Refactor: Do not keep a copy of depth buffer in RegionView3D

The depth cache (located in `RegionView3D::depths`) is used for quick
and simple occlusion testing in:
- particle selection,
- "Draw Curve" operator and
- "Interactive Light Track to Cursor" operator,

However, keeping a texture buffer in cache is not a recommended practice.

For displays with high resolution like 8k this represents something
around 132MB.

Also, currently, each call to `ED_view3d_depth_override` invalidates
the depth cache. So that depth is never reused in multiple calls from
an operator (this was not the case in blender 2.79).

This commit allows to create a depth cache and release it in the same
operator. Thus, the buffer is kept in cache for a short time, freeing
up space.

No functional changes.

1 files changed, 0 insertions, 1 deletions

diff --git a/source/blender/makesdna/DNA_view3d_types.h b/source/blender/makesdna/DNA_view3d_types.h
index fa738c647bb..41350c128ae 100644
--- a/source/blender/makesdna/DNA_view3d_types.h
+++ b/source/blender/makesdna/DNA_view3d_types.h
@@ -72,7 +72,6 @@ typedef struct RegionView3D {
   /** Allocated backup of its self while in localview. */
   struct RegionView3D *localvd;
   struct RenderEngine *render_engine;
-  struct ViewDepths *depths;
 
   /** Animated smooth view. */
   struct SmoothView3DStore *sms;