In this paper, we propose a novel method for normal texture editing based on shading maps. The presented method can be applied on both photo-realistic rendering and non-photorealistic rendering (NPR). By introducing shading interval constraints, the normal texture editing problem is characterized by a quadratic programming approach, which can be accelerated by GPU techniques. Experiments are presented, showing that for a 1024×1024 size normal texture, the computation costs only 3.6 milliseconds. The experimental results show that our proposed method is user-friendly and can be performed in real-time.
normal map; real-time editing; GPU; shape from shading; internal constraints