warp.bvh\_query\_capsule
========================

.. function:: warp._src.lang.bvh_query_capsule(id: uint64, start: vec3f, dir: vec3f, radius: float32, root: int32) -> _BvhQueryCapsule

   .. hlist::
      :columns: 8

      * Kernel

   Construct a conservative capsule sweep query against a BVH.
   
   Iterates over every BVH item whose stored bounding box overlaps the swept capsule. Each node's
   bounds are inflated by ``radius`` before the ray-slab test (an axis-aligned box inflation, not
   a true sphere cap), so the query never misses a primitive within ``radius`` of the segment but
   may return extra candidates near box corners.
   
   To sweep a closed capsule from ``p0`` to ``p1``, pass ``dir = p1 - p0`` (unnormalized) and
   ``max_dist = 1.0`` in :func:`bvh_query_next`; contact at both endpoints is included.
   A zero-length segment (``p0 == p1``) is not supported — use :func:`bvh_query_sphere` instead.
   A negative ``radius`` is clamped to zero. Advance results with :func:`bvh_query_next`.
   
   :param id: The BVH identifier
   :param start: The segment start point (``p0``), in BVH space
   :param dir: The segment direction (``p1 - p0``), in BVH space
   :param radius: The capsule radius; negative values are clamped to zero
   :param root: The node to begin the query from, or -1 (default) for the BVH's global root
   
   :returns: A :class:`warp.BvhQuery`. It is opaque; pass it to :func:`bvh_query_next`.
   
   .. rubric:: Example
   
   .. testcode::
   
       @wp.kernel
       def capsule_sweep(bvh_id: wp.uint64, p0: wp.vec3, p1: wp.vec3, radius: float,
                          count: wp.array[wp.int32]):
           query = wp.bvh_query_capsule(bvh_id, p0, p1 - p0, radius)
           item = int(0)
           while wp.bvh_query_next(query, item, 1.0):
               wp.atomic_add(count, 0, 1)
   
       lowers = wp.array([[0.75, -1, -1]], dtype=wp.vec3)
       uppers = wp.array([[2.0,   1,  1]], dtype=wp.vec3)
       bvh = wp.Bvh(lowers=lowers, uppers=uppers)
       count = wp.zeros(1, dtype=wp.int32)
       wp.launch(capsule_sweep, dim=1,
                 inputs=[bvh.id, wp.vec3(0.0, 0.0, 0.0), wp.vec3(0.5, 0.0, 0.0), 0.3, count])
       print(count.numpy()[0])
   
   .. testoutput::
   
       1