void redraw()
{
	glClear(GL_COLOR_BUFFER_BIT);
    glRotatef(45, -0.0, -0.5, 1);
	glBegin(GL_TRIANGLE_FAN);
	
	glColor3f(1.0, 1.0, 1.0);
	glVertex2f(-0.5, -0.5);
	glColor3f(1.0, 0.0, 1.0);
	glVertex2f(-0.5, 0.5);
	glColor3f(0.0, 1.0, 1.0);
	glVertex2f(0.5, 0.5);
	glColor3f(1.0, 1.0, 0.0);
	glVertex2f(0.5, -0.5);

	glEnd(); // GL_QUADS
	glutSwapBuffers();
}