Sculpt Face Sets

Face Sets are the new system to control the visibility state of the mesh in sculpt and paint modes. They are designed to work in modes where brushes are the primary way of interaction and they provide much more control when working with meshes with complex shapes and overlapping surfaces.

This initial commit includes:
- Sculpt Face Sets data structures and PBVH rendering.
- Face Set overlay and opacity controls.
- Sculpt Undo support.
- Remesher reprojection support. The visibility state of the mesh is also preserved when remeshing.
- Automasking and Mesh filter support.
- Mask expand operator mode to expand Face Sets (Shift + W) and flood fill areas by connectivity (press Ctrl while expanding).
- Sculpt Mode Face Sets and Visibility API.
- Sculpt Face Sets creation and visibility management operators.
- Operator to randomize the Face Sets colors.
- Draw Face Sets brush tool to create and edit the Face Sets. Drawing on the mesh creates a new Face Set. Pressing Ctrl before drawing modifies the Face Set under the brush at the beginning of the stroke.
- Updated keymap and menu to work with Face Sets from Sculpt Mode (H to toggle visibility, Alt + H to show all, Shit + H to hide).
- Pie menu on the W key with Face common Sets operations.

Know limitations:
- Multires support. The Face Sets and Visibility API needs to be implemented for Multires.

Reviewed By: jbakker, #user_interface, Severin

Differential Revision: https://developer.blender.org/D6070

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_paint.h b/source/blender/blenkernel/BKE_paint.h
index 016012d7288..ceb48783e20 100644
--- a/source/blender/blenkernel/BKE_paint.h
+++ b/source/blender/blenkernel/BKE_paint.h
@@ -218,6 +218,8 @@ void BKE_paint_toolslots_brush_update(struct Paint *paint);
 void BKE_paint_toolslots_brush_validate(struct Main *bmain, struct Paint *paint);
 struct Brush *BKE_paint_toolslots_brush_get(struct Paint *paint, int slot_index);
 
+#define SCULPT_FACE_SET_NONE 0
+
 /* Used for both vertex color and weight paint */
 struct SculptVertexPaintGeomMap {
   int *vert_map_mem;
@@ -290,6 +292,9 @@ typedef struct SculptSession {
   struct MeshElemMap *pmap;
   int *pmap_mem;
 
+  /* Mesh Face Sets */
+  int *face_sets;
+
   /* BMesh for dynamic topology sculpting */
   struct BMesh *bm;
   int cd_vert_node_offset;
@@ -304,6 +309,7 @@ typedef struct SculptSession {
   /* PBVH acceleration structure */
   struct PBVH *pbvh;
   bool show_mask;
+  bool show_face_sets;
 
   /* Painting on deformed mesh */
   bool deform_modifiers_active; /* object is deformed with some modifiers */