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

[Paul Miller]

Simon Green wrote:
> 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.


GL_FLOAT_RGB16_NV textures don't seem to be filtered on my 3400FX 
either. But I remember reading something about float textures only being 
point-sampled. Not a huge deal for what I am doing.

Thanks to the wonderful exrdisplay example, I was able to integrate 
native EXR support and display quite easily in our new roto app.


> -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?
> > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > Openexr-devel mailing list
> > > > address@hidden
> > > > http://lists.nongnu.org/mailman/listinfo/openexr-devel


--
Paul Miller | address@hidden | www.fxtech.com | Got Tivo?