warp.hash\_grid\_query\_next
============================

.. function:: warp._src.lang.hash_grid_query_next(query: HashGridQuery, index: int32) -> bool

   .. hlist::
      :columns: 8

      * Kernel

   Advance a hash grid query to the next candidate neighbor and report whether one was found.
   
   Writes the candidate's index to ``index`` and returns ``True``; returns ``False`` once no
   candidates remain (``index`` is then left unchanged). The index refers to the points the grid
   was built from, in their original order. Candidates share a nearby grid cell and may lie farther
   than the query radius, so test the actual distance yourself (see :func:`hash_grid_query`).
   Supports query objects returned by :func:`wp.hash_grid_query() <warp.hash_grid_query>` for all
   coordinate precisions.
   
   :param query: The query to advance, from :func:`hash_grid_query`
   :param index: Output; receives the index of the current candidate neighbor
   
   :returns: ``True`` if another candidate was found (its index written to ``index``), ``False`` if the
             query is exhausted.
   
   .. rubric:: Example
   
   .. testcode::
   
       @wp.kernel
       def count_neighbors(grid_id: wp.uint64, pts: wp.array[wp.vec3], radius: wp.float32, out_count: wp.array[wp.int32]):
           i = wp.tid()
           p = pts[i]
           query = wp.hash_grid_query(grid_id, p, radius)
           index = int(0)
           n = int(0)
           while wp.hash_grid_query_next(query, index):
               if wp.length(p - pts[index]) <= radius:
                   n += 1
           out_count[i] = n
   
       points = wp.array([[0,0,0],[0.1,0,0],[0.5,0,0],[2.0,0,0]], dtype=wp.vec3)
       grid = wp.HashGrid(dim_x=8, dim_y=8, dim_z=8)
       grid.build(points=points, radius=0.3)
   
       out_count = wp.zeros(4, dtype=wp.int32)
       wp.launch(count_neighbors, dim=4, inputs=[grid.id, points, 0.3], outputs=[out_count])
       print(out_count.numpy())
   
   .. testoutput::
   
       [2 2 1 1]
   

.. function:: warp._src.lang.hash_grid_query_next(query: HashGridQuery, index: int32) -> bool
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Advance a hash grid query to the next candidate neighbor and report whether one was found (float16 precision).
   
   The ``float16`` overload of :func:`hash_grid_query_next`, taking the query returned by the
   ``float16`` :func:`hash_grid_query`. Behavior and usage match the default ``float32``
   overload; see it for details and a usage example.
   
   :param query: The query to advance, from :func:`hash_grid_query`
   :param index: Output; receives the index of the current candidate neighbor
   
   :returns: ``True`` if another candidate was found (its index written to ``index``), ``False`` if the
             query is exhausted.
   

.. function:: warp._src.lang.hash_grid_query_next(query: HashGridQuery, index: int32) -> bool
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Advance a hash grid query to the next candidate neighbor and report whether one was found (float64 precision).
   
   The ``float64`` overload of :func:`hash_grid_query_next`, taking the query returned by the
   ``float64`` :func:`hash_grid_query`. Behavior and usage match the default ``float32``
   overload; see it for details and a usage example.
   
   :param query: The query to advance, from :func:`hash_grid_query`
   :param index: Output; receives the index of the current candidate neighbor
   
   :returns: ``True`` if another candidate was found (its index written to ``index``), ``False`` if the
             query is exhausted.