accumulation buffer support

[Roland Scheidegger]

On 29.07.2008 00:15, Svilen wrote:
> Hi,
> 
> I was wondering whether your driver supports accumulation buffers and if 
> yes how to enable them.
> 
> Here is my platform:
> X1600 Mobility Radeon
> Linux, Fedora 9
> Xorg 7.4 (unofficial)
> Mesa 7.1 (unofficial)
> 
> xorg.conf
> ...
>     Section "Device"
>         Identifier "Videocard0"
>         Driver "radeon"
>     EndSection
> ...
> 
> A try to get a glx visual with accumulation buffers fails. On Fedora 8 
> with ATI driver it works.
> Below is the parameter list for glXChooseVisual
> GLX_RGBA                                     ,
> GLX_RED_SIZE                              , 8,
> GLX_GREEN_SIZE                        , 8,
> GLX_BLUE_SIZE                           , 8,
> GLX_ACCUM_RED_SIZE             , 8,
> GLX_ACCUM_GREEN_SIZE       , 8,
> GLX_ACCUM_BLUE_SIZE          , 8,
> GLX_DOUBLEBUFFER               ,
> GLX_NONE
> 
> I'll really appreciate your help

Not sure I think it should work (except I think the last strong should
be "None", not "GLX_NONE"), since all implementations are required to
support configurations with a accumulation buffer. Note that they are
all marked slow however since all open source drivers implement this as
a software fallback only, so it will likely be useless (except for
educational purposes). (Generally, I don't think there's any hardware
out there which really has anything resembling even remotely close to a
special accumulation buffer except maybe some old professional opengl
graphic accelerators - somewhat modern hardware is likely to implement
this with other means, so it's just a render buffer like any other
render buffer would be with EXT_fbo, the special accum functions are
just done by the driver).

Roland