presentation-time: add separate helper for zero-copy

The backend is not able to tell whether a surface is being
presented via direct scan-out or not. The backend will set
ZERO_COPY if the buffer submitted via the output commit was
presented in a zero-copy fashion, but will no know whether the
buffer comes from the compositor or the client.

include/wlr/types/wlr_presentation_time.h

@@ -33,11 +33,12 @@ struct wlr_presentation {
 struct wlr_presentation_feedback {
 	struct wl_list resources; // wl_resource_get_link()
 
-	// Only when the wlr_presentation_surface_sampled_on_output() helper has
+	// Only when the wlr_presentation_surface_textured_on_output() or
-	// been called.
+	// wlr_presentation_surface_scanned_out_on_output() helper has been called.
 	struct wlr_output *output;
 	bool output_committed;
 	uint32_t output_commit_seq;
+	bool zero_copy;
 
 	struct wl_listener output_commit;
 	struct wl_listener output_present;
@@ -85,14 +86,23 @@ void wlr_presentation_event_from_output(struct wlr_presentation_event *event,
 		const struct wlr_output_event_present *output_event);
 
 /**
- * Mark the current surface's buffer as sampled on the given output.
+ * Mark the current surface's buffer as textured on the given output.
  *
  * Instead of calling wlr_presentation_surface_sampled() and managing the
  * struct wlr_presentation_feedback itself, the compositor can call this function
  * before a wlr_output_commit() call to indicate that the surface's current
- * contents will be displayed on the output.
+ * contents have been copied to a buffer which will be displayed on the output.
  */
-void wlr_presentation_surface_sampled_on_output(
+void wlr_presentation_surface_textured_on_output(
+	struct wlr_presentation *presentation, struct wlr_surface *surface,
+	struct wlr_output *output);
+/**
+ * Mark the current surface's buffer as scanned out on the given output.
+ *
+ * Same as wlr_presentation_surface_textured_on_output(), but indicates direct
+ * scan-out.
+ */
+void wlr_presentation_surface_scanned_out_on_output(
 	struct wlr_presentation *presentation, struct wlr_surface *surface,
 	struct wlr_output *output);
 

types/scene/surface.c

@@ -42,15 +42,21 @@ static void handle_scene_buffer_output_sample(
 		wl_container_of(listener, surface, output_sample);
 	const struct wlr_scene_output_sample_event *event = data;
 	struct wlr_scene_output *scene_output = event->output;
+	if (surface->buffer->primary_output != scene_output) {
+		return;
+	}
 
-	if (surface->buffer->primary_output == scene_output) {
+	struct wlr_scene *root = scene_node_get_root(&surface->buffer->node);
-		struct wlr_scene *root = scene_node_get_root(&surface->buffer->node);
+	if (!root->presentation) {
-		struct wlr_presentation *presentation = root->presentation;
+		return;
+	}
 
-		if (presentation) {
+	if (event->direct_scanout) {
-			wlr_presentation_surface_sampled_on_output(
+		wlr_presentation_surface_scanned_out_on_output(
-				presentation, surface->surface, scene_output->output);
+			root->presentation, surface->surface, scene_output->output);
-		}
+	} else {
+		wlr_presentation_surface_textured_on_output(
+			root->presentation, surface->surface, scene_output->output);
 	}
 }
 

types/wlr_presentation_time.c

@@ -295,6 +295,9 @@ static void feedback_handle_output_present(struct wl_listener *listener,
 	if (output_event->presented) {
 		struct wlr_presentation_event event = {0};
 		wlr_presentation_event_from_output(&event, output_event);
+		if (!feedback->zero_copy) {
+			event.flags &= ~WP_PRESENTATION_FEEDBACK_KIND_ZERO_COPY;
+		}
 		wlr_presentation_feedback_send_presented(feedback, &event);
 	}
 	wlr_presentation_feedback_destroy(feedback);
@@ -307,9 +310,9 @@ static void feedback_handle_output_destroy(struct wl_listener *listener,
 	wlr_presentation_feedback_destroy(feedback);
 }
 
-void wlr_presentation_surface_sampled_on_output(
+static void presentation_surface_queued_on_output(
 		struct wlr_presentation *presentation, struct wlr_surface *surface,
-		struct wlr_output *output) {
+		struct wlr_output *output, bool zero_copy) {
 	struct wlr_presentation_feedback *feedback =
 		wlr_presentation_surface_sampled(presentation, surface);
 	if (feedback == NULL) {
@@ -318,6 +321,7 @@ void wlr_presentation_surface_sampled_on_output(
 
 	assert(feedback->output == NULL);
 	feedback->output = output;
+	feedback->zero_copy = zero_copy;
 
 	feedback->output_commit.notify = feedback_handle_output_commit;
 	wl_signal_add(&output->events.commit, &feedback->output_commit);
@@ -326,3 +330,17 @@ void wlr_presentation_surface_sampled_on_output(
 	feedback->output_destroy.notify = feedback_handle_output_destroy;
 	wl_signal_add(&output->events.destroy, &feedback->output_destroy);
 }
+
+void wlr_presentation_surface_textured_on_output(
+		struct wlr_presentation *presentation, struct wlr_surface *surface,
+		struct wlr_output *output) {
+	return presentation_surface_queued_on_output(presentation, surface,
+		output, false);
+}
+
+void wlr_presentation_surface_scanned_out_on_output(
+		struct wlr_presentation *presentation, struct wlr_surface *surface,
+		struct wlr_output *output) {
+	return presentation_surface_queued_on_output(presentation, surface,
+		output, true);
+}