Grass isn't rendered in certain camera positions and angles

[hichemfantar]

I've been able to reproduce the same bug present in pmndrs grass shader example.
https://sketches.isaacmason.com/sketch/nature/grass

2024-08-22.16-25-07.mp4

related to pmndrs/examples#81

[isaac-mason]

The grass geometry likely just needs a bounding sphere set :)

[isaac-mason]

see GrassGeometry :https://github.com/isaac-mason/sketches/blob/main/sketches/nature/grass/src/grass.ts#L253

[hichemfantar]

@isaac-mason i think it's fixed!
do you know how i could apply a similar fix to the pmndrs grass example?
I quote from the discord server ThreeJS uses an objects BoundingSphere for frustum culling. Your grass mesh's bounds are calculated before you scatter your grass. So the engine doesnt know the bounds of the mesh after scattering. You need to recalculate the those bounds after scattering
The proposed solution was to call theInstanceMesh.computeBoundingSphere() in a useEffect but it's not fixing the issue for me.

[isaac-mason]

I've raised a PR in pmndrs/examples :)