100 likes | 107 Views
This paper discusses the implementation and results of using shadow volumes on programmable graphics hardware. It covers motivation, silhouette detection, generation of shadow volumes, implementation details, and future work.
E N D
Shadow Volumes on Programmable Graphics Hardware Speaker: Alvin Date: 2003/11/3 EUROGRAPHICS 2003
Outline • Motivation • Silhouette Detection • Generation of Shadow Volumes • Implementation • Result • Conclusion & Future Work Shadow Volumes on Programmable Graphics Hardware
Motivation • Consistent precision. • Objects can be used with vertex shader. • Gain more CPU time. • No longer needs to synchronize. • Silhouette extraction is speed up. • Becomes very simple. Shadow Volumes on Programmable Graphics Hardware
Silhouette Detection Input Mesh Shadow Volumes on Programmable Graphics Hardware
Generation of Shadow Volumes • Each vertex has a total of three indices and one flag. • Two indices referring to the world space coordinates of the edge’s two end points. • One index referring to the silhouette flag and the vertex-ordering for the given edge. • A flag indicating whether the vertex lie on the edge or extruded to infinity. Shadow Volumes on Programmable Graphics Hardware
Generation of Shadow Volumes Shadow Volumes on Programmable Graphics Hardware
Implementation • On ATI Radeon 9700 card using OpenGL. • Uses a floating point RGBA offscreen buffer. • Supports up to 12 light sources. • Propose • Texture access during vertex processing. • A fast, on the card copy from frame buffer to a vertex attribute array. Shadow Volumes on Programmable Graphics Hardware
Result Shadow Volumes on Programmable Graphics Hardware
Result Shadow Volumes on Programmable Graphics Hardware
Conclusion & Future Work • Perform silhouette detection in hardware. • The shadowing objects can be transformed by vertex shader. • Buffer read-back are already visible in OpenGL 2.0 specification. • Solve the near/far plane intersection problem. • NPR Shadow Volumes on Programmable Graphics Hardware