Unity-Box-Projected-Lighting

A work-in-progress attempt for real-time box projected lighting with GI and reflections.

NOTE: Images are taken at high sample counts with animated noise, and TAA on.

Version 1

This version computes just simple directional lighting from a cubemap shadow mask. It's a direct implementation of the effect from the ARM article.

Version 2

This version is a little more advanced than the first.

It's an extension of the first version...

• We calculate direct lighting with a cubemap that represents the shadow mask. (just like the ARM article)
• Now in this version we calculate the first bounce from the direct lighting for GI.

For sampling, a cosine-weighted hemisphere oriented with the surface normal is used for better ray convergence.

Version 3

This version is again, a little more advanced than the last.

It's an extension of the second version...

• We calculate direct lighting with a cubemap that represents the shadow mask. (just like the ARM article)
• We also calculate the first bounce from the direct lighting for GI just like in the second version.
• Now in this version we calculate a first bounce enviornment lighting term.

For sampling once again, a cosine-weighted hemisphere oriented with the surface normal is used for better ray convergence.

Version 4

This version is again, a little more advanced than the last.

It's an extension of the third version...

• We calculate direct lighting with a cubemap that represents the shadow mask. (just like the ARM article)
• We calculate the first bounce from the direct lighting for GI just like in the second version.
• We also we calculate a first bounce enviornment lighting term just like in the third version.
• Now we calculate enviornment reflections according to PBR material parameters, with a fresnel term.

For sampling once again, a cosine-weighted hemisphere oriented with the surface normal is used for better ray convergence. For the reflections we use an importance sampled GGX function, once again for better ray convergence.

TODO

• Use Blue Noise for better convergence.
• Use existing Mip Maps to reduce sample counts.
• Precomputation for material BDRF for the reflection term.
• Other techniques if possible to create better ray convergence at lower sample counts.

References

• Dynamic Soft Shadows based on Local Cubemaps (Main Inspiration)
• lwjgl3 Random Functions
• Unity SRP Core Random.hlsl Functions
• Unity SRP Core Sampling.hlsl Functions
• Filamented PBR Functions
• Hammersley Functions
• Improved Box Projected Reflections
• GPU Gems Chapter 20: GPU Based Importance Sampling