Return smoothed step function value. This function is an C++ analogue of GLSL smoothstep function.

template<class TYPE> TYPE Smoothstep(const TYPE edge0, const TYPE edge1, const TYPE x);
    template<class TYPE> TVec2<TYPE> Smoothstep(const TVec2<TYPE> &edge0, const TVec2<TYPE> &edge1, const TVec2<TYPE> &x);
    template<class TYPE> TVec3<TYPE> Smoothstep(const TVec3<TYPE> &edge0, const TVec3<TYPE> &edge1, const TVec3<TYPE> &x);
    template<class TYPE> TVec4<TYPE> Smoothstep(const TVec4<TYPE> &edge0, const TVec4<TYPE> &edge1, const TVec4<TYPE> &x);