Normal maps are not sampled when using lightmap (even if the light still on)

[jcostello]

Godot version

4.1

System information

Ubuntu with Nvidia 2060

Issue description

When Lightmap is baked backed, material normals are not sampled even if the light still on. Note that when using dynamic light, only the part hit directly with the light is sampled

Static

Dynamic

Off

Steps to reproduce

Bake lights in MRP

Minimal reproduction project

Lightmap.zip

[patwork]

In v4.2.beta.custom_build [bdd9034]

Lights bake mode: DYNAMIC, LIghtmapGI HIDDEN

Lights bake mode: DYNAMIC, LIghtmapGI VISIBLE

Lights bake mode: STATIC, LIghtmapGI HIDDEN

Lights bake mode: STATIC, LIghtmapGI VISIBLE

[jcostello]

@patwork sorry I dont get your example. The problem is directional vs non-directional bake. The example is not a good case because albedo texture could have fake bumps in it. The problem is that, when baking directional, the normal information of the texture is not baked into the light map. You only see the normals where direct light hits

[Calinou]

As of 4.3.stable, it works if you enable Directional in LightmapGI and bake lightmaps again:

Static + Directional

Dynamic (without Directional)

Closing, as there is no way for it to work without Directional enabled, because the engine can't know which direction the light is coming from. This applies to both direct and indirect light, but the problem of missing normals is mostly visible with direct light (and therefore lights with the Static bake mode, or emissive materials).

Normals typically appear more faint with spherical harmonics (directional lightmaps) than real-time lighting, which is a common issue with any image-based approach to storing light direction. Spherical harmonics are usually in a good position to deliver results close to ground truth (see comparison here). This is being addressed by #101141.