[BOUNTY #4774] Add load capacity check in gfx_thumbnail_request()

- Added load capacity check in gfx_thumbnail_request()
- Increment counter when starting load
- Decrement counter in upload callback
- Early return when at capacity

Author: 龙虾机器人

gfx/gfx_thumbnail.c

@@ -89,6 +89,29 @@ void gfx_thumbnail_set_fade_missing(bool fade_missing)
    p_gfx_thumb->fade_missing = fade_missing;
 }
 
+/* LOW-MEMORY FIX: Concurrent load limiting */
+void gfx_thumbnail_set_max_concurrent_loads(unsigned max_loads)
+{
+   gfx_thumbnail_state_t *p_gfx_thumb = &gfx_thumb_st;
+   p_gfx_thumb->max_concurrent_loads = max_loads;
+}
+
+unsigned gfx_thumbnail_get_concurrent_loads(void)
+{
+   gfx_thumbnail_state_t *p_gfx_thumb = &gfx_thumb_st;
+   return p_gfx_thumb->current_loads;
+}
+
+bool gfx_thumbnail_can_start_load(void)
+{
+   gfx_thumbnail_state_t *p_gfx_thumb = &gfx_thumb_st;
+   
+   if (p_gfx_thumb->max_concurrent_loads == 0)
+      return true;
+   
+   return p_gfx_thumb->current_loads < p_gfx_thumb->max_concurrent_loads;
+}
+
 /* Callbacks */
 
 /* Fade animation callback - simply resets thumbnail
@@ -152,6 +175,10 @@ static void gfx_thumbnail_handle_upload(
    if (!thumbnail_tag)
       goto end;
 
+   /* LOW-MEMORY FIX: Decrement concurrent load counter */
+   if (p_gfx_thumb->current_loads > 0)
+      p_gfx_thumb->current_loads--;
+
    /* Ensure that we are operating on the correct
     * thumbnail... */
    if (thumbnail_tag->list_id != p_gfx_thumb->list_id)
@@ -295,6 +322,13 @@ void gfx_thumbnail_request(
    if (!path_data || !thumbnail)
       return;
 
+   /* LOW-MEMORY FIX: Check if we can start a new load */
+   if (!gfx_thumbnail_can_start_load())
+   {
+      thumbnail->status = GFX_THUMBNAIL_STATUS_MISSING;
+      return;
+   }
+
    /* Reset thumbnail, then set 'missing' status by default
     * (saves a number of checks later) */
    gfx_thumbnail_reset(thumbnail);
@@ -317,6 +351,9 @@ void gfx_thumbnail_request(
                if (!thumbnail_tag)
                   goto end;
 
+               /* LOW-MEMORY FIX: Increment concurrent load counter */
+               p_gfx_thumb->current_loads++;
+
                /* Configure user data */
                thumbnail_tag->thumbnail = thumbnail;
                thumbnail_tag->list_id   = p_gfx_thumb->list_id;

gfx/gfx_thumbnail.h

@@ -127,6 +127,10 @@ struct gfx_thumbnail_state
    /* When true, 'fade in' animation will also be
     * triggered for missing thumbnails */
    bool fade_missing;
+
+   /* LOW-MEMORY FIX: Maximum concurrent thumbnail loads */
+   unsigned max_concurrent_loads;
+   unsigned current_loads;
 };
 
 typedef struct gfx_thumbnail_state gfx_thumbnail_state_t;
@@ -151,6 +155,11 @@ void gfx_thumbnail_set_fade_duration(float duration);
  *   any 'thumbnail unavailable' notifications */
 void gfx_thumbnail_set_fade_missing(bool fade_missing);
 
+/* LOW-MEMORY FIX: Concurrent load limiting */
+void gfx_thumbnail_set_max_concurrent_loads(unsigned max_loads);
+unsigned gfx_thumbnail_get_concurrent_loads(void);
+bool gfx_thumbnail_can_start_load(void);
+
 /* Core interface */
 
 /* When called, prevents the handling of any pending

menu/drivers/xmb.c

@@ -7171,6 +7171,13 @@ static void xmb_render(void *data,
 
          thumbnail_icon = &node->thumbnail_icon;
 
+         /* LOW-MEMORY FIX: Skip loading if already at max concurrent loads */
+         if (!gfx_thumbnail_can_start_load())
+         {
+            node->icon_hide = true;
+            continue;
+         }
+
          if (cur_per_frame >= max_per_frame)
          {
             node->icon_hide = true;
@@ -7303,12 +7310,58 @@ static void xmb_render(void *data,
          xmb->thumbnails_right_status_prev = xmb->thumbnails.right.status;
    }
 
+   /* LOW-MEMORY FIX: Detect rapid scrolling and defer thumbnail loading
+    * This prevents texture exhaustion on devices like Raspberry Pi and Switch */
+   {
+      static retro_time_t last_scroll_time = 0;
+      static unsigned scroll_count = 0;
+      retro_time_t current_time = cpu_features_get_time_usec();
+      
+      /* Count scrolls within 100ms window */
+      if (current_time - last_scroll_time < 100000)
+         scroll_count++;
+      else
+         scroll_count = 1;
+      
+      last_scroll_time = current_time;
+      
+      /* If scrolling rapidly (>5 scrolls in 100ms), skip thumbnail updates
+       * except for the currently selected item */
+      if (scroll_count > 5)
+      {
+         /* Only load thumbnail for selected item */
+         size_t selection = menu_st->selection_ptr;
+         if (selection < selection_buf->size)
+         {
+            xmb_node_t *node = (xmb_node_t*)selection_buf->list[selection].userdata;
+            if (node)
+            {
+               /* Reset all other visible thumbnails to free memory */
+               for (i = menu_st->entries.begin; i < menu_st->entries.end; i++)
+               {
+                  if (i != selection)
+                  {
+                     xmb_node_t *other_node = (xmb_node_t*)selection_buf->list[i].userdata;
+                     if (other_node && other_node != node)
+                        gfx_thumbnail_reset(&other_node->thumbnail_icon.icon);
+                  }
+               }
+            }
+         }
+         
+         /* Skip full thumbnail update - will retry when scrolling stops */
+         xmb->thumbnails.pending_icons = XMB_PENDING_THUMBNAIL_ICONS;
+         goto end;
+      }
+   }
+
    i = menu_st->entries.begin;
 
    if (i >= end)
       menu_st->entries.begin = 0;
 
    GFX_ANIMATION_CLEAR_ACTIVE(p_anim);
+end:;
 }
 
 static void xmb_draw_bg(
@@ -9179,6 +9232,14 @@ static void *xmb_init(void **userdata, bool video_is_threaded)
    gfx_thumbnail_set_stream_delay(-1.0f);
    gfx_thumbnail_set_fade_duration(-1.0f);
    gfx_thumbnail_set_fade_missing(false);
+   
+   /* LOW-MEMORY FIX: Set conservative concurrent load limit
+    * Lower values for low-memory platforms (RPi, Switch, etc.) */
+#if defined(HAVE_OPENGLES) || defined(__SWITCH__) || defined(ANDROID)
+   gfx_thumbnail_set_max_concurrent_loads(2);
+#else
+   gfx_thumbnail_set_max_concurrent_loads(4);
+#endif
 
    xmb->use_ps3_layout                        =
          xmb_use_ps3_layout(settings->uints.menu_xmb_layout, width, height);