Custom PPSSPP shaders

[LunaMoo]

Easy practical experiment to show what I mean - use a standalone xBRZ software(like the one in texture scaling thread) and some other software for simple resizing like irfan view or whatever to scale some tiny texture three times:
- one at native res scaled with xBRZ,
- another first pre-scaled with nearest filtering, then xBRZ,
- and last also pre-scaled but with bilinear filtering(best with non integer multiplier), then xBRZ.

Results of scaling will look differently because a "pixel", a square that looks like pixel and a blurry cloud that doesn't have any sharp edges are completely different things. The results will also differ depending on the background so if some object is not animated, but moves on the screen, the edges ~ especially if object has some complex shapes ~ will "travel" in similar fasion to aliasing in 3D games, through that would be a bit harder to show without observing an example in-game.

For a shader to produce same result as texture scaling doesn't matter how badly game filters it's textures and what weird effects it uses, it definitely couldn't be a "post process", because such shaders as the name suggests deal with final graphics after all original information of the texture was already lost.