Method: Snow::Mat4Array#fetch

Defined in:

ext/snow-math/snow-math.c

#fetch(sm_index) ⇒ Object Also known as: []

Fetches a Mat4 from the array at the index and returns it. The returned Mat4 may be a cached object. In all cases, values returned from a typed array are associated with the memory of the array and not given their own memory. So, modifying a Mat4 fetched from an array modifies the array’s data.

As a result, objects returned by a Mat4Array should not be considered thread-safe, nor should manipulating a Mat4Array be considered thread-safe either. If you want to work with data returned from an array without altering the array data, you should call Mat4#dup or Mat4#copy to get a new Mat4 with a copy of the array object’s data.

call-seq: fetch(index) -> mat4

# File 'ext/snow-math/snow-math.c', line 1434

static VALUE sm_mat4_array_fetch(VALUE sm_self, VALUE sm_index)
{
  mat4_t *arr;
  size_t length = NUM2SIZET(sm_mathtype_array_length(sm_self));
  size_t index = NUM2SIZET(sm_index);
  VALUE sm_inner;
  VALUE sm_cache;
  if (index >= length) {
    rb_raise(rb_eRangeError,
      "Index %zu out of bounds for array with length %zu",
      index, length);
  }

  sm_cache = rb_ivar_get(sm_self, kRB_IVAR_MATHARRAY_CACHE);
  if (!RTEST(sm_cache)) {
    rb_raise(rb_eRuntimeError, "No cache available");
  }
  sm_inner = rb_ary_entry(sm_cache, (long)index);

  if (!RTEST(sm_inner)) {
    /* No cached value, create one. */
    Data_Get_Struct(sm_self, mat4_t, arr);
    sm_inner = Data_Wrap_Struct(s_sm_mat4_klass, 0, 0, arr[index]);
    rb_ivar_set(sm_inner, kRB_IVAR_MATHARRAY_SOURCE, sm_self);
    /* Store the Mat4 in the cache */
    rb_ary_store(sm_cache, (long)index, sm_inner);
  }

  if (OBJ_FROZEN(sm_self)) {
    rb_funcall2(sm_inner, kRB_NAME_FREEZE, 0, 0);
  }

  return sm_inner;
}