Introduce new scene-graph API

A new wlr_scene API has been added, following the design ideas from [1].
The new API contains the minimal set of features required to make the
API useful. The goal is to design a solid fundation and add more
features in the future.

[1]: https://github.com/swaywm/wlroots/issues/1826#issuecomment-564601757
This commit is contained in:
Simon Ser 2019-12-25 18:53:58 +01:00
parent 5f645598d8
commit c7d489b5b6
3 changed files with 378 additions and 0 deletions

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@ -0,0 +1,114 @@
/*
* This an unstable interface of wlroots. No guarantees are made regarding the
* future consistency of this API.
*/
#ifndef WLR_USE_UNSTABLE
#error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
#endif
#ifndef WLR_TYPES_WLR_SCENE_H
#define WLR_TYPES_WLR_SCENE_H
/**
* The scene-graph API provides a declarative way to display surfaces. The
* compositor creates a scene, adds surfaces, then renders the scene on
* outputs.
*
* The scene-graph API only supports basic 2D composition operations (like the
* KMS API or the Wayland protocol does). For anything more complicated,
* compositors need to implement custom rendering logic.
*/
#include <pixman.h>
#include <wayland-server-core.h>
#include <wlr/types/wlr_surface.h>
struct wlr_output;
enum wlr_scene_node_type {
WLR_SCENE_NODE_ROOT,
WLR_SCENE_NODE_SURFACE,
};
struct wlr_scene_node_state {
struct wl_list link; // wlr_scene_node_state.children
struct wl_list children; // wlr_scene_node_state.link
int x, y; // relative to parent
};
/** A node is an object in the scene. */
struct wlr_scene_node {
enum wlr_scene_node_type type;
struct wlr_scene_node *parent;
struct wlr_scene_node_state state;
struct {
struct wl_signal destroy;
} events;
};
/** The root scene-graph node. */
struct wlr_scene {
struct wlr_scene_node node;
};
/** A scene-graph node displaying a single surface. */
struct wlr_scene_surface {
struct wlr_scene_node node;
struct wlr_surface *surface;
// private state
struct wl_listener surface_destroy;
};
/**
* Immediately destroy the scene-graph node.
*/
void wlr_scene_node_destroy(struct wlr_scene_node *node);
/**
* Set the position of the node relative to its parent.
*/
void wlr_scene_node_set_position(struct wlr_scene_node *node, int x, int y);
/**
* Move the node right above the specified sibling.
*/
void wlr_scene_node_place_above(struct wlr_scene_node *node,
struct wlr_scene_node *sibling);
/**
* Move the node right below the specified sibling.
*/
void wlr_scene_node_place_below(struct wlr_scene_node *node,
struct wlr_scene_node *sibling);
/**
* Call `iterator` on each surface in the scene-graph, with the surface's
* position in layout coordinates. The function is called from root to leaves
* (in rendering order).
*/
void wlr_scene_node_for_each_surface(struct wlr_scene_node *node,
wlr_surface_iterator_func_t iterator, void *user_data);
/**
* Create a new scene-graph.
*/
struct wlr_scene *wlr_scene_create(void);
/**
* Manually render the scene-graph on an output. The compositor needs to call
* wlr_renderer_begin before and wlr_renderer_end after calling this function.
* Damage is given in output-buffer-local coordinates and can be set to NULL to
* disable damage tracking.
*/
void wlr_scene_render_output(struct wlr_scene *scene, struct wlr_output *output,
int lx, int ly, pixman_region32_t *damage);
/**
* Add a node displaying a single surface to the scene-graph.
*
* The child sub-surfaces are ignored.
*/
struct wlr_scene_surface *wlr_scene_surface_create(struct wlr_scene_node *parent,
struct wlr_surface *surface);
#endif

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@ -49,6 +49,7 @@ wlr_files += files(
'wlr_primary_selection.c',
'wlr_region.c',
'wlr_relative_pointer_v1.c',
'wlr_scene.c',
'wlr_screencopy_v1.c',
'wlr_server_decoration.c',
'wlr_surface.c',

263
types/wlr_scene.c Normal file
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#include <assert.h>
#include <stdlib.h>
#include <wlr/backend.h>
#include <wlr/render/wlr_renderer.h>
#include <wlr/types/wlr_matrix.h>
#include <wlr/types/wlr_scene.h>
#include <wlr/types/wlr_surface.h>
#include "util/signal.h"
static struct wlr_scene *scene_root_from_node(struct wlr_scene_node *node) {
assert(node->type == WLR_SCENE_NODE_ROOT);
return (struct wlr_scene *)node;
}
static struct wlr_scene_surface *scene_surface_from_node(
struct wlr_scene_node *node) {
assert(node->type == WLR_SCENE_NODE_SURFACE);
return (struct wlr_scene_surface *)node;
}
static void scene_node_state_init(struct wlr_scene_node_state *state) {
wl_list_init(&state->children);
wl_list_init(&state->link);
}
static void scene_node_state_finish(struct wlr_scene_node_state *state) {
wl_list_remove(&state->link);
}
static void scene_node_init(struct wlr_scene_node *node,
enum wlr_scene_node_type type, struct wlr_scene_node *parent) {
assert(type == WLR_SCENE_NODE_ROOT || parent != NULL);
assert(parent == NULL || parent->type == WLR_SCENE_NODE_ROOT);
node->type = type;
node->parent = parent;
scene_node_state_init(&node->state);
wl_signal_init(&node->events.destroy);
if (parent != NULL) {
wl_list_insert(parent->state.children.prev, &node->state.link);
}
}
static void scene_node_finish(struct wlr_scene_node *node) {
wlr_signal_emit_safe(&node->events.destroy, NULL);
struct wlr_scene_node *child, *child_tmp;
wl_list_for_each_safe(child, child_tmp,
&node->state.children, state.link) {
wlr_scene_node_destroy(child);
}
scene_node_state_finish(&node->state);
}
void wlr_scene_node_destroy(struct wlr_scene_node *node) {
if (node == NULL) {
return;
}
scene_node_finish(node);
switch (node->type) {
case WLR_SCENE_NODE_ROOT:;
struct wlr_scene *scene = scene_root_from_node(node);
free(scene);
break;
case WLR_SCENE_NODE_SURFACE:;
struct wlr_scene_surface *scene_surface = scene_surface_from_node(node);
wl_list_remove(&scene_surface->surface_destroy.link);
free(scene_surface);
break;
}
}
struct wlr_scene *wlr_scene_create(void) {
struct wlr_scene *scene = calloc(1, sizeof(struct wlr_scene));
if (scene == NULL) {
return NULL;
}
scene_node_init(&scene->node, WLR_SCENE_NODE_ROOT, NULL);
return scene;
}
static void scene_surface_handle_surface_destroy(struct wl_listener *listener,
void *data) {
struct wlr_scene_surface *scene_surface =
wl_container_of(listener, scene_surface, surface_destroy);
wlr_scene_node_destroy(&scene_surface->node);
}
struct wlr_scene_surface *wlr_scene_surface_create(struct wlr_scene_node *parent,
struct wlr_surface *surface) {
struct wlr_scene_surface *scene_surface =
calloc(1, sizeof(struct wlr_scene_surface));
if (scene_surface == NULL) {
return NULL;
}
scene_node_init(&scene_surface->node, WLR_SCENE_NODE_SURFACE, parent);
scene_surface->surface = surface;
scene_surface->surface_destroy.notify = scene_surface_handle_surface_destroy;
wl_signal_add(&surface->events.destroy, &scene_surface->surface_destroy);
return scene_surface;
}
void wlr_scene_node_set_position(struct wlr_scene_node *node, int x, int y) {
node->state.x = x;
node->state.y = y;
}
void wlr_scene_node_place_above(struct wlr_scene_node *node,
struct wlr_scene_node *sibling) {
assert(node->parent == sibling->parent);
wl_list_remove(&node->state.link);
wl_list_insert(&sibling->state.link, &node->state.link);
}
void wlr_scene_node_place_below(struct wlr_scene_node *node,
struct wlr_scene_node *sibling) {
assert(node->parent == sibling->parent);
wl_list_remove(&node->state.link);
wl_list_insert(sibling->state.link.prev, &node->state.link);
}
static void scene_node_for_each_surface(struct wlr_scene_node *node,
int lx, int ly, wlr_surface_iterator_func_t user_iterator,
void *user_data) {
lx += node->state.x;
ly += node->state.y;
if (node->type == WLR_SCENE_NODE_SURFACE) {
struct wlr_scene_surface *scene_surface = scene_surface_from_node(node);
user_iterator(scene_surface->surface, lx, ly, user_data);
}
struct wlr_scene_node *child;
wl_list_for_each(child, &node->state.children, state.link) {
scene_node_for_each_surface(child, lx, ly, user_iterator, user_data);
}
}
void wlr_scene_node_for_each_surface(struct wlr_scene_node *node,
wlr_surface_iterator_func_t user_iterator, void *user_data) {
scene_node_for_each_surface(node, 0, 0, user_iterator, user_data);
}
static int scale_length(int length, int offset, float scale) {
return round((offset + length) * scale) - round(offset * scale);
}
static void scale_box(struct wlr_box *box, float scale) {
box->width = scale_length(box->width, box->x, scale);
box->height = scale_length(box->height, box->y, scale);
box->x = round(box->x * scale);
box->y = round(box->y * scale);
}
static void scissor_output(struct wlr_output *output, pixman_box32_t *rect) {
struct wlr_renderer *renderer = wlr_backend_get_renderer(output->backend);
assert(renderer);
struct wlr_box box = {
.x = rect->x1,
.y = rect->y1,
.width = rect->x2 - rect->x1,
.height = rect->y2 - rect->y1,
};
int ow, oh;
wlr_output_transformed_resolution(output, &ow, &oh);
enum wl_output_transform transform =
wlr_output_transform_invert(output->transform);
wlr_box_transform(&box, &box, transform, ow, oh);
wlr_renderer_scissor(renderer, &box);
}
static void render_texture(struct wlr_output *output,
pixman_region32_t *output_damage, struct wlr_texture *texture,
const struct wlr_box *box, const float matrix[static 9]) {
struct wlr_renderer *renderer = wlr_backend_get_renderer(output->backend);
assert(renderer);
pixman_region32_t damage;
pixman_region32_init(&damage);
pixman_region32_init_rect(&damage, box->x, box->y, box->width, box->height);
pixman_region32_intersect(&damage, &damage, output_damage);
if (pixman_region32_not_empty(&damage)) {
int nrects;
pixman_box32_t *rects = pixman_region32_rectangles(&damage, &nrects);
for (int i = 0; i < nrects; ++i) {
scissor_output(output, &rects[i]);
wlr_render_texture_with_matrix(renderer, texture, matrix, 1.0);
}
}
pixman_region32_fini(&damage);
}
struct render_data {
struct wlr_output *output;
pixman_region32_t *damage;
};
static void render_surface_iterator(struct wlr_surface *surface,
int x, int y, void *_data) {
struct render_data *data = _data;
struct wlr_output *output = data->output;
pixman_region32_t *output_damage = data->damage;
struct wlr_texture *texture = wlr_surface_get_texture(surface);
if (texture == NULL) {
return;
}
struct wlr_box box = {
.x = x,
.y = y,
.width = surface->current.width,
.height = surface->current.height,
};
scale_box(&box, output->scale);
float matrix[9];
enum wl_output_transform transform =
wlr_output_transform_invert(surface->current.transform);
wlr_matrix_project_box(matrix, &box, transform, 0.0,
output->transform_matrix);
render_texture(output, output_damage, texture, &box, matrix);
}
void wlr_scene_render_output(struct wlr_scene *scene, struct wlr_output *output,
int lx, int ly, pixman_region32_t *damage) {
pixman_region32_t full_region;
pixman_region32_init_rect(&full_region, 0, 0, output->width, output->height);
if (damage == NULL) {
damage = &full_region;
}
struct wlr_renderer *renderer =
wlr_backend_get_renderer(output->backend);
assert(renderer);
if (output->enabled && pixman_region32_not_empty(damage)) {
struct render_data data = {
.output = output,
.damage = damage,
};
scene_node_for_each_surface(&scene->node, lx, ly,
render_surface_iterator, &data);
wlr_renderer_scissor(renderer, NULL);
}
pixman_region32_fini(&full_region);
}