Penumbra Maps Approximate Soft Shadows in RealTime Chris

Penumbra Maps: Approximate Soft Shadows in Real-Time Chris Wyman and Charles Hansen University of Utah Speaker: Alvin Date: 9/29/2003 EUROGRAPH 2003 Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time

Outline n n n Introduction Penumbra Map Discussion Result Conclusions and Future Works Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 2

Introduction n n Shadow Map + Penumbra Map Three-pass process Renders a standard shadow map. n Renders the penumbra map. n Renders the final image. n n Penumbra Map = Light Intensity Map Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 3

Introduction Shadow Map (left) and Penumbra Map (right). Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 4

Penumbra Map n Input: (See from the light center) n n n A standard shadow map. Silhouette vertices and edges. Use Haines’ shadow plateaus. Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 5

Penumbra Cone & Sheet Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 6

Fragment (Bernstein interpolant) Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 7

Discussion n Overlapping penumbra. As an area light increases in size, silhouettes vary more over the light so the generated shadows will become less realistic. As a shadow’s umbra size shrinks, there are noticeably larger, darker shadows. Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 8

Overlapping Penumbra Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 9

Result Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 10

Result Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 11

Result Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 12

Conclusions and Future Works n n Rendering approximate soft shadows in real-time. Allow dynamical models to cast soft shadows. Approximate a full penumbra using vertex programs to adjust the silhouette edge points. Implement in hardware. Alivn/GAME LAB/CSIE/NDHU Penumbra Maps: Approximate Soft Shadows in Real-Time 13