render: make wlr_renderer_begin return a bool

include/wlr/render/wlr_renderer.h

@@ -49,8 +49,10 @@ struct wlr_renderer *wlr_renderer_autocreate(struct wlr_backend *backend);
  *
  * This should be called after wlr_output_attach_render(). Compositors must call
  * wlr_renderer_end() when they are done.
+ *
+ * Returns false on failure, in which case compositors shouldn't try rendering.
  */
-void wlr_renderer_begin(struct wlr_renderer *r, uint32_t width, uint32_t height);
+bool wlr_renderer_begin(struct wlr_renderer *r, uint32_t width, uint32_t height);
 /**
  * Start a render pass on the provided struct wlr_buffer.
  *

render/wlr_renderer.c

@@ -70,12 +70,15 @@ bool renderer_bind_buffer(struct wlr_renderer *r, struct wlr_buffer *buffer) {
 	return r->impl->bind_buffer(r, buffer);
 }
 
-void wlr_renderer_begin(struct wlr_renderer *r, uint32_t width, uint32_t height) {
+bool wlr_renderer_begin(struct wlr_renderer *r, uint32_t width, uint32_t height) {
 	assert(!r->rendering);
 
-	r->impl->begin(r, width, height);
+	if (!r->impl->begin(r, width, height)) {
+		return false;
+	}
 
 	r->rendering = true;
+	return true;
 }
 
 bool wlr_renderer_begin_with_buffer(struct wlr_renderer *r,
@@ -83,7 +86,10 @@ bool wlr_renderer_begin_with_buffer(struct wlr_renderer *r,
 	if (!renderer_bind_buffer(r, buffer)) {
 		return false;
 	}
-	wlr_renderer_begin(r, buffer->width, buffer->height);
+	if (!wlr_renderer_begin(r, buffer->width, buffer->height)) {
+		renderer_bind_buffer(r, NULL);
+		return false;
+	}
 	r->rendering_with_buffer = true;
 	return true;
 }