Sculpt: Opaque vertex type for sculpt

This is a port of sculpt-dev's `SculptVertRef` refactor
(note that `SculptVertRef was renamed to PBVHVertRef`)
to master. `PBVHVertRef` is a structure that abstracts
the concept of a vertex in the sculpt code; it's simply
an `intptr_t` wrapped in a struct.

For `PBVH_FACES` and `PBVH_GRIDS` this struct stores a
vertex index, but for `BMesh` it stores a direct pointer
to a BMVert.  The intptr_t is wrapped in a struct to prevent
the accidental usage of it as an index.

There are many reasons to do this:

* Right now `BMesh` verts are not logical sculpt verts;
  to use the sculpt API they must first be converted to indices.
  This requires a lot of indirect lookups into tables, leading to performance
  loss.  It has also led to greater code complexity and duplication.
* Having an abstract vertex type makes it feasible to have one unified
  temporary attribute API for all three PBVH modes, which in turn
  made it rather trivial to port sculpt brushes to DynTopo in
  sculpt-dev (e.g. the layer brush, draw sharp, the smooth brushes,
  the paint brushes, etc).  This attribute API will be in a future patch.
* We need to do this anyway for the eventual move to C++.

Differential Revision: https://developer.blender.org/D14272
Reviewed By: Brecht Van Lommel
Ref D14272

1 files changed, 12 insertions, 9 deletions

diff --git a/source/blender/blenkernel/BKE_paint.h b/source/blender/blenkernel/BKE_paint.h
index 162459d2005..8b9deadc960 100644
--- a/source/blender/blenkernel/BKE_paint.h
+++ b/source/blender/blenkernel/BKE_paint.h
@@ -13,6 +13,7 @@
 #include "DNA_object_enums.h"
 
 #include "BKE_attribute.h"
+#include "BKE_pbvh.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -397,7 +398,7 @@ typedef struct SculptVertexInfo {
 
 typedef struct SculptBoundaryEditInfo {
   /* Vertex index from where the topology propagation reached this vertex. */
-  int original_vertex;
+  int original_vertex_i;
 
   /* How many steps were needed to reach this vertex from the boundary. */
   int num_propagation_steps;
@@ -408,13 +409,14 @@ typedef struct SculptBoundaryEditInfo {
 
 /* Edge for drawing the boundary preview in the cursor. */
 typedef struct SculptBoundaryPreviewEdge {
-  int v1;
-  int v2;
+  PBVHVertRef v1;
+  PBVHVertRef v2;
 } SculptBoundaryPreviewEdge;
 
 typedef struct SculptBoundary {
   /* Vertex indices of the active boundary. */
-  int *vertices;
+  PBVHVertRef *vertices;
+  int *vertices_i;
   int vertices_capacity;
   int num_vertices;
 
@@ -432,12 +434,13 @@ typedef struct SculptBoundary {
   bool forms_loop;
 
   /* Initial vertex in the boundary which is closest to the current sculpt active vertex. */
-  int initial_vertex;
+  PBVHVertRef initial_vertex;
+  int initial_vertex_i;
 
   /* Vertex that at max_propagation_steps from the boundary and closest to the original active
    * vertex that was used to initialize the boundary. This is used as a reference to check how much
    * the deformation will go into the mesh and to calculate the strength of the brushes. */
-  int pivot_vertex;
+  PBVHVertRef pivot_vertex;
 
   /* Stores the initial positions of the pivot and boundary initial vertex as they may be deformed
    * during the brush action. This allows to use them as a reference positions and vectors for some
@@ -565,7 +568,7 @@ typedef struct SculptSession {
   struct ExpandCache *expand_cache;
 
   /* Cursor data and active vertex for tools */
-  int active_vertex_index;
+  PBVHVertRef active_vertex;
 
   int active_face_index;
   int active_grid_index;
@@ -591,8 +594,8 @@ typedef struct SculptSession {
   struct Scene *scene;
 
   /* Dynamic mesh preview */
-  int *preview_vert_index_list;
-  int preview_vert_index_count;
+  PBVHVertRef *preview_vert_list;
+  int preview_vert_count;
 
   /* Pose Brush Preview */
   float pose_origin[3];