Changed BMW sample and test our own flower obj model , change flower's mtl file to get it working
Ka 0.0 0.0 0.0
Kd 0.0 0.0 0.0
Ks 0.0 0.0 0.0
==>
Ka 0.8 0.8 0.8
Kd 0.8 0.8 0.8
Ks 0.0 0.0 0.0