/*
 * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the name of
 * Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Silicon Graphics.
 *
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
 * ANY KIND,
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>


#define CI_OFFSET_1 16
#define CI_OFFSET_2 32


static void Init(void)
{
   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
   fflush(stderr);

    glClearColor(0.3, 0.1, 0.3, 0.0);
}

static void Reshape(int width, int height)
{

    glViewport(0, 0, (GLint)width, (GLint)height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
    glMatrixMode(GL_MODELVIEW);
}

static void Key(unsigned char key, int x, int y)
{
   switch (key) {
   case 27:
      exit(0);
   default:
      glutPostRedisplay();
      return;
   }
}

static void Draw(void)
{
   static float f = 0;
   while (1) {
      f += .1;
      glClearColor((sin(f)+1)/2.0,(cos(f)+1)/2.0,0.5,1); 
      glClear(GL_COLOR_BUFFER_BIT); 
      glutSwapBuffers();

      {
         static GLint T0 = 0;
         static GLint Frames = 0;
         GLint t = glutGet(GLUT_ELAPSED_TIME);

         Frames++;

         if (t - T0 >= 5000) {
            GLfloat seconds = (t - T0) / 1000.0;
            GLfloat fps = Frames / seconds;
            printf("%d frames in %6.3f seconds = %6.3f FPS\n", Frames, seconds, fps);
            fflush(stdout);
            T0 = t;
            Frames = 0;
         }
      }

   }
   glutPostRedisplay();
}

static GLenum Args(int argc, char **argv)
{
    return GL_TRUE;
}

int main(int argc, char **argv)
{
    GLenum type;

    glutInit(&argc, argv);

    if (Args(argc, argv) == GL_FALSE) {
	exit(1);
    }

    glutInitWindowPosition(0, 0); glutInitWindowSize( 300, 300);

    type = GLUT_RGB | GLUT_ALPHA;
    type |= GLUT_DOUBLE;
    glutInitDisplayMode(type);

    if (glutCreateWindow(*argv) == GL_FALSE) {
	exit(1);
    }

    Init();

    glutReshapeFunc(Reshape);
    glutKeyboardFunc(Key);
    glutDisplayFunc(Draw);
    glutMainLoop();
    return 0;
}