Function dnormalize

third-party/embreeSrc/common/math/vec3fa.h:357–362

! differentiated normalization */

  /*! differentiated normalization */
  __forceinline Vec3fa dnormalize(const Vec3fa& p, const Vec3fa& dp)
  {
    const float pp  = dot(p,p);
    const float pdp = dot(p,dp);
    return (pp*dp-pdp*p)*rcp(pp)*rsqrt(pp);
  }

  ////////////////////////////////////////////////////////////////////////////////
  /// Select