RE: [Openexr-devel] working with "half float" textures in OpenGL

[Simon Green]

Hey Drew,

Yes, Nan and Inf behaviour on NVidia hardware is unchanged, although the
spec leaves this undefined so your mileage on other hardware may vary.

ARB_texture_float is the new extension for float texture types, and
there are also replacements for NV_texture_rectangle and
ATI_pixel_format_float:
http://www.nvidia.com/dev_content/nvopenglspecs/GL_ARB_texture_float.txt
http://www.nvidia.com/dev_content/nvopenglspecs/GL_ARB_color_buffer_floa
t.txt
http://www.nvidia.com/dev_content/nvopenglspecs/GL_ARB_texture_rectangle
.txt

So pretty soon you will be able to do all this in a vendor-independent
way. One caveat is that ATI doesn't currently support filtering or
blending of half types, so you'll still need to detect this case.

-S.

> -----Original Message-----
> From: Drew Hess [mailto:address@hidden 
> Sent: Thursday, February 17, 2005 7:11 PM
> To: Simon Green
> Cc: Paul Miller; address@hidden
> Subject: Re: [Openexr-devel] working with "half float" 
> textures in OpenGL
> 
> 
> 
> Good news, thanks, Simon :)
> 
> Will the Nvidia implementation of GL_ARB_half_float_pixel 
> support NaN and inf ala NV_half_float?
> 
> Is there an ARB extension for half texture types yet?  I have 
> to use GL_RGB_FLOAT16_ATI to get filtering on 3d textures on 
> NV40 hardware, but GL_FLOAT_RGBA16_NV for 2d textures to 
> display OpenEXR frames, would be nice to have a set of ARB 
> types that "just work" so I don't have to remember which 
> vendor's type is the right one in which situation.
> 
> 
> d
> 
> 
> "Simon Green" <address@hidden> writes:
> 
> > Note that the NV_half_float extension has now been replaced with a 
> > cross-vendor ARB extension: 
> > 
> http://www.nvidia.com/dev_content/nvopenglspecs/GL_ARB_half_float_pixe
> > l.
> > txt
> >
> > This should be supported on NVIDIA cards in the next driver release.
> >
> >> -----Original Message-----
> >> From: address@hidden
> >> [mailto:address@hidden 
> >> On Behalf Of Drew Hess
> >> Sent: Thursday, February 17, 2005 3:27 PM
> >> To: Paul Miller
> >> Cc: address@hidden
> >> Subject: Re: [Openexr-devel] working with "half float" 
> >> textures in OpenGL
> >> 
> >> 
> >> 
> >> Hi Paul,
> >> 
> >> These should be helpful:
> >> 
> > http://oss.sgi.com/projects/ogl-sample/registry/NV/half_float.txt
> > http://oss.sgi.com/projects/ogl-sample/registry/NV/float_buffer.txt
> > 
> http://www.ati.com/developer/SIGGRAPH03/Per>
cy_OpenGL_Extensions_SIG03.
> > pd
> > f
> >
> > d
> >
> >
> > Paul Miller <address@hidden> writes:
> >
> >> For those of you who have worked with these, I have a couple of
> >> questions:
> >>
> >> 1. what extension(s) should you check for to detect if the hardware
> >> supports the GL_HALF_FLOAT_NV texture format? This assumes 
> you want 
> >> the broadest range of hardware.  Currently I am checking for 
> >> "GL_NV_half_float" but I haven't tried this on ATI hardware yet.
> >>
> >> 2. is it possible to have an RGBA half-float texture organized with
> >> the channels in a different order (such as BGRA or ARGB)? 
> Or must the 
> >> components be in RGBA order?
> >>
> >> Many thanks!
> >>
> >> --
> >> Paul Miller | address@hidden | www.fxtech.com | Got Tivo?
> >>
> >>
> >>
> >> _______________________________________________
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> >> address@hidden
> >> http://lists.nongnu.org/mailman/listinfo/openexr-devel
>