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, 9 insertions, 10 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_cursor.c b/source/blender/editors/sculpt_paint/paint_cursor.c
index c5ebcf870a3..577540725af 100644
--- a/source/blender/editors/sculpt_paint/paint_cursor.c
+++ b/source/blender/editors/sculpt_paint/paint_cursor.c
@@ -1145,11 +1145,10 @@ static void sculpt_geometry_preview_lines_draw(const uint gpuattr,
   }
 
   GPU_line_width(1.0f);
-  if (ss->preview_vert_index_count > 0) {
-    immBegin(GPU_PRIM_LINES, ss->preview_vert_index_count);
-    for (int i = 0; i < ss->preview_vert_index_count; i++) {
-      immVertex3fv(gpuattr,
-                   SCULPT_vertex_co_for_grab_active_get(ss, ss->preview_vert_index_list[i]));
+  if (ss->preview_vert_count > 0) {
+    immBegin(GPU_PRIM_LINES, ss->preview_vert_count);
+    for (int i = 0; i < ss->preview_vert_count; i++) {
+      immVertex3fv(gpuattr, SCULPT_vertex_co_for_grab_active_get(ss, ss->preview_vert_list[i]));
     }
     immEnd();
   }
@@ -1209,7 +1208,7 @@ typedef struct PaintCursorContext {
   /* Sculpt related data. */
   Sculpt *sd;
   SculptSession *ss;
-  int prev_active_vertex_index;
+  PBVHVertRef prev_active_vertex;
   bool is_stroke_active;
   bool is_cursor_over_mesh;
   bool is_multires;
@@ -1366,7 +1365,7 @@ static void paint_cursor_sculpt_session_update_and_init(PaintCursorContext *pcon
 
   /* This updates the active vertex, which is needed for most of the Sculpt/Vertex Colors tools to
    * work correctly */
-  pcontext->prev_active_vertex_index = ss->active_vertex_index;
+  pcontext->prev_active_vertex = ss->active_vertex;
   if (!ups->stroke_active) {
     pcontext->is_cursor_over_mesh = SCULPT_cursor_geometry_info_update(
         C, &gi, mval_fl, (pcontext->brush->falloff_shape == PAINT_FALLOFF_SHAPE_SPHERE));
@@ -1549,7 +1548,7 @@ static void paint_cursor_preview_boundary_data_update(PaintCursorContext *pconte
   }
 
   ss->boundary_preview = SCULPT_boundary_data_init(
-      pcontext->vc.obact, pcontext->brush, ss->active_vertex_index, pcontext->radius);
+      pcontext->vc.obact, pcontext->brush, ss->active_vertex, pcontext->radius);
 }
 
 static void paint_cursor_draw_3d_view_brush_cursor_inactive(PaintCursorContext *pcontext)
@@ -1575,8 +1574,8 @@ static void paint_cursor_draw_3d_view_brush_cursor_inactive(PaintCursorContext *
 
   paint_cursor_update_object_space_radius(pcontext);
 
-  const bool update_previews = pcontext->prev_active_vertex_index !=
-                               SCULPT_active_vertex_get(pcontext->ss);
+  const bool update_previews = pcontext->prev_active_vertex.i !=
+                               SCULPT_active_vertex_get(pcontext->ss).i;
 
   /* Setup drawing. */
   wmViewport(&pcontext->region->winrct);