Instanced Butterflies animation.
Tested on Oculus Go (with touchpad) and VR BOX2 (with joystick).
For tests on a desktop (Windows 10 + Chrome) the "inline" webxr session and
A,S,D,W,↑,↓ keys for navigation are used.
Transformation matrix "instancing" is based on
webgl2fundamentals:
webgl-instanced-drawing.
EXT_texture_filter_anisotropic extension and
gl.LINEAR_MIPMAP_LINEAR texture filtering mode are used.
WebXR samplesupdated 12 Apr 2020