Fix T63178 Eevee animation render crash

If image buffer is not loaded and blender attempts to reload it (during
`BKE_image_acquire_ibuf`) over and over for each frame rendered.
When attempting this reload, image_load_image_file is calling
`BKE_image_free_buffers` and tag the Image to the (GPU) image_free_queue
(because this run on the rendering thread).

If the main thread decide to redraw the UI and go through `GPU_free_unused_buffers` they all get deleted and if that happens before the rendering thread use them ... segfault.

If I replace the environment textures with correct ones (the file does not seems to contain them), there is no crash when rendering.

I used a list of GPUTexture from blender Image to increase and decrease the
reference counter correctly.

This add very little memory and computation overhead.

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/gpu/intern/gpu_viewport.c b/source/blender/gpu/intern/gpu_viewport.c
index 88b97ee2228..558b3f025a8 100644
--- a/source/blender/gpu/intern/gpu_viewport.c
+++ b/source/blender/gpu/intern/gpu_viewport.c
@@ -632,6 +632,15 @@ void GPU_viewport_free(GPUViewport *viewport)
   if (viewport->vmempool.passes != NULL) {
     BLI_mempool_destroy(viewport->vmempool.passes);
   }
+  if (viewport->vmempool.images != NULL) {
+    BLI_mempool_iter iter;
+    GPUTexture **tex;
+    BLI_mempool_iternew(viewport->vmempool.images, &iter);
+    while ((tex = BLI_mempool_iterstep(&iter))) {
+      GPU_texture_free(*tex);
+    }
+    BLI_mempool_destroy(viewport->vmempool.images);
+  }
 
   DRW_instance_data_list_free(viewport->idatalist);
   MEM_freeN(viewport->idatalist);