Images: refactor how failed image load attempts are remembered

Previously, `ImageTile->ok` and `ImageUser->ok` were used to indicate
whether an image failed to load. There were three possible values
which (probably) had the following meanings:
* `0`: There was an error while loading the image. Don't try to load again.
* `1`: Default value. Try to load the image.
* `2`: The image was loaded successfully.

This image-wide flag did not make sense unfortunately, because loading
may work for some frames of an image sequence but not for others.
Remember than an image data block can also contain a movie.

The purpose of the `->ok` flag was to serve as an optimization to avoid
trying to load a file over and over again when there is an error (e.g. the
file does not exist or is invalid). To get the optimization back, the patch
is changing `MovieCache` so that it can also cache failed load attempts.
As a consequence, `ibuf` is allowed to be `NULL` in a few more places.
I added the appropriate null checks.

This also solves issues when image sequences are used with the
Image Texture node in Geometry nodes (also see D12827).

Differential Revision: https://developer.blender.org/D12957

1 files changed, 3 insertions, 4 deletions

diff --git a/source/blender/blenkernel/intern/image_gpu.c b/source/blender/blenkernel/intern/image_gpu.c
index 9712e912bed..330af1cc505 100644
--- a/source/blender/blenkernel/intern/image_gpu.c
+++ b/source/blender/blenkernel/intern/image_gpu.c
@@ -373,15 +373,14 @@ static GPUTexture *image_get_gpu_texture(Image *ima,
   /* Check if image has been updated and tagged to be updated (full or partial). */
   ImageTile *tile = BKE_image_get_tile(ima, 0);
   if (((ima->gpuflag & IMA_GPU_REFRESH) != 0) ||
-      ((ibuf == NULL || tile == NULL || !tile->ok) &&
-       ((ima->gpuflag & IMA_GPU_PARTIAL_REFRESH) != 0))) {
+      ((ibuf == NULL || tile == NULL) && ((ima->gpuflag & IMA_GPU_PARTIAL_REFRESH) != 0))) {
     image_free_gpu(ima, true);
     BLI_freelistN(&ima->gpu_refresh_areas);
     ima->gpuflag &= ~(IMA_GPU_REFRESH | IMA_GPU_PARTIAL_REFRESH);
   }
   else if (ima->gpuflag & IMA_GPU_PARTIAL_REFRESH) {
     BLI_assert(ibuf);
-    BLI_assert(tile && tile->ok);
+    BLI_assert(tile);
     ImagePartialRefresh *refresh_area;
     while ((refresh_area = BLI_pophead(&ima->gpu_refresh_areas))) {
       const int tile_offset_x = refresh_area->tile_x * IMA_PARTIAL_REFRESH_TILE_SIZE;
@@ -417,7 +416,7 @@ static GPUTexture *image_get_gpu_texture(Image *ima,
 
   /* Check if we have a valid image. If not, we return a dummy
    * texture with zero bind-code so we don't keep trying. */
-  if (tile == NULL || tile->ok == 0) {
+  if (tile == NULL) {
     *tex = image_gpu_texture_error_create(textarget);
     return *tex;
   }