DropShadowFilter low performance on Macs and iPhones

[kozickikarol]

Steps to reproduce:

1. Open https://filters.pixijs.download/main/demo/index.html on mac or iphone.
2. Enable DropShadowFilter
3. It lags even for low quality but for high quality it's really bad - around 3 FPS.

I checked it on few devices and all of them have the same problem.

[bigtimebuddy]

That's expected, the implementation of the drop shadow is not performant on all devices. If someone wants to work on a more performant version of this and other filters, PixiJS is willing to pay for this work!

[0oooooooo0]

The same issue occurs with the OutlineFilter. Is there any solution?

[zumm]

DropShadowFilter uses KawaseBlurFilter as faster alternative to BlurFilter, but in reality KawaseBlurFilter is MUCH slower than BlurFilter (on iPhone at least).