message: fix for handling if Material::createMaterial() fails in the path tracer
diff: @@ -48,8 +48,10 @@ namespace ospray {
  Material *PathTracer::createMaterial(const char *type)
  {
  std::string ptType = std::string("PathTracer_")+type;
  - Material *material = Material::createMaterial(ptType.c_str());
  - if (!material) {
  + Material *material = nullptr;
  + try {
  + material = Material::createMaterial(ptType.c_str());
  + } catch (const std::runtime_error &) {
  std::map<std::string,int> numOccurrances;
  const std::string T = type;
  if (numOccurrances[T] == 0) {
  