output: refactor frame submission API

This is necessary for direct scan-out and other upcoming features. This patch
changes the output API to look like the wl_surface API.

Outputs now have some double-buffered state: the frame to be submitted
(currently only wlr_renderer frames are supported) and the damaged region.
To attach a pending frame, use wlr_output_attach_render. To set the pending
damaged region, use wlr_output_set_damage.

To submit the pending state, call wlr_output_commit. This will submit the
pending frame to the backend.

To migrate from the old API to the new one:

- Replace wlr_output_make_current calls by wlr_output_attach_render
- Replace wlr_output_swap_buffers calls by wlr_output_set_damage and
  wlr_output_commit

examples/fullscreen-shell.c

@@ -89,7 +89,7 @@ static void output_handle_frame(struct wl_listener *listener, void *data) {
 	int width, height;
 	wlr_output_effective_resolution(output->wlr_output, &width, &height);
 
-	if (!wlr_output_make_current(output->wlr_output, NULL)) {
+	if (!wlr_output_attach_render(output->wlr_output, NULL)) {
 		return;
 	}
 
@@ -108,7 +108,7 @@ static void output_handle_frame(struct wl_listener *listener, void *data) {
 	}
 
 	wlr_renderer_end(renderer);
-	wlr_output_swap_buffers(output->wlr_output, NULL, NULL);
+	wlr_output_commit(output->wlr_output);
 }
 
 static void output_set_surface(struct fullscreen_output *output,

examples/multi-pointer.c

@@ -94,14 +94,14 @@ void output_frame_notify(struct wl_listener *listener, void *data) {
 	struct sample_state *sample = output->sample;
 	struct wlr_output *wlr_output = output->output;
 
-	wlr_output_make_current(wlr_output, NULL);
+	wlr_output_attach_render(wlr_output, NULL);
 
 	glClearColor(sample->clear_color[0], sample->clear_color[1],
 		sample->clear_color[2], sample->clear_color[3]);
 	glClear(GL_COLOR_BUFFER_BIT);
 
 	wlr_output_render_software_cursors(wlr_output, NULL);
-	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_output_commit(wlr_output);
 }
 
 static void handle_cursor_motion(struct wl_listener *listener, void *data) {

examples/output-layout.c

@@ -115,7 +115,7 @@ void output_frame_notify(struct wl_listener *listener, void *data) {
 
 	struct wlr_output *wlr_output = output->output;
 
-	wlr_output_make_current(wlr_output, NULL);
+	wlr_output_attach_render(wlr_output, NULL);
 	wlr_renderer_begin(sample->renderer, wlr_output->width, wlr_output->height);
 	wlr_renderer_clear(sample->renderer, (float[]){0.25f, 0.25f, 0.25f, 1});
 
@@ -137,7 +137,7 @@ void output_frame_notify(struct wl_listener *listener, void *data) {
 	}
 
 	wlr_renderer_end(sample->renderer);
-	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_output_commit(wlr_output);
 }
 
 static void update_velocities(struct sample_state *sample,

examples/pointer.c

@@ -98,11 +98,11 @@ void output_frame_notify(struct wl_listener *listener, void *data) {
 	struct wlr_renderer *renderer = wlr_backend_get_renderer(wlr_output->backend);
 	assert(renderer);
 
-	wlr_output_make_current(wlr_output, NULL);
+	wlr_output_attach_render(wlr_output, NULL);
 	wlr_renderer_begin(renderer, wlr_output->width, wlr_output->height);
 	wlr_renderer_clear(renderer, state->clear_color);
 	wlr_output_render_software_cursors(wlr_output, NULL);
-	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_output_commit(wlr_output);
 	wlr_renderer_end(renderer);
 }
 

examples/rotation.c

@@ -60,7 +60,7 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	int32_t width, height;
 	wlr_output_effective_resolution(wlr_output, &width, &height);
 
-	wlr_output_make_current(wlr_output, NULL);
+	wlr_output_attach_render(wlr_output, NULL);
 	wlr_renderer_begin(sample->renderer, wlr_output->width, wlr_output->height);
 	wlr_renderer_clear(sample->renderer, (float[]){0.25f, 0.25f, 0.25f, 1});
 
@@ -72,7 +72,7 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	}
 
 	wlr_renderer_end(sample->renderer);
-	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_output_commit(wlr_output);
 
 	long ms = (now.tv_sec - sample->last_frame.tv_sec) * 1000 +
 		(now.tv_nsec - sample->last_frame.tv_nsec) / 1000000;

examples/simple.c

@@ -56,12 +56,12 @@ void output_frame_notify(struct wl_listener *listener, void *data) {
 		sample->dec = inc;
 	}
 
-	wlr_output_make_current(sample_output->output, NULL);
+	wlr_output_attach_render(sample_output->output, NULL);
 
 	glClearColor(sample->color[0], sample->color[1], sample->color[2], 1.0);
 	glClear(GL_COLOR_BUFFER_BIT);
 
-	wlr_output_swap_buffers(sample_output->output, NULL, NULL);
+	wlr_output_commit(sample_output->output);
 	sample->last_frame = now;
 }
 

examples/tablet.c

@@ -86,7 +86,7 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	int32_t width, height;
 	wlr_output_effective_resolution(wlr_output, &width, &height);
 
-	wlr_output_make_current(wlr_output, NULL);
+	wlr_output_attach_render(wlr_output, NULL);
 	wlr_renderer_begin(sample->renderer, wlr_output->width, wlr_output->height);
 	wlr_renderer_clear(sample->renderer, (float[]){0.25f, 0.25f, 0.25f, 1});
 
@@ -129,7 +129,7 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	}
 
 	wlr_renderer_end(sample->renderer);
-	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_output_commit(wlr_output);
 	sample->last_frame = now;
 }
 

examples/touch.c

@@ -73,7 +73,7 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	int32_t width, height;
 	wlr_output_effective_resolution(wlr_output, &width, &height);
 
-	wlr_output_make_current(wlr_output, NULL);
+	wlr_output_attach_render(wlr_output, NULL);
 	wlr_renderer_begin(sample->renderer, wlr_output->width, wlr_output->height);
 	wlr_renderer_clear(sample->renderer, (float[]){0.25f, 0.25f, 0.25f, 1});
 
@@ -89,7 +89,7 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	}
 
 	wlr_renderer_end(sample->renderer);
-	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_output_commit(wlr_output);
 	sample->last_frame = now;
 }