Description

It appears that the Lightmass Volumetric Lightmap does not work with Landscape textures. When it samples the Landscape with some textured material, the resulting lighting build data does not match the actual texturing of the landscape at all.

This issue was reported and tested in 4.21.2 (CL-4753647). This was reproduced in 4.20.3 (CL-4369336), 4.22 (CL-4958363), and Main 4.23 (CL-4982248)

Steps to Reproduce
  1. Download and open the attached project
  2. Open up the "Landscape_Repro" map, build the lighting, and enable Volumetric Lightmap (Show>Visualize>Volumetric Lightmap)
  3. Observe that the Lightmass Volumetric Lightmap does not have colors matching the colors of nearby Landscape texture
  4. Open the "MeshPlane_Repro" map, build the lighting, and enable Volumetric Lightmap
  5. Observe that the Lightmass Volumetric Lightmap has the colors matching the colors of nearby static mesh plane

Results: Lightmass Volumetric Lightmap indirect light from the landscape is wrong, not matching the texture on the landscape surface.

Expected: Lightmass Volumetric Lightmap indirect light from the landscape is correct, having the same result as indirect light from the static mesh plane of same position, size and material.

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Fixed
ComponentRendering
Affects Versions4.224.20.34.234.21.2
Target Fix4.22
Fix Commit4985775
Main Commit4985777
Release Commit4985775
CreatedFeb 13, 2019
ResolvedFeb 13, 2019
UpdatedFeb 26, 2019