Re: pBuffer
Phil Keslin (philk++at++cthulhu.engr.sgi.com)
Mon, 14 Dec 1998 00:42:12 -0800
Ruediger Westermann wrote:
>
> On Dec 10, 10:32am, Phil Keslin wrote:
> > Subject: Re: pBuffer
> > Rob Jenkins wrote:
> > >
> > > Ruediger Westermann wrote:
> > > >
> > > > Hi Rob,
> > > > Many thanks for your reply.
> > > > The thing i don't understand is that i search the list
> > > > until i find the configuration i want to have (8,8,8,8,>1).
> > > > I only select the visual if the requirement is satisfied.
> > > > However, sometimes there is only one entry (12,12,12,12,24)
> > > > in the list, which can not be allocated.
> > > >
> > > > Any idea ?
> > > >
> > >
> > > Hi
> > >
> > > I CC'd this back to the list in case anyone else was tuned in, I know a
> > > few people have/are grappling with this kinds of issues.
> > >
> > > In my first response I thought you were doing 'bits >= 8' but actaully
> > > you do 'bits == 8' so my words about getting RGBA12 first might not be
> > > relevent.
> > > The other stuff about considering you minimal config and fallback cases
> > > is valid though.
> > > The missing piece in this is probably the PixBuffer::configAttribList
> > > that you use, could you post that and I'll take another swing :-)
> >
> > The answer to the question is very dependent upon the target graphics
> > hardware and the current framebuffer configuration. Some machines won't
> > have sufficient resources to allocate depth and color buffers for a
> > pbuffer simultaneously. If you tell me what configs you are trying to
> > support, I might be able to give you a better feel what you can and
> > cannot do.
> >
>
> Hi Phil,
> here is the attribList
>
> int PixBuffer::configAttribList[] = {GLX_LEVEL, 0,
> GLX_DOUBLEBUFFER, False,
> GLX_STEREO, False,
> GLX_AUX_BUFFERS, 0,
> GLX_RED_SIZE, 8,
> GLX_GREEN_SIZE, 8,
> GLX_BLUE_SIZE, 8,
> GLX_ALPHA_SIZE, 0,
> GLX_DEPTH_SIZE, 1,
> GLX_STENCIL_SIZE, 0,
> GLX_DRAWABLE_TYPE_SGIX,
> GLX_PIXMAP_BIT_SGIX,
> // GLX_RENDER_TYPE_SGIX,
> GLX_RGBA_BIT_SGIX,
> None};
>
> int PixBuffer::pBufferAttribList[] = {GLX_LARGEST_PBUFFER_SGIX,
> False,
> GLX_PRESERVED_CONTENTS_SGIX,
> True,
> None};
>
> Hope that helps.
I need the graphics information as well (gfxinfo and glxinfo). BTW, the
drawable_type should be pbuffer not pixmap. Also, without
largest_pbuffer enabled, the system will only return a pbuffer if the
system can support the requested size. Also, I assume that you are using
glXChooseFBConfigSGIX to acquire the FBConfig needed for the pbuffer
allocation.
- Phil
--
Phil Keslin <philk++at++engr.sgi.com>
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on Mon Dec 14 1998 - 00:41:52 PST