GLSL Swizzling 如何用 C++实现？

Answer 1

There is no way to implement it directly. If you don’t want to enumerate, then there are only two ways that come to my mind:

1. Macro

   SWIZZLING(v1,X,X,X,X) + SWIZZLING(v2,Z,Y,X,X)
   

2. Template

   v1._<X,X,X,X>() + v2._<Z,Y,X,X>()
   

Variadic argument templates are actually simpler to make than macros with variable parameters. You can try it. The main idea is to first create a type of function F such that F(point<3>) == F(point<4>), and secondly to construct a type of piecewise function G to link G(v, X) to v.x Above, finally use variadic argument to do recursion, first get point<1>, then add a field to become point<2>, and do it until it is complete.

Finally, remember to use using + full specialization to point point<X> to type vecX.