[Mesa-dev] [PATCH] radv/nir: avoid packing vertex outputs we can eliminate

[Timothy Arceri]

On 7/11/18 7:40 am, Timothy Arceri wrote:
> On 7/11/18 5:00 am, Eric Anholt wrote:
>> Timothy Arceri <tarceri at itsqueeze.com> writes:
>>
>>> On Mon, Nov 5, 2018, at 4:44 PM, Timothy Arceri wrote:
>>>> On 6/11/18 11:30 am, Eric Anholt wrote:
>>>>> Timothy Arceri <tarceri at itsqueeze.com> writes:
>>>>>
>>>>>> For now I have only enabled this for RADV we can do it
>>>>>> also for radeonsi also but we need to add a CAP for it.
>>>>>
>>>>> If we're doing this at link time, why not push the constant value from
>>>>> the producer into the consumer shader and then cut out the varying
>>>>> entirely?
>>>>>
>>>>
>>>> Maybe we could look to do this between vertex stages but we can do this
>>>
>>> Sorry that should be: "can't do this"
>>>
>>>> for fragment inputs (which is what this patch is for) unless they are
>>>> marked as flat (which almost never happens). Or I'm I missing 
>>>> something?
>>
>> If the vertex shader is providing a constant for all the vertices you're
>> interpolating between, how is that different from being flat?
> 
> We can just copy the flat constants directly across to the fs. 
> Everything else still needs to be interpolated, are you saying there is 
> a simple way to do this?

Oh duh. Right we don't need to apologies. I'll give that a try shouldn't 
be too difficult.