GPU acceleration in Krita

[Andrew Savonichev]

Hi Boudewijn,

Okay, I understand.
I would take a couple of weeks for PoC work to have better understanding
of changes need to be made and issues we may face.

I will get back to you when I have more to discuss.


    - Andrew


On Thu, Apr 6, 2017 at 12:01 PM, Boudewijn Rempt <boud at valdyas.org> wrote:
> On Thu, 6 Apr 2017, Andrew Savonichev wrote:
>
>> Hello,
>>
>> I'd like to know what is the status of GPU usage in Krita. I know
>> Krita can use OpenGL
>> for rendering, but I'm thinking about offloading image processing
>> algorithms to GPU.
>>
>> From my understanding, many algorithms in Krita are data parallel and
>> operate on entire image, what
>> makes them good candidates for offloading.
>>
>> Is there any directions, discussions or maybe some existing work on
>> enabling GPU acceleration?
>> What do you think about adding this to Krita?
>
> Right now, only the canvas uses the gpu. We have had two attempts to
> use the GPU for implementing filters, once using opencl, once with
> glsl. That code is so old and was so unripe, it's probably not even
> useful to look at.
>
> Apart from filters, recomputing the layer stack on the gpu could be
> worth-while, and writing brush engines that run on the gpu could be
> worth-while. In both cases, the problem is getting the pixel data to
> the gpu and back in the main memory.
>
> There are two possible approaches: store everything in main memory and
> copy to the gpu memory when needed, and then when done, back, but that
> is slow. The other approach would be to keep the entire layer stack in
> gpu memory, but that would limit the size of images -- and people do
> work on images that take gigabytes of memory.
>
> But, I am _very_ eager to see progress in this area and would
> love to work with you to see this happen.
>
>
> --
> Boudewijn Rempt | http://www.krita.org, http://www.valdyas.org