progs/demos/glslnoise.c

   1 /*
   2  * GLSL noise demo.
   3  *
   4  * Michal Krol
   5  * 20 February 2006
   6  *
   7  * Based on the original demo by:
   8  * Stefan Gustavson (stegu@itn.liu.se) 2004, 2005
   9  */
  10
  11 #ifdef WIN32
  12 #include <windows.h>
  13 #endif
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <GL/gl.h>
  18 #include <GL/glut.h>
  19 #include <GL/glext.h>
  20
  21 #ifdef WIN32
  22 #define GETPROCADDRESS(F) wglGetProcAddress(F)
  23 #else
  24 #define GETPROCADDRESS(F) glutGetProcAddress(F)
  25 #endif
  26
  27 static GLhandleARB fragShader;
  28 static GLhandleARB vertShader;
  29 static GLhandleARB program;
  30
  31 static GLint uTime;
  32
  33 static GLint t0 = 0;
  34 static GLint frames = 0;
  35
  36 static GLfloat u_time = 0.0f;
  37
  38 static PFNGLCREATESHADEROBJECTARBPROC glCreateShaderObjectARB = NULL;
  39 static PFNGLSHADERSOURCEARBPROC glShaderSourceARB = NULL;
  40 static PFNGLCOMPILESHADERARBPROC glCompileShaderARB = NULL;
  41 static PFNGLCREATEPROGRAMOBJECTARBPROC glCreateProgramObjectARB = NULL;
  42 static PFNGLATTACHOBJECTARBPROC glAttachObjectARB = NULL;
  43 static PFNGLLINKPROGRAMARBPROC glLinkProgramARB = NULL;
  44 static PFNGLUSEPROGRAMOBJECTARBPROC glUseProgramObjectARB = NULL;
  45 static PFNGLGETUNIFORMLOCATIONARBPROC glGetUniformLocationARB = NULL;
  46 static PFNGLUNIFORM1FARBPROC glUniform1fARB = NULL;
  47
  48 static void Redisplay (void)
  49 {
  50    GLint t;
  51
  52         glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  53
  54         glUniform1fARB (uTime, 0.5f * u_time);
  55
  56         glPushMatrix ();
  57         glutSolidSphere (2.0, 20, 10);
  58         glPopMatrix ();
  59
  60         glutSwapBuffers();
  61    frames++;
  62
  63    t = glutGet (GLUT_ELAPSED_TIME);
  64    if (t - t0 >= 5000) {
  65       GLfloat seconds = (GLfloat) (t - t0) / 1000.0f;
  66       GLfloat fps = frames / seconds;
  67       printf ("%d frames in %6.3f seconds = %6.3f FPS\n", frames, seconds, fps);
  68       t0 = t;
  69       frames = 0;
  70    }
  71 }
  72
  73 static void Idle (void)
  74 {
  75         u_time += 0.1f;
  76         glutPostRedisplay ();
  77 }
  78
  79 static void Reshape (int width, int height)
  80 {
  81         glViewport (0, 0, width, height);
  82         glMatrixMode (GL_PROJECTION);
  83         glLoadIdentity ();
  84         glFrustum (-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  85         glMatrixMode (GL_MODELVIEW);
  86         glLoadIdentity ();
  87         glTranslatef (0.0f, 0.0f, -15.0f);
  88 }
  89
  90 static void Key (unsigned char key, int x, int y)
  91 {
  92         (void) x;
  93         (void) y;
  94
  95         switch (key)
  96         {
  97         case 27:
  98                 exit(0);
  99                 break;
 100         }
 101         glutPostRedisplay ();
 102 }
 103
 104 static void Init (void)
 105 {
 106    static const char *fragShaderText =
 107       "uniform float time;\n"
 108       "varying vec3 position;\n"
 109       "void main () {\n"
 110       "   gl_FragColor = vec4 (vec3 (0.5 + 0.5 * noise1 (vec4 (position, time))), 1.0);\n"
 111       "}\n"
 112    ;
 113    static const char *vertShaderText =
 114       "varying vec3 position;\n"
 115       "void main () {\n"
 116       "   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
 117       "   position = 4.0 * gl_Vertex.xyz;\n"
 118       "}\n"
 119    ;
 120
 121         if (!glutExtensionSupported ("GL_ARB_fragment_shader"))
 122         {
 123                 printf ("Sorry, this demo requires GL_ARB_fragment_shader\n");
 124                 exit(1);
 125         }
 126         if (!glutExtensionSupported ("GL_ARB_shader_objects"))
 127         {
 128                 printf ("Sorry, this demo requires GL_ARB_shader_objects\n");
 129                 exit(1);
 130         }
 131         if (!glutExtensionSupported ("GL_ARB_shading_language_100"))
 132         {
 133                 printf ("Sorry, this demo requires GL_ARB_shading_language_100\n");
 134                 exit(1);
 135         }
 136         if (!glutExtensionSupported ("GL_ARB_vertex_shader"))
 137         {
 138                 printf ("Sorry, this demo requires GL_ARB_vertex_shader\n");
 139                 exit(1);
 140         }
 141
 142         glCreateShaderObjectARB = (PFNGLCREATESHADEROBJECTARBPROC)
 143                 GETPROCADDRESS("glCreateShaderObjectARB");
 144         glShaderSourceARB = (PFNGLSHADERSOURCEARBPROC)
 145                 GETPROCADDRESS("glShaderSourceARB");
 146         glCompileShaderARB = (PFNGLCOMPILESHADERARBPROC)
 147                 GETPROCADDRESS("glCompileShaderARB");
 148         glCreateProgramObjectARB = (PFNGLCREATEPROGRAMOBJECTARBPROC)
 149                 GETPROCADDRESS("glCreateProgramObjectARB");
 150         glAttachObjectARB = (PFNGLATTACHOBJECTARBPROC)
 151                 GETPROCADDRESS("glAttachObjectARB");
 152         glLinkProgramARB = (PFNGLLINKPROGRAMARBPROC)
 153                 GETPROCADDRESS ("glLinkProgramARB");
 154         glUseProgramObjectARB = (PFNGLUSEPROGRAMOBJECTARBPROC)
 155                 GETPROCADDRESS("glUseProgramObjectARB");
 156
 157         glGetUniformLocationARB = (PFNGLGETUNIFORMLOCATIONARBPROC)
 158                 GETPROCADDRESS("glGetUniformLocationARB");
 159         glUniform1fARB = (PFNGLUNIFORM1FARBPROC)
 160                 GETPROCADDRESS("glUniform1fARB");
 161
 162         fragShader = glCreateShaderObjectARB (GL_FRAGMENT_SHADER_ARB);
 163         glShaderSourceARB (fragShader, 1, &fragShaderText, NULL);
 164         glCompileShaderARB (fragShader);
 165
 166         vertShader = glCreateShaderObjectARB (GL_VERTEX_SHADER_ARB);
 167         glShaderSourceARB (vertShader, 1, &vertShaderText, NULL);
 168         glCompileShaderARB (vertShader);
 169
 170         program = glCreateProgramObjectARB ();
 171         glAttachObjectARB (program, fragShader);
 172         glAttachObjectARB (program, vertShader);
 173         glLinkProgramARB (program);
 174         glUseProgramObjectARB (program);
 175
 176         uTime = glGetUniformLocationARB (program, "time");
 177
 178         glClearColor (0.0f, 0.1f, 0.3f, 1.0f);
 179         glEnable (GL_CULL_FACE);
 180         glEnable (GL_DEPTH_TEST);
 181
 182         printf ("GL_RENDERER = %s\n", (const char *) glGetString (GL_RENDERER));
 183 }
 184
 185 int main (int argc, char *argv[])
 186 {
 187         glutInit (&argc, argv);
 188         glutInitWindowPosition ( 0, 0);
 189         glutInitWindowSize (200, 200);
 190         glutInitDisplayMode (GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 191         glutCreateWindow (argv[0]);
 192         glutReshapeFunc (Reshape);
 193         glutKeyboardFunc (Key);
 194         glutDisplayFunc (Redisplay);
 195         glutIdleFunc (Idle);
 196         Init ();
 197         glutMainLoop ();
 198         return 0;
 199 }
 200