ClearSkyPBS

A tiny PBS implementation for S.T.A.L.K.E.R. Clear Sky.

Tested on latest (1.5.10) patch. Original shading is deprecated; along with texture layout.

Features

Physically plausible GGX + Lambert model
Filtered importance sampling for specular IBL
Metallic - Roughness workflow

Textures

I've decided to not complicate things with textures. The format and layout is simple to understand:

Name	Red	Green	Blue	Alpha
name.dds	Albedo.r	Albedo.g	Albedo.b	Alpha
name_bump.dds	Normal.x	Normal.y	Roughness	Metalness
name_bump#.dds	Empty	Empty	Empty	Height map

Layout for detail textures is the same. Alpha became a blending factor: data = lerp(base_layer, detail_layer, detail_alpha);

You should use good DXT5 compressor, especially for _bump textures!

G-Buffer

The following G-Buffer layout is used:

Name	Red	Green	Blue	Alpha
s_position	Position.x	Position.y	Position.z	Roughness
s_normal	Normal.x	Normal.y	Normal.z	AO
s_diffuse	Albedo.r	Albedo.g	Albedo.b	Metalness

Screenshots

Requirements

PBR textures (see "Textures" section)
DX10 renderer
r3_gbuffer_opt set to off (you can do it in user.ltx file, or in console)

Known issues

Terrain shader is not converted to new texture format (To be done)

Disclaimer

This is a project done purely for fun. It does not implement advanced rendering techniques, nor aims to be the most accurate renderer ever.
I've tried to cut corners everywhere, just to get somewhat physically plausible shading :)
There is no gamma correction, HDR, and proper tonemapping.
For more informations see tinypbs.h

Credits:

- Michal Iwanicki & Angelo Pesce (DFG approximation)
- xroo (Test map where I've been testing this shader)
- Caesar (CS port of test map from xroo)
- Blazej Kozlowski (Bunny ASCII art)

References:

- https://developer.nvidia.com/gpugems/gpugems3/part-iii-rendering/chapter-20-gpu-based-importance-sampling
- http://miciwan.com/SIGGRAPH2015/course_notes_wip.pdf
- https://graphicrants.blogspot.com/2013/08/specular-brdf-reference.html
- https://schuttejoe.github.io/post/ggximportancesamplingpart1/
- https://www.unrealengine.com/en-US/blog/physically-based-shading-on-mobile

LVutner/ClearSkyPBS