GPU Lightmapper

A GPU accelerated lightmapper for Unity, powered by Vulkan. Easy to use, lightweight (only ~1MB) and works with Unity light components.

Features

• Hardware Ray-Tracing with VK_KHR_ray_query
• Software Ray-Tracing with Compressed Wide BVHs
• Realtime path-traced preview window
• Operating Systems
  • Windows
  • Linux
  • macOS*
• Graphics Cards
  • Nvidia
  • AMD
  • Intel
• Lightmap Modes
  • Non-Directional
  • Dominant Direction
  • Monochromatic L1 SH
• Unity Render Pipelines
  • Built-In
  • URP
  • HDRP
• UV Packing
  • Hole filling
  • Scale Offset mode
  • No Packing mode
  • Chart Splitting mode
  • Efficient LOD chart packing
• Lights
  • Directional
  • Point
  • Spot
  • Area
  • Disc
• Light Cookies
• Open Image Denoise 2.0
• Emissive Materials with Multiple Importance Sampling
• Seam stitching with a least squares solver
• L2 Spherical Harmonics Light Probes
• VRC Light Volumes
• Lightmap Groups
• Terrain Trees Support
• Mixed Lights
  • Baked Indirect
  • Shadowmask
  • Subtractive
• Ambient Occlusion
• URP Adaptive Probe Volumes
• Light Probe Occlusion
• Emissive Multiplier
• Skybox Reflection Probe
• Double-sided GI
• Meta Pass fallback
• Light Volume Denoising

Support

• If you'd like to see it further improved, consider supporting on Patreon
• Alternatively you can consider buying some of my assets on Booth

How to use

Denoiser Setup

Windows

1. Download the Windows .zip from https://github.com/RenderKit/oidn/releases
2. Extract it anywhere on your computer (e.g. C:\oidn)
3. Set the OpenImageDenoise_DIR environment variable to that extracted folder (the folder containing bin, doc, include, lib):
   • Press Start, type "environment variables", and open "Edit environment variables for your account"
   • Click New...
   • Name: OpenImageDenoise_DIR
   • Value: the path to the extracted folder (e.g. C:\oidn)
   • Click OK on all windows
4. Restart Unity and Unity Hub

Linux

• Fedora Linux: sudo dnf install oidn

macOS

• brew install open-image-denoise

Lightmapper Setup

Make sure to also read Updating ⚠️

VPM Package

• Install with the VRChat Creator Companion

UPM Package

• Download the release https://github.com/z3y/glim/releases
• Unzip the folder, open the package manager in unity Window > Package Manager
• Click + add package from disk and select the package.json from that folder

Baking

• Make sure to setup the denoiser first (otherwise denoising will be skipped)
• Setup the scene (mark GameObjects as static, generate lightmap uvs etc.)
• The lightmapper uses regular Unity light components, make sure to set them to baked
• Menu Item Tools > Glim > Bake
• Adjust settings on the created GameObject and press Generate Lighting

Notes

• Scale In Lightmap is calculated differently from the Unity lightmapper, readjust it on the renderers if needed
• Light cookies use the RGB channels by default (unlike built-in where it only uses the alpha)
• Cookies for spot lights are always masked by the spot cone falloff
• Glim can work on macOS via MoltenVK with VK_KHR_ray_query, however the stock MoltenVK does not yet implement it. There is a pending PR that contains the required features. You can temporarily build MoltenVK from that fork, or use the version from https://github.com/owlboy/glim-moltenvk-dist/. Glim releases also do not include macOS builds currently so you would have to also build it yourself.

Additional Light Settings

For additional settings for baking you can add a GlimAdditionalLightSettings component to a Light

• Exposes the inner angle for spot lights and draws a gizmo for the Built-In render pipeline
• Adds an Area (Rectangle) Light option for a cookie texture

Updating

• Make sure to close Unity first before updating to unload all currently loaded assemblies.
• Import the new package.

Lightmap Groups

• By default one lightmap texture is baked containing the entire scene
• To create multiple lightmaps add a Lightmap Group Selector component to a game object
• Right click, Create > Lightmap Group (Glim) asset and assign it to the selector component
• All the child GameObjects will be packed into that group

Discord

Stack

• Written in Rust, using the lightweight Ash Vulkan crate, with minimal dependencies
• Shaders written in Slang

Building

• Add the slang shader compiler at PATH
• cargo build --release
• Copy the compiled dll into the /Editor folder
• Alternatively you can run the test_preview or test_bake tests without Unity

Screenshots

Preview Window

Lightmap

Directional Lightmap