DrawManager: Hide lock acquire behind experimental feature.

The acquire locking of the draw manager introduced other issues.
The current implementation was a hacky solution as we know that the
final solution is something totally different {T98016}.

Related issues:
* {T97988}
* {T97600}

5 files changed, 9 insertions, 3 deletions

diff --git a/release/scripts/startup/bl_ui/space_userpref.py b/release/scripts/startup/bl_ui/space_userpref.py
index e0abb3a8d89..af56b966f17 100644
--- a/release/scripts/startup/bl_ui/space_userpref.py
+++ b/release/scripts/startup/bl_ui/space_userpref.py
@@ -2277,6 +2277,7 @@ class USERPREF_PT_experimental_prototypes(ExperimentalPanel, Panel):
                 ({"property": "use_new_point_cloud_type"}, "T75717"),
                 ({"property": "use_full_frame_compositor"}, "T88150"),
                 ({"property": "enable_eevee_next"}, "T93220"),
+                ({"property": "use_draw_manager_acquire_lock"}, "T98016"),
             ),
         )
 
diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 6ab8d30109e..4bbcf6eaf42 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -1287,7 +1287,7 @@ void DRW_notify_view_update(const DRWUpdateContext *update_ctx)
 
   const bool gpencil_engine_needed = drw_gpencil_engine_needed(depsgraph, v3d);
 
-  if (G.is_rendering) {
+  if (G.is_rendering && U.experimental.use_draw_manager_acquire_lock) {
     return;
   }
 
diff --git a/source/blender/makesdna/DNA_userdef_types.h b/source/blender/makesdna/DNA_userdef_types.h
index 3de6453bbaa..21abb632b94 100644
--- a/source/blender/makesdna/DNA_userdef_types.h
+++ b/source/blender/makesdna/DNA_userdef_types.h
@@ -650,7 +650,8 @@ typedef struct UserDef_Experimental {
   char use_override_templates;
   char enable_eevee_next;
   char use_sculpt_texture_paint;
-  char _pad0[2];
+  char use_draw_manager_acquire_lock;
+  char _pad0[1];
   /** `makesdna` does not allow empty structs. */
 } UserDef_Experimental;
 
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index 1a2017f2dbb..053353b41ba 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -6408,6 +6408,10 @@ static void rna_def_userdef_experimental(BlenderRNA *brna)
   RNA_def_property_boolean_sdna(prop, NULL, "use_sculpt_texture_paint", 1);
   RNA_def_property_ui_text(prop, "Sculpt Texture Paint", "Use texture painting in Sculpt Mode");
 
+  prop = RNA_def_property(srna, "use_draw_manager_acquire_lock", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "use_draw_manager_acquire_lock", 1);
+  RNA_def_property_ui_text(prop, "Draw Manager Locking", "Don't lock UI during background rendering");
+
   prop = RNA_def_property(srna, "use_extended_asset_browser", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_ui_text(prop,
                            "Extended Asset Browser",
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index 02da798495b..d2ade7b0376 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -467,7 +467,7 @@ static bool wm_draw_region_bind(bContext *C, ARegion *region, int view)
   }
 
   if (region->draw_buffer->viewport) {
-    if (G.is_rendering && C != NULL) {
+    if (G.is_rendering && C != NULL && U.experimental.use_draw_manager_acquire_lock) {
       Scene *scene = CTX_data_scene(C);
       RenderEngineType *render_engine_type = RE_engines_find(scene->r.engine);
       if (RE_engine_is_opengl(render_engine_type)) {