Exporters: Max2Babylon: rotated AO causes index failure

[echadwick-wayfair]

When I use Export & Run on this file, the output GLB has an UNRESOLVED_REFERENCE issue, which prevents it from loading in the Sandbox
/materials/1/occlusionTexture/index: Failed to find index (1)

I'm using the same 512x4 PNG texture for both Albedo and Occlusion, except I'm using KHR_texture_transform to rotate the Occlusion 90 degrees.

It works fine if I reset the rotation to zero.

3ds Max 2020.3
Max2Babylon v20191220.1

The material setup. Red box causes the error. Green box exports and runs fine.

Zip contains Max file, texture, and two GLBs ("Rotated" is the erroreous one).
AQ_rotated_3dsmax.zip

glTF Validator:
{ "uri": "ball_grid_occlusion_albedo_Rotated.glb", "mimeType": "model/gltf-binary", "validatorVersion": "2.0.0-dev.3.1", "validatedAt": "2020-01-17T15:57:23.642Z", "issues": { "numErrors": 1, "numWarnings": 0, "numInfos": 0, "numHints": 0, "messages": [ { "code": "UNRESOLVED_REFERENCE", "message": "Unresolved reference: 1.", "severity": 0, "pointer": "/materials/1/occlusionTexture/index" } ], "truncated": false }, "info": { "version": "2.0", "generator": "babylon.js glTF exporter for 3dsmax 2020 v20191220.1", "extensionsUsed": [ "KHR_texture_transform" ], "extensionsRequired": [ "KHR_texture_transform" ], "resources": [ { "pointer": "/buffers/0", "mimeType": "application/gltf-buffer", "storage": "glb", "byteLength": 967580 }, { "pointer": "/images/0", "mimeType": "image/png", "storage": "buffer-view", "image": { "width": 512, "height": 4, "format": "luminance", "primaries": "srgb", "transfer": "srgb", "bits": 8 } } ], "animationCount": 0, "materialCount": 2, "hasMorphTargets": false, "hasSkins": false, "hasTextures": true, "hasDefaultScene": true, "drawCallCount": 4, "totalVertexCount": 23099, "totalTriangleCount": 37557, "maxUVs": 1, "maxInfluences": 0, "maxAttributes": 3 } }

[echadwick-wayfair]

Interestingly, I am able to switch the bitmap from occlusion to metalness, or to roughness, both of which export & load correctly.

[echadwick-wayfair]

Rotating the emissive also causes it.

[Drigax]

Ok, I think I have a proper fix, we missed updating a reference when exporting an texture that's referenced multiple times in the scene, but with different properties, such as rotation.

[echadwick-wayfair]

I imagine if it was me working on it, I'd want to know. Sorry to keep reporting all these little issues. Probably edge cases. But probably valuable nonetheless. I really appreciate all the effort you put into this!

[Drigax]

No worries, every bug helps us make this as reliable as possible 😁