examples/simple-x11-egl.c

   1 // Copyright 2012, 2014 Intel Corporation
   2 //
   3 // All rights reserved.
   4 //
   5 // Redistribution and use in source and binary forms, with or without
   6 // modification, are permitted provided that the following conditions are met:
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   9 //   list of conditions and the following disclaimer.
  10 //
  11 // - Redistributions in binary form must reproduce the above copyright notice,
  12 //   this list of conditions and the following disclaimer in the documentation
  13 //   and/or other materials provided with the distribution.
  14 //
  15 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  16 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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  25
  26 /// @file
  27 ///
  28 /// This little example program renders to an X11 window with EGL and an OpenGL
  29 /// ES2 context.  The program does not include any OpenGL headers and does not
  30 /// need to link to libGL. It declares the needed OpenGL symbols itself and
  31 /// obtains the OpenGL functions with waffle_dl_sym().
  32 ///
  33 /// This example is too simple; it does not perform proper error checking. For
  34 /// a complete example with error checking, see gl_basic.c.
  35
  36 #define WAFFLE_API_VERSION 0x0106
  37 #define WAFFLE_API_EXPERIMENTAL
  38
  39 #include <stdlib.h>
  40 #include <unistd.h>
  41
  42 #include <waffle.h>
  43
  44 // ---------------------------------------------
  45 // OpenGL symbols
  46 // ---------------------------------------------
  47
  48 typedef float GLclampf;
  49 typedef unsigned int GLbitfield;
  50
  51 enum {
  52     GL_COLOR_BUFFER_BIT = 0x00004000,
  53 };
  54
  55 #ifndef _WIN32
  56 #define APIENTRY
  57 #else
  58 #ifndef APIENTRY
  59 #define APIENTRY __stdcall
  60 #endif
  61 #endif
  62
  63 static void (APIENTRY *glClearColor)(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha);
  64 static void (APIENTRY *glClear)(GLbitfield mask);
  65
  66 // ---------------------------------------------
  67
  68 int
  69 main()
  70 {
  71     struct waffle_display *dpy;
  72     struct waffle_config *config;
  73     struct waffle_window *window;
  74     struct waffle_context *ctx;
  75
  76     const int32_t init_attrs[] = {
  77         WAFFLE_PLATFORM, WAFFLE_PLATFORM_X11_EGL,
  78         0,
  79     };
  80
  81     const int32_t config_attrs[] = {
  82         WAFFLE_CONTEXT_API,         WAFFLE_CONTEXT_OPENGL_ES2,
  83
  84         WAFFLE_RED_SIZE,            8,
  85         WAFFLE_BLUE_SIZE,           8,
  86         WAFFLE_GREEN_SIZE,          8,
  87
  88         0,
  89     };
  90
  91     const int32_t window_width = 320;
  92     const int32_t window_height = 240;
  93
  94     waffle_init(init_attrs);
  95     dpy = waffle_display_connect(NULL);
  96
  97     // Exit if OpenGL ES2 is unsupported.
  98     if (!waffle_display_supports_context_api(dpy, WAFFLE_CONTEXT_OPENGL_ES2)
  99         || !waffle_dl_can_open(WAFFLE_DL_OPENGL_ES2))
 100     {
 101         exit(EXIT_FAILURE);
 102     }
 103
 104     // Get OpenGL functions.
 105     glClearColor = waffle_dl_sym(WAFFLE_DL_OPENGL_ES2, "glClearColor");
 106     glClear = waffle_dl_sym(WAFFLE_DL_OPENGL_ES2, "glClear");
 107
 108     config = waffle_config_choose(dpy, config_attrs);
 109     window = waffle_window_create(config, window_width, window_height);
 110     ctx = waffle_context_create(config, NULL);
 111
 112     waffle_window_show(window);
 113     waffle_make_current(dpy, window, ctx);
 114
 115     // Draw red.
 116     glClearColor(1.0, 0.0, 0.0, 1.0);
 117     glClear(GL_COLOR_BUFFER_BIT);
 118     waffle_window_swap_buffers(window);
 119     sleep(1); // Sleep so that user can see window.
 120
 121     // Draw green.
 122     glClearColor(0.0, 1.0, 0.0, 1.0);
 123     glClear(GL_COLOR_BUFFER_BIT);
 124     waffle_window_swap_buffers(window);
 125     sleep(1);
 126
 127     // Draw blue.
 128     glClearColor(0.0, 0.0, 1.0, 1.0);
 129     glClear(GL_COLOR_BUFFER_BIT);
 130     waffle_window_swap_buffers(window);
 131     sleep(1);
 132
 133     // Clean up.
 134     waffle_make_current(dpy, NULL, NULL);
 135     waffle_window_destroy(window);
 136     waffle_context_destroy(ctx);
 137     waffle_config_destroy(config);
 138     waffle_display_disconnect(dpy);
 139
 140     waffle_teardown();
 141
 142     return 0;
 143 }