Fix T98052: Eevee / Workbench background render crash with GPU subdivision

The problem is that depsgraph evaluation happens before the OpenGL context
is initialized, and so modifier evaluation happens without GPU subdivision.
Later the BKE_subsurf_modifier_can_do_gpu_subdiv test in the draw code gives
a different result.

This just checks if the mesh has information for GPU subdivision in the draw
code, and if so uses it. This is only set if the test for supported GPU
subdivision passes in the modifier evaluation.

Additionally it may be good to perform OpenGL context initialization earlier
so background render can take advantage of GPU subdivision, but this is more
complicated.

Differential Revision: https://developer.blender.org/D14969

source/blender/blenkernel/BKE_subdiv_modifier.h

@@ -42,18 +42,14 @@ bool BKE_subsurf_modifier_force_disable_gpu_evaluation_for_mesh(
  * \param skip_check_is_last: When true, we assume that the modifier passed is the last enabled
  * modifier in the stack.
  */
-bool BKE_subsurf_modifier_can_do_gpu_subdiv_ex(const struct Scene *scene,
-                                               const struct Object *ob,
-                                               const struct Mesh *mesh,
-                                               const struct SubsurfModifierData *smd,
-                                               int required_mode,
-                                               bool skip_check_is_last);
-
 bool BKE_subsurf_modifier_can_do_gpu_subdiv(const struct Scene *scene,
                                             const struct Object *ob,
                                             const struct Mesh *mesh,
+                                            const struct SubsurfModifierData *smd,
                                             int required_mode);
 
+bool BKE_subsurf_modifier_has_gpu_subdiv(const struct Mesh *mesh);
+
 extern void (*BKE_subsurf_modifier_free_gpu_cache_cb)(struct Subdiv *subdiv);
 
 /**

source/blender/blenkernel/intern/subdiv_modifier.c

@@ -3,6 +3,8 @@
 
 #include "BKE_subdiv_modifier.h"
 
+#include "BLI_session_uuid.h"
+
 #include "MEM_guardedalloc.h"
 
 #include "DNA_mesh_types.h"
@@ -105,12 +107,11 @@ bool BKE_subsurf_modifier_force_disable_gpu_evaluation_for_mesh(const SubsurfMod
   return subsurf_modifier_use_autosmooth_or_split_normals(smd, mesh);
 }
 
-bool BKE_subsurf_modifier_can_do_gpu_subdiv_ex(const Scene *scene,
+bool BKE_subsurf_modifier_can_do_gpu_subdiv(const Scene *scene,
-                                               const Object *ob,
+                                            const Object *ob,
-                                               const Mesh *mesh,
+                                            const Mesh *mesh,
-                                               const SubsurfModifierData *smd,
+                                            const SubsurfModifierData *smd,
-                                               int required_mode,
+                                            int required_mode)
-                                               bool skip_check_is_last)
 {
   if ((U.gpu_flag & USER_GPU_FLAG_SUBDIVISION_EVALUATION) == 0) {
     return false;
@@ -122,33 +123,17 @@ bool BKE_subsurf_modifier_can_do_gpu_subdiv_ex(const Scene *scene,
     return false;
   }
 
-  if (!skip_check_is_last) {
+  ModifierData *md = modifier_get_last_enabled_for_mode(scene, ob, required_mode);
-    ModifierData *md = modifier_get_last_enabled_for_mode(scene, ob, required_mode);
+  if (md != (const ModifierData *)smd) {
-    if (md != (const ModifierData *)smd) {
+    return false;
-      return false;
-    }
   }
 
   return is_subdivision_evaluation_possible_on_gpu();
 }
 
-bool BKE_subsurf_modifier_can_do_gpu_subdiv(const Scene *scene,
+bool BKE_subsurf_modifier_has_gpu_subdiv(const Mesh *mesh)
-                                            const Object *ob,
-                                            const Mesh *mesh,
-                                            int required_mode)
 {
-  ModifierData *md = modifier_get_last_enabled_for_mode(scene, ob, required_mode);
+  return BLI_session_uuid_is_generated(&mesh->runtime.subsurf_session_uuid);
-
-  if (!md) {
-    return false;
-  }
-
-  if (md->type != eModifierType_Subsurf) {
-    return false;
-  }
-
-  return BKE_subsurf_modifier_can_do_gpu_subdiv_ex(
-      scene, ob, mesh, (SubsurfModifierData *)md, required_mode, true);
 }
 
 void (*BKE_subsurf_modifier_free_gpu_cache_cb)(Subdiv *subdiv) = NULL;

source/blender/draw/intern/draw_cache_impl_mesh.c

@@ -1822,9 +1822,7 @@ void DRW_mesh_batch_cache_create_requested(struct TaskGraph *task_graph,
     do_uvcage = !editmesh_eval_final->runtime.is_original;
   }
 
-  const int required_mode = BKE_subsurf_modifier_eval_required_mode(DRW_state_is_scene_render(),
+  const bool do_subdivision = BKE_subsurf_modifier_has_gpu_subdiv(me);
-                                                                    is_editmode);
-  const bool do_subdivision = BKE_subsurf_modifier_can_do_gpu_subdiv(scene, ob, me, required_mode);
 
   MeshBufferList *mbuflist = &cache->final.buff;
 

source/blender/modifiers/intern/MOD_subsurf.c

@@ -236,8 +236,7 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
      * assigned at this stage of modifier stack evaluation. */
     const bool is_editmode = (mesh->edit_mesh != NULL);
     const int required_mode = BKE_subsurf_modifier_eval_required_mode(is_render_mode, is_editmode);
-    if (BKE_subsurf_modifier_can_do_gpu_subdiv_ex(
+    if (BKE_subsurf_modifier_can_do_gpu_subdiv(scene, ctx->object, mesh, smd, required_mode)) {
-            scene, ctx->object, mesh, smd, required_mode, false)) {
       subdiv_cache_cpu_evaluation_settings(ctx, mesh, smd);
       return result;
     }