x2048

@lhofhansl I'd love you feedback on the way pipelines are built, [side-by-side](https://github.com/minetest/minetest/pull/12465/files#diff-88bb9bd60c1c782ad159ee8bbdbd4b08eecc44cf323d296176d79584ccd8b825) would be a good example. And the framework itself [pipeline.h](https://github.com/minetest/minetest/pull/12465/files#diff-043273e0a5f92bde8f6aa5450527b65d9152507d0e7d31a9b625434f58505892) / [pipeline.cpp](https://github.com/minetest/minetest/pull/12465/files#diff-4f9c3366af016d89d46bb5b358cd81f42f7bfdc587dbf81d3f82ff68af7032da) may need a pair of eyes....

@lhofhansl I've made slight changes to the pipeline framework, removing duplicated code here and there.

Hmm... I can't confirm. Sun and entity self-shadowing can be seen here:  Area where shadows are rendered is dependent on view angle and it may be noticed if you...

@Andrey2470T , the godrays are on a [separate branch](https://github.com/x2048/minetest/tree/volumetric_light), to keep this PR scoped.

@lhofhansl Can it be a driver problem? I can see all shadows with any AA setting (might be AA does not work for me at all?)

@Andrey2470T This is a known limitation, and I've made the transition subtle in the latest commit.

@lhofhansl I have tried to reproduce the issue on both Intel HD 4000 and AMD Renoir, with different settings in minetest.conf and vanilla one, nothing. Shadows are always added [here](https://github.com/x2048/minetest/blob/11273d5f318344e2f86ed4f5ca2b21c1a3a52b1f/src/client/render/factory.cpp#L50)...

@lhofhansl We use extra textures for normals and depth in the g buffer. I kept them to enable experimenting with shaders, but we can turn it off if VRAM becomes...

Can you also disable the weather mod in MTG and enable debug output in ShadowRenderer (search for #if 0 in the file)? I've also spent some time fly-testing and found...

Enabling debug output will tell you whether SM textures are properly generated (then it's a shader issue) or empty (pipeline / renderer issue).