Fix #139986: Cycles crash on some scene updates, after Embree upgrade

Device::const_copy_to is sometimes called when the Embree BVH has been freed
and not replaced yet. Previously this was a simpler pointer copy, now there is
a function call. Make sure it's just a function copy.

Thanks to Nikita Sirgienko for figuring this out.

Pull Request: https://projects.blender.org/blender/blender/pulls/140457

intern/cycles/device/cpu/device_impl.cpp

@@ -187,15 +187,11 @@ void CPUDevice::const_copy_to(const char *name, void *host, const size_t size)
   if (strcmp(name, "data") == 0) {
     assert(size <= sizeof(KernelData));
 
-    // Update scene handle (since it is different for each device on multi devices)
+    /* Update scene handle (since it is different for each device on multi devices).
+     * This must be a raw pointer copy since at some points during scene update this
+     * pointer may be invalid. */
     KernelData *const data = (KernelData *)host;
-    data->device_bvh =
-#  if RTC_VERSION >= 40400
-        rtcGetSceneTraversable(embree_scene)
-#  else
-        embree_scene
-#  endif
-        ;
+    data->device_bvh = embree_traversable;
   }
 #endif
   kernel_const_copy(&kernel_globals, name, host, size);
@@ -272,7 +268,11 @@ void CPUDevice::build_bvh(BVH *bvh, Progress &progress, bool refit)
     }
 
     if (bvh->params.top_level) {
-      embree_scene = bvh_embree->scene;
+#  if RTC_VERSION >= 40400
+      embree_traversable = rtcGetSceneTraversable(bvh_embree->scene);
+#  else
+      embree_traversable = bvh_embree->scene;
+#  endif
     }
   }
   else

intern/cycles/device/cpu/device_impl.h

@@ -45,7 +45,11 @@ class CPUDevice : public Device {
   OSLGlobals osl_globals;
 #endif
 #ifdef WITH_EMBREE
-  RTCScene embree_scene = nullptr;
+#  if RTC_VERSION >= 40400
+  RTCTraversable embree_traversable = nullptr;
+#  else
+  RTCScene embree_traversable = nullptr;
+#  endif
   RTCDevice embree_device;
 #endif
 #ifdef WITH_PATH_GUIDING

intern/cycles/device/oneapi/device_impl.cpp

@@ -181,7 +181,11 @@ void OneapiDevice::build_bvh(BVH *bvh, Progress &progress, bool refit)
 #    endif
 
     if (bvh->params.top_level) {
-      embree_scene = bvh_embree->scene;
+#    if RTC_VERSION >= 40400
+      embree_traversable = rtcGetSceneTraversable(bvh_embree->scene);
+#    else
+      embree_traversable = bvh_embree->scene;
+#    endif
 #    if RTC_VERSION >= 40302
       RTCError error_code = bvh_embree->offload_scenes_to_gpu(all_embree_scenes);
       if (error_code != RTC_ERROR_NONE) {
@@ -585,18 +589,14 @@ void OneapiDevice::const_copy_to(const char *name, void *host, const size_t size
              << string_human_readable_size(size) << ")";
 
 #  ifdef WITH_EMBREE_GPU
-  if (embree_scene != nullptr && strcmp(name, "data") == 0) {
+  if (embree_traversable != nullptr && strcmp(name, "data") == 0) {
     assert(size <= sizeof(KernelData));
 
-    /* Update scene handle(since it is different for each device on multi devices) */
+    /* Update scene handle(since it is different for each device on multi devices).
+     * This must be a raw pointer copy since at some points during scene update this
+     * pointer may be invalid. */
     KernelData *const data = (KernelData *)host;
-    data->device_bvh =
-#    if RTC_VERSION >= 40400
-        rtcGetSceneTraversable(embree_scene)
-#    else
-        embree_scene
-#    endif
-        ;
+    data->device_bvh = embree_traversable;
 
     /* We need this number later for proper local memory allocation. */
     scene_max_shaders_ = data->max_shaders;

intern/cycles/device/oneapi/device_impl.h

@@ -23,7 +23,11 @@ class OneapiDevice : public GPUDevice {
   SyclQueue *device_queue_ = nullptr;
 #  ifdef WITH_EMBREE_GPU
   RTCDevice embree_device = nullptr;
-  RTCScene embree_scene = nullptr;
+#    if RTC_VERSION >= 40400
+  RTCTraversable embree_traversable = nullptr;
+#    else
+  RTCScene embree_traversable = nullptr;
+#    endif
 #    if RTC_VERSION >= 40302
   thread_mutex scene_data_mutex;
   vector<RTCScene> all_embree_scenes;