import time, math
from pyglet.gl import *

window = pyglet.window.Window()


class BlendFilter:
    def __init__(self, srcFunc=GL_ZERO, destFunc=GL_SRC_ALPHA, color=[1,1,1,1]):
        self.srcFunc = srcFunc
        self.destFunc = destFunc
        self.color = color

    def draw(self):
        glMatrixMode(GL_PROJECTION)
        glPushMatrix()
        glLoadIdentity()
        glMatrixMode(GL_MODELVIEW)
        
        glEnable(GL_BLEND)
        glBlendFunc(self.srcFunc, self.destFunc)
        glColor4f(self.color[0],self.color[1],self.color[2],self.color[3])
        glBegin(GL_QUADS)
        glVertex2f(-1, -1)
        glVertex2f(-1, 1)
        glVertex2f(1, 1)
        glVertex2f(1, -1)
        glEnd()
        
        glMatrixMode(GL_PROJECTION)
        glPopMatrix()
        glMatrixMode(GL_MODELVIEW)


class TexAlphaSquare:
    def __init__(self, width=1.0, height=1.0, xpos=0.0, ypos=0.0, heading=0, texturefile=None):
        self.width = width
        self.height = height
        self.xpos = xpos
        self.ypos = ypos
        self.heading = heading
        if texturefile:
            self.texture = pyglet.image.load(texturefile).get_texture()
        else:
            self.texture = None
    def draw(self):
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
        if self.texture:
            glEnable(GL_TEXTURE_2D)
            glBindTexture(GL_TEXTURE_2D, self.texture.id)
        glColor4f(1,1,1,1)
        glPushMatrix()
        glTranslatef(self.xpos, self.ypos, 0)
        glRotatef(self.heading, 0, 0, 1)
        glBegin(GL_QUADS)
        glTexCoord2f(0, 0)
        glVertex2f(-self.width/2.0, -self.height/2.0)
        glTexCoord2f(1, 0)
        glVertex2f(self.width/2.0, -self.height/2.0)
        glTexCoord2f(1, 1)
        glVertex2f(self.width/2.0, self.height/2.0)
        glTexCoord2f(0, 1)
        glVertex2f(-self.width/2.0, self.height/2.0)
        glEnd()
        glPopMatrix()
        if self.texture:
            glBindTexture(GL_TEXTURE_2D, 0)
            glDisable(GL_TEXTURE_2D)
        glDisable(GL_BLEND)

objects = [ TexAlphaSquare(10, 10, texturefile='hst9904a.jpg'), TexAlphaSquare(3, 3, xpos=3, ypos=0, texturefile='rocket.tif') ]

thefilter = BlendFilter(GL_ZERO, GL_SRC_ALPHA,  color=[1,1,1,0.5])
#thefilter = BlendFilter(GL_ZERO, GL_SRC_COLOR,  color=[1,0,0.5,1])
#thefilter = BlendFilter(GL_ONE_MINUS_DST_COLOR, GL_ZERO,  color=[1,1,1,1])


@window.event
def on_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()
    thefilter.draw()
    

def update(dt):
    global objects
    angle = (time.time() % 10) * 36
    objects[1].xpos = 3 * math.sin(angle * math.pi/180.0)
    objects[1].ypos = 3 * math.cos(angle * math.pi/180.0)
    objects[1].heading = 270 - angle
    thefilter.color[3] = (1.0+math.sin(time.time()))/2.0


pyglet.clock.schedule_interval(update,1/60.0)
pyglet.app.run()