“Stylized Haloed Outlines on the GPU” by Loviscach

  • ©Jörn Loviscach

  • ©Jörn Loviscach



Entry Number: 092


    Stylized Haloed Outlines on the GPU



    Methods to emphasize outlines form a major branch of nonphotorealistic rendering. Recently, McGuire and Hughes [2004] have demonstrated how to render stylized outline strokes entirely with graphics hardware, extending an approach proposed by Card and Mitchell [2002]. To this end, not only the original 3D mesh but also additional geometry is sent to the graphics card. The additional geometry contains degenerated quadrangles along all edges of the original mesh. A special vertex shader tests for each edge if it forms a border between a front- and a back-facing polygon. If so, the zero-area quadrangle is extruded into a visible fin.
    We present a related approach with the following improvements, see Fig. 1: The outline strokes are visible both inside and outside the silhouette and possess soft halos; smoothly curved outlines are generated even from low-resolution meshes; complex outline styles such as sketch-like strokes are generated; the amount of data per vertex is reduced.


    1. Card, D., and Mitchell, J. L. 2002. Non-photorealistic rendering with pixel and vertex shaders. In ShaderX: Vertex and Pixel Shaders Tips and Tricks, W. Engel, Ed. Wordware, 319–333.
    2. Isenberg, T., Halper, N., and Strothotte, T. 2002. Stylizing silhouettes at interactive rates: From silhouette edges to silhouette strokes. Computer Graphics Forum 21, 3, 249–258.
    3. McGuire, M., and Hughes, J. F. 2004. Hardware-determined feature edges. In Proc. NPAR 2004, 135–147.


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