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, 7 deletions

diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index 8c356bc1600..c9f345b3123 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -786,12 +786,6 @@ static void view3d_main_region_free(ARegion *region)
       RE_engine_free(rv3d->render_engine);
     }
 
-    if (rv3d->depths) {
-      if (rv3d->depths->depths) {
-        MEM_freeN(rv3d->depths->depths);
-      }
-      MEM_freeN(rv3d->depths);
-    }
     if (rv3d->sms) {
       MEM_freeN(rv3d->sms);
     }
@@ -815,7 +809,6 @@ static void *view3d_main_region_duplicate(void *poin)
       new->clipbb = MEM_dupallocN(rv3d->clipbb);
     }
 
-    new->depths = NULL;
     new->render_engine = NULL;
     new->sms = NULL;
     new->smooth_timer = NULL;