wishlist: support multiple shaders/buffers

[claudeha]

Hi, many thanks for this addon, I had fun with this coding some simple visualization things for LibreELEC on RPi4.

But compared with Shadertoy website, there are some things missing, for my purposes the most relevant missing feature is support for multiple buffers / shaders, that would let me do feedback effects like reaction-diffusion, game of life, and so on.

For some examples, see https://www.shadertoy.com/results?query=reaction%20diffusion

Perhaps one way of implementing the user-facing parts could scan for .glsl suffix in the channel specifications (where currently audio and image files are supported), and compile them as shaders. There would need to be a double-buffering scheme, because you can't safely read from a texture you are writing too via a framebuffer. This wouldn't be 100% the same as the Shadertoy website but would be less invasive than changing the presets.json file format.

[ValentinDrean]

In this same perspective, that would allow to make this kind of project to visualize soundn from Kodi right ? This would be very nice !

https://www.shadertoy.com/view/lsSfDD

Here is why Spectrogram would be cool to have in Kodi ( ＾◡＾)っ ❤

https://en.wikipedia.org/wiki/Spectrogram