Fix possible wrongly highlighted tiles

Run into it when was re-working tiles in the Cycles X project.
Make sure the storage of highlighted tiles is emptied when the
render is finished or cancelled).

The error is only possible to happen if the engine did not do
something correct, but is still good to deal with such situations
more gracefully.

1 files changed, 15 insertions, 0 deletions

diff --git a/source/blender/render/intern/pipeline.c b/source/blender/render/intern/pipeline.c
index bf42adbab87..0f9e1c944f5 100644
--- a/source/blender/render/intern/pipeline.c
+++ b/source/blender/render/intern/pipeline.c
@@ -1870,6 +1870,21 @@ static void render_pipeline_free(Render *re)
   }
   /* Destroy the opengl context in the correct thread. */
   RE_gl_context_destroy(re);
+
+  /* In the case the engine did not mark tiles as finished (un-highlight, which could happen in the
+   * case of cancelled render) ensure the storage is empty. */
+  if (re->highlighted_tiles != NULL) {
+    BLI_mutex_lock(&re->highlighted_tiles_mutex);
+
+    /* Rendering is supposed to be finished here, so no new tiles are expected to be written.
+     * Only make it so possible read-only access to the highlighted tiles is thread-safe. */
+    BLI_assert(re->highlighted_tiles);
+
+    BLI_gset_free(re->highlighted_tiles, MEM_freeN);
+    re->highlighted_tiles = NULL;
+
+    BLI_mutex_unlock(&re->highlighted_tiles_mutex);
+  }
 }
 
 /* general Blender frame render call */