Triangle.gltf does not displayed in Babylon JS Sandbox

The model which can not be displayed seemed to be a model without default scene.
There is no default scene in Triangle.gltf which is the minimum sample of glTF Tutorial.
Is it the intended behavior that Triangle.gltf does not appear on the BabylonJS Sandbox?

github.com

KhronosGroup/glTF-Tutorials/blob/master/gltfTutorial/gltfTutorial_003_MinimalGltfFile.md

Previous: [Basic glTF Structure](gltfTutorial_002_BasicGltfStructure.md) | [Table of Contents](README.md) | Next: [Scenes and Nodes](gltfTutorial_004_ScenesNodes.md)


# A Minimal glTF File

The following is a minimal but complete glTF asset, containing a single, indexed triangle. You can copy and paste it into a `gltf` file, and every glTF-based application should be able to load and render it. This section will explain the basic concepts of glTF based on this example.

```javascript
{
  "scene": 0,
  "scenes" : [
    {
      "nodes" : [ 0 ]
    }
  ],
  
  "nodes" : [
    {
      "mesh" : 0
    }

This file has been truncated. show original

bghgary · March 2, 2019, 7:45pm

Yes. This is the expected behavior. It was incorrect before. See https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#scenes

When scene is undefined, runtime is not required to render anything at load time.

cx20 · March 3, 2019, 4:58am

I understood that it was the expected behavior.
However, it is a little doubtful whether it is appropriate behavior.
I have found similar discussions in the past.

Handling multiple scenes without a default scene #815

github.com/KhronosGroup/glTF

Handling multiple scenes without a default scene

opened 06:59PM - 14 Jan 17 UTC

closed 11:57AM - 15 Jun 17 UTC

javagl

specification 2.0 resolved

The [1.0 specification says about scenes](https://github.com/KhronosGroup/glTF/t…ree/master/specification/1.0#scenes) : > The glTF asset contains one or more scenes, the set of visual objects to render. Scenes are defined in a dictionary object `scenes`. An additional property, `scene` (note singular), identifies which of the scenes in the dictionary is to be displayed at load time. Hereby, [the `glTF.scene` property is not required](https://github.com/KhronosGroup/glTF/tree/master/specification/1.0#gltfscene) Several loaders and viewers are assuming that the `glTF.scene` property is present. Moreover, it is not clear what should happen when there are *multiple* `scenes`, but no default `scene`. Should viewers then load and display *all* scenes? Or only the first scene? Or an arbitrary one? (This question has some analogies to the `cameras`: There is no default `camera`, and viewers seem to be free to pick any camera for the initial rendering). --- Pull request where this issue originated from: https://github.com/KhronosGroup/glTF-Sample-Models/pull/18#issuecomment-271922646 Related issues: https://github.com/KhronosGroup/glTF/issues/39 , https://github.com/KhronosGroup/glTF/issues/150 , and maybe others...

I think the following behavior is desirable as a viewer.

if there’s no scene , then scenes[0] is selected.

Otherwise, I think that features should be provided that can be selected from multiple scenes.

bghgary · March 4, 2019, 5:29pm

Towards the end of the thread, it ended with the language I quoted in the spec. If you feel strongly about the spec, please submit an issue to the glTF GitHub.

I made this change because of glTF: files with no scenes give "/scene: Failed to find index (0)" · Issue #5900 · BabylonJS/Babylon.js · GitHub, but I can modify the code such that:

/scene is not defined and /scenes is empty, then load nothing
/scene is not defined and /scenes is not empty, then load the first scene.

That will satisfy both issue 5900 and this issue.

cx20 · March 4, 2019, 6:03pm

Thank you for considering.

/scene is not defined and /scenes is empty, then load nothing

/scene is not defined and /scenes is not empty, then load the first scene.

I think that behavior is user-friendly as a viewer.

bghgary · March 4, 2019, 6:06pm

PR: Fix for default scene loading in glTF loader by bghgary · Pull Request #5998 · BabylonJS/Babylon.js · GitHub

@cx20 Thanks for bringing this up!

cx20 · March 4, 2019, 10:47pm

Thank you for fixing. I confirmed that it has been fixed by alpha30.

BTW, I think that it is another problem, but when trying to display Triangle.gltf it seems that a shader error is output to the console. Could you confirm it?
https://sandbox.babylonjs.com/?assetUrl=https://rawcdn.githack.com/KhronosGroup/glTF-Sample-Models/ec880043ae0cead374d7e3a965cc8323c51b06e1/2.0/Triangle/glTF/Triangle.gltf

Deltakosh · March 4, 2019, 10:52pm

cc @sebavan

sebavan · March 4, 2019, 11:27pm

Update pbrBRDFFunctions.fx · BabylonJS/Babylon.js@e8a329c · GitHub fixes it. it will be in the next nightly, thanks for reporting it.

cx20 · March 5, 2019, 3:24pm

Thank you for your fixing. I confirmed that the shader error was resolved in the updated version of alpha30.

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Triangle.gltf does not displayed in Babylon JS Sandbox

Handling multiple scenes without a default scene #815

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