bytemedia

dev_draw.c (7632B)

#define _POSIX_C_SOURCE 200112L
#include "xdg-shell-client-protocol.h"
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h> /* exit(), EXIT_FAILURE */
#include <stdio.h> /* fputs(), stderr */
#include <string.h>
#include <sys/mman.h>
#include <time.h>
#include <unistd.h>
#include <wayland-client.h>
/* Shared memory support code */
static void
randname(char *buf)
{
	struct timespec ts;
	clock_gettime(CLOCK_REALTIME, &ts);
	long r = ts.tv_nsec;
	for(int i = 0; i < 6; ++i)
	{
		buf[i] = 'A' + (r & 15) + (r & 16) * 2;
		r >>= 5;
	}
}
static int
create_shm_file(void)
{
	int retries = 100;
	do
	{
		char name[] = "/wl_shm-XXXXXX";
		randname(name + sizeof(name) - 7);
		--retries;
		int fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
		if(fd >= 0)
		{
			shm_unlink(name);
			return fd;
		}
	} while(retries > 0 && errno == EEXIST);
	return -1;
}
static int
allocate_shm_file(size_t size)
{
	int fd = create_shm_file();
	if(fd < 0) return -1;
	int ret;
	do
	{
		ret = ftruncate(fd, size);
	} while(ret < 0 && errno == EINTR);
	if(ret < 0)
	{
		close(fd);
		return -1;
	}
	return fd;
}
/* Wayland code */
struct client_state
{
	/* Globals */
	struct wl_display *wl_display;
	struct wl_registry *wl_registry;
	struct wl_compositor *wl_compositor;
	struct xdg_wm_base *xdg_wm_base;
	struct wl_shm *wl_shm;
	struct wl_buffer *wl_buffer;
	uint32_t *shm_data;
	/* Objects */
	struct wl_surface *wl_surface;
	struct xdg_surface *xdg_surface;
	struct xdg_toplevel *xdg_toplevel;
	/* State */
	float offset;
	uint32_t last_frame;
	int32_t width, height, size, stride;
	bool closed;
};
static void
draw_frame(struct client_state *state)
{
	int t = (int)state->offset;
	/* Let the fun begin! */
	if(fread(state->shm_data, state->size, 1, stdin) == -1) {
		state->closed = true;
	}
}
static void
allocate_wl_shm_buffer(struct client_state *state)
{
	struct wl_shm_pool *pool;
	int shm_fd = allocate_shm_file(state->size);
	if(shm_fd == -1)
	{
		return;
	}
	state->shm_data = mmap(NULL, state->size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
	if(state->shm_data == MAP_FAILED)
	{
		close(shm_fd);
		return;
	}
	pool             = wl_shm_create_pool(state->wl_shm, shm_fd, state->size);
	state->wl_buffer = wl_shm_pool_create_buffer(
	    pool, 0, state->width, state->height, state->stride, WL_SHM_FORMAT_XRGB8888);
	wl_shm_pool_destroy(pool);
	close(shm_fd);
}
static void
xdg_toplevel_configure(void *data,
                       struct xdg_toplevel *xdg_toplevel,
                       int32_t width,
                       int32_t height,
                       struct wl_array *states)
{
	struct client_state *state = data;
	if(width != 0 && height != 0)
	{
		munmap(state->shm_data, state->width * state->height * 4);
		state->width  = width;
		state->height = height;
		state->stride = width * 4;
		state->size = state->stride * height;
		allocate_wl_shm_buffer(state);
	}
}
static void
xdg_toplevel_close(void *data, struct xdg_toplevel *toplevel)
{
	struct client_state *state = data;
	state->closed              = true;
}
static const struct xdg_toplevel_listener xdg_toplevel_listener = {
    .configure = xdg_toplevel_configure,
    .close     = xdg_toplevel_close,
};
static void
xdg_surface_configure(void *data, struct xdg_surface *xdg_surface, uint32_t serial)
{
	struct client_state *state = data;
	xdg_surface_ack_configure(xdg_surface, serial);
	draw_frame(state);
	wl_surface_attach(state->wl_surface, state->wl_buffer, 0, 0);
	wl_surface_commit(state->wl_surface);
}
static const struct xdg_surface_listener xdg_surface_listener = {
    .configure = xdg_surface_configure,
};
static void
xdg_wm_base_ping(void *data, struct xdg_wm_base *xdg_wm_base, uint32_t serial)
{
	xdg_wm_base_pong(xdg_wm_base, serial);
}
static const struct xdg_wm_base_listener xdg_wm_base_listener = {
    .ping = xdg_wm_base_ping,
};
static const struct wl_callback_listener wl_surface_frame_listener;
static void
wl_surface_frame_done(void *data, struct wl_callback *cb, uint32_t time)
{
	/* Destroy this callback */
	wl_callback_destroy(cb);
	/* Request another frame */
	struct client_state *state = data;
	cb                         = wl_surface_frame(state->wl_surface);
	wl_callback_add_listener(cb, &wl_surface_frame_listener, state);
	/* Update scroll amount at 24 pixels per second */
	if(state->last_frame != 0)
	{
		int elapsed = time - state->last_frame;
		state->offset += elapsed / 1000.0 * 24;
	}
	/* Submit a frame for this event */
	draw_frame(state);
	wl_surface_attach(state->wl_surface, state->wl_buffer, 0, 0);
	wl_surface_damage_buffer(state->wl_surface, 0, 0, INT32_MAX, INT32_MAX);
	wl_surface_commit(state->wl_surface);
	state->last_frame = time;
}
static const struct wl_callback_listener wl_surface_frame_listener = {
    .done = wl_surface_frame_done,
};
static void
registry_global(void *data,
                struct wl_registry *wl_registry,
                uint32_t name,
                const char *interface,
                uint32_t version)
{
	struct client_state *state = data;
	if(strcmp(interface, wl_shm_interface.name) == 0)
	{
		state->wl_shm = wl_registry_bind(wl_registry, name, &wl_shm_interface, 1);
		allocate_wl_shm_buffer(state);
	}
	else if(strcmp(interface, wl_compositor_interface.name) == 0)
	{
		state->wl_compositor = wl_registry_bind(wl_registry, name, &wl_compositor_interface, 4);
	}
	else if(strcmp(interface, xdg_wm_base_interface.name) == 0)
	{
		state->xdg_wm_base = wl_registry_bind(wl_registry, name, &xdg_wm_base_interface, 1);
		xdg_wm_base_add_listener(state->xdg_wm_base, &xdg_wm_base_listener, state);
	}
}
static void
registry_global_remove(void *data, struct wl_registry *wl_registry, uint32_t name)
{
	/* This space deliberately left blank */
}
static const struct wl_registry_listener wl_registry_listener = {
    .global        = registry_global,
    .global_remove = registry_global_remove,
};
static void
fatal(const char *message) {
	fputs(message, stderr);
	exit(EXIT_FAILURE);
}
int
main(int argc, char *argv[])
{
	struct client_state state = {0};
	state.width               = 800;
	state.height              = 600;
	state.closed              = false;
	state.stride = state.width * 4;
	state.size = state.stride * state.height;
	state.wl_display          = wl_display_connect(NULL);
	if(!state.wl_display) fatal("Failed to connect to wayland display, exiting...\n");
	state.wl_registry         = wl_display_get_registry(state.wl_display);
	wl_registry_add_listener(state.wl_registry, &wl_registry_listener, &state);
	wl_display_roundtrip(state.wl_display);
	if(!state.wl_shm) fatal("wl_shm protocol not found, exiting...\n");
	if(!state.wl_compositor) fatal("wl_compositor protocol not found, exiting...\n");
	if(!state.xdg_wm_base) fatal("xdg_wm_base protocol not found, exiting...\n");
	state.wl_surface  = wl_compositor_create_surface(state.wl_compositor);
	state.xdg_surface = xdg_wm_base_get_xdg_surface(state.xdg_wm_base, state.wl_surface);
	xdg_surface_add_listener(state.xdg_surface, &xdg_surface_listener, &state);
	state.xdg_toplevel = xdg_surface_get_toplevel(state.xdg_surface);
	xdg_toplevel_add_listener(state.xdg_toplevel, &xdg_toplevel_listener, &state);
	xdg_toplevel_set_title(state.xdg_toplevel, "/dev/draw for wayland");
	wl_surface_commit(state.wl_surface);
	struct wl_callback *cb = wl_surface_frame(state.wl_surface);
	wl_callback_add_listener(cb, &wl_surface_frame_listener, &state);
	while(wl_display_dispatch(state.wl_display) && !state.closed)
	{
		/* This space deliberately left blank */
	}
	munmap(state.shm_data, state.size);
	return 0;
}