/* Kullanımı: YUKARI ve AŞAĞI OK tuşları ve X, Y, Z tuşları */

#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_UP 101
#define KEY_DOWN 103
#define KEY_X 120
#define KEY_Y 121
#define KEY_Z 122

GLuint face;
GLuint cube;

#define DELTA 5
int x = 0;
int rotateX = 0;
int y = 0;
int rotateY = 0;
int z = 0;
int rotateZ = 0;
int speed = 0;

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

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

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

  initGL();
  init_scene();

  glutDisplayFunc(&window_display);
  glutReshapeFunc(&window_reshape);
  glutIdleFunc(&window_idle);
  glutKeyboardFunc(&window_key);
  glutSpecialFunc(&window_special_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);
  render_scene();
  glutSwapBuffers();
}

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;
  case KEY_X:
    rotateX = !rotateX;
    glutPostRedisplay();
    break;
  case KEY_Y:
    rotateY = !rotateY;
    glutPostRedisplay();
    break;
  case KEY_Z:
    rotateZ = !rotateZ;
    glutPostRedisplay();
    break;
  default:
    printf ("Pressing %d doesn't do anything.\n", key);
    break;
  }
}

GLvoid window_special_key(int key, int x, int y)
{
  switch (key) {
  case KEY_UP:
    speed = (speed + DELTA + 360) % 360;
    glutPostRedisplay();
    break;

  case KEY_DOWN:
    speed = (speed - DELTA + 360) % 360;
    glutPostRedisplay();
    break;

  default:
    printf ("Pressing %d doesn't do anything.\n", key);
    break;
  }
}

GLvoid window_idle()
{
  if (rotateX) x = (x + speed + 360) % 360;
  if (rotateY) y = (y + speed + 360) % 360;
  if (rotateZ) z = (z + speed + 360) % 360;
  if (speed > 0 && (rotateX || rotateY || rotateZ))
    glutPostRedisplay();
}

void render_scene()
{
  glRotatef(x, 1, 0, 0);
  glRotatef(y, 0, 1, 0);
  glRotatef(z, 0, 0, 1);
  glCallList(cube);
}