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, 25 insertions, 1 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_intern.h b/source/blender/editors/sculpt_paint/sculpt_intern.h
index 91656cb2ad5..a935e32cc08 100644
--- a/source/blender/editors/sculpt_paint/sculpt_intern.h
+++ b/source/blender/editors/sculpt_paint/sculpt_intern.h
@@ -54,6 +54,7 @@ bool sculpt_poll_view3d(struct bContext *C);
 typedef enum SculptUpdateType {
   SCULPT_UPDATE_COORDS = 1 << 0,
   SCULPT_UPDATE_MASK = 1 << 1,
+  SCULPT_UPDATE_VISIBILITY = 1 << 2,
 } SculptUpdateType;
 
 /* Stroke */
@@ -236,9 +237,17 @@ struct SculptPoseIKChain *SCULPT_pose_ik_chain_init(struct Sculpt *sd,
                                                     struct Brush *br,
                                                     const float initial_location[3],
                                                     const float radius);
-
 void SCULPT_pose_ik_chain_free(struct SculptPoseIKChain *ik_chain);
 
+/* Sculpt Visibility API */
+void sculpt_visibility_sync_all_face_sets_to_vertices(struct SculptSession *ss);
+void sculpt_visibility_sync_all_vertex_to_face_sets(struct SculptSession *ss);
+
+/* Dynamic topology */
+void sculpt_pbvh_clear(Object *ob);
+void sculpt_dyntopo_node_layers_add(struct SculptSession *ss);
+void sculpt_dynamic_topology_disable(bContext *C, struct SculptUndoNode *unode);
+
 /* Undo */
 
 typedef enum {
@@ -249,6 +258,7 @@ typedef enum {
   SCULPT_UNDO_DYNTOPO_END,
   SCULPT_UNDO_DYNTOPO_SYMMETRIZE,
   SCULPT_UNDO_GEOMETRY,
+  SCULPT_UNDO_FACE_SETS,
 } SculptUndoType;
 
 typedef struct SculptUndoNode {
@@ -298,6 +308,9 @@ typedef struct SculptUndoNode {
   float pivot_pos[3];
   float pivot_rot[4];
 
+  /* Sculpt Face Sets */
+  int *face_sets;
+
   size_t undo_size;
 } SculptUndoNode;
 
@@ -386,6 +399,7 @@ typedef struct SculptThreadedTaskData {
   bool mask_expand_invert_mask;
   bool mask_expand_use_normals;
   bool mask_expand_keep_prev_mask;
+  bool mask_expand_create_face_set;
 
   float transform_mats[8][4][4];
 
@@ -395,6 +409,8 @@ typedef struct SculptThreadedTaskData {
   float dirty_mask_max;
   bool dirty_mask_dirty_only;
 
+  int face_set;
+
   ThreadMutex mutex;
 
 } SculptThreadedTaskData;
@@ -528,6 +544,9 @@ typedef struct StrokeCache {
   bool is_rake_rotation_valid;
   struct SculptRakeData rake_data;
 
+  /* Face Sets */
+  int paint_face_set;
+
   /* Symmetry index between 0 and 7 bit combo 0 is Brush only;
    * 1 is X mirror; 2 is Y mirror; 3 is XY; 4 is Z; 5 is XZ; 6 is YZ; 7 is XYZ */
   int symmetry;
@@ -612,6 +631,11 @@ typedef struct FilterCache {
   float *edge_factor;
   float *prev_mask;
   float mask_expand_initial_co[3];
+
+  int new_face_set;
+  int *prev_face_set;
+
+  int active_face_set;
 } FilterCache;
 
 void sculpt_cache_calc_brushdata_symm(StrokeCache *cache,