[Mesa-dev] Thoughts on fp64 for GLES?

[Tapani Pälli]

On 1/25/19 8:25 AM, Stéphane Marchesin wrote:
> On Thu, Jan 24, 2019 at 10:17 PM Tapani Pälli <tapani.palli at intel.com> wrote:
>>
>> Hi;
>>
>> On 1/25/19 4:57 AM, Stéphane Marchesin wrote:
>>> Hi,
>>>
>>> We'd like to expose fp64 functionality on Chrome OS where we only have
>>> GLES. It seems like a simple approach is to enable this extension for
>>> GLES:
>>> https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_gpu_shader_fp64.txt
>>>
>>> Anyone knows if what's the right thing to do? It seems to me that the
>>> extension might just work on GLES without any changes, but I could be
>>> missing something.
>>
>> Sorry for not responding the the actual question but could you share the
>> usecase? Back when this was enabled for HW that supports it we did not
>> find applications (just some fractal shadertoy things), would be
>> interesting to know how it is being used.
> 
> Yes, it's for running virgl on top of GLES. To emulate fp64 in GL on
> the guest side, we need fp64 on the host...
> 

OK thanks. One thing that comes to mind (specific to GLSL ES) is that 
should double type have precision qualifier support? Maybe some specific 
rules what happens when expression has both floats and doubles with some 
precision qualifiers ... there might be a lot more things to this but 
this is what comes first to my mind.

// Tapani