message: glTF punctual light color is optional.  Check vector before referencing.
diff: @@ -332,7 +332,10 @@ namespace ospray {
  } else
  newLight = createNode(lightName, l.type);
  - auto lightColor =
  + // Color is optional, default:[1.0,1.0,1.0]
  + auto lightColor = vec3f(1.f);
  + if (!l.color.empty())
  + lightColor =
  vec3f{(float)l.color[0], (float)l.color[1], (float)l.color[2]};
  newLight->createChild("color", "vec3f", lightColor);
  