Function error_handler

tutorials/verify/rtcore_helpers.h:879–889

error reporting function */

  /* error reporting function */
  void error_handler(void* userPtr, const RTCError code, const char* str = nullptr)
  {
    if (code == RTC_ERROR_NONE) 
      return;
    
    std::string errorStr;
    errorStr += "Embree: ";
    errorStr += string_of(code);
    if (str) errorStr += " (" + std::string(str) + ")";
    throw std::runtime_error(errorStr);
  }
}