Add option for casting against leaf nodes only about three-mesh-bvh HOT 6 CLOSED

@mquander

Do you feel this be an option on the bounds tree constructor or the raycaster, a la firstHitOnly so it can be more easily used globally?

Constructor Option

geometry.computeBoundsTree({ intersectLeafNodesOnly: true });

// ...

geometry.intersectLeafNodesOnly = false;

Raycaster Option

raycaster.intersectLeafNodesOnly = true;
raycaster.intersectObjects( scene );

I'm thinking both options could be available and if the raycaster option is set to true then it overrides the setting on the geometry bounds tree. The same thing could be added for firstHitOnly so it's available as a constructor option, as well.

from three-mesh-bvh.

The default return value for a raycast hit includes the following values which won't all be available on a leaf node hit:

{
  distance,
  point,
  face,
  faceIndex,
  object,
  uv
}

I'm imagining face, faceIndex, and uv all being set to null in the case of a leaf node hit. Maybe an extra boolean value of leafNodeHit or reference to the hit tree node can be included to indicate that triangles were not checked.

from three-mesh-bvh.

Lastly I'm expecting that the behavior when Raycaster.firstHitOnly = false is to return the hits on all leaf nodes that the ray intersects. I'm not sure if there's a better option.

from three-mesh-bvh.

It seems to me like an option on the bounds tree to stop at leaf nodes and an option on the raycaster to only get the first intersection are independently useful and reasonable:

1. computeTruncatedBoundsTree + firstHitOnly = cheap construction, cheap raycast, get closest leaf node volume intersected
2. computeTruncatedBoundsTree + !firstHitOnly = cheap construction, more expensive raycast, get all leaf node volumes intersected
3. computeFullBoundsTree + firstHitOnly = same as in current implementation
4. computeFullBoundsTree + !firstHitOnly = same as in current implementation

from three-mesh-bvh.

I agree there should be two different flags -- sorry I was unclear. My question was about whether or not there should be an "intersectLeafNodesOnly" flag on both the raycaster and in the BVH constructor.

The flag on the BVH would mean that only that BVH would stop checking at the leafs. If it was set on the raycaster then the raycast would stop at the leaf on every bounds tree being cast against, like a global override. I think the flag in the constructor options is generally more flexible and has more utility so I vote for that until there's a need otherwise.

from three-mesh-bvh.

Tree construction and raycasting got way faster and more memory-efficient since we wrote this, and we think it can get even better, so I'm not sure it seems like a high priority anymore.

from three-mesh-bvh.