Approximate Soft Shadows win an Image‐Space Flood‐Fill Algorithm

Most former soft shadow algorithms have either suffered from restricted self‐shadowing capabilities, been too slow for interactive applications, or could only be used with a limited types of geometry. In this paper, we propose an efficient image‐based approach for computing soft shadows. Our method is based on shadow mapping and provides the associated benefits. We use pixel‐based visibility computations for rendering penumbra regions directly into the screen‐space. This is accomplished by using a modified flood‐fill algorithm which enables us to implement the algorithm using programmable graphics hardware. Even though the resulting images are most often high quality, we do not claim that the proposed method is physically correct. The computation time and memory requirements for soft shadows depend on image resolution and the number of lights, not geometric scene complexity.

[1]  Hans-Peter Seidel,et al.  Soft Shadow Maps for Linear Lights , 2000, Rendering Techniques.

[2]  David Salesin,et al.  Rendering antialiased shadows with depth maps , 1987, SIGGRAPH.

[3]  François X. Sillion,et al.  A Survey of Real‐time Soft Shadows Algorithms , 2003, Comput. Graph. Forum.

[4]  Peter-Pike J. Sloan,et al.  Interactive technical illustration , 1999, SI3D.

[5]  Laurent Moll,et al.  Efficient image-based methods for rendering soft shadows , 2000, SIGGRAPH.

[6]  Lance Williams,et al.  Casting curved shadows on curved surfaces , 1978, SIGGRAPH.

[7]  Hans-Peter Seidel,et al.  Single Sample Soft Shadows Using Depth Maps , 2002, Graphics Interface.

[8]  Chris Wyman,et al.  Penumbra Maps , .

[9]  Tomas Akenine-Möller,et al.  Approximate Soft Shadows on Arbitrary Surfaces using Penumbra Wedges , 2002, Rendering Techniques.

[10]  HanrahanPat,et al.  Shadow silhouette maps , 2003 .

[11]  Dipl.-Ing,et al.  Real-time Rendering , 2022 .

[12]  Jinxiang Dong,et al.  Soft shadow maps for area light by area approximation , 2002, 10th Pacific Conference on Computer Graphics and Applications, 2002. Proceedings..

[13]  Hans-Peter Seidel,et al.  Hardware-accelerated rendering of antialiased shadows with shadow maps , 2001, Proceedings. Computer Graphics International 2001.

[14]  Franklin C. Crow,et al.  Shadow algorithms for computer graphics , 1977, SIGGRAPH.

[15]  Pat Hanrahan,et al.  Shadow silhouette maps , 2003, ACM Trans. Graph..

[16]  James R. Clifton,et al.  State-of-the-art report , 1995 .

[17]  Tomas Akenine-Möller,et al.  Real-time rendering, 2nd Edition , 2002 .

[18]  Tomas Akenine-Möller,et al.  On the Degree of Vertices in a Shadow Volume Silhouette , 2003, J. Graphics, GPU, & Game Tools.

[19]  Paul S. Heckbert,et al.  Simulating Soft Shadows with Graphics Hardware , 1997 .

[20]  StammingerMarc,et al.  Perspective shadow maps , 2002 .

[21]  George Drettakis,et al.  Perspective shadow maps , 2002, ACM Trans. Graph..

[22]  Tomas Akenine-Möller,et al.  An optimized soft shadow volume algorithm with real-time performance , 2003, HWWS '03.

[23]  S. Pizer,et al.  The Image Processing Handbook , 1994 .

[24]  Eric Haines,et al.  Soft Planar Shadows Using Plateaus , 2001, J. Graphics, GPU, & Game Tools.

[25]  François X. Sillion,et al.  Fast calculation of soft shadow textures using convolution , 1998, SIGGRAPH.

[26]  Donald P. Greenberg,et al.  Direct illumination with lazy visibility evaluation , 1999, SIGGRAPH.

[27]  Tomas Akenine-Möller,et al.  A geometry-based soft shadow volume algorithm using graphics hardware , 2003, ACM Trans. Graph..