Question about retrieving triangle index on mobile

[tjaved970]

Hi,

I'm loading a glTF asset that was optimized using gltfpack (meshes merged). I need to show object level properties to users based on click/picking. To do that I need to map a click back to the original mesh / primitive / triangle index. Tried using gl_PrimitiveID in the fragment shader but that didnt work on android.

Questions:

Is there a way in Filament to retrieve the picked triangle index or primitive index?

If not directly what is the recommended approach to retrieve this information?

[pixelflinger]

there is no support for this at the moment.

[tjaved970]

thanks for responding! Could you give some directions as to how we could achieve picking the triangle indexes? is cpu side raycasting the only option?