for evaluation purposes */
NlaEvalStrip *nlastrips_ctime_get_strip (ListBase *list, ListBase *strips, short index, float ctime)
{
        NlaStrip *strip, *estrip=NULL;
        NlaEvalStrip *nes;
        short side= 0;
        
        /* loop over strips, checking if they fall within the range */
        for (strip= strips->first; strip; strip= strip->next) {
                /* check if current time occurs within this strip  */
                if (IN_RANGE_INCL(ctime, strip->start, strip->end)) {
                        /* this strip is active, so try to use it */
                        estrip= strip;
                        side= NES_TIME_WITHIN;
                        break;
                }
                
                /* if time occurred before current strip... */
                if (ctime < strip->start) {
                        if (strip == strips->first) {
                                /* before first strip - only try to use it if it extends backwards in time too */
                                if (strip->extendmode == NLASTRIP_EXTEND_HOLD)
                                        estrip= strip;
                                        
                                /* side is 'before' regardless of whether there's a useful strip */
                                side= NES_TIME_BEFORE;
                        }
                        else {
                                /* before next strip - previous strip has ended, but next hasn't begun, 
                                 * so blending mode depends on whether strip is being held or not...
                                 *      - only occurs when no transition strip added, otherwise the transition would have
                                 *        been picked up above...
                                 */
                                strip= strip->prev;
                                
                                if (strip->extendmode != NLASTRIP_EXTEND_NOTHING)
                                        estrip= strip;
                                side= NES_TIME_AFTER;
                        }
                        break;
                }
                
                /* if time occurred after current strip... */
                if (ctime > strip->end) {
                        /* only if this is the last strip should we do anything, and only if that is being held */
                        if (strip == strips->last) {
                                if (strip->extendmode != NLASTRIP_EXTEND_NOTHING)
                                        estrip= strip;
                                        
                                side= NES_TIME_AFTER;
                                break;
                        }
                        
                        /* otherwise, skip... as the 'before' case will catch it more elegantly! */
                }
        }
        
        /* check if a valid strip was found
         *      - must not be muted (i.e. will have contribution
         */
        if ((estrip == NULL) || (estrip->flag & NLASTRIP_FLAG_MUTED)) 
                return NULL;
                
        /* if ctime was not within the boundaries of the strip, clamp! */
        switch (side) {
                case NES_TIME_BEFORE: /* extend first frame only */
                        ctime= estrip->start;
                        break;
                case NES_TIME_AFTER: /* extend last frame only */
                        ctime= estrip->end;
                        break;
        }
        
        /* evaluate strip's evaluation controls  
         *      - skip if no influence (i.e. same effect as muting the strip)
         *      - negative influence is not supported yet... how would that be defined?
         */
        // TODO: this sounds a bit hacky having a few isolated F-Curves stuck on some data it operates on...
        nlastrip_evaluate_controls(estrip, ctime);
        if (estrip->influence <= 0.0f)
                return NULL;
                
        /* check if strip has valid data to evaluate,
         * and/or perform any additional type-specific actions
         */
        switch (estrip->type) {
                case NLASTRIP_TYPE_CLIP: 
                        /* clip must have some action to evaluate */
                        if (estrip->act == NULL)
                                return NULL;
                        break;
                case NLASTRIP_TYPE_TRANSITION:
                        /* there must be strips to transition from and to (i.e. prev and next required) */
                        if (ELEM(NULL, estrip->prev, estrip->next))
                                return NULL;
                                
                        /* evaluate controls for the relevant extents of the bordering strips... */
                        nlastrip_evaluate_controls(estrip->prev, estrip->start);
                        nlastrip_evaluate_controls(estrip->next, estrip->end);
                        break;
        }
        
        /* add to list of strips we need to evaluate */
        nes= MEM_callocN(sizeof(NlaEvalStrip), "NlaEvalStrip");
        
        nes->strip= estrip;
        nes->strip_mode= side;
        nes->track_index= index;
        nes->strip_time= estrip->strip_time;
        
        if (list)
                BLI_addtail(list, nes);
        
        return nes;
}

/* ---------------------- */

/* find an NlaEvalChannel that matches the given criteria 
 *      - ptr and prop are the RNA data to find a match for
 */
static NlaEvalChannel *nlaevalchan_find_match (ListBase *channels, PointerRNA *ptr, PropertyRNA *prop, int array_index)
{
        NlaEvalChannel *nec;
        
        /* sanity check */
        if (channels == NULL)
                return NULL;
        
        /* loop through existing channels, checking for a channel which affects the same property */
        for (nec= channels->first; nec; nec= nec->next) {
                /* - comparing the PointerRNA's is done by comparing the pointers
                 *   to the actual struct the property resides in, since that all the
                 *   other data stored in PointerRNA cannot allow us to definitively 
                 *      identify the data 
                 */
                if ((nec->ptr.data == ptr->data) && (nec->prop == prop) && (nec->index == array_index))
                        return nec;
        }
        
        /* not found */
        return NULL;
}

/* verify that an appropriate NlaEvalChannel for this F-Curve exists */
static NlaEvalChannel *nlaevalchan_verify (PointerRNA *ptr, ListBase *channels, NlaEvalStrip *nes, FCurve *fcu, short *newChan)
{
        NlaEvalChannel *nec;
        NlaStrip *strip= nes->strip;
        PropertyRNA *prop;
        PointerRNA new_ptr;
        char *path = NULL;
        short free_path=0;
        
        /* sanity checks */
        if (channels == NULL)
                return NULL;
        
        /* get RNA pointer+property info from F-Curve for more convenient handling */
                /* get path, remapped as appropriate to work in its new environment */
        free_path= animsys_remap_path(strip->remap, fcu->rna_path, &path);
        
                /* a valid property must be available, and it must be animateable */
        if (RNA_path_resolve(ptr, path, &new_ptr, &prop) == 0) {
                if (G.f & G_DEBUG) printf("NLA Strip Eval: Cannot resolve path \n");
                return NULL;
        }
                /* only ok if animateable */
        else if (RNA_property_animateable(&new_ptr, prop) == 0) {
                if (G.f & G_DEBUG) printf("NLA Strip Eval: Property not animateable \n");
                return NULL;
        }
        
        /* try to find a match */
        nec= nlaevalchan_find_match(channels, &new_ptr, prop, fcu->array_index);
        
        /* allocate a new struct for this if none found */
        if (nec == NULL) {
                nec= MEM_callocN(sizeof(NlaEvalChannel), "NlaEvalChannel");
                *newChan= 1;
                BLI_addtail(channels, nec);
                
                nec->ptr= new_ptr; 
                nec->prop= prop;
                nec->index= fcu->array_index;
        }
        else
                *newChan= 0;
        
        /* we can now return */
        return nec;
}

/* accumulate (i.e. blend) the given value on to the channel it affects */
static void nlaevalchan_accumulate (NlaEvalChannel *nec, NlaEvalStrip *nes, short newChan, float value)
{
        NlaStrip *strip= nes->strip;
        short blendmode= strip->blendmode;
        float inf= strip->influence;
        
        /* if channel is new, just store value regardless of blending factors, etc. */
        if (newChan) {
                nec->value= value;
                return;
        }
                
        /* if this is being performed as part of transition evaluation, incorporate
         * an additional weighting factor for the influence
         */
        if (nes->strip_mode == NES_TIME_TRANSITION_END) 
                inf *= nes->strip_time;
        
        /* premultiply the value by the weighting factor */
        if (IS_EQ(inf, 0)) return;
        value *= inf;
        
        /* perform blending */
        switch (blendmode) {
                case NLASTRIP_MODE_ADD:
                        /* simply add the scaled value on to the stack */
                        nec->value += value;
                        break;
                        
                case NLASTRIP_MODE_SUBTRACT:
                        /* simply subtract the scaled value from the stack */
                        nec->value -= value;
                        break;
                        
                case NLASTRIP_MODE_MULTIPLY:
                        /* multiply the scaled value with the stack */
                        nec->value *= value;
                        break;
                
                case NLASTRIP_MODE_REPLACE:
                default: // TODO: do we really want to blend by default? it seems more uses might prefer add...
                        /* do linear interpolation 
                         *      - the influence of the accumulated data (elsewhere, that is called dstweight) 
                         *        is 1 - influence, since the strip's influence is srcweight
                         */
                        nec->value= nec->value * (1.0f - inf)   +   value;
                        break;
        }
}

/* accumulate the results of a temporary buffer with the results of the full-buffer */
static void nlaevalchan_buffers_accumulate (ListBase *channels, ListBase *tmp_buffer, NlaEvalStrip *nes)
{
        NlaEvalChannel *nec, *necn, *necd;
        
        /* optimise - abort if no channels */
        if (tmp_buffer->first == NULL)
                return;
        
        /* accumulate results in tmp_channels buffer to the accumulation buffer */
        for (nec= tmp_buffer->first; nec; nec= necn) {
                /* get pointer to next channel in case we remove the current channel from the temp-buffer */
                necn= nec->next;
                
                /* try to find an existing matching channel for this setting in the accumulation buffer */
                necd= nlaevalchan_find_match(channels, &nec->ptr, nec->prop, nec->index);
                
                /* if there was a matching channel already in the buffer, accumulate to it,
                 * otherwise, add the current channel to the buffer for efficiency
                 */
                if (necd)
                        nlaevalchan_accumulate(necd, nes, 0, nec->value);
                else {
                        BLI_remlink(tmp_buffer, nec);
                        BLI_addtail(channels, nec);
                }
        }
        
        /* free temp-channels that haven't been assimilated into the buffer */
        BLI_freelistN(tmp_buffer);
}

/* ---------------------- */
/* F-Modifier stack joining/separation utilities - should we generalise these for BLI_listbase.h interface? */

/* Temporarily join two lists of modifiers together, storing the result in a third list */
static void nlaeval_fmodifiers_join_stacks (ListBase *result, ListBase *list1, ListBase *list2)
{
        FModifier *fcm1, *fcm2;
        
        /* if list1 is invalid...  */
        if ELEM(NULL, list1, list1->first) {
                if (list2 && list2->first) {
                        result->first= list2->first;
                        result->last= list2->last;
                }
        }
        /* if list 2 is invalid... */
        else if ELEM(NULL, list2, list2->first) {
                result->first= list1->first;
                result->last= list1->last;
        }
        else {
                /* list1 should be added first, and list2 second, with the endpoints of these being the endpoints for result 
                 *      - the original lists must be left unchanged though, as we need that fact for restoring
                 */
                result->first= list1->first;
                result->last= list2->last;
                
                fcm1= list1->last;
                fcm2= list2->first;
                
                fcm1->next= fcm2;
                fcm2->prev= fcm1;
        }
}

/* Split two temporary lists of modifiers */
static void nlaeval_fmodifiers_split_stacks (ListBase *list1, ListBase *list2)
{
        FModifier *fcm1, *fcm2;
        
        /* if list1/2 is invalid... just skip */
        if ELEM(NULL, list1, list2)
                return;
        if ELEM(NULL, list1->first, list2->first)
                return;
                
        /* get endpoints */
        fcm1= list1->last;
        fcm2= list2->first;
        
        /* clear their links */
        fcm1->next= NULL;
        fcm2->prev= NULL;
}

/* ---------------------- */

/* evaluate action-clip strip */
static void nlastrip_evaluate_actionclip (PointerRNA *ptr, ListBase *channels, ListBase *modifiers, NlaEvalStrip *nes)
{
        ListBase tmp_modifiers = {NULL, NULL};
        NlaStrip *strip= nes->strip;
        FCurve *fcu;
        float evaltime;
        
        /* sanity checks for action */
        if (strip == NULL)
                return;
                
        if (strip->act == NULL) {
                printf("NLA-Strip Eval Error: Strip '%s' has no Action\n", strip->name);
                return;
        }
        
        action_idcode_patch_check(ptr->id.data, strip->act);
        
        /* join this strip's modifiers to the parent's modifiers (own modifiers first) */
        nlaeval_fmodifiers_join_stacks(&tmp_modifiers, &strip->modifiers, modifiers);
        
        /* evaluate strip's modifiers which modify time to evaluate the base curves at */
        evaltime= evaluate_time_fmodifiers(&tmp_modifiers, NULL, 0.0f, strip->strip_time);
        
        /* evaluate all the F-Curves in the action, saving the relevant pointers to data that will need to be used */
        for (fcu= strip->act->curves.first; fcu; fcu= fcu->next) {
                NlaEvalChannel *nec;
                float value = 0.0f;
                short newChan = -1;
                
                /* check if this curve should be skipped */
                if (fcu->flag & (FCURVE_MUTED|FCURVE_DISABLED)) 
                        continue;
                if ((fcu->grp) && (fcu->grp->flag & AGRP_MUTED))
                        continue;
                        
                /* evaluate the F-Curve's value for the time given in the strip 
                 * NOTE: we use the modified time here, since strip's F-Curve Modifiers are applied on top of this 
                 */
                value= evaluate_fcurve(fcu, evaltime);
                
                /* apply strip's F-Curve Modifiers on this value 
                 * NOTE: we apply the strip's original evaluation time not the modified one (as per standard F-Curve eval)
                 */
                evaluate_value_fmodifiers(&tmp_modifiers, fcu, &value, strip->strip_time);
                
                
                /* get an NLA evaluation channel to work with, and accumulate the evaluated value with the value(s)
                 * stored in this channel if it has been used already
                 */
                nec= nlaevalchan_verify(ptr, channels, nes, fcu, &newChan);
                if (nec)
                        nlaevalchan_accumulate(nec, nes, newChan, value);
        }
        
        /* unlink this strip's modifiers from the parent's modifiers again */
        nlaeval_fmodifiers_split_stacks(&strip->modifiers, modifiers);
}

/* evaluate transition strip */
static void nlastrip_evaluate_transition (PointerRNA *ptr, ListBase *channels, ListBase *modifiers, NlaEvalStrip *nes)
{
        ListBase tmp_channels = {NULL, NULL};
        ListBase tmp_modifiers = {NULL, NULL};
        NlaEvalStrip tmp_nes;
        NlaStrip *s1, *s2;
        
        /* join this strip's modifiers to the parent's modifiers (own modifiers first) */
        nlaeval_fmodifiers_join_stacks(&tmp_modifiers, &nes->strip->modifiers, modifiers);
        
        /* get the two strips to operate on 
         *      - we use the endpoints of the strips directly flanking our strip
         *        using these as the endpoints of the transition (destination and source)
         *      - these should have already been determined to be valid...
         *      - if this strip is being played in reverse, we need to swap these endpoints
         *        otherwise they will be interpolated wrong
         */
        if (nes->strip->flag & NLASTRIP_FLAG_REVERSE) {
                s1= nes->strip->next;
                s2= nes->strip->prev;
        }
        else {
                s1= nes->strip->prev;
                s2= nes->strip->next;
        }
        
        /* prepare template for 'evaluation strip' 
         *      - based on the transition strip's evaluation strip data
         *      - strip_mode is NES_TIME_TRANSITION_* based on which endpoint
         *      - strip_time is the 'normalised' (i.e. in-strip) time for evaluation,
         *        which doubles up as an additional weighting factor for the strip influences
         *        which allows us to appear to be 'interpolating' between the two extremes
         */
        tmp_nes= *nes;
        
        /* evaluate these strips into a temp-buffer (tmp_channels) */
        // FIXME: modifier evalation here needs some work...
                /* first strip */
        tmp_nes.strip_mode= NES_TIME_TRANSITION_START;
        tmp_nes.strip= s1;
        nlastrip_evaluate(ptr, &tmp_channels, &tmp_modifiers, &tmp_nes);
        
                /* second strip */
        tmp_nes.strip_mode= NES_TIME_TRANSITION_END;
        tmp_nes.strip= s2;
        nlastrip_evaluate(ptr, &tmp_channels, &tmp_modifiers, &tmp_nes);
        
        
        /* assumulate temp-buffer and full-buffer, using the 'real' strip */
        nlaevalchan_buffers_accumulate(channels, &tmp_channels, nes);
        
        /* unlink this strip's modifiers from the parent's modifiers again */
        nlaeval_fmodifiers_split_stacks(&nes->strip->modifiers, modifiers);
}

/* evaluate meta-strip */
static void nlastrip_evaluate_meta (PointerRNA *ptr, ListBase *channels, ListBase *modifiers, NlaEvalStrip *nes)
{
        ListBase tmp_channels = {NULL, NULL};
        ListBase tmp_modifiers = {NULL, NULL};
        NlaStrip *strip= nes->strip;
        NlaEvalStrip *tmp_nes;
        float evaltime;
        
        /* meta-strip was calculated normally to have some time to be evaluated at
         * and here we 'look inside' the meta strip, treating it as a decorated window to
         * it's child strips, which get evaluated as if they were some tracks on a strip 
         * (but with some extra modifiers to apply).
         *
         * NOTE: keep this in sync with animsys_evaluate_nla()
         */
         
        /* join this strip's modifiers to the parent's modifiers (own modifiers first) */
        nlaeval_fmodifiers_join_stacks(&tmp_modifiers, &strip->modifiers, modifiers); 
        
        /* find the child-strip to evaluate */
        evaltime= (nes->strip_time * (strip->end - strip->start)) + strip->start;
        tmp_nes= nlastrips_ctime_get_strip(NULL, &strip->strips, -1, evaltime);
        if (tmp_nes == NULL)
                return;
                
        /* evaluate child-strip into tmp_channels buffer before accumulating 
         * in the accumulation buffer
         */
        nlastrip_evaluate(ptr, &tmp_channels, &tmp_modifiers, tmp_nes);
        
        /* assumulate temp-buffer and full-buffer, using the 'real' strip */
        nlaevalchan_buffers_accumulate(channels, &tmp_channels, nes);
        
        /* free temp eval-strip */
        MEM_freeN(tmp_nes);
        
        /* unlink this strip's modifiers from the parent's modifiers again */
        nlaeval_fmodifiers_split_stacks(&strip->modifiers, modifiers);
}

/* evaluates the given evaluation strip */
void nlastrip_evaluate (PointerRNA *ptr, ListBase *channels, ListBase *modifiers, NlaEvalStrip *nes)
{
        NlaStrip *strip= nes->strip;
        
        /* to prevent potential infinite recursion problems (i.e. transition strip, beside meta strip containing a transition
         * several levels deep inside it), we tag the current strip as being evaluated, and clear this when we leave
         */
        // TODO: be careful with this flag, since some edit tools may be running and have set this while animplayback was running
        if (strip->flag & NLASTRIP_FLAG_EDIT_TOUCHED)
                return;
        strip->flag |= NLASTRIP_FLAG_EDIT_TOUCHED;
        
        /* actions to take depend on the type of strip */
        switch (strip->type) {
                case NLASTRIP_TYPE_CLIP: /* action-clip */
                        nlastrip_evaluate_actionclip(ptr, channels, modifiers, nes);
                        break;
                case NLASTRIP_TYPE_TRANSITION: /* transition */
                        nlastrip_evaluate_transition(ptr, channels, modifiers, nes);
                        break;
                case NLASTRIP_TYPE_META: /* meta */
                        nlastrip_evaluate_meta(ptr, channels, modifiers, nes);
                        break;
                        
                default: /* do nothing */
                        break;
        }
        
        /* clear temp recursion safe-check */
        strip->flag &= ~NLASTRIP_FLAG_EDIT_TOUCHED;
}

/* write the accumulated settings to */
void nladata_flush_channels (ListBase *channels)
{
        NlaEvalChannel *nec;
        
        /* sanity checks */
        if (channels == NULL)
                return;
        
        /* for each channel with accumulated values, write its value on the property it affects */
        for (nec= channels->first; nec; nec= nec->next) {
                PointerRNA *ptr= &nec->ptr;
                PropertyRNA *prop= nec->prop;
                int array_index= nec->index;
                float value= nec->value;
                
                /* write values - see animsys_write_rna_setting() to sync the code */
                switch (RNA_property_type(prop)) 
                {
                        case PROP_BOOLEAN:
                                if (RNA_property_array_length(ptr, prop))
                                        RNA_property_boolean_set_index(ptr, prop, array_index, ANIMSYS_FLOAT_AS_BOOL(value));
                                else
                                        RNA_property_boolean_set(ptr, prop, ANIMSYS_FLOAT_AS_BOOL(value));
                                break;
                        case PROP_INT:
                                if (RNA_property_array_length(ptr, prop))
                                        RNA_property_int_set_index(ptr, prop, array_index, (int)value);
                                else
                                        RNA_property_int_set(ptr, prop, (int)value);
                                break;
                        case PROP_FLOAT:
                                if (RNA_property_array_length(ptr, prop))
                                        RNA_property_float_set_index(ptr, prop, array_index, value);
                                else
                                        RNA_property_float_set(ptr, prop, value);
                                break;
                        case PROP_ENUM:
                                RNA_property_enum_set(ptr, prop, (int)value);
                                break;
                        default:
                                // can't do anything with other types of property....
                                break;
                }
        }
}

/* ---------------------- */

/* NLA Evaluation function - values are calculated and stored in temporary "NlaEvalChannels" 
 * ! This is exported so that keyframing code can use this for make use of it for anim layers support
 * > echannels: (list<NlaEvalChannels>) evaluation channels with calculated values
 */
static void animsys_evaluate_nla (ListBase *echannels, PointerRNA *ptr, AnimData *adt, float ctime)
{
        NlaTrack *nlt;
        short track_index=0;
        short has_strips = 0;
        
        ListBase estrips= {NULL, NULL};
        NlaEvalStrip *nes;
        
        /* 1. get the stack of strips to evaluate at current time (influence calculated here) */
        for (nlt=adt->nla_tracks.first; nlt; nlt=nlt->next, track_index++) { 
                /* stop here if tweaking is on and this strip is the tweaking track (it will be the first one that's 'disabled')... */
                if ((adt->flag & ADT_NLA_EDIT_ON) && (nlt->flag & NLATRACK_DISABLED))
                        break;
                        
                /* skip if we're only considering a track tagged 'solo' */
                if ((adt->flag & ADT_NLA_SOLO_TRACK) && (nlt->flag & NLATRACK_SOLO)==0)
                        continue;
                /* skip if track is muted */
                if (nlt->flag & NLATRACK_MUTED) 
                        continue;
                        
                /* if this track has strips (but maybe they won't be suitable), set has_strips 
                 *      - used for mainly for still allowing normal action evaluation...
                 */
                if (nlt->strips.first)
                        has_strips= 1;
                        
                /* otherwise, get strip to evaluate for this channel */
                nes= nlastrips_ctime_get_strip(&estrips, &nlt->strips, track_index, ctime);
                if (nes) nes->track= nlt;
        }
        
        /* add 'active' Action (may be tweaking track) as last strip to evaluate in NLA stack
         *      - only do this if we're not exclusively evaluating the 'solo' NLA-track
         */
        if ((adt->action) && !(adt->flag & ADT_NLA_SOLO_TRACK)) {
                /* if there are strips, evaluate action as per NLA rules */
                if ((has_strips) || (adt->actstrip)) {
                        /* make dummy NLA strip, and add that to the stack */
                        NlaStrip dummy_strip= {NULL};
                        ListBase dummy_trackslist;
                        
                        dummy_trackslist.first= dummy_trackslist.last= &dummy_strip;
                        
                        if ((nlt) && !(adt->flag & ADT_NLA_EDIT_NOMAP)) {
                                /* edit active action in-place according to its active strip, so copy the data  */
                                memcpy(&dummy_strip, adt->actstrip, sizeof(NlaStrip));
                                dummy_strip.next = dummy_strip.prev = NULL;
                        }
                        else {
                                /* set settings of dummy NLA strip from AnimData settings */
                                dummy_strip.act= adt->action;
                                dummy_strip.remap= adt->remap;
                                
                                /* action range is calculated taking F-Modifiers into account (which making new strips doesn't do due to the troublesome nature of that) */
                                calc_action_range(dummy_strip.act, &dummy_strip.actstart, &dummy_strip.actend, 1);
                                dummy_strip.start = dummy_strip.actstart;
                                dummy_strip.end = (IS_EQF(dummy_strip.actstart, dummy_strip.actend)) ?  (dummy_strip.actstart + 1.0f): (dummy_strip.actend);
                                
                                dummy_strip.blendmode= adt->act_blendmode;
                                dummy_strip.extendmode= adt->act_extendmode;
                                dummy_strip.influence= adt->act_influence;
                        }
                        
                        /* add this to our list of evaluation strips */
                        nlastrips_ctime_get_strip(&estrips, &dummy_trackslist, -1, ctime);
                }
                else {
                        /* special case - evaluate as if there isn't any NLA data */
                        // TODO: this is really just a stop-gap measure...
                        animsys_evaluate_action(ptr, adt->action, adt->remap, ctime);
                        return;
                }
        }
        
        /* only continue if there are strips to evaluate */
        if (estrips.first == NULL)
                return;
        
        
        /* 2. for each strip, evaluate then accumulate on top of existing channels, but don't set values yet */
        for (nes= estrips.first; nes; nes= nes->next) 
                nlastrip_evaluate(ptr, echannels, NULL, nes);
                
        /* 3. free temporary evaluation data that's not used elsewhere */
        BLI_freelistN(&estrips);
}

/* NLA Evaluation function (mostly for use through do_animdata) 
 *      - All channels that will be affected are not cleared anymore. Instead, we just evaluate into 
 *              some temp channels, where values can be accumulated in one go.
 */
static void animsys_calculate_nla (PointerRNA *ptr, AnimData *adt, float ctime)
{
        ListBase echannels= {NULL, NULL};
        
        // TODO: need to zero out all channels used, otherwise we have problems with threadsafety
        // and also when the user jumps between different times instead of moving sequentially...
        
        /* evaluate the NLA stack, obtaining a set of values to flush */
        animsys_evaluate_nla(&echannels, ptr, adt, ctime);
        
        /* flush effects of accumulating channels in NLA to the actual data they affect */
        nladata_flush_channels(&echannels);
        
        /* free temp data */
        BLI_freelistN(&echannels);
}

/* ***************************************** */ 
/* Overrides System - Public API */

/* Clear all overides */

/* Add or get existing Override for given setting */
#if 0
AnimOverride *BKE_animsys_validate_override (PointerRNA *UNUSED(ptr), char *UNUSED(path), int UNUSED(array_index))
{
        // FIXME: need to define how to get overrides
        return NULL;
} 
#endif

/* -------------------- */

/* Evaluate Overrides */
static void animsys_evaluate_overrides (PointerRNA *ptr, AnimData *adt)
{
        AnimOverride *aor;
        
        /* for each override, simply execute... */
        for (aor= adt->overrides.first; aor; aor= aor->next)
                animsys_write_rna_setting(ptr, aor->rna_path, aor->array_index, aor->value);
}

/* ***************************************** */
/* Evaluation System - Public API */

/* Overview of how this system works:
 *      1) Depsgraph sorts data as necessary, so that data is in an order that means 
 *              that all dependences are resolved before dependants.
 *      2) All normal animation is evaluated, so that drivers have some basis values to
 *              work with
 *              a.      NLA stacks are done first, as the Active Actions act as 'tweaking' tracks
 *                      which modify the effects of the NLA-stacks
 *              b.      Active Action is evaluated as per normal, on top of the results of the NLA tracks
 *
 * --------------< often in a separate phase... >------------------ 
 *
 *      3) Drivers/expressions are evaluated on top of this, in an order where dependences are
 *              resolved nicely. 
 *         Note: it may be necessary to have some tools to handle the cases where some higher-level
 *              drivers are added and cause some problematic dependencies that didn't exist in the local levels...
 *
 * --------------< always executed >------------------ 
 *
 * Maintainance of editability of settings (XXX):
 *      In order to ensure that settings that are animated can still be manipulated in the UI without requiring
 *      that keyframes are added to prevent these values from being overwritten, we use 'overrides'. 
 *
 * Unresolved things:
 *      - Handling of multi-user settings (i.e. time-offset, group-instancing) -> big cache grids or nodal system? but stored where?
 *      - Multiple-block dependencies (i.e. drivers for settings are in both local and higher levels) -> split into separate lists? 
 *
 * Current Status:
 *      - Currently (as of September 2009), overrides we haven't needed to (fully) implement overrides. 
 *        However, the code fo this is relatively harmless, so is left in the code for now.
 */

/* Evaluation loop for evaluation animation data 
 *
 * This assumes that the animation-data provided belongs to the ID block in question,
 * and that the flags for which parts of the anim-data settings need to be recalculated 
 * have been set already by the depsgraph. Now, we use the recalc 
 */
void BKE_animsys_evaluate_animdata (Scene *scene, ID *id, AnimData *adt, float ctime, short recalc)
{
        PointerRNA id_ptr;
        
        /* sanity checks */
        if ELEM(NULL, id, adt)
                return;
        
        /* get pointer to ID-block for RNA to use */
        RNA_id_pointer_create(id, &id_ptr);
        
        /* recalculate keyframe data:
         *      - NLA before Active Action, as Active Action behaves as 'tweaking track'
         *        that overrides 'rough' work in NLA
         */
        // TODO: need to double check that this all works correctly
        if ((recalc & ADT_RECALC_ANIM) || (adt->recalc & ADT_RECALC_ANIM))
        {
                /* evaluate NLA data */
                if ((adt->nla_tracks.first) && !(adt->flag & ADT_NLA_EVAL_OFF))
                {
                        /* evaluate NLA-stack 
                         *      - active action is evaluated as part of the NLA stack as the last item
                         */
                        animsys_calculate_nla(&id_ptr, adt, ctime);
                }
                /* evaluate Active Action only */
                else if (adt->action)
                        animsys_evaluate_action(&id_ptr, adt->action, adt->remap, ctime);
                
                /* reset tag */
                adt->recalc &= ~ADT_RECALC_ANIM;
        }
        
        /* recalculate drivers 
         *      - Drivers need to be evaluated afterwards, as they can either override 
         *        or be layered on top of existing animation data.
         *      - Drivers should be in the appropriate order to be evaluated without problems...
         */
        if ((recalc & ADT_RECALC_DRIVERS) /*&& (adt->recalc & ADT_RECALC_DRIVERS)*/) // XXX for now, don't check yet, as depsgraph hasn't been updated
        {
                animsys_evaluate_drivers(&id_ptr, adt, ctime);
        }
        
        /* always execute 'overrides' 
         *      - Overrides allow editing, by overwriting the value(s) set from animation-data, with the
         *        value last set by the user (and not keyframed yet). 
         *      - Overrides are cleared upon frame change and/or keyframing
         *      - It is best that we execute this everytime, so that no errors are likely to occur.
         */
        animsys_evaluate_overrides(&id_ptr, adt);
        
        /* execute and clear all cached property update functions */
        if (scene)
        {
                Main *bmain = G.main; // xxx - to get passed in!
                RNA_property_update_cache_flush(bmain, scene);
                RNA_property_update_cache_free();
        }
        
        /* clear recalc flag now */
        adt->recalc= 0;
}

/* Evaluation of all ID-blocks with Animation Data blocks - Animation Data Only
 *
 * This will evaluate only the animation info available in the animation data-blocks
 * encountered. In order to enforce the system by which some settings controlled by a
 * 'local' (i.e. belonging in the nearest ID-block that setting is related to, not a
 * standard 'root') block are overridden by a larger 'user'
 */
void BKE_animsys_evaluate_all_animation (Main *main, Scene *scene, float ctime)
{
        ID *id;

        if (G.f & G_DEBUG)
                printf("Evaluate all animation - %f \n", ctime);
        
        /* macros for less typing 
         *      - only evaluate animation data for id if it has users (and not just fake ones)
         *      - whether animdata exists is checked for by the evaluation function, though taking 
         *        this outside of the function may make things slightly faster?
         */
#define EVAL_ANIM_IDS(first, aflag) \
        for (id= first; id; id= id->next) { \
                if (ID_REAL_USERS(id) > 0) { \
                        AnimData *adt= BKE_animdata_from_id(id); \
                        BKE_animsys_evaluate_animdata(scene, id, adt, ctime, aflag); \
                } \
        }
        /* another macro for the "embedded" nodetree cases 
         *      - this is like EVAL_ANIM_IDS, but this handles the case "embedded nodetrees" 
         *        (i.e. scene/material/texture->nodetree) which we need a special exception
         *        for, otherwise they'd get skipped
         *      - ntp = "node tree parent" = datablock where node tree stuff resides
         */
#define EVAL_ANIM_NODETREE_IDS(first, NtId_Type, aflag) \
        for (id= first; id; id= id->next) { \
                if (ID_REAL_USERS(id) > 0) { \
                        AnimData *adt= BKE_animdata_from_id(id); \
                        NtId_Type *ntp= (NtId_Type *)id; \
                        if (ntp->nodetree) { \
                                AnimData *adt2= BKE_animdata_from_id((ID *)ntp->nodetree); \
                                BKE_animsys_evaluate_animdata(scene, (ID *)ntp->nodetree, adt2, ctime, ADT_RECALC_ANIM); \
                        } \
                        BKE_animsys_evaluate_animdata(scene, id, adt, ctime, aflag); \
                } \
        }
        
        /* optimisation: 
         * when there are no actions, don't go over database and loop over heaps of datablocks, 
         * which should ultimately be empty, since it is not possible for now to have any animation 
         * without some actions, and drivers wouldn't get affected by any state changes
         *
         * however, if there are some curves, we will need to make sure that their 'ctime' property gets
         * set correctly, so this optimisation must be skipped in that case...
         */
        if ((main->action.first == NULL) && (main->curve.first == NULL)) {
                if (G.f & G_DEBUG)
                        printf("\tNo Actions, so no animation needs to be evaluated...\n");
                        
                return;
        }
        
        /* nodes */
        EVAL_ANIM_IDS(main->nodetree.first, ADT_RECALC_ANIM);
        
        /* textures */
        EVAL_ANIM_NODETREE_IDS(main->tex.first, Tex, ADT_RECALC_ANIM);
        
        /* lamps */
        EVAL_ANIM_IDS(main->lamp.first, ADT_RECALC_ANIM);
        
        /* materials */
        EVAL_ANIM_NODETREE_IDS(main->mat.first, Material, ADT_RECALC_ANIM);
        
        /* cameras */
        EVAL_ANIM_IDS(main->camera.first, ADT_RECALC_ANIM);
        
        /* shapekeys */
        EVAL_ANIM_IDS(main->key.first, ADT_RECALC_ANIM);
        
        /* metaballs */
        EVAL_ANIM_IDS(main->mball.first, ADT_RECALC_ANIM);
        
        /* curves */
        EVAL_ANIM_IDS(main->curve.first, ADT_RECALC_ANIM);
        
        /* armatures */
        EVAL_ANIM_IDS(main->armature.first, ADT_RECALC_ANIM);
        
        /* lattices */
        EVAL_ANIM_IDS(main->latt.first, ADT_RECALC_ANIM);
        
        /* meshes */
        EVAL_ANIM_IDS(main->mesh.first, ADT_RECALC_ANIM);
        
        /* particles */
        EVAL_ANIM_IDS(main->particle.first, ADT_RECALC_ANIM);
        
        /* lamps */
        EVAL_ANIM_IDS(main->speaker.first, ADT_RECALC_ANIM);

        /* objects */
                /* ADT_RECALC_ANIM doesn't need to be supplied here, since object AnimData gets 
                 * this tagged by Depsgraph on framechange. This optimisation means that objects
                 * linked from other (not-visible) scenes will not need their data calculated.
                 */
        EVAL_ANIM_IDS(main->object.first, 0); 
        
        /* worlds */
        EVAL_ANIM_IDS(main->world.first, ADT_RECALC_ANIM);
        
        /* scenes */
        EVAL_ANIM_NODETREE_IDS(main->scene.first, Scene, ADT_RECALC_ANIM);
}

/* ***************************************** */