Fix T66262: slow preview icon loading

4 files changed, 25 insertions, 15 deletions

diff --git a/source/blender/editors/include/ED_render.h b/source/blender/editors/include/ED_render.h
index 7689a9f97cd..d36d2559f26 100644
--- a/source/blender/editors/include/ED_render.h
+++ b/source/blender/editors/include/ED_render.h
@@ -93,7 +93,8 @@ void ED_preview_icon_job(const struct bContext *C,
                          struct ID *id,
                          unsigned int *rect,
                          int sizex,
-                         int sizey);
+                         int sizey,
+                         const bool delay);
 void ED_preview_kill_jobs(struct wmWindowManager *wm, struct Main *bmain);
 
 void ED_preview_draw(const struct bContext *C, void *idp, void *parentp, void *slot, rcti *rect);
diff --git a/source/blender/editors/interface/interface_icons.c b/source/blender/editors/interface/interface_icons.c
index 6f1f4dde1ab..59889e74230 100644
--- a/source/blender/editors/interface/interface_icons.c
+++ b/source/blender/editors/interface/interface_icons.c
@@ -1417,11 +1417,13 @@ static void icon_set_image(const bContext *C,
     return;
   }
 
+  const bool delay = prv_img->rect[size] != NULL;
   icon_create_rect(prv_img, size);
 
   if (use_job) {
     /* Job (background) version */
-    ED_preview_icon_job(C, prv_img, id, prv_img->rect[size], prv_img->w[size], prv_img->h[size]);
+    ED_preview_icon_job(
+        C, prv_img, id, prv_img->rect[size], prv_img->w[size], prv_img->h[size], delay);
   }
   else {
     if (!scene) {
diff --git a/source/blender/editors/render/render_internal.c b/source/blender/editors/render/render_internal.c
index 352593a15ad..9ac93f07300 100644
--- a/source/blender/editors/render/render_internal.c
+++ b/source/blender/editors/render/render_internal.c
@@ -914,7 +914,6 @@ static int screen_render_invoke(bContext *C, wmOperator *op, const wmEvent *even
   wmJob *wm_job;
   RenderJob *rj;
   Image *ima;
-  int jobflag;
   const bool is_animation = RNA_boolean_get(op->ptr, "animation");
   const bool is_write_still = RNA_boolean_get(op->ptr, "write_still");
   const bool use_viewport = RNA_boolean_get(op->ptr, "use_viewport");
@@ -973,12 +972,6 @@ static int screen_render_invoke(bContext *C, wmOperator *op, const wmEvent *even
   /* ensure at least 1 area shows result */
   sa = render_view_open(C, event->x, event->y, op->reports);
 
-  jobflag = WM_JOB_EXCL_RENDER | WM_JOB_PRIORITY | WM_JOB_PROGRESS;
-
-  if (RNA_struct_property_is_set(op->ptr, "layer")) {
-    jobflag |= WM_JOB_SUSPEND;
-  }
-
   /* job custom data */
   rj = MEM_callocN(sizeof(RenderJob), "render job");
   rj->main = bmain;
@@ -1038,12 +1031,20 @@ static int screen_render_invoke(bContext *C, wmOperator *op, const wmEvent *even
     name = "Render";
   }
 
-  wm_job = WM_jobs_get(
-      CTX_wm_manager(C), CTX_wm_window(C), scene, name, jobflag, WM_JOB_TYPE_RENDER);
+  wm_job = WM_jobs_get(CTX_wm_manager(C),
+                       CTX_wm_window(C),
+                       scene,
+                       name,
+                       WM_JOB_EXCL_RENDER | WM_JOB_PRIORITY | WM_JOB_PROGRESS,
+                       WM_JOB_TYPE_RENDER);
   WM_jobs_customdata_set(wm_job, rj, render_freejob);
   WM_jobs_timer(wm_job, 0.2, NC_SCENE | ND_RENDER_RESULT, 0);
   WM_jobs_callbacks(wm_job, render_startjob, NULL, NULL, render_endjob);
 
+  if (RNA_struct_property_is_set(op->ptr, "layer")) {
+    WM_jobs_delay_start(wm_job, 0.2);
+  }
+
   /* get a render result image, and make sure it is empty */
   ima = BKE_image_verify_viewer(bmain, IMA_TYPE_R_RESULT, "Render Result");
   BKE_image_signal(rj->main, ima, NULL, IMA_SIGNAL_FREE);
diff --git a/source/blender/editors/render/render_preview.c b/source/blender/editors/render/render_preview.c
index c6b1acfbd94..fbabdc2f3c1 100644
--- a/source/blender/editors/render/render_preview.c
+++ b/source/blender/editors/render/render_preview.c
@@ -1340,8 +1340,13 @@ void ED_preview_icon_render(
   BLI_freelistN(&ip.sizes);
 }
 
-void ED_preview_icon_job(
-    const bContext *C, void *owner, ID *id, unsigned int *rect, int sizex, int sizey)
+void ED_preview_icon_job(const bContext *C,
+                         void *owner,
+                         ID *id,
+                         unsigned int *rect,
+                         int sizex,
+                         int sizey,
+                         const bool delay)
 {
   wmJob *wm_job;
   IconPreview *ip, *old_ip;
@@ -1353,7 +1358,7 @@ void ED_preview_icon_job(
                        CTX_wm_window(C),
                        owner,
                        "Icon Preview",
-                       WM_JOB_EXCL_RENDER | WM_JOB_SUSPEND,
+                       WM_JOB_EXCL_RENDER,
                        WM_JOB_TYPE_RENDER_PREVIEW);
 
   ip = MEM_callocN(sizeof(IconPreview), "icon preview");
@@ -1385,10 +1390,11 @@ void ED_preview_icon_job(
 
   /* setup job */
   WM_jobs_customdata_set(wm_job, ip, icon_preview_free);
+  WM_jobs_timer(wm_job, 0.1, NC_WINDOW, NC_WINDOW);
   /* Wait 2s to start rendering icon previews, to not bog down user interaction.
    * Particularly important for heavy scenes and Eevee using OpenGL that blocks
    * the user interface drawing. */
-  WM_jobs_timer(wm_job, 2.0, NC_WINDOW, NC_WINDOW);
+  WM_jobs_delay_start(wm_job, (delay) ? 2.0 : 0.0);
   WM_jobs_callbacks(wm_job, icon_preview_startjob_all_sizes, NULL, NULL, icon_preview_endjob);
 
   WM_jobs_start(CTX_wm_manager(C), wm_job);