[Mesa-dev] EXT_texture_snorm - is it possible in GL2?

Ian Romanick idr at freedesktop.org
Tue Mar 15 08:23:04 PDT 2011


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On 03/10/2011 02:46 PM, Marek Olšák wrote:

> The specification of GL_EXT_texture_snorm says:
> 
>     OpenGL 3.0 is required.
> 
>     This extension is written against the OpenGL 3.0 specification.

And then all of the chapter headings in the spec say "Additions to
Chapter # of the OpenGL 2.0 Specification".  lol

> which simply means we cannot advertise the extension on GL2.1. Would
> anyone be against violating the requirement?
> 
> The thing is even some of GL2 hardware can do it, and GL3 likely won't
> be supported anytime soon due to unresolved patent issues.

My recollection is that AMD (where all of the spec authors live) only
wanted to advertise it with OpenGL 3.x, and they didn't want to specify
the interactions.  It looks like the only interactions are with
GL_ARB_texture_rg.  I think it's safe to advertise this on 2.x hardware
as long as GL_ARB_texture_rg is also supported.  This makes sense given
that the most common usage is for normal maps.
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