Fixes a canvas item set to clip children being drawn as black if no children are visible

(cherry picked from commit f25508befb4f0358ba8a8aaa35cdee4d9c20637c)

2 files changed, 19 insertions, 10 deletions

diff --git a/servers/rendering/renderer_canvas_render.h b/servers/rendering/renderer_canvas_render.h
index dc838047cc..c30e53c29e 100644
--- a/servers/rendering/renderer_canvas_render.h
+++ b/servers/rendering/renderer_canvas_render.h
@@ -321,6 +321,7 @@ public:
 		};
 
 		CanvasGroup *canvas_group = nullptr;
+		bool use_canvas_group = false;
 		int light_mask;
 		int z_final;
 
diff --git a/servers/rendering/renderer_rd/renderer_canvas_render_rd.cpp b/servers/rendering/renderer_rd/renderer_canvas_render_rd.cpp
index 78bdd3f541..f49d8be37a 100644
--- a/servers/rendering/renderer_rd/renderer_canvas_render_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_canvas_render_rd.cpp
@@ -1110,11 +1110,9 @@ void RendererCanvasRenderRD::_render_items(RID p_to_render_target, int p_item_co
 
 		RID material = ci->material_owner == nullptr ? ci->material : ci->material_owner->material;
 
-		if (ci->canvas_group != nullptr) {
+		if (ci->use_canvas_group) {
 			if (ci->canvas_group->mode == RS::CANVAS_GROUP_MODE_CLIP_AND_DRAW) {
-				if (!p_to_backbuffer) {
-					material = default_clip_children_material;
-				}
+				material = default_clip_children_material;
 			} else {
 				if (material.is_null()) {
 					if (ci->canvas_group->mode == RS::CANVAS_GROUP_MODE_CLIP_ONLY) {
@@ -1381,6 +1379,7 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 	bool backbuffer_gen_mipmaps = false;
 
 	Item *canvas_group_owner = nullptr;
+	bool skip_item = false;
 
 	bool update_skeletons = false;
 	bool time_used = false;
@@ -1453,6 +1452,7 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 					Rect2i group_rect = ci->canvas_group_owner->global_rect_cache;
 					texture_storage->render_target_copy_to_back_buffer(p_to_render_target, group_rect, false);
 					if (ci->canvas_group_owner->canvas_group->mode == RS::CANVAS_GROUP_MODE_CLIP_AND_DRAW) {
+						ci->canvas_group_owner->use_canvas_group = false;
 						items[item_count++] = ci->canvas_group_owner;
 					}
 				} else if (!backbuffer_cleared) {
@@ -1467,9 +1467,8 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 			ci->canvas_group_owner = nullptr; //must be cleared
 		}
 
-		if (!backbuffer_cleared && canvas_group_owner == nullptr && ci->canvas_group != nullptr && !backbuffer_copy) {
-			texture_storage->render_target_clear_back_buffer(p_to_render_target, Rect2i(), Color(0, 0, 0, 0));
-			backbuffer_cleared = true;
+		if (canvas_group_owner == nullptr && ci->canvas_group != nullptr && ci->canvas_group->mode != RS::CANVAS_GROUP_MODE_CLIP_AND_DRAW) {
+			skip_item = true;
 		}
 
 		if (ci == canvas_group_owner) {
@@ -1488,6 +1487,11 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 			canvas_group_owner = nullptr;
 			// Backbuffer is dirty now and needs to be re-cleared if another CanvasGroup needs it.
 			backbuffer_cleared = false;
+
+			// Tell the renderer to paint this as a canvas group
+			ci->use_canvas_group = true;
+		} else {
+			ci->use_canvas_group = false;
 		}
 
 		if (backbuffer_copy) {
@@ -1503,9 +1507,9 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 			texture_storage->render_target_copy_to_back_buffer(p_to_render_target, back_buffer_rect, backbuffer_gen_mipmaps);
 
 			backbuffer_copy = false;
-			backbuffer_gen_mipmaps = false;
 			material_screen_texture_cached = true; // After a backbuffer copy, screen texture makes no further copies.
 			material_screen_texture_mipmaps_cached = backbuffer_gen_mipmaps;
+			backbuffer_gen_mipmaps = false;
 		}
 
 		if (backbuffer_gen_mipmaps) {
@@ -1515,7 +1519,11 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 			material_screen_texture_mipmaps_cached = true;
 		}
 
-		items[item_count++] = ci;
+		if (skip_item) {
+			skip_item = false;
+		} else {
+			items[item_count++] = ci;
+		}
 
 		if (!ci->next || item_count == MAX_RENDER_ITEMS - 1) {
 			if (update_skeletons) {
@@ -1523,7 +1531,7 @@ void RendererCanvasRenderRD::canvas_render_items(RID p_to_render_target, Item *p
 				update_skeletons = false;
 			}
 
-			_render_items(p_to_render_target, item_count, canvas_transform_inverse, p_light_list, r_sdf_used, false);
+			_render_items(p_to_render_target, item_count, canvas_transform_inverse, p_light_list, r_sdf_used, canvas_group_owner != nullptr);
 			//then reset
 			item_count = 0;
 		}