Sculpt: Cloth Brush simulation area property

This makes possible to choose between a local and a global simulation
when the cloth brush is used. Local simulation is the current default.
When global simulation is enabled, the cloth brush simulates the entire
mesh without taking any simulation limits into account.

This was possible before by setting the simulation limits to 10 (the
current maximum value allowed) so the entire mesh was inside the limits,
but this was a hack as the limits scale with the radius and there should
not be any limitation on how big the simulated area can be to be able to
simulate an entire object. This also allows to make a more clear
distinction between cloth brush presets that are intended to be used in
local areas to add details or globally to generate the base shape of the
mesh.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8481

5 files changed, 56 insertions, 15 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_cursor.c b/source/blender/editors/sculpt_paint/paint_cursor.c
index e3027ead1f1..c5f1063d494 100644
--- a/source/blender/editors/sculpt_paint/paint_cursor.c
+++ b/source/blender/editors/sculpt_paint/paint_cursor.c
@@ -1612,8 +1612,9 @@ static void paint_cursor_draw_3d_view_brush_cursor_inactive(PaintCursorContext *
   /* Main inactive cursor. */
   paint_cursor_draw_main_inactive_cursor(pcontext);
 
-  /* Cloth brush simulation areas. */
-  if (brush->sculpt_tool == SCULPT_TOOL_CLOTH) {
+  /* Cloth brush local simulation areas. */
+  if (brush->sculpt_tool == SCULPT_TOOL_CLOTH &&
+      brush->cloth_simulation_area_type == BRUSH_CLOTH_SIMULATION_AREA_LOCAL) {
     const float white[3] = {1.0f, 1.0f, 1.0f};
     const float zero_v[3] = {0.0f};
     /* This functions sets its own drawing space in order to draw the simulation limits when the
@@ -1691,9 +1692,10 @@ static void paint_cursor_cursor_draw_3d_view_brush_cursor_active(PaintCursorCont
       SCULPT_cloth_plane_falloff_preview_draw(
           pcontext->pos, ss, pcontext->outline_col, pcontext->outline_alpha);
     }
-    else if (brush->cloth_force_falloff_type == BRUSH_CLOTH_FORCE_FALLOFF_RADIAL) {
+    else if (brush->cloth_force_falloff_type == BRUSH_CLOTH_FORCE_FALLOFF_RADIAL &&
+             brush->cloth_simulation_area_type == BRUSH_CLOTH_SIMULATION_AREA_LOCAL) {
       /* Display the simulation limits if sculpting outside them. */
-      /* This does not makes much sense of plane fallof as the fallof is infinte. */
+      /* This does not makes much sense of plane fallof as the fallof is infinte or global. */
 
       if (len_v3v3(ss->cache->true_location, ss->cache->true_initial_location) >
           ss->cache->radius * (1.0f + brush->cloth_sim_limit)) {
diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index 48c13d69136..89fc0ac1a58 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -5513,15 +5513,21 @@ static void do_brush_action(Sculpt *sd, Object *ob, Brush *brush, UnifiedPaintSe
     BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnode);
   }
   else if (brush->sculpt_tool == SCULPT_TOOL_CLOTH) {
-    SculptSearchSphereData data = {
-        .ss = ss,
-        .sd = sd,
-        .radius_squared = square_f(ss->cache->initial_radius * (1.0 + brush->cloth_sim_limit)),
-        .original = false,
-        .ignore_fully_ineffective = false,
-        .center = ss->cache->initial_location,
-    };
-    BKE_pbvh_search_gather(ss->pbvh, SCULPT_search_sphere_cb, &data, &nodes, &totnode);
+    if (brush->cloth_simulation_area_type == BRUSH_CLOTH_SIMULATION_AREA_LOCAL) {
+      SculptSearchSphereData data = {
+          .ss = ss,
+          .sd = sd,
+          .radius_squared = square_f(ss->cache->initial_radius * (1.0 + brush->cloth_sim_limit)),
+          .original = false,
+          .ignore_fully_ineffective = false,
+          .center = ss->cache->initial_location,
+      };
+      BKE_pbvh_search_gather(ss->pbvh, SCULPT_search_sphere_cb, &data, &nodes, &totnode);
+    }
+    else {
+      /* Gobal simulation, get all nodes. */
+      BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnode);
+    }
   }
   else {
     const bool use_original = sculpt_tool_needs_original(brush->sculpt_tool) ? true :
diff --git a/source/blender/editors/sculpt_paint/sculpt_cloth.c b/source/blender/editors/sculpt_paint/sculpt_cloth.c
index dac8ef99fc0..c0862795594 100644
--- a/source/blender/editors/sculpt_paint/sculpt_cloth.c
+++ b/source/blender/editors/sculpt_paint/sculpt_cloth.c
@@ -108,6 +108,11 @@ static float cloth_brush_simulation_falloff_get(const Brush *brush,
                                                 const float location[3],
                                                 const float co[3])
 {
+  /* Global simulation does not have any falloff as the entire mesh is being simulated. */
+  if (brush->cloth_simulation_area_type == BRUSH_CLOTH_SIMULATION_AREA_GLOBAL) {
+    return 1.0f;
+  }
+
   const float distance = len_v3v3(location, co);
   const float limit = radius + (radius * brush->cloth_sim_limit);
   const float falloff = radius + (radius * brush->cloth_sim_limit * brush->cloth_sim_falloff);
@@ -249,7 +254,11 @@ static void do_cloth_brush_build_constraints_task_cb_ex(
     radius_squared = ss->cache->initial_radius * ss->cache->initial_radius;
   }
 
-  const float cloth_sim_radius_squared = data->cloth_sim_radius * data->cloth_sim_radius;
+  /* Only limit the contraint creation to a radius when the simulation is local. */
+  const float cloth_sim_radius_squared = brush->cloth_simulation_area_type ==
+                                                 BRUSH_CLOTH_SIMULATION_AREA_LOCAL ?
+                                             data->cloth_sim_radius * data->cloth_sim_radius :
+                                             FLT_MAX;
 
   BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
   {
diff --git a/source/blender/makesdna/DNA_brush_types.h b/source/blender/makesdna/DNA_brush_types.h
index 7b3e9dabe9f..9d9c2354220 100644
--- a/source/blender/makesdna/DNA_brush_types.h
+++ b/source/blender/makesdna/DNA_brush_types.h
@@ -351,6 +351,11 @@ typedef enum eBrushClothForceFalloffType {
   BRUSH_CLOTH_FORCE_FALLOFF_PLANE = 1,
 } eBrushClothForceFalloffType;
 
+typedef enum eBrushClothSimulationAreaType {
+  BRUSH_CLOTH_SIMULATION_AREA_LOCAL = 0,
+  BRUSH_CLOTH_SIMULATION_AREA_GLOBAL = 1,
+} eBrushClothSimulationAreaType;
+
 typedef enum eBrushPoseDeformType {
   BRUSH_POSE_DEFORM_ROTATE_TWIST = 0,
   BRUSH_POSE_DEFORM_SCALE_TRASLATE = 1,
@@ -546,7 +551,7 @@ typedef struct Brush {
   char gpencil_sculpt_tool;
   /** Active grease pencil weight tool. */
   char gpencil_weight_tool;
-  char _pad1[6];
+  char _pad1[2];
 
   float autosmooth_factor;
 
@@ -585,6 +590,7 @@ typedef struct Brush {
   /* cloth */
   int cloth_deform_type;
   int cloth_force_falloff_type;
+  int cloth_simulation_area_type;
 
   float cloth_mass;
   float cloth_damping;
diff --git a/source/blender/makesrna/intern/rna_brush.c b/source/blender/makesrna/intern/rna_brush.c
index d20cec518bc..11b563dae52 100644
--- a/source/blender/makesrna/intern/rna_brush.c
+++ b/source/blender/makesrna/intern/rna_brush.c
@@ -1983,6 +1983,16 @@ static void rna_def_brush(BlenderRNA *brna)
       {0, NULL, 0, NULL, NULL},
   };
 
+  static const EnumPropertyItem brush_cloth_simulation_area_type_items[] = {
+      {BRUSH_CLOTH_SIMULATION_AREA_LOCAL,
+       "LOCAL",
+       0,
+       "Local",
+       "Simulates only a specific area arround the brush limited by a fixed radius"},
+      {BRUSH_CLOTH_SIMULATION_AREA_GLOBAL, "GLOBAL", 0, "Global", "Simulates the entire mesh"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
   static const EnumPropertyItem brush_smooth_deform_type_items[] = {
       {BRUSH_SMOOTH_DEFORM_LAPLACIAN,
        "LAPLACIAN",
@@ -2153,6 +2163,14 @@ static void rna_def_brush(BlenderRNA *brna)
       prop, "Force Falloff", "Shape used in the brush to apply force to the cloth");
   RNA_def_property_update(prop, 0, "rna_Brush_update");
 
+  prop = RNA_def_property(srna, "cloth_simulation_area_type", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, brush_cloth_simulation_area_type_items);
+  RNA_def_property_ui_text(
+      prop,
+      "Simulation Area",
+      "Part of the mesh that is going to be simulated when the stroke is active");
+  RNA_def_property_update(prop, 0, "rna_Brush_update");
+
   prop = RNA_def_property(srna, "smooth_deform_type", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(prop, brush_smooth_deform_type_items);
   RNA_def_property_ui_text(prop, "Deformation", "Deformation type that is used in the brush");