text: /*
   * Copyright © 2011 Benjamin Franzke
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  
  #include "config.h"
  
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdbool.h>
  #include <math.h>
  #include <assert.h>
  #include <signal.h>
  
  #include <linux/input.h>
  
  #include <wayland-client.h>
  #include <wayland-egl.h>
  #include <wayland-cursor.h>
  
  #include <GLES2/gl2.h>
  #include <EGL/egl.h>
  #include <EGL/eglext.h>
  
  #include "xdg-shell-client-protocol.h"
  #include <sys/types.h>
  #include <unistd.h>
  
  #include "shared/helpers.h"
  #include "shared/platform.h"
  #include "shared/weston-egl-ext.h"
  
  struct window;
  struct seat;
  
  struct display {
  	struct wl_display *display;
  	struct wl_registry *registry;
  	struct wl_compositor *compositor;
  	struct xdg_wm_base *wm_base;
  	struct wl_seat *seat;
  	struct wl_pointer *pointer;
  	struct wl_touch *touch;
  	struct wl_keyboard *keyboard;
  	struct wl_shm *shm;
  	struct wl_cursor_theme *cursor_theme;
  	struct wl_cursor *default_cursor;
  	struct wl_surface *cursor_surface;
  	struct {
  		EGLDisplay dpy;
  		EGLContext ctx;
  		EGLConfig conf;
  	} egl;
  	struct window *window;
  
  	PFNEGLSWAPBUFFERSWITHDAMAGEEXTPROC swap_buffers_with_damage;
  };
  
  struct geometry {
  	int width, height;
  };
  
  struct window {
  	struct display *display;
  	struct geometry geometry, window_size;
  	struct {
  		GLuint rotation_uniform;
  		GLuint pos;
  		GLuint col;
  	} gl;
  
  	uint32_t benchmark_time, frames;
  	struct wl_egl_window *native;
  	struct wl_surface *surface;
  	struct xdg_surface *xdg_surface;
  	struct xdg_toplevel *xdg_toplevel;
  	EGLSurface egl_surface;
  	struct wl_callback *callback;
  	int fullscreen, maximized, opaque, buffer_size, frame_sync, delay;
  	bool wait_for_configure;
  };
  
  static const char *vert_shader_text =
  	"uniform mat4 rotation;\n"
  	"attribute vec4 pos;\n"
  	"attribute vec4 color;\n"
  	"varying vec4 v_color;\n"
  	"void main() {\n"
  	"  gl_Position = rotation * pos;\n"
  	"  v_color = color;\n"
  	"}\n";
  
  static const char *frag_shader_text =
  	"precision mediump float;\n"
  	"varying vec4 v_color;\n"
  	"void main() {\n"
  	"  gl_FragColor = v_color;\n"
  	"}\n";
  
  static int running = 1;
  
  static void
  init_egl(struct display *display, struct window *window)
  {
  	static const struct {
  		char *extension, *entrypoint;
  	} swap_damage_ext_to_entrypoint[] = {
  		{
  			.extension = "EGL_EXT_swap_buffers_with_damage",
  			.entrypoint = "eglSwapBuffersWithDamageEXT",
  		},
  		{
  			.extension = "EGL_KHR_swap_buffers_with_damage",
  			.entrypoint = "eglSwapBuffersWithDamageKHR",
  		},
  	};
  
  	static const EGLint context_attribs[] = {
  		EGL_CONTEXT_CLIENT_VERSION, 2,
  		EGL_NONE
  	};
  	const char *extensions;
  
  	EGLint config_attribs[] = {
  		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
  		EGL_RED_SIZE, 1,
  		EGL_GREEN_SIZE, 1,
  		EGL_BLUE_SIZE, 1,
  		EGL_ALPHA_SIZE, 1,
  		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
  		EGL_NONE
  	};
  
  	EGLint major, minor, n, count, i, size;
  	EGLConfig *configs;
  	EGLBoolean ret;
  
  	if (window->opaque || window->buffer_size == 16)
  		config_attribs[9] = 0;
  
  	display->egl.dpy =
  		weston_platform_get_egl_display(EGL_PLATFORM_WAYLAND_KHR,
  						display->display, NULL);
  	assert(display->egl.dpy);
  
  	ret = eglInitialize(display->egl.dpy, &major, &minor);
  	assert(ret == EGL_TRUE);
  	ret = eglBindAPI(EGL_OPENGL_ES_API);
  	assert(ret == EGL_TRUE);
  
  	if (!eglGetConfigs(display->egl.dpy, NULL, 0, &count) || count < 1)
  		assert(0);
  
  	configs = calloc(count, sizeof *configs);
  	assert(configs);
  
  	ret = eglChooseConfig(display->egl.dpy, config_attribs,
  			      configs, count, &n);
  	assert(ret && n >= 1);
  
  	for (i = 0; i < n; i++) {
  		eglGetConfigAttrib(display->egl.dpy,
  				   configs[i], EGL_BUFFER_SIZE, &size);
  		if (window->buffer_size == size) {
  			display->egl.conf = configs[i];
  			break;
  		}
  	}
  	free(configs);
  	if (display->egl.conf == NULL) {
  		fprintf(stderr, "did not find config with buffer size %d\n",
  			window->buffer_size);
  		exit(EXIT_FAILURE);
  	}
  
  	display->egl.ctx = eglCreateContext(display->egl.dpy,
  					    display->egl.conf,
  					    EGL_NO_CONTEXT, context_attribs);
  	assert(display->egl.ctx);
  
  	display->swap_buffers_with_damage = NULL;
  	extensions = eglQueryString(display->egl.dpy, EGL_EXTENSIONS);
  	if (extensions &&
  	    weston_check_egl_extension(extensions, "EGL_EXT_buffer_age")) {
  		for (i = 0; i < (int) ARRAY_LENGTH(swap_damage_ext_to_entrypoint); i++) {
  			if (weston_check_egl_extension(extensions,
  						       swap_damage_ext_to_entrypoint[i].extension)) {
  				/* The EXTPROC is identical to the KHR one */
  				display->swap_buffers_with_damage =
  					(PFNEGLSWAPBUFFERSWITHDAMAGEEXTPROC)
  					eglGetProcAddress(swap_damage_ext_to_entrypoint[i].entrypoint);
  				break;
  			}
  		}
  	}
  
  	if (display->swap_buffers_with_damage)
  		printf("has EGL_EXT_buffer_age and %s\n", swap_damage_ext_to_entrypoint[i].extension);
  
  }
  
  static void
  fini_egl(struct display *display)
  {
  	eglTerminate(display->egl.dpy);
  	eglReleaseThread();
  }
  
  static GLuint
  create_shader(struct window *window, const char *source, GLenum shader_type)
  {
  	GLuint shader;
  	GLint status;
  
  	shader = glCreateShader(shader_type);
  	assert(shader != 0);
  
  	glShaderSource(shader, 1, (const char **) &source, NULL);
  	glCompileShader(shader);
  
  	glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
  	if (!status) {
  		char log[1000];
  		GLsizei len;
  		glGetShaderInfoLog(shader, 1000, &len, log);
  		fprintf(stderr, "Error: compiling %s: %.*s\n",
  			shader_type == GL_VERTEX_SHADER ? "vertex" : "fragment",
  			len, log);
  		exit(1);
  	}
  
  	return shader;
  }
  
  static void
  init_gl(struct window *window)
  {
  	GLuint frag, vert;
  	GLuint program;
  	GLint status;
  
  	frag = create_shader(window, frag_shader_text, GL_FRAGMENT_SHADER);
  	vert = create_shader(window, vert_shader_text, GL_VERTEX_SHADER);
  
  	program = glCreateProgram();
  	glAttachShader(program, frag);
  	glAttachShader(program, vert);
  	glLinkProgram(program);
  
  	glGetProgramiv(program, GL_LINK_STATUS, &status);
  	if (!status) {
  		char log[1000];
  		GLsizei len;
  		glGetProgramInfoLog(program, 1000, &len, log);
  		fprintf(stderr, "Error: linking:\n%.*s\n", len, log);
  		exit(1);
  	}
  
  	glUseProgram(program);
  
  	window->gl.pos = 0;
  	window->gl.col = 1;
  
  	glBindAttribLocation(program, window->gl.pos, "pos");
  	glBindAttribLocation(program, window->gl.col, "color");
  	glLinkProgram(program);
  
  	window->gl.rotation_uniform =
  		glGetUniformLocation(program, "rotation");
  }
  
  static void
  handle_surface_configure(void *data, struct xdg_surface *surface,
  			 uint32_t serial)
  {
  	struct window *window = data;
  
  	xdg_surface_ack_configure(surface, serial);
  
  	window->wait_for_configure = false;
  }
  
  static const struct xdg_surface_listener xdg_surface_listener = {
  	handle_surface_configure
  };
  
  static void
  handle_toplevel_configure(void *data, struct xdg_toplevel *toplevel,
  			  int32_t width, int32_t height,
  			  struct wl_array *states)
  {
  	struct window *window = data;
  	uint32_t *p;
  
  	window->fullscreen = 0;
  	window->maximized = 0;
  	wl_array_for_each(p, states) {
  		uint32_t state = *p;
  		switch (state) {
  		case XDG_TOPLEVEL_STATE_FULLSCREEN:
  			window->fullscreen = 1;
  			break;
  		case XDG_TOPLEVEL_STATE_MAXIMIZED:
  			window->maximized = 1;
  			break;
  		}
  	}
  
  	if (width > 0 && height > 0) {
  		if (!window->fullscreen && !window->maximized) {
  			window->window_size.width = width;
  			window->window_size.height = height;
  		}
  		window->geometry.width = width;
  		window->geometry.height = height;
  	} else if (!window->fullscreen && !window->maximized) {
  		window->geometry = window->window_size;
  	}
  
  	if (window->native)
  		wl_egl_window_resize(window->native,
  				     window->geometry.width,
  				     window->geometry.height, 0, 0);
  }
  
  static void
  handle_toplevel_close(void *data, struct xdg_toplevel *xdg_toplevel)
  {
  	running = 0;
  }
  
  static const struct xdg_toplevel_listener xdg_toplevel_listener = {
  	handle_toplevel_configure,
  	handle_toplevel_close,
  };
  
  static void
  create_surface(struct window *window)
  {
  	struct display *display = window->display;
  	EGLBoolean ret;
  
  	window->surface = wl_compositor_create_surface(display->compositor);
  
  	window->native =
  		wl_egl_window_create(window->surface,
  				     window->geometry.width,
  				     window->geometry.height);
  	window->egl_surface =
  		weston_platform_create_egl_surface(display->egl.dpy,
  						   display->egl.conf,
  						   window->native, NULL);
  
  	window->xdg_surface = xdg_wm_base_get_xdg_surface(display->wm_base,
  							  window->surface);
  	xdg_surface_add_listener(window->xdg_surface,
  				 &xdg_surface_listener, window);
  
  	window->xdg_toplevel =
  		xdg_surface_get_toplevel(window->xdg_surface);
  	xdg_toplevel_add_listener(window->xdg_toplevel,
  				  &xdg_toplevel_listener, window);
  
  	xdg_toplevel_set_title(window->xdg_toplevel, "simple-egl");
  
  	window->wait_for_configure = true;
  	wl_surface_commit(window->surface);
  
  	ret = eglMakeCurrent(window->display->egl.dpy, window->egl_surface,
  			     window->egl_surface, window->display->egl.ctx);
  	assert(ret == EGL_TRUE);
  
  	if (!window->frame_sync)
  		eglSwapInterval(display->egl.dpy, 0);
  
  	if (!display->wm_base)
  		return;
  
  	if (window->fullscreen)
  		xdg_toplevel_set_fullscreen(window->xdg_toplevel, NULL);
  }
  
  static void
  destroy_surface(struct window *window)
  {
  	/* Required, otherwise segfault in egl_dri2.c: dri2_make_current()
  	 * on eglReleaseThread(). */
  	eglMakeCurrent(window->display->egl.dpy, EGL_NO_SURFACE, EGL_NO_SURFACE,
  		       EGL_NO_CONTEXT);
  
  	weston_platform_destroy_egl_surface(window->display->egl.dpy,
  					    window->egl_surface);
  	wl_egl_window_destroy(window->native);
  
  	if (window->xdg_toplevel)
  		xdg_toplevel_destroy(window->xdg_toplevel);
  	if (window->xdg_surface)
  		xdg_surface_destroy(window->xdg_surface);
  	wl_surface_destroy(window->surface);
  
  	if (window->callback)
  		wl_callback_destroy(window->callback);
  }
  
  static void
  redraw(void *data, struct wl_callback *callback, uint32_t time)
  {
  	struct window *window = data;
  	struct display *display = window->display;
  	static const GLfloat verts[3][2] = {
  		{ -0.5, -0.5 },
  		{  0.5, -0.5 },
  		{  0,    0.5 }
  	};
  	static const GLfloat colors[3][3] = {
  		{ 1, 0, 0 },
  		{ 0, 1, 0 },
  		{ 0, 0, 1 }
  	};
  	GLfloat angle;
  	GLfloat rotation[4][4] = {
  		{ 1, 0, 0, 0 },
  		{ 0, 1, 0, 0 },
  		{ 0, 0, 1, 0 },
  		{ 0, 0, 0, 1 }
  	};
  	static const uint32_t speed_div = 5, benchmark_interval = 5;
  	struct wl_region *region;
  	EGLint rect[4];
  	EGLint buffer_age = 0;
  	struct timeval tv;
  
  	assert(window->callback == callback);
  	window->callback = NULL;
  
  	if (callback)
  		wl_callback_destroy(callback);
  
  	gettimeofday(&tv, NULL);
  	time = tv.tv_sec * 1000 + tv.tv_usec / 1000;
  	if (window->frames == 0)
  		window->benchmark_time = time;
  	if (time - window->benchmark_time > (benchmark_interval * 1000)) {
  		printf("%d frames in %d seconds: %f fps\n",
  		       window->frames,
  		       benchmark_interval,
  		       (float) window->frames / benchmark_interval);
  		window->benchmark_time = time;
  		window->frames = 0;
  	}
  
  	angle = (time / speed_div) % 360 * M_PI / 180.0;
  	rotation[0][0] =  cos(angle);
  	rotation[0][2] =  sin(angle);
  	rotation[2][0] = -sin(angle);
  	rotation[2][2] =  cos(angle);
  
  	if (display->swap_buffers_with_damage)
  		eglQuerySurface(display->egl.dpy, window->egl_surface,
  				EGL_BUFFER_AGE_EXT, &buffer_age);
  
  	glViewport(0, 0, window->geometry.width, window->geometry.height);
  
  	glUniformMatrix4fv(window->gl.rotation_uniform, 1, GL_FALSE,
  			   (GLfloat *) rotation);
  
  	glClearColor(0.0, 0.0, 0.0, 0.5);
  	glClear(GL_COLOR_BUFFER_BIT);
  
  	glVertexAttribPointer(window->gl.pos, 2, GL_FLOAT, GL_FALSE, 0, verts);
  	glVertexAttribPointer(window->gl.col, 3, GL_FLOAT, GL_FALSE, 0, colors);
  	glEnableVertexAttribArray(window->gl.pos);
  	glEnableVertexAttribArray(window->gl.col);
  
  	glDrawArrays(GL_TRIANGLES, 0, 3);
  
  	glDisableVertexAttribArray(window->gl.pos);
  	glDisableVertexAttribArray(window->gl.col);
  
  	usleep(window->delay);
  
  	if (window->opaque || window->fullscreen) {
  		region = wl_compositor_create_region(window->display->compositor);
  		wl_region_add(region, 0, 0,
  			      window->geometry.width,
  			      window->geometry.height);
  		wl_surface_set_opaque_region(window->surface, region);
  		wl_region_destroy(region);
  	} else {
  		wl_surface_set_opaque_region(window->surface, NULL);
  	}
  
  	if (display->swap_buffers_with_damage && buffer_age > 0) {
  		rect[0] = window->geometry.width / 4 - 1;
  		rect[1] = window->geometry.height / 4 - 1;
  		rect[2] = window->geometry.width / 2 + 2;
  		rect[3] = window->geometry.height / 2 + 2;
  		display->swap_buffers_with_damage(display->egl.dpy,
  						  window->egl_surface,
  						  rect, 1);
  	} else {
  		eglSwapBuffers(display->egl.dpy, window->egl_surface);
  	}
  	window->frames++;
  }
  
  static void
  pointer_handle_enter(void *data, struct wl_pointer *pointer,
  		     uint32_t serial, struct wl_surface *surface,
  		     wl_fixed_t sx, wl_fixed_t sy)
  {
  	struct display *display = data;
  	struct wl_buffer *buffer;
  	struct wl_cursor *cursor = display->default_cursor;
  	struct wl_cursor_image *image;
  
  	if (display->window->fullscreen)
  		wl_pointer_set_cursor(pointer, serial, NULL, 0, 0);
  	else if (cursor) {
  		image = display->default_cursor->images[0];
  		buffer = wl_cursor_image_get_buffer(image);
  		if (!buffer)
  			return;
  		wl_pointer_set_cursor(pointer, serial,
  				      display->cursor_surface,
  				      image->hotspot_x,
  				      image->hotspot_y);
  		wl_surface_attach(display->cursor_surface, buffer, 0, 0);
  		wl_surface_damage(display->cursor_surface, 0, 0,
  				  image->width, image->height);
  		wl_surface_commit(display->cursor_surface);
  	}
  }
  
  static void
  pointer_handle_leave(void *data, struct wl_pointer *pointer,
  		     uint32_t serial, struct wl_surface *surface)
  {
  }
  
  static void
  pointer_handle_motion(void *data, struct wl_pointer *pointer,
  		      uint32_t time, wl_fixed_t sx, wl_fixed_t sy)
  {
  }
  
  static void
  pointer_handle_button(void *data, struct wl_pointer *wl_pointer,
  		      uint32_t serial, uint32_t time, uint32_t button,
  		      uint32_t state)
  {
  	struct display *display = data;
  
  	if (!display->window->xdg_toplevel)
  		return;
  
  	if (button == BTN_LEFT && state == WL_POINTER_BUTTON_STATE_PRESSED)
  		xdg_toplevel_move(display->window->xdg_toplevel,
  				  display->seat, serial);
  }
  
  static void
  pointer_handle_axis(void *data, struct wl_pointer *wl_pointer,
  		    uint32_t time, uint32_t axis, wl_fixed_t value)
  {
  }
  
  static const struct wl_pointer_listener pointer_listener = {
  	pointer_handle_enter,
  	pointer_handle_leave,
  	pointer_handle_motion,
  	pointer_handle_button,
  	pointer_handle_axis,
  };
  
  static void
  touch_handle_down(void *data, struct wl_touch *wl_touch,
  		  uint32_t serial, uint32_t time, struct wl_surface *surface,
  		  int32_t id, wl_fixed_t x_w, wl_fixed_t y_w)
  {
  	struct display *d = (struct display *)data;
  
  	if (!d->wm_base)
  		return;
  
  	xdg_toplevel_move(d->window->xdg_toplevel, d->seat, serial);
  }
  
  static void
  touch_handle_up(void *data, struct wl_touch *wl_touch,
  		uint32_t serial, uint32_t time, int32_t id)
  {
  }
  
  static void
  touch_handle_motion(void *data, struct wl_touch *wl_touch,
  		    uint32_t time, int32_t id, wl_fixed_t x_w, wl_fixed_t y_w)
  {
  }
  
  static void
  touch_handle_frame(void *data, struct wl_touch *wl_touch)
  {
  }
  
  static void
  touch_handle_cancel(void *data, struct wl_touch *wl_touch)
  {
  }
  
  static const struct wl_touch_listener touch_listener = {
  	touch_handle_down,
  	touch_handle_up,
  	touch_handle_motion,
  	touch_handle_frame,
  	touch_handle_cancel,
  };
  
  static void
  keyboard_handle_keymap(void *data, struct wl_keyboard *keyboard,
  		       uint32_t format, int fd, uint32_t size)
  {
  	/* Just so we don’t leak the keymap fd */
  	close(fd);
  }
  
  static void
  keyboard_handle_enter(void *data, struct wl_keyboard *keyboard,
  		      uint32_t serial, struct wl_surface *surface,
  		      struct wl_array *keys)
  {
  }
  
  static void
  keyboard_handle_leave(void *data, struct wl_keyboard *keyboard,
  		      uint32_t serial, struct wl_surface *surface)
  {
  }
  
  static void
  keyboard_handle_key(void *data, struct wl_keyboard *keyboard,
  		    uint32_t serial, uint32_t time, uint32_t key,
  		    uint32_t state)
  {
  	struct display *d = data;
  
  	if (!d->wm_base)
  		return;
  
  	if (key == KEY_F11 && state) {
  		if (d->window->fullscreen)
  			xdg_toplevel_unset_fullscreen(d->window->xdg_toplevel);
  		else
  			xdg_toplevel_set_fullscreen(d->window->xdg_toplevel, NULL);
  	} else if (key == KEY_ESC && state)
  		running = 0;
  }
  
  static void
  keyboard_handle_modifiers(void *data, struct wl_keyboard *keyboard,
  			  uint32_t serial, uint32_t mods_depressed,
  			  uint32_t mods_latched, uint32_t mods_locked,
  			  uint32_t group)
  {
  }
  
  static const struct wl_keyboard_listener keyboard_listener = {
  	keyboard_handle_keymap,
  	keyboard_handle_enter,
  	keyboard_handle_leave,
  	keyboard_handle_key,
  	keyboard_handle_modifiers,
  };
  
  static void
  seat_handle_capabilities(void *data, struct wl_seat *seat,
  			 enum wl_seat_capability caps)
  {
  	struct display *d = data;
  
  	if ((caps & WL_SEAT_CAPABILITY_POINTER) && !d->pointer) {
  		d->pointer = wl_seat_get_pointer(seat);
  		wl_pointer_add_listener(d->pointer, &pointer_listener, d);
  	} else if (!(caps & WL_SEAT_CAPABILITY_POINTER) && d->pointer) {
  		wl_pointer_destroy(d->pointer);
  		d->pointer = NULL;
  	}
  
  	if ((caps & WL_SEAT_CAPABILITY_KEYBOARD) && !d->keyboard) {
  		d->keyboard = wl_seat_get_keyboard(seat);
  		wl_keyboard_add_listener(d->keyboard, &keyboard_listener, d);
  	} else if (!(caps & WL_SEAT_CAPABILITY_KEYBOARD) && d->keyboard) {
  		wl_keyboard_destroy(d->keyboard);
  		d->keyboard = NULL;
  	}
  
  	if ((caps & WL_SEAT_CAPABILITY_TOUCH) && !d->touch) {
  		d->touch = wl_seat_get_touch(seat);
  		wl_touch_set_user_data(d->touch, d);
  		wl_touch_add_listener(d->touch, &touch_listener, d);
  	} else if (!(caps & WL_SEAT_CAPABILITY_TOUCH) && d->touch) {
  		wl_touch_destroy(d->touch);
  		d->touch = NULL;
  	}
  }
  
  static const struct wl_seat_listener seat_listener = {
  	seat_handle_capabilities,
  };
  
  static void
  xdg_wm_base_ping(void *data, struct xdg_wm_base *shell, uint32_t serial)
  {
  	xdg_wm_base_pong(shell, serial);
  }
  
  static const struct xdg_wm_base_listener wm_base_listener = {
  	xdg_wm_base_ping,
  };
  
  static void
  registry_handle_global(void *data, struct wl_registry *registry,
  		       uint32_t name, const char *interface, uint32_t version)
  {
  	struct display *d = data;
  
  	if (strcmp(interface, "wl_compositor") == 0) {
  		d->compositor =
  			wl_registry_bind(registry, name,
  					 &wl_compositor_interface,
  					 MIN(version, 4));
  	} else if (strcmp(interface, "xdg_wm_base") == 0) {
  		d->wm_base = wl_registry_bind(registry, name,
  					      &xdg_wm_base_interface, 1);
  		xdg_wm_base_add_listener(d->wm_base, &wm_base_listener, d);
  	} else if (strcmp(interface, "wl_seat") == 0) {
  		d->seat = wl_registry_bind(registry, name,
  					   &wl_seat_interface, 1);
  		wl_seat_add_listener(d->seat, &seat_listener, d);
  	} else if (strcmp(interface, "wl_shm") == 0) {
  		d->shm = wl_registry_bind(registry, name,
  					  &wl_shm_interface, 1);
  		d->cursor_theme = wl_cursor_theme_load(NULL, 32, d->shm);
  		if (!d->cursor_theme) {
  			fprintf(stderr, "unable to load default theme\n");
  			return;
  		}
  		d->default_cursor =
  			wl_cursor_theme_get_cursor(d->cursor_theme, "left_ptr");
  		if (!d->default_cursor) {
  			fprintf(stderr, "unable to load default left pointer\n");
  			// TODO: abort ?
  		}
  	}
  }
  
  static void
  registry_handle_global_remove(void *data, struct wl_registry *registry,
  			      uint32_t name)
  {
  }
  
  static const struct wl_registry_listener registry_listener = {
  	registry_handle_global,
  	registry_handle_global_remove
  };
  
  static void
  signal_int(int signum)
  {
  	running = 0;
  }
  
  static void
  usage(int error_code)
  {
  	fprintf(stderr, "Usage: simple-egl [OPTIONS]\n\n"
  		"  -d <us>\tBuffer swap delay in microseconds\n"
  		"  -f\tRun in fullscreen mode\n"
  		"  -o\tCreate an opaque surface\n"
  		"  -s\tUse a 16 bpp EGL config\n"
  		"  -b\tDon't sync to compositor redraw (eglSwapInterval 0)\n"
  		"  -h\tThis help text\n\n");
  
  	exit(error_code);
  }
  
  int
  main(int argc, char **argv)
  {
  	struct sigaction sigint;
  	struct display display = { 0 };
  	struct window  window  = { 0 };
  	int i, ret = 0;
  
  	window.display = &display;
  	display.window = &window;
  	window.geometry.width  = 250;
  	window.geometry.height = 250;
  	window.window_size = window.geometry;
  	window.buffer_size = 32;
  	window.frame_sync = 1;
  	window.delay = 0;
  
  	for (i = 1; i < argc; i++) {
  		if (strcmp("-d", argv[i]) == 0 && i+1 < argc)
  			window.delay = atoi(argv[++i]);
  		else if (strcmp("-f", argv[i]) == 0)
  			window.fullscreen = 1;
  		else if (strcmp("-o", argv[i]) == 0)
  			window.opaque = 1;
  		else if (strcmp("-s", argv[i]) == 0)
  			window.buffer_size = 16;
  		else if (strcmp("-b", argv[i]) == 0)
  			window.frame_sync = 0;
  		else if (strcmp("-h", argv[i]) == 0)
  			usage(EXIT_SUCCESS);
  		else
  			usage(EXIT_FAILURE);
  	}
  
  	display.display = wl_display_connect(NULL);
  	assert(display.display);
  
  	display.registry = wl_display_get_registry(display.display);
  	wl_registry_add_listener(display.registry,
  				 &registry_listener, &display);
  
  	wl_display_roundtrip(display.display);
  
  	init_egl(&display, &window);
  	create_surface(&window);
  	init_gl(&window);
  
  	display.cursor_surface =
  		wl_compositor_create_surface(display.compositor);
  
  	sigint.sa_handler = signal_int;
  	sigemptyset(&sigint.sa_mask);
  	sigint.sa_flags = SA_RESETHAND;
  	sigaction(SIGINT, &sigint, NULL);
  
  	/* The mainloop here is a little subtle.  Redrawing will cause
  	 * EGL to read events so we can just call
  	 * wl_display_dispatch_pending() to handle any events that got
  	 * queued up as a side effect. */
  	while (running && ret != -1) {
  		if (window.wait_for_configure) {
  			ret = wl_display_dispatch(display.display);
  		} else {
  			ret = wl_display_dispatch_pending(display.display);
  			redraw(&window, NULL, 0);
  		}
  	}
  
  	fprintf(stderr, "simple-egl exiting\n");
  
  	destroy_surface(&window);
  	fini_egl(&display);
  
  	wl_surface_destroy(display.cursor_surface);
  	if (display.cursor_theme)
  		wl_cursor_theme_destroy(display.cursor_theme);
  
  	if (display.wm_base)
  		xdg_wm_base_destroy(display.wm_base);
  
  	if (display.compositor)
  		wl_compositor_destroy(display.compositor);
  
  	wl_registry_destroy(display.registry);
  	wl_display_flush(display.display);
  	wl_display_disconnect(display.display);
  
  	return 0;
  }
  