Fix T62087: Crash when rendering in Cycles

The issue was discovered only after recent changes, but roots back
to much older changes.

What was happening is scene's ID recalc flags where never cleared,
which caused ensure_view_layer() to always run copy-on-write on the
scene. This resulted in certain runtime data being cleared, without
proper flag stored in the dependency graph.

This was caused by ID recalc clear function checking whether any ID
was tagged for recalc in that graph or not. This was happening due
to all areas using DEG_id_type_tag() which can only set flags on the
graph from viewport scenes, and could not inform render dependency
graph.

Now ID tyoe tagging is happening on per-graph level, which avoids
possibility of flags running out of sync.

In a bit longer term we also need to get rid of two functions which
are clearing flags: DEG_id_type_tag() and deg_graph_clear_tags().

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/depsgraph/DEG_depsgraph.h b/source/blender/depsgraph/DEG_depsgraph.h
index a7e2bcbe292..9770c7d49a3 100644
--- a/source/blender/depsgraph/DEG_depsgraph.h
+++ b/source/blender/depsgraph/DEG_depsgraph.h
@@ -126,6 +126,7 @@ void DEG_graph_id_tag_update(struct Main *bmain,
 /* Mark a particular datablock type as having changing. This does
  * not cause any updates but is used by external render engines to detect if for
  * example a datablock was removed. */
+void DEG_graph_id_type_tag(struct Depsgraph *depsgraph, short id_type);
 void DEG_id_type_tag(struct Main *bmain, short id_type);
 
 void DEG_ids_clear_recalc(struct Main *bmain, Depsgraph *depsgraph);