Recent advances in NPR have enabled real-time rendering of 3D models shaded with hatching strokes for use in interactive applications. The key challenges in real-time hatching are to convey tone by dynamically adjusting stroke density, while controlling stroke size and maintaining frame-to-frame coherence. In this paper, we introduce two new real-time hatching schemes that leverage recent advances in texture mapping hardware. Both schemes provide enhanced control of tone, thereby avoiding blending or aliasing artifacts present in previous systems. The first scheme, which relies on volume rendering hardware, admits the use of color. The second scheme, which uses pixel shaders, allows per-pixel lighting operations such as texture modulation. Both schemes run at interactive rates on inexpensive PC graphics cards.
