Use the wlroots scene-graph API

References: https://github.com/swaywm/wlroots/pull/1966

cage.c

@@ -28,6 +28,7 @@
 #include <wlr/types/wlr_idle.h>
 #include <wlr/types/wlr_idle_inhibit_v1.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_screencopy_v1.h>
 #include <wlr/types/wlr_server_decoration.h>
 #if CAGE_HAS_XWAYLAND
@@ -342,6 +343,13 @@ main(int argc, char *argv[])
 		goto end;
 	}
 
+	server.scene = wlr_scene_create();
+	if (!server.scene) {
+		wlr_log(WLR_ERROR, "Unable to create scene");
+		ret = 1;
+		goto end;
+	}
+
 	compositor = wlr_compositor_create(server.wl_display, server.renderer);
 	if (!compositor) {
 		wlr_log(WLR_ERROR, "Unable to create the wlroots compositor");

output.c

@@ -26,6 +26,7 @@
 #include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_output_damage.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_surface.h>
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
@@ -105,63 +106,19 @@ output_surface_for_each_surface(struct cg_output *output, struct wlr_surface *su
 	wlr_surface_for_each_surface(surface, output_for_each_surface_iterator, &data);
 }
 
-static void
-output_view_for_each_surface(struct cg_output *output, struct cg_view *view, cg_surface_iterator_func_t iterator,
-			     void *user_data)
-{
-	struct surface_iterator_data data = {
-		.user_iterator = iterator,
-		.user_data = user_data,
-		.output = output,
-		.ox = view->lx,
-		.oy = view->ly,
-	};
-
-	wlr_output_layout_output_coords(output->server->output_layout, output->wlr_output, &data.ox, &data.oy);
-	view_for_each_surface(view, output_for_each_surface_iterator, &data);
-}
-
-void
-output_view_for_each_popup_surface(struct cg_output *output, struct cg_view *view, cg_surface_iterator_func_t iterator,
-				   void *user_data)
-{
-	struct surface_iterator_data data = {
-		.user_iterator = iterator,
-		.user_data = user_data,
-		.output = output,
-		.ox = view->lx,
-		.oy = view->ly,
-	};
-
-	wlr_output_layout_output_coords(output->server->output_layout, output->wlr_output, &data.ox, &data.oy);
-	view_for_each_popup_surface(view, output_for_each_surface_iterator, &data);
-}
-
-void
-output_drag_icons_for_each_surface(struct cg_output *output, struct wl_list *drag_icons,
-				   cg_surface_iterator_func_t iterator, void *user_data)
-{
-	struct cg_drag_icon *drag_icon;
-	wl_list_for_each (drag_icon, drag_icons, link) {
-		if (drag_icon->wlr_drag_icon->mapped) {
-			double ox = drag_icon->lx;
-			double oy = drag_icon->ly;
-			wlr_output_layout_output_coords(output->server->output_layout, output->wlr_output, &ox, &oy);
-			output_surface_for_each_surface(output, drag_icon->wlr_drag_icon->surface, ox, oy, iterator,
-							user_data);
-		}
-	}
-}
-
 static void
 output_for_each_surface(struct cg_output *output, cg_surface_iterator_func_t iterator, void *user_data)
 {
-	struct cg_view *view;
-	wl_list_for_each_reverse (view, &output->server->views, link) {
-		output_view_for_each_surface(output, view, iterator, user_data);
-	}
+	struct surface_iterator_data data = {
+		.user_iterator = iterator,
+		.user_data = user_data,
+		.output = output,
+		.ox = 0,
+		.oy = 0,
+	};
+	wlr_output_layout_output_coords(output->server->output_layout, output->wlr_output, &data.ox, &data.oy);
 
-	output_drag_icons_for_each_surface(output, &output->server->seat->drag_icons, iterator, user_data);
+	wlr_scene_node_for_each_surface(&output->server->scene->node, output_for_each_surface_iterator, &data);
 }
 
 struct send_frame_done_data {
@@ -182,7 +139,7 @@ send_frame_done(struct cg_output *output, struct send_frame_done_data *data)
 }
 
 static void
-count_surface_iterator(struct cg_output *output, struct wlr_surface *surface, struct wlr_box *_box, void *data)
+count_surface_iterator(struct wlr_surface *surface, int sx, int sy, void *data)
 {
 	size_t *n = data;
 	(*n)++;
@@ -207,7 +164,7 @@ scan_out_primary_view(struct cg_output *output)
 	}
 
 	size_t n_surfaces = 0;
-	output_view_for_each_surface(output, view, count_surface_iterator, &n_surfaces);
+	wlr_scene_node_for_each_surface(&view->scene_surface->node, count_surface_iterator, &n_surfaces);
 	if (n_surfaces > 1) {
 		return false;
 	}

output.h

@@ -28,10 +28,6 @@ typedef void (*cg_surface_iterator_func_t)(struct cg_output *output, struct wlr_
 void handle_new_output(struct wl_listener *listener, void *data);
 void output_surface_for_each_surface(struct cg_output *output, struct wlr_surface *surface, double ox, double oy,
 				     cg_surface_iterator_func_t iterator, void *user_data);
-void output_view_for_each_popup_surface(struct cg_output *output, struct cg_view *view,
-					cg_surface_iterator_func_t iterator, void *user_data);
-void output_drag_icons_for_each_surface(struct cg_output *output, struct wl_list *drag_icons,
-					cg_surface_iterator_func_t iterator, void *user_data);
 void output_damage_surface(struct cg_output *output, struct wlr_surface *surface, double lx, double ly, bool whole);
 void output_set_window_title(struct cg_output *output, const char *title);
 

render.c

@@ -13,6 +13,7 @@
 #include <wlr/types/wlr_matrix.h>
 #include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_surface.h>
 #include <wlr/util/box.h>
 #include <wlr/util/log.h>
@@ -46,84 +47,6 @@ struct render_data {
 	pixman_region32_t *damage;
 };
 
-static void
-render_texture(struct wlr_output *wlr_output, pixman_region32_t *output_damage, struct wlr_texture *texture,
-	       const struct wlr_box *box, const float matrix[static 9])
-{
-	pixman_region32_t damage;
-	pixman_region32_init(&damage);
-	pixman_region32_union_rect(&damage, &damage, box->x, box->y, box->width, box->height);
-	pixman_region32_intersect(&damage, &damage, output_damage);
-	if (!pixman_region32_not_empty(&damage)) {
-		goto damage_finish;
-	}
-
-	int nrects;
-	pixman_box32_t *rects = pixman_region32_rectangles(&damage, &nrects);
-	for (int i = 0; i < nrects; i++) {
-		scissor_output(wlr_output, &rects[i]);
-		wlr_render_texture_with_matrix(wlr_output->renderer, texture, matrix, 1.0f);
-	}
-
-damage_finish:
-	pixman_region32_fini(&damage);
-}
-
-static void
-render_surface_iterator(struct cg_output *output, struct wlr_surface *surface, struct wlr_box *box, void *user_data)
-{
-	struct render_data *data = user_data;
-	struct wlr_output *wlr_output = output->wlr_output;
-	pixman_region32_t *output_damage = data->damage;
-
-	struct wlr_texture *texture = wlr_surface_get_texture(surface);
-	if (!texture) {
-		wlr_log(WLR_DEBUG, "Cannot obtain surface texture");
-		return;
-	}
-
-	scale_box(box, wlr_output->scale);
-
-	float matrix[9];
-	enum wl_output_transform transform = wlr_output_transform_invert(surface->current.transform);
-	wlr_matrix_project_box(matrix, box, transform, 0.0f, wlr_output->transform_matrix);
-
-	render_texture(wlr_output, output_damage, texture, box, matrix);
-}
-
-static void
-render_drag_icons(struct cg_output *output, pixman_region32_t *damage, struct wl_list *drag_icons)
-{
-	struct render_data data = {
-		.damage = damage,
-	};
-	output_drag_icons_for_each_surface(output, drag_icons, render_surface_iterator, &data);
-}
-
-/**
- * Render all toplevels without descending into popups.
- */
-static void
-render_view_toplevels(struct cg_view *view, struct cg_output *output, pixman_region32_t *damage)
-{
-	struct render_data data = {
-		.damage = damage,
-	};
-	double ox = view->lx;
-	double oy = view->ly;
-	wlr_output_layout_output_coords(output->server->output_layout, output->wlr_output, &ox, &oy);
-	output_surface_for_each_surface(output, view->wlr_surface, ox, oy, render_surface_iterator, &data);
-}
-
-static void
-render_view_popups(struct cg_view *view, struct cg_output *output, pixman_region32_t *damage)
-{
-	struct render_data data = {
-		.damage = damage,
-	};
-	output_view_for_each_popup_surface(output, view, render_surface_iterator, &data);
-}
-
 void
 output_render(struct cg_output *output, pixman_region32_t *damage)
 {
@@ -151,18 +74,9 @@ output_render(struct cg_output *output, pixman_region32_t *damage)
 		wlr_renderer_clear(server->renderer, color);
 	}
 
-	// TODO: render only top view, possibly use focused view for this, see #35.
-	struct cg_view *view;
-	wl_list_for_each_reverse (view, &server->views, link) {
-		render_view_toplevels(view, output, damage);
-	}
-
-	struct cg_view *focused_view = seat_get_focus(server->seat);
-	if (focused_view) {
-		render_view_popups(focused_view, output, damage);
-	}
-
-	render_drag_icons(output, damage, &server->seat->drag_icons);
+	double lx = 0, ly = 0;
+	wlr_output_layout_output_coords(output->server->output_layout, output->wlr_output, &lx, &ly);
+	wlr_scene_render_output(server->scene, wlr_output, lx, ly, damage);
 
 renderer_end:
 	/* Draw software cursor in case hardware cursors aren't

seat.c

@@ -18,6 +18,7 @@
 #include <wlr/types/wlr_idle.h>
 #include <wlr/types/wlr_keyboard_group.h>
 #include <wlr/types/wlr_primary_selection.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_seat.h>
 #include <wlr/types/wlr_surface.h>
 #include <wlr/types/wlr_touch.h>
@@ -632,6 +633,8 @@ drag_icon_update_position(struct cg_drag_icon *drag_icon)
 	}
 
 	drag_icon_damage(drag_icon);
+
+	wlr_scene_node_set_position(&drag_icon->scene_surface->node, drag_icon->lx, drag_icon->ly);
 }
 
 static void
@@ -642,6 +645,7 @@ handle_drag_icon_destroy(struct wl_listener *listener, void *data)
 	drag_icon_damage(drag_icon);
 	wl_list_remove(&drag_icon->link);
 	wl_list_remove(&drag_icon->destroy.link);
+	wlr_scene_node_destroy(&drag_icon->scene_surface->node);
 	free(drag_icon);
 }
 
@@ -684,6 +688,11 @@ handle_start_drag(struct wl_listener *listener, void *data)
 	}
 	drag_icon->seat = seat;
 	drag_icon->wlr_drag_icon = wlr_drag_icon;
+	drag_icon->scene_surface = wlr_scene_surface_create(&seat->server->scene->node, wlr_drag_icon->surface);
+	if (!drag_icon->scene_surface) {
+		free(drag_icon);
+		return;
+	}
 
 	drag_icon->destroy.notify = handle_drag_icon_destroy;
 	wl_signal_add(&wlr_drag_icon->events.destroy, &drag_icon->destroy);

seat.h

@@ -77,6 +77,7 @@ struct cg_drag_icon {
 	struct wl_list link; // seat::drag_icons
 	struct cg_seat *seat;
 	struct wlr_drag_icon *wlr_drag_icon;
+	struct wlr_scene_surface *scene_surface;
 
 	/* The drag icon has a position in layout coordinates. */
 	double lx, ly;

server.h

@@ -36,6 +36,7 @@ struct cg_server {
 
 	enum cg_multi_output_mode output_mode;
 	struct wlr_output_layout *output_layout;
+	struct wlr_scene *scene;
 	/* Includes disabled outputs; depending on the output_mode
 	 * some outputs may be disabled. */
 	struct wl_list outputs; // cg_output::link

view.c

@@ -13,6 +13,7 @@
 #include <string.h>
 #include <wayland-server-core.h>
 #include <wlr/types/wlr_output.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_surface.h>
 
 #include "output.h"
@@ -173,6 +174,9 @@ view_maximize(struct cg_view *view, struct wlr_box *layout_box)
 {
 	view->lx = layout_box->x;
 	view->ly = layout_box->y;
+
+	wlr_scene_node_set_position(&view->scene_surface->node, view->lx, view->ly);
+
 	view->impl->maximize(view, layout_box->width, layout_box->height);
 }
 
@@ -184,6 +188,8 @@ view_center(struct cg_view *view, struct wlr_box *layout_box)
 
 	view->lx = (layout_box->width - width) / 2;
 	view->ly = (layout_box->height - height) / 2;
+
+	wlr_scene_node_set_position(&view->scene_surface->node, view->lx, view->ly);
 }
 
 void
@@ -225,6 +231,8 @@ view_unmap(struct cg_view *view)
 		child->destroy(child);
 	}
 
+	wlr_scene_node_destroy(&view->scene_surface->node);
+
 	view->wlr_surface = NULL;
 }
 
@@ -233,6 +241,12 @@ view_map(struct cg_view *view, struct wlr_surface *surface)
 {
 	view->wlr_surface = surface;
 
+	view->scene_surface = wlr_scene_surface_create(&view->server->scene->node, surface);
+	if (!view->scene_surface) {
+		wl_resource_post_no_memory(surface->resource);
+		return;
+	}
+
 	struct wlr_subsurface *subsurface;
 	wl_list_for_each (subsurface, &view->wlr_surface->current.subsurfaces_below, current.link) {
 		subsurface_create(view, subsurface);

view.h

@@ -26,6 +26,7 @@ struct cg_view {
 	struct wl_list link; // server::views
 	struct wl_list children; // cg_view_child::link
 	struct wlr_surface *wlr_surface;
+	struct wlr_scene_surface *scene_surface;
 
 	/* The view has a position in layout coordinates. */
 	int lx, ly;

xdg_shell.c

@@ -9,6 +9,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <wayland-server-core.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
 
@@ -60,6 +61,14 @@ static void
 handle_xdg_popup_map(struct wl_listener *listener, void *data)
 {
 	struct cg_xdg_popup *popup = wl_container_of(listener, popup, map);
+	struct wlr_scene_node *parent_node = &popup->view_child.view->scene_surface->node;
+	popup->scene_surface = wlr_scene_surface_create(parent_node, popup->view_child.wlr_surface);
+	if (!popup->scene_surface) {
+		return;
+	}
+	double sx, sy;
+	wlr_xdg_popup_get_position(popup->wlr_popup, &sx, &sy);
+	wlr_scene_node_set_position(&popup->scene_surface->node, sx, sy);
 	view_damage_whole(popup->view_child.view);
 }
 
@@ -67,6 +76,7 @@ static void
 handle_xdg_popup_unmap(struct wl_listener *listener, void *data)
 {
 	struct cg_xdg_popup *popup = wl_container_of(listener, popup, unmap);
+	wlr_scene_node_destroy(&popup->scene_surface->node);
 	view_damage_whole(popup->view_child.view);
 }
 

xdg_shell.h

@@ -22,6 +22,7 @@ struct cg_xdg_shell_view {
 struct cg_xdg_popup {
 	struct cg_view_child view_child;
 	struct wlr_xdg_popup *wlr_popup;
+	struct wlr_scene_surface *scene_surface;
 
 	struct wl_listener destroy;
 	struct wl_listener map;