Screen filter(such as super2xsai) support?
Posted: April 17th, 2017, 3:54 am
Is there any plan to support screen filer such as super2xsai? I think that screen filters are needed for visual enhancement.
I think SDL itself only provides the SDL_HINT_RENDER_SCALE_QUALITY hint for controlling the scaling method.
For SDLPoP that's currently left at the default setting (= nearest pixel sampling).
We could easily add an option to enable linear filtering, but that basically only causes blurring...
I'm not familiar with other scaling methods like super2xSAI, but it sounds interesting.
I found this long list of pixel scaling algorithms on Wikipedia:
https://en.wikipedia.org/wiki/Pixel-art ... algorithms
And here some other pages, where they compare several algorithms for the same input image:
http://wiki.scummvm.org/index.php/User_ ... ic_filters
https://www.dosbox.com/wiki/Scaler
If we want to add something like this, maybe it would be best to use GPU shaders...
I found this example of a GPU implementation (in GLSL) of the AdvMAME2x filter:
https://gist.github.com/singron/3161079
(linked from this blog post: http://singron.blogspot.nl/2012/07/shaders.html)