Improving the 'PCSS' shader

[QuadStorm]

A while ago I released a PCSS shader of sort; however, it's not from perfect:
-Depth search distance must be manually set (this is supposed to be automatic)
-No automatic adjustment of fudgeFactors with the light angle
-Blending between cascades not looking too good
So I need help polishing up this shader.

This is what I'm working on now, actually trying to implement it correctly: https://gist.github.com/QuadStorm/0ceed8e3a436e0bea4d640ca954702b8

Images:







Resources:
Blockland Attempts
Latest version of the 'old' shader: https://gist.github.com/QuadStorm/c87fdef316109aa265535d466791a296
Old PCSS shader release thread

PDFs
http://developer.download.nvidia.com/shaderlibrary/docs/shadow_PCSS.pdf
https://http.download.nvidia.com/developer/presentations/2005/SIGGRAPH/Percentage_Closer_Soft_Shadows.pdf
https://www.realtimeshadows.com/sites/default/files/sig2013-course-softshadows.pdf
http://developer.download.nvidia.com/presentations/2008/GDC/GDC08_SoftShadowMapping.pdf

Other Implementations
NVIDIA demo pcss: https://pastebin.com/n9XHi6n8 - originally from https://developer.nvidia.com/gameworksdownload "OpenGL Graphics and Compute Samples"
Some random paste with a opengl 120 implementation of PCSS: https://pastebin.com/Eg7PEDCx

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[Potatoh]

can you do ascii shaders

[QuadStorm]

can you do ascii shaders

pretty sure reshade has an ascii shader
i'm not really the guy to ask to make shaders as you can see from the OP

[QuadStorm]

The first two issue points are mostly OK with this large rewrite: https://gist.github.com/QuadStorm/b88dafdf380023d9db6afe4a864ede2b

[QuadStorm]

Made penumbra size vary width with shadow_coord.z or the cascade index (0 being closest cascade of the 4) and blending between cascades appears more tolerable.



The shader now actually does two comparisons, and may or may not be a tad bit faster. If anyone can figure out what the blocker search distance (searchDistance) is supposed to be optimally, I'll be forever grateful.

[QuadStorm]

Another PDF: https://http.download.nvidia.com/developer/presentations/2005/I3D/I3D_05_Percentage_Closer_Soft_Shadows.pdf
Like I said in the last post, the main issue I have now is having the blocker search distance (searchDistance) done right without having to add a variable that has to be adjusted. Blending between cascades looks alright for now, and the fudge factors, while a bit high are ok as well.

[QuadStorm]

https://gist.github.com/QuadStorm/ddb7ecce4658ae48ab6b0dbc6b6ba430 is the latest version as of now, redoing the blocker search section and making it a separate function, however there's a pretty major graphics bug at a distance, which is why I made another gist instead of updating the other one.

EDIT: The distant issue is mostly gone, at the cost of far shadows being sharper than they should be.