Interpolation-based image scaling

The MPV player user shader for interpolation-based image scaling. Designed for experimental, testing or educational use.

Usage

If you place this shader in the same folder as your mpv.conf, you can use it with glsl-shaders-append="~~/interpolation_based_image_scaling.glsl".
The shader is controlled under user configurable section by changing macro values and by directly implementing filter kernel.
Requires vo=gpu-next.

The shader is not optimised for speed.
Antiringing behaves a bit differently compared with the same technique implemented in separated passes.
In general, you may expect slightly different results from different implementations of resampling algorithms.
For linearize and delinearize macros see pl_shader_linearize and pl_shader_delinearize functions in https://github.com/haasn/libplacebo/blob/master/src/shaders/colorspace.c
In general for sintax of mpv user shaders see https://libplacebo.org/custom-shaders/