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

#define R 0.5

#define W 6                       
#define D 6        

GLfloat light0pos[] = { -150.0, -10.0, -150.0, 1.0 };
GLfloat light1pos[] = { 150.0, 0.0, 10.0, 1.0 };
GLfloat param_d[] = { 0.7, 0.7, 0.7, 1.0 };
GLfloat param_s[] = { 1.0, 1.0, 1.0, 1.0 };

static double a = 0.0, b = 0.0;

void idle(void)
{
  glutPostRedisplay();
}

void display(void)
{
  int i;
  int j;
  const static GLfloat bcolor[] = { 0.8, 0.3, 0.2, 1.0 }; /* 球の色 */
  static int r = 0; /* 回転角 */

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glLoadIdentity();
  gluLookAt(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

  /* 光源の位置設定 */
  glLightfv(GL_LIGHT0, GL_POSITION, light0pos);
  glLightfv(GL_LIGHT1, GL_POSITION, light1pos);

  /* 図形の回転 */
  glTranslated(a,0.0,b);
  glRotated((double)r, 0.0, 1.0, 0.0);

  /* 図形の描画 */
  glPushMatrix();
  glMaterialfv(GL_FRONT, GL_DIFFUSE, bcolor);
  glutSolidSphere(R, 32, 16);
  glPopMatrix();

  glutSwapBuffers();

  /* 一周回ったら回転角を 0 に戻す */
  if (++r >= 360) r = 0;
}

void resize(int w, int h)
{
  glViewport(0, 0, w, h);

  /* 透視変換行列の設定 */
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(30.0, (double)w / (double)h, 1.0, 100.0);

  /* モデルビュー変換行列の設定 */
  glMatrixMode(GL_MODELVIEW);
}

void mouse(int button, int state, int x, int y)
{
  switch (button) {
  case GLUT_LEFT_BUTTON:
    if (state == GLUT_DOWN) {
      /* アニメーション開始 */
      glutIdleFunc(idle);
    }
    else {
      /* アニメーション停止 */
      glutIdleFunc(0);
    }
    break;
  case GLUT_RIGHT_BUTTON:
    if (state == GLUT_DOWN) {
      /* コマ送り (1ステップだけ進める) */
        glutPostRedisplay();
    }
    break;
  default:
    break;
  }
}
  
void keyboard(unsigned char key, int x, int y)
{
  switch (key) {
  case 'q':
  case 'Q':
  case '\033':  /* '\033' は ESC の ASCII コード */
    exit(0);
  case 'i':  /* 前 */
  a = a;
  b = b + 0.03;
  glutPostRedisplay();
  break;
  case 'k':  /* 後 */
  a = a;
  b = b - 0.03;
  glutPostRedisplay();
  break;
  case 'l':  /* 左 */
  a = a - 0.03;
  b = b;
  glutPostRedisplay();
  break; case ';':  /* 右 */
  a = a + 0.03;
  b = b;
  glutPostRedisplay();
  break;
  default:
    break;
  }
}

void init(void)
{
  glClearColor(1.0, 1.0, 1.0, 1.0);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_CULL_FACE);
  glCullFace(GL_FRONT);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_LIGHT1);
  glLightfv(GL_LIGHT1, GL_DIFFUSE, param_d);
  glLightfv(GL_LIGHT1, GL_SPECULAR, param_s);

}

int main(int argc, char *argv[])
{
  glutInitWindowPosition(100, 100);
  glutInitWindowSize(320, 240);
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
  glutCreateWindow(argv[0]);
  glutDisplayFunc(display);
  glutReshapeFunc(resize);
  glutMouseFunc(mouse);
  glutKeyboardFunc(keyboard);
  init();
  glutMainLoop();
  return 0;
}