Media faces (MoAP) on PBR objects render dark / tinted by the material; media should always be fullbright with no material #1461

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opened 2026-11-05 07:33:55 +00:00 by sky_line · 0 comments

sky_line commented

2026-11-05 07:33:55 +00:00

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Bug

A media face (MoAP / parcel media / shared media) on an object that has a PBR (glTF) material renders dark or tinted. It takes on the material's properties (base colour factor / tint, metallic / roughness, emissive, normal map, lighting and shadowing) instead of showing the media as-is.

Expected

Media faces always render fullbright, with no material applied:

the media texture is shown at its own colour;
the PBR material's base colour, tint, metallic, roughness, normal, occlusion and emissive are ignored;
no lighting or shadowing applies to the media texel: no sun, local lights, GI, AO, stochastic or RT shadows, reflections or probes;
the face's alpha behaviour follows the media, not the material's alpha mode.

This applies to both PBR and legacy (Blinn-Phong) materials, in every path: deferred, forward/blend, mirrors, probes, captures and snapshots.

Notes for the fix

Find where a face with active media is classified (media texture binding) and make "media active" select the fullbright / unlit route ahead of any material route. Don't add a branch inside the PBR shader.
Check that the GI and RT hit shading treat a media face as an emitter of its own colour (fullbright), not as a PBR surface.
Check the material-override (glTF override) path, so an override can't re-apply a tint to a media face.

## Bug A media face (MoAP / parcel media / shared media) on an object that has a PBR (glTF) material renders dark or tinted. It takes on the material's properties (base colour factor / tint, metallic / roughness, emissive, normal map, lighting and shadowing) instead of showing the media as-is. ## Expected **Media faces always render fullbright, with no material applied:** - the media texture is shown at its own colour; - the PBR material's base colour, tint, metallic, roughness, normal, occlusion and emissive are ignored; - no lighting or shadowing applies to the media texel: no sun, local lights, GI, AO, stochastic or RT shadows, reflections or probes; - the face's alpha behaviour follows the media, not the material's alpha mode. This applies to both PBR and legacy (Blinn-Phong) materials, in every path: deferred, forward/blend, mirrors, probes, captures and snapshots. ## Notes for the fix - Find where a face with active media is classified (media texture binding) and make "media active" select the fullbright / unlit route ahead of any material route. Don't add a branch inside the PBR shader. - Check that the GI and RT hit shading treat a media face as an emitter of its own colour (fullbright), not as a PBR surface. - Check the material-override (glTF override) path, so an override can't re-apply a tint to a media face.

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2026-11-05 07:33:55 +00:00

sky_line added this to the Slipstream project

2026-11-05 07:33:55 +00:00