/* $Id: glutskel.c,v 1.1 1999/08/19 00:55:42 jtg Exp $ */

/*
 * A skeleton/template GLUT program
 *
 * Written by Brian Paul and in the public domain.
 */


/*
 * $Log: glutskel.c,v $
 * Revision 1.1  1999/08/19 00:55:42  jtg
 * Initial revision
 *
 * Revision 1.2  1998/11/07 14:20:14  brianp
 * added simple rotation, animation of cube
 *
 * Revision 1.1  1998/11/07 14:14:37  brianp
 * Initial revision
 *
 */


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


static GLfloat Xrot = 0, Yrot = 0, Zrot = 0;
static GLboolean Anim = GL_FALSE;


static void Idle( void )
{
   Xrot += 3.0;
   Yrot += 4.0;
   Zrot += 2.0;
   glutPostRedisplay();
}


static void Display( void )
{
   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

   glPushMatrix();
   glRotatef(Xrot, 1, 0, 0);
   glRotatef(Yrot, 0, 1, 0);
   glRotatef(Zrot, 0, 0, 1);

   glutSolidCube(2.0);

   glPopMatrix();

   glutSwapBuffers();
}


static void Reshape( int width, int height )
{
   glViewport( 0, 0, width, height );
   glMatrixMode( GL_PROJECTION );
   glLoadIdentity();
   glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
   glMatrixMode( GL_MODELVIEW );
   glLoadIdentity();
   glTranslatef( 0.0, 0.0, -15.0 );
}


static void Key( unsigned char key, int x, int y )
{
   const GLfloat step = 3.0;
   (void) x;
   (void) y;
   switch (key) {
      case 'a':
         Anim = !Anim;
         if (Anim)
            glutIdleFunc(Idle);
         else
            glutIdleFunc(NULL);
         break;
      case 'z':
         Zrot -= step;
         break;
      case 'Z':
         Zrot += step;
         break;
      case 27:
         exit(0);
         break;
   }
   glutPostRedisplay();
}


static void SpecialKey( int key, int x, int y )
{
   const GLfloat step = 3.0;
   (void) x;
   (void) y;
   switch (key) {
      case GLUT_KEY_UP:
         Xrot -= step;
         break;
      case GLUT_KEY_DOWN:
         Xrot += step;
         break;
      case GLUT_KEY_LEFT:
         Yrot -= step;
         break;
      case GLUT_KEY_RIGHT:
         Yrot += step;
         break;
   }
   glutPostRedisplay();
}


static void Init( void )
{
   /* setup lighting, etc */
   glEnable(GL_DEPTH_TEST);
   glEnable(GL_LIGHTING);
   glEnable(GL_LIGHT0);
}


int main( int argc, char *argv[] )
{
   glutInit( &argc, argv );
   glutInitWindowPosition( 0, 0 );
   glutInitWindowSize( 400, 400 );
   glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
   glutCreateWindow(argv[0]);
   glutReshapeFunc( Reshape );
   glutKeyboardFunc( Key );
   glutSpecialFunc( SpecialKey );
   glutDisplayFunc( Display );
   Init();
   glutMainLoop();
   return 0;
}