ConstantSizeSphere: the size is not constant when changing the FOV of a perspective camera

Summary

The ConstantSizeSphere is not constant when FOV > 50°.

Steps to reproduce

1. Create a ConstantSizeSphere
2. Change the FOV of the camera

Expected behaviour:

The sphere's apparent size remain constant.

Actual behaviour:

The sphere's apparent size increases exponentially starting at FOV ≈ 50°.

Informations

• Giro3D version: 0.39
• Browser (Firefox, Chrome, Opera, Safari...) and version: N/A
• OS (Linux, MacOS, Windows...) N/A

Screenshots

fov_constant_size_sphere