Change the material of a primitive in a ModelMesh

Is there a way of changing the material linked to a primitive in a ModelMesh created from a glTF model?

The goal is to highlight the picked node by changing the material’s parameters but ModelMaterial.selValue is applied over every primitive linked to that material. I think that the best solution is to temporary link the primitive to a special ‘highlight’ material but it does not have any effect over the rendered model. Maybe there is a better solution to solve the problem so I am open to suggestions!

Thanks!

[pjcozzi]

Or maybe modify the gltf file is a better choice.

Yes, this should be more simple than changing the loading code.

What about shader level, can we change the material of nodes in runtime rather than modify it?

Yes, if you use a custom fragment shader with an extra uniform that is the highlight color that is multiple with the computed color (default to white for no highlight). Note that you won’t be able to change a material from opaque to translucent or vice versa without more work since the render state also would need to change.

[yqrashawn]

@pjcozzi Thanks for your reply. I’m on this these days. I modified the parseNodes parsMeshes parsMaterials function. But model loading went really slow because of so many for loops. There are some functions looping to read the technique in material after the parse func, which cost much. And gltf can’t find mesh’s parent nodes and material’s parent meshes, which leads to more loops.

Is there anything I missed or better way I hadn’t found?

Or maybe modify the gltf file is a better choice.

What about shader level, can we change the material of nodes in runtime rather than modify it? Thus I can achieve highlighting or translucent.