[GSoC 2017] Retroplayer: Video Shaders

VelocityRa commented 7 years ago

Description

This PR adds support for rendering multi-pass shader presets, as defined in this libretro spec. The spec essentially introduces shader “preset” files: a standardized file format which allow for multi-pass shader configurations to achieve advanced filtering, without manually copying and pasting shader code all over the place.

They have other features too, but this is their core functionality and reason of existence. The biggest advantage of implementing this would be the vast library of pre-existing shaders written in this format, both for OpenGL (ES), and Direct3D.

Not all can be used yet because they porting to HLSL (thankfully the libretro/RetroArch team is on board with helping us port them), but there are hundreds of presets available.

Here's RetroArch's page on shader presets.

Here's a few other examples.

Motivation and Context

Shaders can be used to:

Smartly scale retro games for higher resolutions using pixel art scaling algorithms. Here's Zelda in 4K.
Emulate the look of old CRT or NTSC monitors for a retro feel.
Provide an easy way to apply borders to the screen.
Remove dithering artifacts
Provide anti-aliasing and smooth scaling

Adjust everything about the colour of the image in a robust way without changing application-wide settings. These including gamma, luminance, contrast, saturation. These are just a few examples, there can be more applications that I haven’t thought of. If I end up not implementing support for libretro’s shaders, I aim to develop/port a few shaders that will be provided by default, but shader developers can extend this by providing more.

How Has This Been Tested?

TODO

Screenshots Video:

Link

Types of change

[ ] Bug fix (non-breaking change which fixes an issue)
[x] Improvement (non-breaking change which improves existing functionality)
[x] New feature (non-breaking change which adds functionality)
[x] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

TODO

[ ] My code follows the Code guidelines of this project
[x] My change requires a change to the documentation, either Doxygen or wiki
[ ] I have updated the documentation accordingly
[x] I have read the CONTRIBUTING document
[ ] I have added tests to cover my change
[ ] All new and existing tests passed

garbear commented 4 years ago

@VelocityRa I rebased this branch on 18.6 (for safety, old commit was e3ddbc4dacd4327b812285c0e81aa8f03ad2cc5e). Ready for you to squash against it

Hedda commented 4 years ago

Are these Video Shaders for RetroPlayer gaming still on the roadmap?

VelocityRa commented 4 years ago

The code is probably PR-ready but I still haven't gotten around to resolving the distribution issue for shaders/presets.

Hedda commented 4 years ago

The code is probably PR-ready but I still haven't gotten around to resolving the distribution issue for shaders/presets.

Are you thinking about distributing them as Add-ons for Kodi so that the user can install only if they really want to have them?

VelocityRa commented 4 years ago

I'm not sure. I don't plan on working on it for the foreseeable future, sorry.

garbear / xbmc