/* colorcube.c */
// Rotating, colorized cube

#include <GLUT/glut.h>
#include <math.h>

void cube()
{
	glBegin(GL_QUADS);

	glColor3f(1, 0, 0);
	glVertex3f(-0.5,-0.5,-0.5);
	glVertex3f(-0.5, 0.5,-0.5);
	glVertex3f( 0.5, 0.5,-0.5);
	glVertex3f( 0.5,-0.5,-0.5);

	glColor3f(0, 1, 0);
	glVertex3f( 0.5,-0.5,0.5);
	glVertex3f( 0.5, 0.5,0.5);
	glVertex3f(-0.5, 0.5,0.5);
	glVertex3f(-0.5,-0.5,0.5);

	glColor3f(0, 0, 1);
	glVertex3f( 0.5,-0.5,-0.5);
	glVertex3f( 0.5, -0.5,0.5);
	glVertex3f(-0.5, -0.5,0.5);
	glVertex3f(-0.5,-0.5,-0.5);

	glColor3f(1, 1, 0);
	glVertex3f(-0.5,0.5,-0.5);
	glVertex3f(-0.5, 0.5,0.5);
	glVertex3f( 0.5, 0.5,0.5);
	glVertex3f( 0.5,0.5,-0.5);

	glColor3f(1,0, 1);
	glVertex3f(-0.5,-0.5, 0.5);
	glVertex3f(-0.5, 0.5, 0.5);
	glVertex3f(-0.5, 0.5,-0.5);
	glVertex3f(-0.5,-0.5,-0.5);

	glColor3f(0,1, 1);
	glVertex3f(0.5,-0.5,-0.5);
	glVertex3f(0.5, 0.5,-0.5);
	glVertex3f( 0.5, 0.5,0.5);
	glVertex3f( 0.5,-0.5,0.5);

	glEnd();
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	
	glRotatef(2, 1,1,1);
	cube();
	
	glutSwapBuffers();
}

void reshape(GLsizei w, GLsizei h)
{
	// Viewport is a separate setting
	glViewport(0, 0, w, h);
	// Projection in projection matrix
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glFrustum(-1, 1, -1, 1, 1, 20); // left, right, bottom, top, near, far
	// Camera placement in modelview matrix
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(0, 0, 2,  0, 0, 0,  0, 1, 0); // camera, look-at-point, up-vector
}

void timer(int i)
{
	glutTimerFunc(20, timer, i);
	glutPostRedisplay();
}

int main(int argc, char **argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
	glutCreateWindow("colorcube");
	glutDisplayFunc(display);
	glutTimerFunc(20, timer, 0);
	glutReshapeFunc(reshape);
	
	glEnable(GL_CULL_FACE);
	glEnable(GL_DEPTH_TEST);
	
	glutMainLoop();
}