Bad performance with GPU acceleration and tablets, especially when trying to resize your brush

[Frozen Death Knight]

Been trying the new GPU acceleration feature in the Beta and found out that brushes were very unresponsive when I used my tablet. I can't use ctrl+alt+L click to do simple things as changing brush sizes and the program became overall very unresponsive when using those tools.

Down below is a performance test using an 8k canvas with a 1k+ pixel sized round brush. The first test was using just a mouse for resizing the brush and filling the screen with paint, which worked fine. The problems started when I switched over to my tablet (you can see when I released the ctrl+alt+L click keybind and the brush resizing just kept going).

You can also see the lag when I wrote "Tablet now" on the canvas.

[Frozen Death Knight]

Another example. This time I'm using a file which I have no problems with when painting in 1.8.5.

[Frozen Death Knight]

Made some additional tests on a very small canvas (600x800 pixels). The lag is very noticeable even there as well.

[Chris B]

Hey Frozen Death Knight,

I believe not all the brushes are taking advantage of OpenCL yet so we should see this improve as the beta goes on.

[Frozen Death Knight]

Been trying the latest Beta and for the most part, hardware acceleration actually works! Massive brushes are significantly faster than in 1.8.5. Haven't been able to get my recording software to work, but I noticed significant speed boosts with 3k+ pixel sized brushes, which are practically impossible to use in older versions of Affinity. One problem I have however encountered is that there is some start-up lag happening at the beginning of your brush strokes, so if you do multiple brush strokes in rapid successions Affinity loses its more consistent performance like when OpenCL is turned off.

However, I have found a pretty program breaking bug when I attempted to do multiple strokes in rapid succession. Affinity loses pixel information in square like patterns on some brush strokes, creating artefacts like these (no, I did not erase anything):

I tried to press undo to regain that lost canvas data, but it was permanently gone (of some reason the lost data reappears in some undo strokes but they remove the other data in some inverted pattern). Pretty important that this issue gets sorted out before the Beta ends, since this is a very serious bug.

[Frozen Death Knight]

I was actually able to save the bug in a document that the devs can use to replicate.

Bug.afphoto

Check the History panel as well. There are also corrupted history thumbnails that show the problem.