Add cloth pressure vertex group and unlock cloth shrink values range

Introduced a way to specify cloth pressure force influence with a vertex
group. This will allow users to only have pressure affect certain parts
of the mesh.

In addition to this, the "shrink factor" is now also unlocked to allow
negative values and thus allowing the cloth mesh to grow as well.

Reviewed By: Jaques Lucke

Differential Revision: http://developer.blender.org/D6347

1 files changed, 25 insertions, 32 deletions

diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index 2be312bc4d9..d26dca4a252 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -134,6 +134,7 @@ void cloth_init(ClothModifierData *clmd)
   clmd->sim_parms->uniform_pressure_force = 0.0f;
   clmd->sim_parms->target_volume = 0.0f;
   clmd->sim_parms->pressure_factor = 1.0f;
+  clmd->sim_parms->vgroup_pressure = 0;
 
   // also from softbodies
   clmd->sim_parms->maxgoal = 1.0f;
@@ -651,8 +652,9 @@ int cloth_uses_vgroup(ClothModifierData *clmd)
 {
   return (((clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_SELF) &&
            (clmd->coll_parms->vgroup_selfcol > 0)) ||
-          (clmd->sim_parms->vgroup_struct > 0) || (clmd->sim_parms->vgroup_bend > 0) ||
-          (clmd->sim_parms->vgroup_shrink > 0) || (clmd->sim_parms->vgroup_mass > 0));
+          (clmd->sim_parms->vgroup_pressure > 0) || (clmd->sim_parms->vgroup_struct > 0) ||
+          (clmd->sim_parms->vgroup_bend > 0) || (clmd->sim_parms->vgroup_shrink > 0) ||
+          (clmd->sim_parms->vgroup_mass > 0));
 }
 
 /**
@@ -660,27 +662,16 @@ int cloth_uses_vgroup(ClothModifierData *clmd)
  */
 static void cloth_apply_vgroup(ClothModifierData *clmd, Mesh *mesh)
 {
-  /* Can be optimized to do all groups in one loop. */
-  int i = 0;
-  int j = 0;
-  MDeformVert *dvert = NULL;
-  Cloth *clothObj = NULL;
-  int mvert_num;
-  /* float goalfac = 0; */ /* UNUSED */
-  ClothVertex *verts = NULL;
-
   if (!clmd || !mesh) {
     return;
   }
 
-  clothObj = clmd->clothObject;
+  int mvert_num = mesh->totvert;
 
-  mvert_num = mesh->totvert;
-
-  verts = clothObj->verts;
+  ClothVertex *verts = clmd->clothObject->verts;
 
   if (cloth_uses_vgroup(clmd)) {
-    for (i = 0; i < mvert_num; i++, verts++) {
+    for (int i = 0; i < mvert_num; i++, verts++) {
 
       /* Reset Goal values to standard */
       if (clmd->sim_parms->vgroup_mass > 0) {
@@ -697,9 +688,9 @@ static void cloth_apply_vgroup(ClothModifierData *clmd, Mesh *mesh)
       verts->flags &= ~CLOTH_VERT_FLAG_PINNED;
       verts->flags &= ~CLOTH_VERT_FLAG_NOSELFCOLL;
 
-      dvert = CustomData_get(&mesh->vdata, i, CD_MDEFORMVERT);
+      MDeformVert *dvert = CustomData_get(&mesh->vdata, i, CD_MDEFORMVERT);
       if (dvert) {
-        for (j = 0; j < dvert->totweight; j++) {
+        for (int j = 0; j < dvert->totweight; j++) {
           if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_mass - 1)) {
             verts->goal = dvert->dw[j].weight;
 
@@ -726,19 +717,21 @@ static void cloth_apply_vgroup(ClothModifierData *clmd, Mesh *mesh)
             verts->bend_stiff = dvert->dw[j].weight;
           }
 
-          if (clmd->coll_parms->flags & CLOTH_COLLSETTINGS_FLAG_SELF) {
-            if (dvert->dw[j].def_nr == (clmd->coll_parms->vgroup_selfcol - 1)) {
-              if (dvert->dw[j].weight > 0.0f) {
-                verts->flags |= CLOTH_VERT_FLAG_NOSELFCOLL;
-              }
+          if (dvert->dw[j].def_nr == (clmd->coll_parms->vgroup_selfcol - 1)) {
+            if (dvert->dw[j].weight > 0.0f) {
+              verts->flags |= CLOTH_VERT_FLAG_NOSELFCOLL;
             }
           }
-          if (clmd->sim_parms->vgroup_shrink > 0) {
-            if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_shrink - 1)) {
-              /* Used for linear interpolation between min and max
-               * shrink factor based on weight. */
-              verts->shrink_factor = dvert->dw[j].weight;
-            }
+
+          if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_shrink - 1)) {
+            /* Used for linear interpolation between min and max
+             * shrink factor based on weight. */
+            verts->shrink_factor = dvert->dw[j].weight;
+          }
+
+          if (dvert->dw[j].def_nr == (clmd->sim_parms->vgroup_pressure - 1)) {
+            /* Used to define how much the pressure settings should affect the given vertex */
+            verts->pressure_factor = dvert->dw[j].weight;
           }
         }
       }
@@ -750,10 +743,10 @@ static float cloth_shrink_factor(ClothModifierData *clmd, ClothVertex *verts, in
 {
   /* Linear interpolation between min and max shrink factor based on weight. */
   float base = 1.0f - clmd->sim_parms->shrink_min;
-  float delta = clmd->sim_parms->shrink_min - clmd->sim_parms->shrink_max;
+  float shrink_factor_delta = clmd->sim_parms->shrink_min - clmd->sim_parms->shrink_max;
 
-  float k1 = base + delta * verts[i1].shrink_factor;
-  float k2 = base + delta * verts[i2].shrink_factor;
+  float k1 = base + shrink_factor_delta * verts[i1].shrink_factor;
+  float k2 = base + shrink_factor_delta * verts[i2].shrink_factor;
 
   /* Use geometrical mean to average two factors since it behaves better
    * for diagonals when a rectangle transforms into a trapezoid. */