Re: [PyOpenGL-Users] Odd framebuffer error

[Derakon <de...@gm...>]

After having a few days of not working on this, I came back fresh and
quickly found the problem. Alejandro was right: I didn't have a valid
OpenGL context when the framebuffer object was first created. I was
creating the framebuffer on a class instantiation, when I should have
been creating it the first time the class paint function is called.
Problem solved, on to bigger and better problems!

Thanks again for all your help, everyone.

-Chris

On Thu, Dec 2, 2010 at 8:37 AM, Derakon <de...@gm...> wrote:
> The problem I'm running into is with calling glBindFramebuffer, not
> anything after that. I might have problems with drawing to the
> framebuffer, but currently I have to way to tell as my program doesn't
> make it that far. This implies to me that there's some kind of setup
> step that I'm missing, maybe.
>
> I guess my next step is to get my test app running on the Windows side
> (I went straight from test-app-on-OSX to real-app-on-Windows since I
> didn't anticipate platform difficulties), and if that works, start
> figuring out what it's doing differently from the real app.
>
> -Chris
>
> On Thu, Dec 2, 2010 at 5:16 AM, Mike C. Fletcher <mcf...@vr...> wrote:
>> On 10-11-30 02:40 PM, Derakon wrote:
>> ...
>>
>>> I made a test program that works fine (on my OSX laptop), but I'm
>>> running into an error when I try to adapt the code to the main program
>>> (on a considerably more powerful Windows 7 box). Each small texture is
>>> contained in a Tile class instance, and a single Tile can be placed
>>> and oriented arbitrarily. Meanwhile, the entire working area is tiled
>>> with MegaTile instances; Tiles are pre-rendered onto MegaTiles using
>>> framebuffers as needed. However, I'm getting a 1286 error when I call
>>> glEnd() after rendering a Tile. From what I can tell this means I
>>> didn't set up the framebuffer properly, but it looks fine to me. I
>>> must be missing something.
>>>
>> Win32 has some funkiness relating to FBOs, from OpenGLContext's shadow
>> tutorial:
>>
>>            fbo = glGenFramebuffers(1)
>>            '''It has to be bound to configure it.'''
>>            glBindFramebuffer(GL_FRAMEBUFFER, fbo )
>>            '''The texture itself is the same as the last tutorial.'''
>>            texture = glGenTextures( 1 )
>>            glBindTexture( GL_TEXTURE_2D, texture )
>>            glTexImage2D(
>>                GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
>>                shadowMapSize, shadowMapSize, 0,
>>                GL_DEPTH_COMPONENT, GL_FLOAT, None
>>            )
>>            '''We attach the texture to the FBO's depth attachment
>> point.  There
>>            is also a combined depth-stencil attachment point when certain
>>            extensions are available.  We don't actually need a stencil
>> buffer
>>            just now, so we can ignore that.
>>
>>            The final argument is the "mip-map-level" of the texture,
>>            which currently always must be 0.
>>            '''
>>            glFramebufferTexture2D(
>>                GL_FRAMEBUFFER,
>>                GL_DEPTH_ATTACHMENT,
>>                GL_TEXTURE_2D,
>>                texture,
>>                0 #mip-map level...
>>            )
>>            if sys.platform == 'win32':
>>                color = glGenRenderbuffers(1)
>>                glBindRenderbuffer( GL_RENDERBUFFER, color )
>>                glRenderbufferStorage(
>>                    GL_RENDERBUFFER,
>>                    GL_RGBA,
>>                    shadowMapSize,
>>                    shadowMapSize,
>>                )
>>                glFramebufferRenderbuffer( GL_FRAMEBUFFER,
>> GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color )
>>                glBindRenderbuffer( GL_RENDERBUFFER, 0 )
>>            holder = mode.cache.holder(
>>                light,(fbo,texture),key=key
>>            )
>>
>> don't have time to track down why that was done this morning, but I'd
>> suspect that's likely where you're getting tripped up.
>>
>> HTH,
>> Mike
>>
>> --
>> ________________________________________________
>>  Mike C. Fletcher
>>  Designer, VR Plumber, Coder
>>  http://www.vrplumber.com
>>  http://blog.vrplumber.com
>>
>>
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