Fix missing GPU image free in background mode

This is legacy code from before Eevee and Workbench rendering in background
mode was supported. Avoid memory leak by only queueing GPU textures to be
freed when we know they have been allocated.

Differential Revision: https://developer.blender.org/D8172

1 files changed, 40 insertions, 33 deletions

diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index d768ce373b6..f07e3ed70d7 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -60,7 +60,8 @@
 
 #include "PIL_time.h"
 
-static void gpu_free_image_immediate(Image *ima);
+static void gpu_free_image(Image *ima, const bool immediate);
+static void gpu_free_unused_buffers(void);
 
 //* Checking powers of two for images since OpenGL ES requires it */
 #ifdef WITH_DDS
@@ -859,9 +860,13 @@ GPUTexture *GPU_texture_from_blender(Image *ima, ImageUser *iuser, ImBuf *ibuf,
     return NULL;
   }
 
+  /* Free any unused GPU textures, since we know we are in a thread with OpenGL
+   * context and might as well ensure we have as much space free as possible. */
+  gpu_free_unused_buffers();
+
   /* currently, gpu refresh tagging is used by ima sequences */
   if (ima->gpuflag & IMA_GPU_REFRESH) {
-    gpu_free_image_immediate(ima);
+    gpu_free_image(ima, true);
     ima->gpuflag &= ~IMA_GPU_REFRESH;
   }
 
@@ -1338,47 +1343,47 @@ void GPU_paint_update_image(Image *ima, ImageUser *iuser, int x, int y, int w, i
 #endif
 }
 
-static LinkNode *image_free_queue = NULL;
-static ThreadMutex img_queue_mutex = BLI_MUTEX_INITIALIZER;
+/* Delayed GPU texture free. Image datablocks can be deleted by any thread,
+ * but there may not be any active OpenGL context. In that case we push them
+ * into a queue and free the buffers later. */
+static LinkNode *gpu_texture_free_queue = NULL;
+static ThreadMutex gpu_texture_queue_mutex = BLI_MUTEX_INITIALIZER;
 
-static void gpu_queue_image_for_free(Image *ima)
+static void gpu_free_unused_buffers()
 {
-  BLI_mutex_lock(&img_queue_mutex);
-  BLI_linklist_prepend(&image_free_queue, ima);
-  BLI_mutex_unlock(&img_queue_mutex);
-}
-
-void GPU_free_unused_buffers(Main *bmain)
-{
-  if (!BLI_thread_is_main()) {
+  if (gpu_texture_free_queue == NULL) {
     return;
   }
 
-  BLI_mutex_lock(&img_queue_mutex);
-
-  /* images */
-  for (LinkNode *node = image_free_queue; node; node = node->next) {
-    Image *ima = node->link;
+  BLI_mutex_lock(&gpu_texture_queue_mutex);
 
-    /* check in case it was freed in the meantime */
-    if (bmain && BLI_findindex(&bmain->images, ima) != -1) {
-      GPU_free_image(ima);
+  if (gpu_texture_free_queue != NULL) {
+    for (LinkNode *node = gpu_texture_free_queue; node; node = node->next) {
+      GPUTexture *tex = node->link;
+      GPU_texture_free(tex);
     }
-  }
 
-  BLI_linklist_free(image_free_queue, NULL);
-  image_free_queue = NULL;
+    BLI_linklist_free(gpu_texture_free_queue, NULL);
+    gpu_texture_free_queue = NULL;
+  }
 
-  BLI_mutex_unlock(&img_queue_mutex);
+  BLI_mutex_unlock(&gpu_texture_queue_mutex);
 }
 
-static void gpu_free_image_immediate(Image *ima)
+static void gpu_free_image(Image *ima, const bool immediate)
 {
   for (int eye = 0; eye < 2; eye++) {
     for (int i = 0; i < TEXTARGET_COUNT; i++) {
-      /* free glsl image binding */
       if (ima->gputexture[i][eye] != NULL) {
-        GPU_texture_free(ima->gputexture[i][eye]);
+        if (immediate) {
+          GPU_texture_free(ima->gputexture[i][eye]);
+        }
+        else {
+          BLI_mutex_lock(&gpu_texture_queue_mutex);
+          BLI_linklist_prepend(&gpu_texture_free_queue, ima->gputexture[i][eye]);
+          BLI_mutex_unlock(&gpu_texture_queue_mutex);
+        }
+
         ima->gputexture[i][eye] = NULL;
       }
     }
@@ -1387,14 +1392,16 @@ static void gpu_free_image_immediate(Image *ima)
   ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
 }
 
-void GPU_free_image(Image *ima)
+void GPU_free_unused_buffers()
 {
-  if (!BLI_thread_is_main()) {
-    gpu_queue_image_for_free(ima);
-    return;
+  if (BLI_thread_is_main()) {
+    gpu_free_unused_buffers();
   }
+}
 
-  gpu_free_image_immediate(ima);
+void GPU_free_image(Image *ima)
+{
+  gpu_free_image(ima, BLI_thread_is_main());
 }
 
 void GPU_free_images(Main *bmain)