[pygame] PyOpenGL and pygame.display.flip

["sylvain.boussekey" <sylvain.boussekey@xxxxxxxxxxxxxxx>]

Hi everyone,

I'm running into difficulties when using an opengl window in pygame. 
For reasons I don't catch, sometimes, when I draw quads with pyopengl, I 
have to call pygame.display.flip to actually display anything, and 
sometimes, I don't, resulting in a blinking horrific mess when I draw 
multiple quads overlapping themselves.

I really don't know when it happen but it does in one project, not in 
one another. Can't tell the difference...

I'm using flags OPENGL | DOUBLEBUF | HWSURFACE for my pygame window

Here's what I execute at the beginning of my drawing state :

def clear():
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

And here's my function to draw quads :

def drawtexturedquad(imgid, pos, proj=True, siz=(1, 1), r=1.0, g=1.0, 
b=1.0, alpha=1.0):
    if proj:
        glMatrixMode(GL_MODELVIEW)
    else:
        glMatrixMode(GL_PROJECTION)

    glLoadIdentity()
    glPushMatrix()
    glEnable(GL_TEXTURE_2D)
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

    glTranslated(-1, -1, 0)
    glTranslated(pos[0], pos[1], 0)
    glScalef(siz[0], siz[1], 1)

    glColor4f(r, g, b, alpha)

    glBindTexture(GL_TEXTURE_2D, imgid)

    glBegin(GL_QUADS)

    glTexCoord2f(0.0, 1.0)
    glVertex2f(-1.0, 1.0)

    glTexCoord2f(1.0, 1.0)
    glVertex2f(1.0, 1.0)

    glTexCoord2f(1.0, 0.0)
    glVertex2f(1.0, -1.0)

    glTexCoord2f(0.0, 0.0)
    glVertex2f(-1.0, -1.0)

    glEnd()
    glPopMatrix()
    glFlush()