import sys, time, math, os, random
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *

startDir = os.getcwd()



class AlphaSquare:
    def __init__(self, width=1.0, height=1.0, xpos=0.0, ypos=0.0, color=[1,1,1,1]):
        self.width = width
        self.height = height
        self.xpos = xpos
        self.ypos = ypos
        self.color = color
    def draw(self):
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
        glColor4fv(self.color)
        glPushMatrix()
        glTranslatef(self.xpos, self.ypos, 0)
        glBegin(GL_QUADS)
        glVertex2f(-self.width/2.0, -self.height/2.0)
        glVertex2f(self.width/2.0, -self.height/2.0)
        glVertex2f(self.width/2.0, self.height/2.0)
        glVertex2f(-self.width/2.0, self.height/2.0)
        glEnd()
        glPopMatrix()
        glDisable(GL_BLEND)

objects = []

def createObjects():
    global objects
    square1 = AlphaSquare(3, 3, color=[1, 1, 1, 1])
    objects.append(square1)
    square2 = AlphaSquare(3, 3, xpos=2, ypos=0, color=[1,0,0,1])
    objects.append(square2)


def draw():
    glClearColor(0, 0.3, 0.5, 0)
    glClear(GL_COLOR_BUFFER_BIT)
    
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluOrtho2D(-5, 5, -5, 5)
    glMatrixMode(GL_MODELVIEW)

    for o in objects:
        o.draw()
    
    glutSwapBuffers()


def keyboard(key, x, y):
    if key == chr(27):
        sys.exit(0)

def specialkey(key,x,y):
    global objects
    if key == GLUT_KEY_LEFT:
        objects[0].xpos -= 0.25
    elif key == GLUT_KEY_RIGHT:
        objects[0].xpos += 0.25
    elif key == GLUT_KEY_UP:
        objects[0].ypos += 0.25
    elif key == GLUT_KEY_DOWN:
        objects[0].ypos -= 0.25


def update(dummy):
    glutTimerFunc(16, update, 0)
    global objects
    objects[1].xpos = 2 * math.sin(time.time())
    objects[1].ypos = 2 * math.cos(time.time())
    objects[1].color[3] = (1+math.sin(time.time()))/2.0
    glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE)
glutInitWindowSize(400,400)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutSpecialFunc(specialkey)
glutTimerFunc(1, update, 0)
os.chdir(startDir)
createObjects()
glutMainLoop()