Created
October 8, 2013 03:51
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basic alpha blending - a semi-transparent square blended over an opaque square
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import time, math | |
from pyglet.gl import * | |
window = pyglet.window.Window() | |
class AlphaSquare: | |
def __init__(self, color): | |
self.xpos = 0 | |
self.ypos = 0 | |
self.color = color | |
self.vlist = pyglet.graphics.vertex_list(4, ('v2f', [-128,-128, 128,-128, -128,128, 128,128])) | |
def draw(self): | |
glEnable(GL_BLEND) | |
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) | |
glColor4f(self.color[0],self.color[1],self.color[2],self.color[3]) | |
glPushMatrix() | |
glTranslatef(self.xpos, self.ypos, 0) | |
self.vlist.draw(GL_TRIANGLE_STRIP) | |
glPopMatrix() | |
glDisable(GL_BLEND) | |
solidSquare = AlphaSquare([1, 1, 1, 1]) | |
solidSquare.xpos = 320 | |
solidSquare.ypos = 240 | |
transpSquare = AlphaSquare([1, 0, 0, 0.5]) | |
transpSquare.xpos = 320 | |
transpSquare.ypos = 240 | |
@window.event | |
def on_draw(): | |
global transpSquare, solidSquare | |
glClearColor(0, 0.3, 0.5, 0) | |
glClear(GL_COLOR_BUFFER_BIT) | |
glLoadIdentity() | |
solidSquare.draw() | |
transpSquare.draw() | |
def update(dt): | |
global transpSquare | |
transpSquare.xpos = 320 + 128 * math.sin(time.time()) | |
transpSquare.ypos = 240 + 128 * math.cos(time.time()) | |
pyglet.clock.schedule_interval(update,1/60.0) | |
pyglet.app.run() |
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