GPU Progressive Lightmapper Sneak Peek
Now available in Preview for Windows in 2018.3
On machines with powerful GPUs, lightmap baking will be significantly faster. We built a pure path-tracing-based algorithm on top of RadeonRays and OpenCL for baking lightmaps in Unity, bringing performance improvements that are over 10x the typical performance of Unity’s CPU lightmapper. Linux and macOS support is coming in 2019.1.
2018.3 Preview release includes
The GPU lightmapper has the same feature set as the CPU progressive lightmapper and has the same support for progressive updates, multiple lightmaps, direct lighting, indirect lighting, AO, all light types, environment lighting, emission, multiple bounces, and compositing, culling and convergence testing.
Before going out of preview, the remaining features from the CPU lightmapper will be added, to reach feature parity. As of 2019.2 the following features have not been added yet:
- Multiple submeshes
- Sampling improvements
- AO texture export
- Experimental Custom Bake API
- A-Trous filtering
The GPU Progressive Lightmapper is a GPU-accelerated version of the Progressive Lightmapper. The only user-facing difference is (ideally) a drastic performance boost (~10x), while maintaining feature parity. The CPU version of the Progressive Lightmapper will be maintained for developers without powerful GPUs. Also, the installed main memory in PCs usually exceeds the installed video memory so for some very large worlds, the CPU Progressive Lightmapper is the only viable option.
Preview on Windows in Unity 2018.3, with Linux and macOS support coming in 2019.1.
The Progressive Lightmapper goes through a short preparation step (geometry and instance updates, G-buffer, and chart-mask generation) and starts producing the output very quickly. Lightmaps are updated interactively in the Editor and light probes are shown as soon as a new intermediate result is ready. This permits a very fast iteration workflow.
Unity’s previous lightmapping solutions were entirely CPU-based. By taking advantage of the parallel architecture of modern GPUs, the new GPU Progressive Lightmapper can calculate huge numbers of rays simultaneously: opening up interactive workflows to the user. Using Radeon-Rays, GPU acceleration speeds up baking, giving instant feedback to the artist. The effect of changing lighting, materials and skyboxes upon global illumination can be seen updating interactively while the artist is still working in the Scene.