Sculpt: New brush cursor, active vertex and normal radius

This commit includes the new brush cursor, active vertex updates and the normal radius brush property for all sculpt brushes.
  -The new brush cursor previews the real stroke radius over the mesh and the sampled sculpt normal.
  -The active vertex is used in sculpt tools and brushes as a starting point for an operation, similar to a preselection. It is also mirrored following the enabled symmetry options to preview the stroke symmetry.
  -The normal radius brush property limits the radius that is going to be used to sample the sculpt normal and area center. It controls how closely the cursor follows the surface and it improves the behavior of most brushes, making them suitable for hard surface sculpting.

Reviewed By: campbellbarton, brecht

Differential Revision: https://developer.blender.org/D3594

1 files changed, 13 insertions, 1 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_intern.h b/source/blender/editors/sculpt_paint/sculpt_intern.h
index bc9a4c1d85b..9f1cb7a53a4 100644
--- a/source/blender/editors/sculpt_paint/sculpt_intern.h
+++ b/source/blender/editors/sculpt_paint/sculpt_intern.h
@@ -45,7 +45,18 @@ bool sculpt_poll(struct bContext *C);
 bool sculpt_poll_view3d(struct bContext *C);
 
 /* Stroke */
+
+typedef struct SculptCursorGeometryInfo {
+  float location[3];
+  float normal[3];
+  float active_vertex_co[3];
+} SculptCursorGeometryInfo;
+
 bool sculpt_stroke_get_location(struct bContext *C, float out[3], const float mouse[2]);
+bool sculpt_cursor_geometry_info_update(bContext *C,
+                                        SculptCursorGeometryInfo *out,
+                                        const float mouse[2],
+                                        bool use_sampled_normal);
 
 /* Dynamic topology */
 void sculpt_pbvh_clear(Object *ob);
@@ -162,6 +173,7 @@ typedef struct SculptThreadedTaskData {
   float (*area_cos)[3];
   float (*area_nos)[3];
   int *count;
+  bool any_vertex_sampled;
 
   ThreadMutex mutex;
 
@@ -226,7 +238,7 @@ float tex_strength(struct SculptSession *ss,
                    const int thread_id);
 
 /* just for vertex paint. */
-void sculpt_pbvh_calc_area_normal(const struct Brush *brush,
+bool sculpt_pbvh_calc_area_normal(const struct Brush *brush,
                                   Object *ob,
                                   PBVHNode **nodes,
                                   int totnode,