#include <GL/glut.h>

void idle(void)
{
  glutPostRedisplay();
}

void display(void)
{
  int i, j;
  static int r = 0;
  GLdouble vertex[8][3] = {
    { 0.0, 0.0, 0.0 }, { 1.0, 0.0, 0.0 },
    { 1.0, 1.0, 0.0 }, { 0.0, 1.0, 0.0 },
    { 0.0, 0.0, 1.0 }, { 1.0, 0.0, 1.0 },
    { 1.0, 1.0, 1.0 }, { 0.0, 1.0, 1.0 }
  };
  int face[6][4] = {
    { 0, 3, 2, 1 }, { 1, 2, 6, 5 }, { 4, 5, 6, 7 },
    { 0, 4, 7, 3 }, { 0, 1, 5, 4 }, { 2, 3, 7, 6 }
  };
  GLdouble normal[6][3] = {
    { 0.0, 0.0,-1.0 }, { 1.0, 0.0, 0.0 }, { 0.0, 0.0, 1.0 },
    {-1.0, 0.0, 0.0 }, { 0.0,-1.0, 0.0 }, { 0.0, 1.0, 0.0 }
  };
  GLfloat lpos[4] = {5.0, 5.0, 0.0, 1.0};
  GLfloat lcol[4] = {0.5, 1.0, 0.5, 1.0};
  GLfloat mcol[4] = {1.0, 0.5, 0.5, 1.0};
  
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glEnable(GL_DEPTH_TEST);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  
  glLoadIdentity();
  gluLookAt(3.0, 4.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

  /* glLightfv(GL_LIGHT0, GL_POSITION, lpos); *//* 追加 */
  /* glLightfv(GL_LIGHT0, GL_DIFFUSE, lcol); *//* 追加 */
  /* glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mcol); *//* 追加 */

  glRotated((GLdouble)r, 0.0, 1.0, 0.0);
  
  glBegin(GL_QUADS);
  for (j = 0; j < 6; j++) {
    glNormal3dv(normal[j]);
    for (i = 0; i < 4; i++) {
      glVertex3dv(vertex[face[j][i]]);
    }
  }
  glEnd();

  glDisable(GL_LIGHT0);
  glDisable(GL_LIGHTING);
  glDisable(GL_DEPTH_TEST);
  glutSwapBuffers();

  if (++r >= 360) r = 0;
}

void resize(int w, int h)
{
  glViewport(0, 0, w, h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(30.0, 1.0, 1.0, 10.0);
  glMatrixMode(GL_MODELVIEW);
}

void keyboard(unsigned char key, int x, int y)
{
  if (key == '\033') exit(0);
}

int main(int argc, char *argv[])
{
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
  glutCreateWindow(argv[0]);
  glClearColor(1.0, 1.0, 1.0, 0.0);
  glutDisplayFunc(display);
  glutKeyboardFunc(keyboard);
  glutIdleFunc(idle);
  glutReshapeFunc(resize);
  glutMainLoop();
}