V3D UIF texture format conversion with TFU

[Macoy Madson]

Thanks for your reply!

I have created https://gitlab.freedesktop.org/mesa/mesa/-/issues/10734 .

I understand you are all very busy so any help I can get is hugely 
appreciated!

On 3/1/24 12:09 PM, Alejandro Piñeiro wrote:
> Hi,
>
> sorry, I realized that you sent first this email to me privately, but 
> didn't have time to reply.
>
> On 1/3/24 14:33, Macoy Madson wrote:
>> Hello,
>>
>> I have been looking at the code in Gallium/drivers/v3d related to 
>> texture conversion, specifically v3dx_tfu.c.
>>
>> I have been trying to find how to convert a texture from raster 
>> format RGBA8 to UIF (either XOR or NO_XOR). I tried break-pointing 
>> the v3dX(tfu) function, but it doesn't appear to be called in my 
>> simple textured triangle OpenGL program on a Raspberry Pi 4 
>> (VideoCore VI v. 42).
>>
>> I am looking for where this conversion takes place, as it appears the 
>> VideoCore expects textures to be in another format before they can be 
>> sampled properly.
>>
>> Is there anyone here who can point me to any one of the following:
>>
>> - How v3dX(tfu) ends up getting used (e.g., a user-space program I 
>> can run to blit/convert a raster texture into a UIF texture)
>>
>> - Any notes on the TFU interface itself (what the registers expect, 
>> beyond what can clearly infer from v3dX(tfu))
>>
>> - If the TFU isn't used to convert to UIF, where the conversion takes 
>> place
>>
>> I may have misunderstood the texture sampler. I am sampling a texture 
>> successfully (pixels are the color I expect) but the pixels are 
>> completely "out of order", which is what hints me that they need to 
>> be in UIF instead of raster format.
>>
>> I would greatly appreciate someone to bounce a few V3D questions off of.
>>
>> Thanks,
>>
>> Macoy Madson
>>
>> (Apologies if this was received before; I checked the archive and 
>> didn't see it, so I subscribed to the list and re-sent in case I need 
>> to be a subscriber to send. I sent this to mesa-dev since I am 
>> looking for low level details, so if this should go to the mesa list 
>> instead please let me know.)
>
>
> For this kind of things it is usually done through gitlab issues. 
> Would it be possible if you create an issue with that, and 
> additionally adding the simple texture triangle program that you 
> mentioned before?
>
>
> Thanks
>
>
>>
>>