warp.transform\_vector
======================

.. currentmodule:: warp._src.lang

.. function:: transform_vector(xform: Transformation[Float], vec: Vector[Float, Literal[3]]) -> Vector[Float, Literal[3]]

   .. wp-function-tags::
      :kernel: true
      :python: true
      :differentiable: true

   Return ``vec`` transformed by the rotation of ``xform``, ignoring its translation.
   
   ``xform.q`` must have unit length; otherwise the result may distort. Use
   :func:`~warp.transform_point` to transform positions.
   
   :param xform: Transformation whose rotation is applied.
   :param vec: Direction vector to transform, which need not be normalized.
   
   :returns: ``quat_rotate(xform.q, vec)``, equivalent to using homogeneous coordinate ``w = 0``.
   
   See :func:`~warp.transform_point` for a usage example.

.. function:: transform_vector(mat: Matrix[Float, Literal[4], Literal[4]], vec: Vector[Float, Literal[3]]) -> Vector[Float, Literal[3]]
   :noindex:

   .. wp-function-tags::
      :kernel: true
      :python: true
      :differentiable: true

   Return ``vec`` transformed by the 4x4 matrix ``mat``, using homogeneous coordinate ``w = 0``.
   
   Matrices that use row-vector conventions, such as those from USD, must be transposed. When
   ``mat`` contains non-uniform scale, transform normals using the inverse transpose of its
   upper-left 3x3 linear component, then normalize the result. Use :func:`~warp.transform_point`
   to transform positions.
   
   :param mat: Transformation matrix, applied to a column vector.
   :param vec: Direction vector to transform, which need not be normalized.
   
   :returns: The first three components of ``mat * (vec.x, vec.y, vec.z, 0)``, ignoring translation.
   
   See :func:`~warp.transform_point` for a usage example.