Yet another tweak to stretch volume variation.
authorLukas Tönne <lukas.toenne@gmail.com>
Tue, 14 Oct 2014 09:49:58 +0000 (11:49 +0200)
committerLukas Tönne <lukas.toenne@gmail.com>
Tue, 14 Oct 2014 09:51:36 +0000 (11:51 +0200)
Make sure the 1.0 value is not affected by smoothing, and min/max limits
never go above or below 1.0 respectively. This was a request by
animators since not modifying the mesh in its rest pose is regarded as
crucial.

source/blender/blenkernel/intern/constraint.c
source/blender/blenloader/intern/versioning_270.c
source/blender/makesrna/intern/rna_constraint.c

index 3a9eb31f061e0fe86235f388a786cb3ef5d777f6..97515244422d9ec47490a1596b89f85c027ddd9a 100644 (file)
@@ -2613,6 +2613,8 @@ static void stretchto_new_data(void *cdata)
        data->plane = 0;
        data->orglength = 0.0; 
        data->bulge = 1.0;
+       data->bulge_max = 1.0f;
+       data->bulge_min = 1.0f;
 }
 
 static void stretchto_id_looper(bConstraint *con, ConstraintIDFunc func, void *userdata)
@@ -2689,37 +2691,28 @@ static void stretchto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
                
                bulge = powf(data->orglength / dist, data->bulge);
                
-               if (data->flag & STRETCHTOCON_USE_BULGE_MAX) {
-                       const float bulge_median = ((data->flag & STRETCHTOCON_USE_BULGE_MIN) ?
-                                                   0.5f * (data->bulge_min + data->bulge_max) : 0.0f);
-                       const float bulge_range = data->bulge_max - bulge_median;
-                       float bulge_smoothed;
-
-                       bulge_smoothed = bulge_median + bulge_range * atanf(bulge - bulge_median) / (0.5f * M_PI);
-
-                       if (data->flag & STRETCHTOCON_USE_BULGE_MIN) {
-                               CLAMP_MIN(bulge, data->bulge_min);
+               if (bulge > 1.0f) {
+                       if (data->flag & STRETCHTOCON_USE_BULGE_MAX) {
+                               float bulge_max = max_ff(data->bulge_max, 1.0f);
+                               float hard = min_ff(bulge, bulge_max);
+                               
+                               float range = bulge_max - 1.0f;
+                               float scale = (range > 0.0f) ? 1.0f / range : 0.0f;
+                               float soft = 1.0f + range * atanf((bulge - 1.0f) * scale) / (0.5f * M_PI);
+                               
+                               bulge = interpf(soft, hard, data->bulge_smooth);
                        }
-                       CLAMP_MAX(bulge, data->bulge_max);
-
-                       bulge = interpf(bulge_smoothed, bulge, data->bulge_smooth);
                }
-               else if (data->flag & STRETCHTOCON_USE_BULGE_MIN) {
-                       /* The quadratic formula below creates a smooth asymptote
-                        * of the clamped bulge value. By scaling x with the inverse smooth factor
-                        * the smoothed area becomes smaller ("less smoothing").
-                        * For very small smoothing factor below epsilon it is replaced
-                        * by the clamped version to avoid floating point precision issues.
-                        */
-                       const float epsilon = 0.000001f;
-                       if (data->bulge_smooth < epsilon) {
-                               CLAMP_MIN(bulge, data->bulge_min);
-                       }
-                       else {
-                               float scale = data->bulge_smooth;
-                               float inv_scale = 1.0f / scale;
-                               float x = (bulge - data->bulge_min) * 0.5f * inv_scale;
-                               bulge = scale * (x + sqrtf((x * x) + 1.0f)) + data->bulge_min;
+               if (bulge < 1.0f) {
+                       if (data->flag & STRETCHTOCON_USE_BULGE_MIN) {
+                               float bulge_min = CLAMPIS(data->bulge_max, 0.0f, 1.0f);
+                               float hard = max_ff(bulge, bulge_min);
+                               
+                               float range = 1.0f - bulge_min;
+                               float scale = (range > 0.0f) ? 1.0f / range : 0.0f;
+                               float soft = 1.0f - range * atanf((1.0f - bulge) * scale) / (0.5f * M_PI);
+                               
+                               bulge = interpf(soft, hard, data->bulge_smooth);
                        }
                }
                
index d8da0a12b502df8a945ced2ba42cbcb5c49d8328..bd1b5f2c2698a0c5b074bdeef3ab7d9146485e4e 100644 (file)
@@ -114,6 +114,19 @@ static void do_version_constraints_radians_degrees_270_5(ListBase *lb)
        }
 }
 
+static void do_version_constraints_stretch_to_limits(ListBase *lb)
+{
+       bConstraint *con;
+
+       for (con = lb->first; con; con = con->next) {
+               if (con->type == CONSTRAINT_TYPE_STRETCHTO) {
+                       bStretchToConstraint *data = (bStretchToConstraint *)con->data;
+                       data->bulge_min = 1.0f;
+                       data->bulge_max = 1.0f;
+               }
+       }
+}
+
 void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *main)
 {
        if (!MAIN_VERSION_ATLEAST(main, 270, 0)) {
@@ -405,4 +418,21 @@ void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *main)
                        image->gen_color[3] = 1.0f;
                }
        }
+
+       if (!DNA_struct_elem_find(fd->filesdna, "bStretchToConstraint", "float", "bulge_min")) {
+               Object *ob;
+
+               /* Update Transform constraint (again :|). */
+               for (ob = main->object.first; ob; ob = ob->id.next) {
+                       do_version_constraints_stretch_to_limits(&ob->constraints);
+
+                       if (ob->pose) {
+                               /* Bones constraints! */
+                               bPoseChannel *pchan;
+                               for (pchan = ob->pose->chanbase.first; pchan; pchan = pchan->next) {
+                                       do_version_constraints_stretch_to_limits(&pchan->constraints);
+                               }
+                       }
+               }
+       }
 }
index aab2d35c0e42e1550a6a811bac8a5476a31582e8..77355dbad0eef913d9c2000a212a36e9f01d4137 100644 (file)
@@ -1377,12 +1377,12 @@ static void rna_def_constraint_stretch_to(BlenderRNA *brna)
        RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_update");
 
        prop = RNA_def_property(srna, "bulge_min", PROP_FLOAT, PROP_NONE);
-       RNA_def_property_range(prop, 0.0, 100.f);
+       RNA_def_property_range(prop, 0.0, 1.0f);
        RNA_def_property_ui_text(prop, "Volume Variation Minimum", "Minimum volume stretching factor");
        RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_update");
 
        prop = RNA_def_property(srna, "bulge_max", PROP_FLOAT, PROP_NONE);
-       RNA_def_property_range(prop, 0.0, 100.f);
+       RNA_def_property_range(prop, 1.0, 100.0f);
        RNA_def_property_ui_text(prop, "Volume Variation Maximum", "Maximum volume stretching factor");
        RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_update");