[Mesa-dev] [PATCH 1/6] Scaffolding for ARB_shader_bit_encoding.

[Ian Romanick]

On 05/02/2012 02:42 PM, Olivier Galibert wrote:
> On Wed, May 02, 2012 at 02:17:31PM -0700, Ian Romanick wrote:
>> I've been trying to keep this list alphabetized.
>
> Ok.
>
>>> +   if (ctx->Const.NativeIntegers) {
>>> +      ctx->Extensions.ARB_shader_bit_encoding = GL_TRUE;
>>> +   }
>>> +
>>
>> Is this actually true?  It seems like there's some GL 3.x hardware that
>> can't do this.  Though, I may be mistaken.
>
> It's doubtful.  Registers tend to be untyped, only the operators are
> typed.  Bitwise conversion is a very fancy way of saying "nop",
> gpu-wise :-)

The problem is whether or not registers are untyped.  The (potential) 
problem is that this spec requires that floating point numbers are 
stored as IEEE single precision.  In any case, I did a bit of searching 
through my archives, and it looks like all GL3 GPUs should be able to do 
this.  It appears this is why this small subset of functionality was 
split out from GL_ARB_gpu_shader5.