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meta4d-me / CatDogEngine

A cross-platform game engine/editor written in modern C++ (WIP)
GNU General Public License v2.0
161 stars 17 forks source link

PBR Review #444

Closed roeas closed 9 months ago

T-rvw commented 10 months ago

Try to compare dds to see the difference? Or keep a source image file for debug purpose (for example, .tga).

roeas commented 10 months ago

Old: image New: image According to a this doc Physically Based Rendering in Filament , the first image seems to be an approximation. Which one should I keep?

T-rvw commented 10 months ago

Old: image New: image According to a this doc Physically Based Rendering in Filament , the first image seems to be an approximation. Which one should I keep?

đŸ¤”Interesting findings. Why an approximation is the good one? I will have a look at it.

T-rvw commented 10 months ago

Here is a LUT_GGX from khronos group's gltf viewer project. Need to flip y due to axis system difference.

More similar to new.png by using compare tool: lut_ggx_flip_y

But seems more accurate than new.png if you take a look at the left-bottom green part. image

So maybe we should copy the lut texture from gltf viewer? To understand these three luts' difference, should write a generate tool by ourselves. An approximation generator based on UE4 implementation is here : https://github.com/HectorMF/BRDFGenerator?tab=readme-ov-file .