Tweak API to support adding evaluated meshes to main database

One of the usecases is to create mesh from an object is a manner similar to
how Apply Modifiers does it, and have it in the bmain so it can be referenced
by other objects.

This usecase is something what went unnoticed in the previous API changes, so
here is a followup.

Summary of changes:

* bpy.meshes.new_from_object() behaves almost the same as before this change.
  The difference now is that it now ensures all referenced data-blocks are
	original (for example, materials referenced by the mesh).

* object.to_mesh() now creates free-standing Mesh data-block which is outside
  of any bmain. The object owns it, which guarantees the memory never leaks.

  It is possible to force free memory by calling object.to_mesh_clear().

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D4875

1 files changed, 7 insertions, 5 deletions

diff --git a/intern/cycles/blender/blender_util.h b/intern/cycles/blender/blender_util.h
index 2a964d0e4d0..972d7296727 100644
--- a/intern/cycles/blender/blender_util.h
+++ b/intern/cycles/blender/blender_util.h
@@ -43,7 +43,7 @@ CCL_NAMESPACE_BEGIN
 void python_thread_state_save(void **python_thread_state);
 void python_thread_state_restore(void **python_thread_state);
 
-static inline BL::Mesh object_to_mesh(BL::BlendData &data,
+static inline BL::Mesh object_to_mesh(BL::BlendData & /*data*/,
                                       BL::Object &object,
                                       BL::Depsgraph & /*depsgraph*/,
                                       bool /*calc_undeformed*/,
@@ -75,11 +75,11 @@ static inline BL::Mesh object_to_mesh(BL::BlendData &data,
      * UV are not empty. */
     if (mesh.is_editmode() ||
         (mesh.use_auto_smooth() && subdivision_type == Mesh::SUBDIVISION_NONE)) {
-      mesh = data.meshes.new_from_object(object);
+      mesh = object.to_mesh();
     }
   }
   else {
-    mesh = data.meshes.new_from_object(object);
+    mesh = object.to_mesh();
   }
 
 #if 0
@@ -102,11 +102,13 @@ static inline BL::Mesh object_to_mesh(BL::BlendData &data,
   return mesh;
 }
 
-static inline void free_object_to_mesh(BL::BlendData &data, BL::Object &object, BL::Mesh &mesh)
+static inline void free_object_to_mesh(BL::BlendData & /*data*/,
+                                       BL::Object &object,
+                                       BL::Mesh &mesh)
 {
   /* Free mesh if we didn't just use the existing one. */
   if (object.data().ptr.data != mesh.ptr.data) {
-    data.meshes.remove(mesh, false, true, false);
+    object.to_mesh_clear();
   }
 }