In-depth Description of image filters/shaders.

[Sonic Angel Knight]

I need help describing some of the image filters used in games... or emulators. Since most of this is used in emulators, i'll use that as reference, mostly cause i dunno if consoles have actual image filter/shader effects. So i'll take community information about it. To start off, is a list of plugins. These were found for the emulator Kega Fusion 3.64

• 2xSaI
• Bilinear
• Eagle
• hq4x
• lq4x
• Scale4x
• ScanLineTv
• Super2xSaI
• SuperEagle
• SuperScale75
• SuperScale

If anyone knows anymore i may missed, tell me so i can add them to the list as well as description of how they work and your recommendation of it based on opinion.

So far the HQX is one i like best since it smoothes out all pixels on my HD TV.

 

[FAST6191]

Shader effects necessarily brings in shader languages so I am not going there for the time being. Ultimately you would probably want to reference video and image scaling algorithms as it still uses the same maths but
Anyway http://www.imagemagick.org/discourse-server/viewtopic.php?t=23046 has links to a few source code implementations of scaling algorithms.
Wikipedia also does surprisingly well as part of this
https://en.wikipedia.org/wiki/Pixel_art_scaling_algorithms
It skips some of the higher level stuff but it also means that you might get spared having to learn some fairly in depth maths, or trying to parse source code. For instance https://docs.gimp.org/en/plug-in-convmatrix.html

It has other uses but you are not going to get too far without grasping that.

http://www.infognition.com/articles/video_resize_shootout.html
http://avisynth.nl/index.php/Resize
https://web.archive.org/web/20070311203915/http://www.general-cathexis.com/interpolation.html

Also relevant here
http://bogost.com/games/a_television_simulator/

Best depends entirely upon what I am doing -- my little sub GHz xbox is not going to be able to manage some of the really crazy stuff I can cook up, likewise you can also build algorithms for specific games, or indeed level by level/layer by layer in specific games.