1. A Survey of Real-time Soft Shadows Algorithms Speaker: Alvin Date: 2003/7/23 EUROGRAPHICS 2003 J.-M. Hasenfratz, M. Lapierre, N. Holzschuch and F.X. Sillion

2. Issues Composition of multiple shadows. Composition of multiple shadows. Shadows from several light sources. Shadows from several light sources. Shadows from several objects. Shadows from several objects. Physically exact or fake shadows. Physically exact or fake shadows. Shadows from an extended light source. Shadows from an extended light source. Approximating the penumbra region. Approximating the penumbra region. Illumination in the umbra region. Illumination in the umbra region. Shadows from different object. Shadows from different object.

3. Issues Real-time. Real-time. Shadows of special object. Shadows of special object. Constraints on the scene. Constraints on the scene. Basic techniques for real time shadows. Basic techniques for real time shadows.

4. Classification Controlling the time. Controlling the time. Use of a different LOD for the occluders. Use of a different LOD for the occluders. Add more samples on the light source, or to subdivide large light sources into a set of smaller ones. Add more samples on the light source, or to subdivide large light sources into a set of smaller ones. Image-based methods can change the resolution of the buffer. Image-based methods can change the resolution of the buffer.

5. Classification Controlling the aspect. Controlling the aspect. Physically exact (time permitting). Physically exact (time permitting). -Method based on point samples. Physically exact on simple scenes. Physically exact on simple scenes. -Methods compute the percentage of visibility. Always approximate. Always approximate. -Method compute only the inner- or the outer- penumbra.

6. Classification Number and shape of the light sources. Number and shape of the light sources. Field of emission. Field of emission. Shape. Shape. Number. Number. Constraints on the scene Constraints on the scene Receiver. Receiver. Self-shadowing. Self-shadowing. Silhouette. Silhouette.

7. Classification New Generation of GPUs New Generation of GPUs Shadow-map. Shadow-map. Imaging subset. Imaging subset. Programmable GPU. Programmable GPU.

8. The Comparison Table

9. Conclusions No method can simultaneously solve all the problem here mentioned. No method can simultaneously solve all the problem here mentioned. The two main directions appear attractive to render high-quality soft shadows in real-time. The two main directions appear attractive to render high-quality soft shadows in real-time. By programming graphics hardware. By programming graphics hardware. By taking advantage simultaneously of both image-based and object-based techniques. By taking advantage simultaneously of both image-based and object-based techniques.