#include <GL/gl.h>	     
#include <GL/glu.h>	    
#include <GL/glut.h>    

#include <stdio.h>      
#include <stdlib.h>     
#include <math.h>

#define WIDTH  480
#define HEIGHT 480

#define RED   0
#define GREEN 0
#define BLUE  0
#define ALPHA 1

#define KEY_ESC 27
#define KEY_SPC 32

GLuint face;
GLuint cube;

void init_scene();
void render_scene();
GLvoid initGL();
GLvoid window_display();
GLvoid window_reshape(GLsizei width, GLsizei height);
GLvoid window_key(unsigned char key, int x, int y); 

int main(int argc, char **argv) 
{  
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH);

  glutInitWindowSize(WIDTH, HEIGHT);
  glutInitWindowPosition(0, 0);
  glutCreateWindow("Cube");

  initGL();  
  init_scene();

  glutDisplayFunc(&window_display);
  glutReshapeFunc(&window_reshape);
  glutKeyboardFunc(&window_key);

  glutMainLoop();  

  return 1;
}

GLvoid initGL()	
{
  glClearColor(RED, GREEN, BLUE, ALPHA);	
  glClearDepth(1.0);				
  glDepthFunc(GL_LESS);                       
  glEnable(GL_DEPTH_TEST);                    
}

void init_scene()
{
  face = glGenLists(2);
  cube = face+1;

  glNewList(face, GL_COMPILE);
    glBegin(GL_POLYGON);
      glVertex3f(0, 0, 0);
      glVertex3f(1, 0, 0);
      glVertex3f(1, 1, 0);
      glVertex3f(0, 1, 0);  
    glEnd();  
  glEndList();

  glNewList(cube, GL_COMPILE);
    glTranslatef(-0.5, -0.5, 0.5);
  
    glColor3f(1, 0, 0);
    glCallList(face);

    glColor3f(1, 1, 0);
    glPushMatrix();
    glTranslatef(0, 0, -1);
    glCallList(face);
    glPopMatrix();
    
    glColor3f(0, 1, 0);
    glPushMatrix();
    glRotatef(90, 0, 1, 0);
    glCallList(face);
    glPopMatrix();

    glColor3f(0, 1, 1);
    glPushMatrix();
    glTranslatef(1, 0, 0);
    glRotatef(90, 0, 1, 0);
    glCallList(face);
    glPopMatrix();
    
    glColor3f(0, 0, 1);
    glPushMatrix();
    glRotatef(-90, 1, 0, 0);
    glCallList(face);
    glPopMatrix();

    glColor3f(1, 0, 1);
    glPushMatrix();
    glTranslatef(0, 1, 0);
    glRotatef(-90, 1, 0, 0);
    glCallList(face);
    glPopMatrix();

  glEndList();
}

GLvoid window_display()
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	    
  glLoadIdentity();
  gluLookAt(0, 0, 5, 0, 0, 0, 0, 1, 0); // COP, VRP, VUP (defines view)
  render_scene();
  glFlush();
}

GLvoid window_reshape(GLsizei width, GLsizei height)
{
  if (height == 0) 
    height = 1; 
  
  glViewport(0, 0, width, height);

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(45, (GLdouble)width/(GLdouble)height, 1, 10); 
  glMatrixMode(GL_MODELVIEW);
}
 
GLvoid window_key(unsigned char key, int x, int y) 
{  
  switch (key) {    
  case KEY_ESC:  
    exit(1);                   	
    break; 
    
  default:
    printf ("Pressing %d doesn't do anything.\n", key);
    break;
  }	
}

void render_scene()
{
  glRotatef(20 , 0, 1, 0);
  glRotatef(20, 1, 0, 0);
  glCallList(cube);
}