| 1 | // based on |
| 2 | // https://www.khronos.org/registry/EGL/extensions/MESA/EGL_MESA_platform_gbm.txt |
| 3 | |
| 4 | #include <stdio.h> |
| 5 | #include <stdlib.h> |
| 6 | #include <string.h> |
| 7 | #include <unistd.h> |
| 8 | |
| 9 | #include <sys/types.h> |
| 10 | #include <sys/stat.h> |
| 11 | #include <fcntl.h> |
| 12 | |
| 13 | #include <gbm.h> |
| 14 | #include <EGL/egl.h> |
| 15 | #include <EGL/eglext.h> |
| 16 | #include <GLES2/gl2.h> |
| 17 | |
| 18 | struct my_display { |
| 19 | struct gbm_device *gbm; |
| 20 | EGLDisplay egl; |
| 21 | }; |
| 22 | |
| 23 | struct my_config { |
| 24 | struct my_display dpy; |
| 25 | EGLConfig egl; |
| 26 | }; |
| 27 | |
| 28 | struct my_window { |
| 29 | struct my_config config; |
| 30 | struct gbm_surface *gbm; |
| 31 | EGLSurface egl; |
| 32 | }; |
| 33 | |
| 34 | PFNEGLGETPLATFORMDISPLAYEXTPROC getPlatformDisplayEXT; |
| 35 | PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC createPlatformWindowSurfaceEXT; |
| 36 | |
| 37 | static void |
| 38 | check_extensions(void) |
| 39 | { |
| 40 | const char *client_extensions = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS); |
| 41 | |
| 42 | if (!client_extensions) { |
| 43 | abort(); |
| 44 | } |
| 45 | if (!strstr(client_extensions, "EGL_MESA_platform_gbm")) { |
| 46 | abort(); |
| 47 | } |
| 48 | |
| 49 | if (!strstr(client_extensions, "EGL_EXT_platform_base")) { |
| 50 | abort(); |
| 51 | } |
| 52 | |
| 53 | getPlatformDisplayEXT = |
| 54 | (void *) eglGetProcAddress("eglGetPlatformDisplayEXT"); |
| 55 | createPlatformWindowSurfaceEXT = |
| 56 | (void *) eglGetProcAddress("eglCreatePlatformWindowSurfaceEXT"); |
| 57 | |
| 58 | } |
| 59 | |
| 60 | static struct my_display |
| 61 | get_display(void) |
| 62 | { |
| 63 | struct my_display dpy; |
| 64 | EGLint major, minor; |
| 65 | |
| 66 | int fd = open("/dev/dri/card0", O_RDWR | FD_CLOEXEC); |
| 67 | if (fd < 0) |
| 68 | abort(); |
| 69 | |
| 70 | dpy.gbm = gbm_create_device(fd); |
| 71 | if (!dpy.gbm) |
| 72 | abort(); |
| 73 | |
| 74 | dpy.egl = getPlatformDisplayEXT(EGL_PLATFORM_GBM_MESA, dpy.gbm, NULL); |
| 75 | |
| 76 | if (dpy.egl == EGL_NO_DISPLAY) |
| 77 | abort(); |
| 78 | |
| 79 | if (eglInitialize(dpy.egl, &major, &minor)) |
| 80 | printf ("EGL %d.%d\n", major, minor); |
| 81 | else |
| 82 | abort(); |
| 83 | |
| 84 | return dpy; |
| 85 | } |
| 86 | |
| 87 | static struct my_config |
| 88 | get_config(struct my_display dpy) |
| 89 | { |
| 90 | struct my_config config = { |
| 91 | .dpy = dpy, |
| 92 | }; |
| 93 | |
| 94 | EGLint egl_config_attribs[] = { |
| 95 | EGL_BUFFER_SIZE, 32, |
| 96 | EGL_DEPTH_SIZE, EGL_DONT_CARE, |
| 97 | EGL_STENCIL_SIZE, EGL_DONT_CARE, |
| 98 | EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT, |
| 99 | EGL_SURFACE_TYPE, EGL_WINDOW_BIT, |
| 100 | EGL_NONE, |
| 101 | }; |
| 102 | |
| 103 | EGLint num_configs; |
| 104 | if (!eglGetConfigs(dpy.egl, NULL, 0, &num_configs)) |
| 105 | abort(); |
| 106 | |
| 107 | EGLConfig *configs = malloc(num_configs * sizeof(EGLConfig)); |
| 108 | if (!eglChooseConfig(dpy.egl, egl_config_attribs, |
| 109 | configs, num_configs, &num_configs)) { |
| 110 | abort(); |
| 111 | } |
| 112 | if (num_configs == 0) |
| 113 | abort(); |
| 114 | |
| 115 | for (int i = 0; i < num_configs; ++i) { |
| 116 | EGLint gbm_format; |
| 117 | struct gbm_format_name_desc desc; |
| 118 | |
| 119 | if (!eglGetConfigAttrib(dpy.egl, configs[i], |
| 120 | EGL_NATIVE_VISUAL_ID, &gbm_format)) { |
| 121 | abort(); |
| 122 | } |
| 123 | |
| 124 | printf ("found gbm_format: %s\n", gbm_format_get_name (gbm_format, &desc)); |
| 125 | if (gbm_format == GBM_FORMAT_ARGB8888) { |
| 126 | config.egl = configs[i]; |
| 127 | free(configs); |
| 128 | return config; |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | // no egl config matching gbm format |
| 133 | abort(); |
| 134 | } |
| 135 | |
| 136 | static struct my_window |
| 137 | get_window(struct my_config config) |
| 138 | { |
| 139 | struct my_window window = { |
| 140 | .config = config, |
| 141 | }; |
| 142 | |
| 143 | window.gbm = gbm_surface_create(config.dpy.gbm, |
| 144 | 256, 256, |
| 145 | GBM_FORMAT_XRGB8888, |
| 146 | GBM_BO_USE_RENDERING); |
| 147 | if (!window.gbm) |
| 148 | abort(); |
| 149 | |
| 150 | window.egl = createPlatformWindowSurfaceEXT(config.dpy.egl, |
| 151 | config.egl, |
| 152 | window.gbm, |
| 153 | NULL); |
| 154 | if (window.egl == EGL_NO_SURFACE) |
| 155 | abort(); |
| 156 | |
| 157 | return window; |
| 158 | } |
| 159 | |
| 160 | int |
| 161 | main(void) |
| 162 | { |
| 163 | check_extensions(); |
| 164 | |
| 165 | struct my_display dpy = get_display(); |
| 166 | struct my_config config = get_config(dpy); |
| 167 | struct my_window window = get_window(config); |
| 168 | EGLContext context; |
| 169 | |
| 170 | context = eglCreateContext(dpy.egl, config.egl, EGL_NO_CONTEXT, NULL); |
| 171 | eglMakeCurrent(dpy.egl, window.egl, window.egl, context); |
| 172 | |
| 173 | /* just so we have some gles symbols too */ |
| 174 | glClearColor(1.0, 1.0, 1.0, 1.0); |
| 175 | glClear(GL_COLOR_BUFFER_BIT); |
| 176 | glFlush(); |
| 177 | |
| 178 | return EXIT_SUCCESS; |
| 179 | } |