setOptional method
Implementation
void setOptional(RenderingContext gl, object, String name) {
  final v = object.getValue(name);
  if (v != null) setValue(gl, name, v);
}void setOptional(RenderingContext gl, object, String name) {
  final v = object.getValue(name);
  if (v != null) setValue(gl, name, v);
}