Function Vector_swizzle_set

source/blender/python/mathutils/mathutils_Vector.cc:2857–2938

* Set the items of this vector using a swizzle. * - If value is a vector or list this operates like an array copy, except that * the destination is effectively re-ordered as defined by the swizzle. At * most `min(len(source), len(destination))` values will be copied. * - If the value is scalar, it is copied to all axes listed in the swizzle. * - If an axis appears more than once in the sw

 * \return 0 on success and -1 on failure. On failure, the vector will be unchanged.
 */
static int Vector_swizzle_set(VectorObject *self, PyObject *value, void *closure)
{
  size_t size_from;
  float scalarVal;

  size_t axis_from;
  size_t axis_to;

  uint swizzleClosure;

  float tvec[MAX_DIMENSIONS];
  float vec_assign[MAX_DIMENSIONS];

  if (BaseMath_ReadCallback_ForWrite(self) == -1) {
    return -1;
  }

  /* Check that the closure can be used with this vector: even 2D vectors have
   * swizzles defined for axes z and w, but they would be invalid. */
  swizzleClosure = POINTER_AS_INT(closure);
  axis_from = 0;

  while (swizzleClosure & SWIZZLE_VALID_AXIS) {
    axis_to = swizzleClosure & SWIZZLE_AXIS;
    if (axis_to >= self->vec_num) {
      PyErr_SetString(PyExc_AttributeError,
                      "Vector swizzle: "
                      "specified axis not present");
      return -1;
    }
    swizzleClosure = swizzleClosure >> SWIZZLE_BITS_PER_AXIS;
    axis_from++;
  }

  if (((scalarVal = PyFloat_AsDouble(value)) == -1 && PyErr_Occurred()) == 0) {
    int i;

    for (i = 0; i < MAX_DIMENSIONS; i++) {
      vec_assign[i] = scalarVal;
    }

    size_from = axis_from;
  }
  else if (PyErr_Clear(), /* run but ignore the result */
           (size_from = size_t(mathutils_array_parse(
                vec_assign, 2, 4, value, "Vector.**** = swizzle assignment"))) == size_t(-1))
  {
    return -1;
  }

  if (axis_from != size_from) {
    PyErr_SetString(PyExc_AttributeError, "Vector swizzle: size does not match swizzle");
    return -1;
  }

  /* Copy vector contents onto swizzled axes. */
  axis_from = 0;
  swizzleClosure = POINTER_AS_INT(closure);