#include <GL/glut.h>

static int year=0, day=0;

void display() {
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glPushMatrix();
	glColor3f(1.0, 1.0, 0.0);
	glutSolidSphere(1.0, 20, 16);
	glRotatef((GLfloat)year, 0.0, 1.0, 0.0);
	glTranslatef(2.0, 0.0, 0.0);
	glRotatef((GLfloat)day, 0.0, 1.0, 0.0);
	glColor3f(0.0, 0.0, 1.0);
	glutWireSphere(0.2, 10, 8);
	glPopMatrix();
	glutSwapBuffers();
}

void reshape(int w, int h) {
	glViewport(0,0,(GLsizei)w, (GLsizei)h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
    if (w <= h)
        glOrtho(-4.0, 4.0, -4.0 * (GLfloat) h / (GLfloat) w,
            4.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);
    else
        glOrtho(-4.0 * (GLfloat) w / (GLfloat) h,
            4.0 * (GLfloat) w / (GLfloat) h, -4.0, 4.0, -10.0, 10.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y) {
	switch(key) {
		case 'd' : day=(day+10)%360;
			break;
		case 'D' : day=(day-10)%360;
			break;
		case 'y' : year=(year+5)%360;
			break;
		case 'Y' : year=(year-5)%360;
			break;
		default:;
	}
	glutPostRedisplay();
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); 
    glutInitWindowSize(500, 500);
	glutInitWindowPosition(100,100);
    glutCreateWindow("HW4-2");
	glClearColor(0.0, 0.0, 0.0, 1.0);
    glutDisplayFunc(display);

	glMatrixMode(GL_PROJECTION);
	glutReshapeFunc(reshape);
	glutKeyboardFunc(keyboard);
    glEnable(GL_DEPTH_TEST);		/* Enable hidden-surface removal */

    glutMainLoop();
}