Too strong reflection on GLB models in Android with IBL indirect light compared to ModelViewer

[runqiuzh]

Hi there,

I'm a beginner in this 3D rendering area, and just finished the major part of my first Android app with Filament (thanks to the community!). My app is for virtual try on of glasses on the human face, so I had to use Android ARCore AugmentedFace, and thus can't directly use ModelViewer to load my GLB models due to the shared EGL context issue and occlusion effect with the human face, but I tried to implement an equivalent version of ModelViewer to meet my app's needs. However, even though I thought I finished all the necessary parts for GLB model loading and rendering, with exactly the same indirect lighting and direct lighting condition as the gltf viewer sample (top-down directional light with 100_000 intensity, and the default_env_ibl IBL file for indirect light with 30_000 intensity), my glasses models showed very strong reflection, especially on the transparent lenses. The reflection looked so strong that we couldn't see the original color of the lenses or frames, and everything became foggy and white (the default_env_ibl mainly uses white/gray light). In contrast, when I loaded my models in the gltf viewer sample code with ModelViewer, the color looked very good with the same default_env_ibl file and 30_000 intensity.

My guess is I overlooked or missed some setups for lighting or rendering. But I haven't found any clue after multiple days of investigating and debugging. Sorry I'm not allowed to share the 3D models here, but I would appreciate any suggestions/insights on this issue. Many thanks in advance!

[runqiuzh]

It turned out the issue was because I flipped horizontally the Filament camera which messed up the lighting calculation.