Lightmap generation process
Learn how Unity generates lightmaps.
阅读时间1 分钟最后更新于 1 个月前
The lightmap generation process is as follows:
-
UV Mapping: By default, Unity uses the mesh’s imported UVs. You can also make Unity generate a per-mesh UV layout with UV charts for each mesh. A margin separates charts within the same layout.
-
Packing: Unity packs multiple UV layouts into a shared UV atlas. Padding between different UV layouts in the atlas optimizes texture space and prevents bleeding.
-
Texture generation: Unity converts the UV atlas into the final lightmap texture that contains the pre-calculated lighting data.
Unity uses real-time lightmap UVs for the Realtime Global Illumination system and baked lightmap UVs for the Baked Global Illumination system. There are two reasons for this:
- There's no direct correspondence in the grouping of instances between real-time and baked lightmaps; instances that are in the same real-time lightmap might be in two different baked lightmaps, and vice versa.
- Meshes that appear at different scales share lightmap UVs in baked lightmaps, but don't share UVs in real-time lightmaps.