code: func Vec2Sub(dest, v1, v2 Vec2) {
  	dest[0] = v1[0] - v2[0]
  	dest[1] = v1[1] - v2[1]
  }
docs: // Vec2Sub performs a vector subtraction. dest = v1 - v2.
  //
  //     dest  [out]  The result vector.
  //     v1    [in]   The base vector.
  //     v2    [in]   The vector to subtract from v1.