vcs.maemo.org Git - sdlhildon/blob - sdlgles/test/gles2.c

   1 /* gles1 - a simple SDL_gles OpenGL|ES 1.1 sample
   2  *
   3  * This file is in the public domain, furnished "as is", without technical
   4  * support, and with no warranty, express or implied, as to its usefulness for
   5  * any purpose.
   6  */
   7
   8 #include <stdlib.h>
   9 #include <stdio.h>
  10 #include <stdbool.h>
  11 #include <assert.h>
  12
  13 #include <SDL.h>
  14 #include <SDL_gles.h>
  15
  16 #include <GLES2/gl2.h>
  17
  18 static SDL_Surface *screen;
  19 static SDL_GLES_Context *context;
  20
  21 static GLuint program;
  22 static bool fullscreen = false;
  23
  24 static GLuint compile_shader(GLenum type, const char *src)
  25 {
  26         GLuint shader = glCreateShader(type);
  27         GLint compiled;
  28
  29         assert(shader != 0),
  30         glShaderSource(shader, 1, &src, NULL);
  31         glCompileShader(shader);
  32         glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
  33         assert(compiled);
  34
  35         return shader;
  36 }
  37
  38 static void init()
  39 {
  40         const char vertex_shader_src[] =
  41                 "attribute vec4 pos;\n"
  42                 "void main()\n"
  43                 "{\n"
  44                 "       gl_Position = pos;\n"
  45                 "}\n";
  46
  47         const char fragment_shader_src[] =
  48                 "precision mediump float;\n"
  49                 "void main()\n"
  50                 "{\n"
  51                 "       gl_FragColor = vec4 ( 1.0, 0.0, 0.0, 1.0 );\n"
  52                 "}\n";
  53
  54         GLuint vertex_shader = compile_shader(GL_VERTEX_SHADER, vertex_shader_src);
  55         GLuint fragment_shader = compile_shader(GL_FRAGMENT_SHADER, fragment_shader_src);
  56
  57         program = glCreateProgram();
  58         assert(program);
  59
  60         glAttachShader(program, vertex_shader);
  61         glAttachShader(program, fragment_shader);
  62
  63         glBindAttribLocation(program, 0, "pos");
  64
  65         GLint linked;
  66         glLinkProgram(program);
  67         glGetProgramiv(program, GL_LINK_STATUS, &linked);
  68         assert(linked);
  69
  70         glClearColor(0.0f, 0.0f, 0.2f, 0.0f);
  71 }
  72
  73 static void render()
  74 {
  75         GLfloat tri_v[] =       {0.0f,  0.5f, 0.0f,
  76                                                 -0.5f, -0.5f, 0.0f,
  77                                                  0.5f, -0.5f, 0.0f};
  78
  79         glViewport(0, 0, screen->w, screen->h);
  80         glClear(GL_COLOR_BUFFER_BIT);
  81         glUseProgram(program);
  82
  83         glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, tri_v);
  84         glEnableVertexAttribArray(0);
  85
  86         glDrawArrays(GL_TRIANGLES, 0, 3);
  87
  88         SDL_GLES_SwapBuffers();
  89 }
  90
  91 static void toggle_fullscreen()
  92 {
  93         int res;
  94
  95         fullscreen = !fullscreen;
  96
  97         screen = SDL_SetVideoMode(0, 0, 16, SDL_SWSURFACE |
  98                 (fullscreen ? SDL_FULLSCREEN : 0));
  99         assert(screen);
 100
 101         res = SDL_GLES_SetVideoMode();
 102         if (res != 0) puts(SDL_GetError());
 103         assert(res == 0);
 104
 105         render();
 106 }
 107
 108 int main()
 109 {
 110         int res;
 111         res = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);
 112         assert(res == 0);
 113
 114         res = SDL_GLES_Init(SDL_GLES_VERSION_2_0);
 115         assert(res == 0);
 116
 117         screen = SDL_SetVideoMode(0, 0, 16, SDL_SWSURFACE);
 118         assert(screen);
 119
 120         SDL_WM_SetCaption("SDLgles v2 test", "SDLgles v2 test");
 121         SDL_ShowCursor(SDL_DISABLE);
 122
 123         context = SDL_GLES_CreateContext();
 124         if (!context) puts(SDL_GetError());
 125         assert(context);
 126
 127         res = SDL_GLES_MakeCurrent(context);
 128         assert(res == 0);
 129
 130         init();
 131         render();
 132
 133         SDL_Event event;
 134         while (SDL_WaitEvent(&event)) {
 135                 switch (event.type) {
 136                         case SDL_QUIT:
 137                                 goto quit;
 138                         case SDL_MOUSEBUTTONDOWN:
 139                                 toggle_fullscreen();
 140                                 break;
 141                 }
 142         }
 143
 144 quit:
 145         SDL_GLES_DeleteContext(context);
 146
 147         SDL_GLES_Quit();
 148         SDL_Quit();
 149
 150         return 0;
 151 }