a triangle with one animated vertex

animtriangle.py

# animtriangle.py
# by Dave Pape, for DMS 423
#
# draws a triangle with one moving vertex

from pyglet.gl import *

window = pyglet.window.Window()

vlist = pyglet.graphics.vertex_list(3, ('v2f', [0,0, 400,50, 200,300]))

@window.event
def on_draw():
    glClear(pyglet.gl.GL_COLOR_BUFFER_BIT)
    glColor3f(1,0,0)
    vlist.draw(GL_TRIANGLES)

direction = -1

def update(dt):
    global direction
    vlist.vertices[4] += direction
    if vlist.vertices[4] < 0:
        direction = 1
    elif vlist.vertices[4] > 300:
        direction = -1
    
pyglet.clock.schedule_interval(update,1/60.0)
pyglet.app.run()