[Bug]: Rasterizer and BatchRenderer render a synthetic GLB black when a sparse low-intensity emissive atlas is present

[NoahLinckeScout]

Bug Description

Rasterizer and BatchRenderer render a synthetic GLB black when a sparse low-intensity emissive atlas is present

Steps to Reproduce

The repro script generates:

• one simple atlas-mapped box
• one dark base-color atlas
• one metallic-roughness atlas
• one normal map
• two emissive variants:
  • with_emissive: sparse low-intensity emissive speckles
  • no_emissive: all black emissive

The only difference between the two variants is the emissive texture.

Expected:

• all panels render with the same textured base material, with only minor emissive differences

Actual:

• in both Rasterizer and BatchRenderer, with_emissive renders almost completely black
• in both renderers, no_emissive preserves the textured base material

repro.py

Command:

python repro.py

Artifact:

• comparison.png

The artifact is a 3x2 panel:

• rasterizer: with_emissive
• rasterizer: no_emissive
• batch: with_emissive
• batch: no_emissive
• nyx: with_emissive
• nyx: no_emissive

The geometry is intentionally minimal: a single large box close to the camera, so the material flip is easy to see.

This script assumes an environment that includes genesis-world, gs-nyx, and gs-nyx-plugin.

Expected Behavior

All panels render with the same textured base material, with only minor emissive differences

Screenshots/Videos

Environment

Environment:

• OS: Ubuntu 22.04
• CPU: AMD Ryzen Threadripper 7970X
• GPU: NVIDIA RTX 5000 Ada Generation
• Driver: 570.211.01
• Host CUDA runtime: 12.8
• Python wheel stack: torch 2.12.0+cu126

Release version or Commit ID

Version scope:

• reproduces on 0.3.12
• reproduces on 0.4.7
• reproduces on 1.0.0
• reproduces on 1.1.1