scene_graph: Maintain `wlr_scene_node`s for the sway tree.

include/sway/output.h

@@ -5,6 +5,7 @@
 #include <wayland-server-core.h>
 #include <wlr/types/wlr_damage_ring.h>
 #include <wlr/types/wlr_output.h>
+#include <wlr/types/wlr_scene.h>
 #include "config.h"
 #include "sway/tree/node.h"
 #include "sway/tree/view.h"
@@ -19,7 +20,21 @@ struct sway_output_state {
 
 struct sway_output {
 	struct sway_node node;
+
+	struct {
+		struct wlr_scene_tree *tiling;
+		struct wlr_scene_tree *fullscreen;
+	} layers;
+
+	// when a container is fullscreen, in case the fullscreen surface is
+	// translucent (can see behind) we must make sure that the background is a
+	// solid color in order to conform to the wayland protocol. This rect
+	// ensures that when looking through a surface, all that will be seen
+	// is black.
+	struct wlr_scene_rect *fullscreen_background;
+
 	struct wlr_output *wlr_output;
+	struct wlr_scene_output *scene_output;
 	struct sway_server *server;
 	struct wl_list link;
 

include/sway/tree/container.h

@@ -3,6 +3,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_scene.h>
 #include "list.h"
 #include "sway/tree/node.h"
 
@@ -68,6 +69,26 @@ struct sway_container {
 	struct sway_node node;
 	struct sway_view *view;
 
+	struct wlr_scene_tree *scene_tree;
+
+	struct {
+		struct wlr_scene_tree *tree;
+
+		struct wlr_scene_tree *border;
+		struct wlr_scene_tree *background;
+	} title_bar;
+
+	struct {
+		struct wlr_scene_tree *tree;
+
+		struct wlr_scene_rect *top;
+		struct wlr_scene_rect *bottom;
+		struct wlr_scene_rect *left;
+		struct wlr_scene_rect *right;
+	} border;
+
+	struct wlr_scene_tree *content_tree;
+
 	struct sway_container_state current;
 	struct sway_container_state pending;
 

include/sway/tree/node.h

@@ -2,6 +2,7 @@
 #define _SWAY_NODE_H
 #include <wayland-server-core.h>
 #include <stdbool.h>
+#include <wlr/types/wlr_scene.h>
 #include "list.h"
 
 #define MIN_SANE_W 100
@@ -75,4 +76,15 @@ list_t *node_get_children(struct sway_node *node);
 
 bool node_has_ancestor(struct sway_node *node, struct sway_node *ancestor);
 
+// when destroying a sway tree, it's not known which order the tree will be
+// destroyed. To prevent freeing of scene_nodes recursing up the tree,
+// let's use this helper function to disown them to the staging node.
+void scene_node_disown_children(struct wlr_scene_tree *tree);
+
+// a helper function used to allocate tree nodes. If an allocation failure
+// occurs a flag is flipped that can be checked later to destroy a parent
+// of this scene node preventing memory leaks.
+struct wlr_scene_tree *alloc_scene_tree(struct wlr_scene_tree *parent,
+		bool *failed);
+
 #endif

include/sway/tree/root.h

@@ -3,6 +3,7 @@
 #include <wayland-server-core.h>
 #include <wayland-util.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/render/wlr_texture.h>
 #include "sway/tree/container.h"
 #include "sway/tree/node.h"
@@ -16,6 +17,31 @@ struct sway_root {
 	struct wlr_output_layout *output_layout;
 
 	struct wl_listener output_layout_change;
+
+	// scene node layout:
+	// - root
+	// 	- staging
+	// 	- layer shell stuff
+	// 	- tiling
+	// 	- floating
+	// 	- fullscreen stuff
+	// 	- seat stuff
+	// 	- ext_session_lock
+	struct wlr_scene *root_scene;
+
+	// since wlr_scene nodes can't be orphaned and must always
+	// have a parent, use this staging scene_tree so that a
+	// node always have a valid parent. Nothing in this
+	// staging node will be visible.
+	struct wlr_scene_tree *staging;
+
+	struct {
+		struct wlr_scene_tree *tiling;
+		struct wlr_scene_tree *floating;
+		struct wlr_scene_tree *fullscreen;
+		struct wlr_scene_tree *fullscreen_global;
+	} layers;
+
 #if HAVE_XWAYLAND
 	struct wl_list xwayland_unmanaged; // sway_xwayland_unmanaged::link
 #endif

include/sway/tree/view.h

@@ -2,6 +2,7 @@
 #define _SWAY_VIEW_H
 #include <wayland-server-core.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_scene.h>
 #include "sway/config.h"
 #if HAVE_XWAYLAND
 #include <wlr/xwayland.h>
@@ -69,6 +70,9 @@ struct sway_view {
 	enum sway_view_type type;
 	const struct sway_view_impl *impl;
 
+	struct wlr_scene_tree *scene_tree;
+	struct wlr_scene_tree *content_tree;
+
 	struct sway_container *container; // NULL if unmapped and transactions finished
 	struct wlr_surface *surface; // NULL for unmapped views
 	struct sway_xdg_decoration *xdg_decoration;

include/sway/tree/workspace.h

@@ -2,6 +2,7 @@
 #define _SWAY_WORKSPACE_H
 
 #include <stdbool.h>
+#include <wlr/types/wlr_scene.h>
 #include "sway/config.h"
 #include "sway/tree/container.h"
 #include "sway/tree/node.h"
@@ -23,6 +24,12 @@ struct sway_workspace_state {
 
 struct sway_workspace {
 	struct sway_node node;
+
+	struct {
+		struct wlr_scene_tree *tiling;
+		struct wlr_scene_tree *fullscreen;
+	} layers;
+
 	struct sway_container *fullscreen;
 
 	char *name;

sway/desktop/output.c

@@ -856,9 +856,6 @@ void output_damage_whole_container(struct sway_output *output,
 		.height = con->current.height + 2,
 	};
 	scale_box(&box, output->wlr_output->scale);
-	if (wlr_damage_ring_add_box(&output->damage_ring, &box)) {
-		wlr_output_schedule_frame(output->wlr_output);
-	}
 	// Damage subsurfaces as well, which may extend outside the box
 	if (con->view) {
 		damage_child_views_iterator(con, output);
@@ -914,6 +911,8 @@ static void begin_destroy(struct sway_output *output) {
 
 	wlr_damage_ring_finish(&output->damage_ring);
 
+	wlr_scene_output_destroy(output->scene_output);
+	output->scene_output = NULL;
 	output->wlr_output->data = NULL;
 	output->wlr_output = NULL;
 
@@ -1039,11 +1038,24 @@ void handle_new_output(struct wl_listener *listener, void *data) {
 		return;
 	}
 
+	// Create the scene output here so we're not accidentally creating one for
+	// the fallback output
+	struct wlr_scene_output *scene_output =
+		wlr_scene_output_create(root->root_scene, wlr_output);
+	if (!scene_output) {
+		sway_log(SWAY_ERROR, "Failed to create a scene output");
+		return;
+	}
+
 	struct sway_output *output = output_create(wlr_output);
 	if (!output) {
+		sway_log(SWAY_ERROR, "Failed to create a sway output");
+		wlr_scene_output_destroy(scene_output);
 		return;
 	}
+
 	output->server = server;
+	output->scene_output = scene_output;
 	wlr_damage_ring_init(&output->damage_ring);
 
 	wl_signal_add(&root->output_layout->events.destroy, &output->layout_destroy);

sway/tree/container.c

@@ -27,6 +27,24 @@
 #include "log.h"
 #include "stringop.h"
 
+static struct wlr_scene_rect *alloc_rect_node(struct wlr_scene_tree *parent,
+		bool *failed) {
+	if (*failed) {
+		return NULL;
+	}
+
+	// just pass in random values. These will be overwritten when
+	// they need to be used.
+	struct wlr_scene_rect *rect = wlr_scene_rect_create(
+		parent, 0, 0, (float[4]){0.f, 0.f, 0.f, 1.f});
+	if (!rect) {
+		sway_log(SWAY_ERROR, "Failed to allocate a wlr_scene_rect");
+		*failed = true;
+	}
+
+	return rect;
+}
+
 struct sway_container *container_create(struct sway_view *view) {
 	struct sway_container *c = calloc(1, sizeof(struct sway_container));
 	if (!c) {
@@ -34,14 +52,62 @@ struct sway_container *container_create(struct sway_view *view) {
 		return NULL;
 	}
 	node_init(&c->node, N_CONTAINER, c);
-	c->pending.layout = L_NONE;
-	c->view = view;
-	c->alpha = 1.0f;
+
+	// Container tree structure
+	// - scene tree
+	//   - title bar
+	//     - border
+	//     - background
+	//     - title text
+	//     - marks text
+	//   - border
+	//     - border top/bottom/left/right
+	//     - content_tree (we put the content node here so when we disable the
+	//       border everything gets disabled. We only render the content iff there
+	//       is a border as well)
+	bool failed = false;
+	c->scene_tree = alloc_scene_tree(root->staging, &failed);
+
+	c->title_bar.tree = alloc_scene_tree(c->scene_tree, &failed);
+	c->title_bar.border = alloc_scene_tree(c->title_bar.tree, &failed);
+	c->title_bar.background = alloc_scene_tree(c->title_bar.tree, &failed);
+
+	// for opacity purposes we need to carfully create the scene such that
+	// none of our rect nodes as well as text buffers don't overlap. To do
+	// this we have to create rects such that they go around text buffers
+	for (int i = 0; i < 4; i++) {
+		alloc_rect_node(c->title_bar.border, &failed);
+	}
+
+	for (int i = 0; i < 5; i++) {
+		alloc_rect_node(c->title_bar.background, &failed);
+	}
+
+	c->border.tree = alloc_scene_tree(c->scene_tree, &failed);
+	c->content_tree = alloc_scene_tree(c->border.tree, &failed);
+
+	if (view) {
+		// only containers with views can have borders
+		c->border.top = alloc_rect_node(c->border.tree, &failed);
+		c->border.bottom = alloc_rect_node(c->border.tree, &failed);
+		c->border.left = alloc_rect_node(c->border.tree, &failed);
+		c->border.right = alloc_rect_node(c->border.tree, &failed);
+	}
+
+	if (failed) {
+		wlr_scene_node_destroy(&c->scene_tree->node);
+		free(c);
+		return NULL;
+	}
 
 	if (!view) {
 		c->pending.children = create_list();
 		c->current.children = create_list();
 	}
+
+	c->pending.layout = L_NONE;
+	c->view = view;
+	c->alpha = 1.0f;
 	c->marks = create_list();
 	c->outputs = create_list();
 
@@ -85,6 +151,8 @@ void container_destroy(struct sway_container *con) {
 		}
 	}
 
+	scene_node_disown_children(con->content_tree);
+	wlr_scene_node_destroy(&con->scene_tree->node);
 	free(con);
 }
 

sway/tree/node.c

@@ -159,3 +159,32 @@ bool node_has_ancestor(struct sway_node *node, struct sway_node *ancestor) {
 	}
 	return false;
 }
+
+void scene_node_disown_children(struct wlr_scene_tree *tree) {
+	// this function can be called as part of destruction code that will be invoked
+	// upon an allocation failure. Let's not crash on NULL due to an allocation error.
+	if (!tree) {
+		return;
+	}
+
+	struct wlr_scene_node *child, *tmp_child;
+	wl_list_for_each_safe(child, tmp_child, &tree->children, link) {
+		wlr_scene_node_reparent(child, root->staging);
+	}
+}
+
+struct wlr_scene_tree *alloc_scene_tree(struct wlr_scene_tree *parent,
+		bool *failed) {
+	// fallthrough
+	if (*failed) {
+		return NULL;
+	}
+
+	struct wlr_scene_tree *tree = wlr_scene_tree_create(parent);
+	if (!tree) {
+		sway_log(SWAY_ERROR, "Failed to allocate a scene node");
+		*failed = true;
+	}
+
+	return tree;
+}

sway/tree/output.c

@@ -87,9 +87,41 @@ static void restore_workspaces(struct sway_output *output) {
 	output_sort_workspaces(output);
 }
 
+static void destroy_scene_layers(struct sway_output *output) {
+	wlr_scene_node_destroy(&output->fullscreen_background->node);
+
+	scene_node_disown_children(output->layers.tiling);
+	scene_node_disown_children(output->layers.fullscreen);
+
+	wlr_scene_node_destroy(&output->layers.tiling->node);
+	wlr_scene_node_destroy(&output->layers.fullscreen->node);
+}
+
 struct sway_output *output_create(struct wlr_output *wlr_output) {
 	struct sway_output *output = calloc(1, sizeof(struct sway_output));
 	node_init(&output->node, N_OUTPUT, output);
+
+	bool failed = false;
+	output->layers.tiling = alloc_scene_tree(root->staging, &failed);
+	output->layers.fullscreen = alloc_scene_tree(root->staging, &failed);
+
+	if (!failed) {
+		output->fullscreen_background = wlr_scene_rect_create(
+			output->layers.fullscreen, 0, 0, (float[4]){0.f, 0.f, 0.f, 1.f});
+
+		if (!output->fullscreen_background) {
+			sway_log(SWAY_ERROR, "Unable to allocate a background rect");
+			failed = true;
+		}
+	}
+
+	if (failed) {
+		destroy_scene_layers(output);
+		wlr_scene_output_destroy(output->scene_output);
+		free(output);
+		return NULL;
+	}
+
 	output->wlr_output = wlr_output;
 	wlr_output->data = output;
 	output->detected_subpixel = wlr_output->subpixel;
@@ -238,6 +270,8 @@ void output_destroy(struct sway_output *output) {
 				"which is still referenced by transactions")) {
 		return;
 	}
+
+	destroy_scene_layers(output);
 	list_free(output->workspaces);
 	list_free(output->current.workspaces);
 	wl_event_source_remove(output->repaint_timer);

sway/tree/root.c

@@ -3,6 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/types/wlr_scene.h>
 #include <wlr/util/transform.h>
 #include "sway/desktop/transaction.h"
 #include "sway/input/seat.h"
@@ -30,7 +31,33 @@ struct sway_root *root_create(struct wl_display *wl_display) {
 		sway_log(SWAY_ERROR, "Unable to allocate sway_root");
 		return NULL;
 	}
+
+	struct wlr_scene *root_scene = wlr_scene_create();
+	if (!root_scene) {
+		sway_log(SWAY_ERROR, "Unable to allocate root scene node");
+		free(root);
+		return NULL;
+	}
+
 	node_init(&root->node, N_ROOT, root);
+	root->root_scene = root_scene;
+
+	bool failed = false;
+	root->staging = alloc_scene_tree(&root_scene->tree, &failed);
+
+	root->layers.tiling = alloc_scene_tree(&root_scene->tree, &failed);
+	root->layers.floating = alloc_scene_tree(&root_scene->tree, &failed);
+	root->layers.fullscreen = alloc_scene_tree(&root_scene->tree, &failed);
+	root->layers.fullscreen_global = alloc_scene_tree(&root_scene->tree, &failed);
+
+	if (failed) {
+		wlr_scene_node_destroy(&root_scene->tree.node);
+		free(root);
+		return NULL;
+	}
+
+	wlr_scene_node_set_enabled(&root->staging->node, false);
+
 	root->output_layout = wlr_output_layout_create(wl_display);
 	wl_list_init(&root->all_outputs);
 #if HAVE_XWAYLAND
@@ -53,6 +80,7 @@ void root_destroy(struct sway_root *root) {
 	list_free(root->scratchpad);
 	list_free(root->non_desktop_outputs);
 	list_free(root->outputs);
+	wlr_scene_node_destroy(&root->root_scene->tree.node);
 	free(root);
 }
 

sway/tree/view.c

@@ -37,6 +37,14 @@
 
 bool view_init(struct sway_view *view, enum sway_view_type type,
 		const struct sway_view_impl *impl) {
+	bool failed = false;
+	view->scene_tree = alloc_scene_tree(root->staging, &failed);
+	view->content_tree = alloc_scene_tree(view->scene_tree, &failed);
+	if (failed) {
+		wlr_scene_node_destroy(&view->scene_tree->node);
+		return false;
+	}
+
 	view->type = type;
 	view->impl = impl;
 	view->executed_criteria = create_list();
@@ -67,7 +75,7 @@ void view_destroy(struct sway_view *view) {
 	list_free(view->executed_criteria);
 
 	view_assign_ctx(view, NULL);
-
+	wlr_scene_node_destroy(&view->scene_tree->node);
 	free(view->title_format);
 
 	if (view->impl->destroy) {

sway/tree/workspace.c

@@ -71,6 +71,18 @@ struct sway_workspace *workspace_create(struct sway_output *output,
 		return NULL;
 	}
 	node_init(&ws->node, N_WORKSPACE, ws);
+
+	bool failed = false;
+	ws->layers.tiling = alloc_scene_tree(root->staging, &failed);
+	ws->layers.fullscreen = alloc_scene_tree(root->staging, &failed);
+
+	if (failed) {
+		wlr_scene_node_destroy(&ws->layers.tiling->node);
+		wlr_scene_node_destroy(&ws->layers.fullscreen->node);
+		free(ws);
+		return NULL;
+	}
+
 	ws->name = strdup(name);
 	ws->prev_split_layout = L_NONE;
 	ws->layout = output_get_default_layout(output);
@@ -131,6 +143,11 @@ void workspace_destroy(struct sway_workspace *workspace) {
 		return;
 	}
 
+	scene_node_disown_children(workspace->layers.tiling);
+	scene_node_disown_children(workspace->layers.fullscreen);
+	wlr_scene_node_destroy(&workspace->layers.tiling->node);
+	wlr_scene_node_destroy(&workspace->layers.fullscreen->node);
+
 	free(workspace->name);
 	free(workspace->representation);
 	list_free_items_and_destroy(workspace->output_priority);