[pygame] Depth Screenshot

[Ian Mallett <geometrian@xxxxxxxxx>]

Hello,

I'm trying to debug a weird FBO/depth problem, and it would be great to have screenshots of the depth.  My current method does not work:

def ScreenSurf(rect=AUTO,type=RGB,framebuffer=0):

    if rect == AUTO:
        size = glGetFloatv(GL_VIEWPORT)

        size = [int(round(size[2])),int(round(size[3]))]
        rect = [0,0,size[0],size[1]]

    glPixelStorei(GL_PACK_ROW_LENGTH,0)
    glPixelStorei(GL_PACK_SKIP_ROWS,0)

    glPixelStorei(GL_PACK_SKIP_PIXELS,0)
    if type==RGBA:

        glPixelStorei(GL_PACK_ALIGNMENT,4)
    elif type==RGB:

        glPixelStorei(GL_PACK_ALIGNMENT,1)
    elif type==DEPTH:

        glPixelStorei(GL_PACK_ALIGNMENT,2)
    try:

        data = "">
        print len(data)

    except:
        previous = glGetIntegerv(GL_READ_BUFFER)

        glReadBuffer(GL_COLOR_ATTACHMENT0_EXT+framebuffer)
        data = "">

        glReadBuffer(previous)
    if type==RGBA:

        return pygame.image.fromstring(data,(rect[2],rect[3]),'RGBA',1)
    elif type==RGB:

        return pygame.image.fromstring(data,(rect[2],rect[3]),'RGB',1)
    elif type==DEPTH:

        #What goes here?

The surface that is returned is then saved (pygame.image.save()).  

The issue is that in the case of depth, data is of length x*y.  In the case of RGB color, it is 3*rect[2]*rect[3].  In the case of RGBA, it is 4*rect[2]*rect[3].  PyGame doesn't know how to convert it (there's no pygame.image.fromstring(data,size,'R',1), for instance).  What's a decent way to save the depth as an image?  

Thanks,
Ian