Multires: Subdivide Simple and Subdivide Linear

This introduces two alternative subdivision modes that generates
displacement on the grids that look as Simple subdivisions but while
using the Catmull-Clark subdivision type in the modifier. This way,
Simple and Catmull-Clark subdivision can be combined when creating new
levels if needed, for example, to sculpt hard surface objects.

Subdivide simple smooths the sculpted data when creating a new
subdivision level. Subdivide linear also preserves the sharpness
in the sculpted data.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D7415

1 files changed, 14 insertions, 2 deletions

diff --git a/source/blender/blenkernel/BKE_multires.h b/source/blender/blenkernel/BKE_multires.h
index 62366f7952b..927aad287a6 100644
--- a/source/blender/blenkernel/BKE_multires.h
+++ b/source/blender/blenkernel/BKE_multires.h
@@ -180,13 +180,25 @@ bool multiresModifier_reshapeFromCCG(const int tot_level,
                                      struct SubdivCCG *subdiv_ccg);
 
 /* Subdivide multires displacement once. */
-void multiresModifier_subdivide(struct Object *object, struct MultiresModifierData *mmd);
+
+typedef enum eMultiresSubdivideModeType {
+  MULTIRES_SUBDIVIDE_CATMULL_CLARK,
+  MULTIRES_SUBDIVIDE_SIMPLE,
+  MULTIRES_SUBDIVIDE_LINEAR,
+} eMultiresSubdivideModeType;
+
+void multiresModifier_subdivide(struct Object *object,
+                                struct MultiresModifierData *mmd,
+                                const eMultiresSubdivideModeType mode);
+void multires_subdivide_create_tangent_displacement_linear_grids(struct Object *object,
+                                                                 struct MultiresModifierData *mmd);
 
 /* Subdivide displacement to the given level.
  * If level is lower than the current top level nothing happens. */
 void multiresModifier_subdivide_to_level(struct Object *object,
                                          struct MultiresModifierData *mmd,
-                                         const int top_level);
+                                         const int top_level,
+                                         const eMultiresSubdivideModeType mode);
 
 /* Subdivision integration, defined in multires_subdiv.c */