diyac/output.c

#define _POSIX_C_SOURCE 200112L
#include <time.h>
#include <stdlib.h>
#include <wlr/types/wlr_scene.h>
#include <wlr/types/wlr_output_layout.h>
#include "output.h"

static void output_frame(struct wl_listener *listener, void *data) {
    /* This function is called every time an output is ready to display a frame,
     * generally at the output's refresh rate (e.g. 60Hz). */
    struct diyac_output *output = wl_container_of(listener, output, frame);
    struct wlr_scene *scene = output->server->scene;

    struct wlr_scene_output *scene_output = wlr_scene_get_scene_output(
        scene, output->wlr_output);

    /* Render the scene if needed and commit the output */
    wlr_scene_output_commit(scene_output, NULL);

    struct timespec now;
    clock_gettime(CLOCK_MONOTONIC, &now);
    wlr_scene_output_send_frame_done(scene_output, &now);
}

static void output_request_state(struct wl_listener *listener, void *data) {
    /* This function is called when the backend requests a new state for
     * the output. For example, Wayland and X11 backends request a new mode
     * when the output window is resized. */
    struct diyac_output *output = wl_container_of(listener, output, request_state);
    const struct wlr_output_event_request_state *event = data;
    wlr_output_commit_state(output->wlr_output, event->state);
}

static void output_destroy(struct wl_listener *listener, void *data) {
    struct diyac_output *output = wl_container_of(listener, output, destroy);

    wl_list_remove(&output->frame.link);
    wl_list_remove(&output->request_state.link);
    wl_list_remove(&output->destroy.link);
    wl_list_remove(&output->link);
    free(output);
}

void diyac_server_new_output(struct wl_listener *listener, void *data) {
    /* This event is raised by the backend when a new output (aka a display or
     * monitor) becomes available. */
    struct diyac_server *server =
        wl_container_of(listener, server, new_output);
    struct wlr_output *wlr_output = data;

    /* Configures the output created by the backend to use our allocator
     * and our renderer. Must be done once, before commiting the output */
    wlr_output_init_render(wlr_output, server->allocator, server->renderer);

    /* The output may be disabled, switch it on. */
    struct wlr_output_state state;
    wlr_output_state_init(&state);
    wlr_output_state_set_enabled(&state, true);

    /* Some backends don't have modes. DRM+KMS does, and we need to set a mode
     * before we can use the output. The mode is a tuple of (width, height,
     * refresh rate), and each monitor supports only a specific set of modes. We
     * just pick the monitor's preferred mode, a more sophisticated compositor
     * would let the user configure it. */
    struct wlr_output_mode *mode = wlr_output_preferred_mode(wlr_output);
    if (mode != NULL) {
        wlr_output_state_set_mode(&state, mode);
    }

    /* Atomically applies the new output state. */
    wlr_output_commit_state(wlr_output, &state);
    wlr_output_state_finish(&state);

    /* Allocates and configures our state for this output */
    struct diyac_output *output = calloc(1, sizeof(*output));
    output->wlr_output = wlr_output;
    output->server = server;

    /* Sets up a listener for the frame event. */
    output->frame.notify = output_frame;
    wl_signal_add(&wlr_output->events.frame, &output->frame);

    /* Sets up a listener for the state request event. */
    output->request_state.notify = output_request_state;
    wl_signal_add(&wlr_output->events.request_state, &output->request_state);

    /* Sets up a listener for the destroy event. */
    output->destroy.notify = output_destroy;
    wl_signal_add(&wlr_output->events.destroy, &output->destroy);

    wl_list_insert(&server->outputs, &output->link);

    /* Adds this to the output layout. The add_auto function arranges outputs
     * from left-to-right in the order they appear. A more sophisticated
     * compositor would let the user configure the arrangement of outputs in the
     * layout.
     *
     * The output layout utility automatically adds a wl_output global to the
     * display, which Wayland clients can see to find out information about the
     * output (such as DPI, scale factor, manufacturer, etc).
     */
    struct wlr_output_layout_output *l_output = wlr_output_layout_add_auto(server->output_layout,
        wlr_output);
    struct wlr_scene_output *scene_output = wlr_scene_output_create(server->scene, wlr_output);
    wlr_scene_output_layout_add_output(server->scene_layout, l_output, scene_output);
}