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Re: Floating point PBuffers

I think that, if you want 128-bit colors (4x 32-bit float channels),
you'll need to specify the kCGLPFAColorFloat attribute,
or you'll get an error when you try to create the pbuffer.
("invalid pixel format")

Jeff

Claire Rogers <email@hidden> wrote: 

Thanks for that.  I was looking for something to specifically state
floating point pixels like I use
under windows.  I did actually Find 	

kCGLPFAColorFloat         =  58,	/* color buffers store floating point
pixels    */

in the headers, but nothing equivalent under agl.  I'll have a play and
see if I can make it work.

Claire

On 15 Sep 2004, at 18:59, Pete Warden wrote: 
I'm using 16 bit float pbuffers successfully. They only work on later
ATI Radeon cards at the moment, 9500, 9600 and 9700, or R350+ if
you're looking at the chipset name in the system profiler. They aren't
supported on any NVidia cards on OS X yet. Look for
"APPLE_float_pixels" in the extensions string.

Here's the pixel format attributes I use:

    CGLPixelFormatAttribute pixelFormatAttributes[]={
        kCGLPFANoRecovery,
        kCGLPFAAccelerated,
        kCGLPFAWindow,
        kCGLPFAColorSize,(CGLPixelFormatAttribute)(bitsPerPixel),
        (CGLPixelFormatAttribute)0};

If you set bitsPerPixel to 32, you'll get a plain 8 bit buffer, 64
gives you a half float buffer, and 128 gives you 32 bit floats.
There's some restrictions on these pbuffers, you can't do any blending
for example.

Pete 

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