Re: [PyOpenGL-Users] bug in glDrawBuffers?

[Mike C. F. <mcf...@vr...>]

Gijs wrote:
> Hello List,
>
> I am trying to use glDrawBuffers to render to multiple textures using 
> shaders. However, I'm running into a problem (otherwise I wouldn't be 
> posting here ofcourse :) ). When I call glDrawBuffers with *any* 
> buffer-type, it fails with the following error:
>   
Can you add this to tests/test.py and then alter it with fragments of 
your usage/code until it shows your error:

    def test_glDrawBuffers_list_valid( self ):
        """Test that glDrawBuffers with list argument where value is set"""
        fbo = glGenFramebuffersEXT(1)
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo)
        try:
            img1,img2 = glGenTextures(2)
            for img in img1,img2:
                glBindTexture( GL_TEXTURE_2D, img )
                glTexImage2D(
                    GL_TEXTURE_2D, 0, GL_RGB8, 
                    300, 300, 0, GL_RGB,
                    GL_INT,
                    None # no data transferred
                )
            glFramebufferTexture2DEXT(
                GL_FRAMEBUFFER_EXT,
                GL_COLOR_ATTACHMENT0_EXT,
                GL_TEXTURE_2D, img1, 0
            )
            glFramebufferTexture2DEXT(
                GL_FRAMEBUFFER_EXT,
                GL_COLOR_ATTACHMENT1_EXT,
                GL_TEXTURE_2D, img2, 0
            )
            drawingBuffers = [
                GL_COLOR_ATTACHMENT0_EXT,
                GL_COLOR_ATTACHMENT1_EXT,
            ]
            glDrawBuffers(2, drawingBuffers )
        finally:
            glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 )

then send back the error-ing version so that I can look into what's 
going wrong without having to guess too much?
> Hope someone knows what's going on under the hood.
>   
I *think* this should be working, I haven't had time to sit down and do 
shadow-casting myself, so I don't have any real-world code to test it.  
The code is pretty much just passing your values off to the C code, so 
there's not a lot under the hood that's PyOpenGL specific.

HTH,
Mike

-- 
________________________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://www.vrplumber.com
  http://blog.vrplumber.com