Geometry Image-based Shadow Volume Algorithm for Subdivision Surfaces

Abstract How to generate shadow volumes efficiently for subdivision surfaces remains a challenging task for computer graphics community. We present a geometry image based algorithm that runs on GPUs (Graphics Process Units). By using GPU shaders, two geometry images containing position and normal vector information will be computed from the control meshes. By detecting silhouettes and extruding shadow volumes from the geometry images using shaders, all calculations of the shadow volume algorithm can be fully accelerated by commodity GPUs. A prototype system has been implemented on a Windows 2000 system with a NVIDIA GeForce 7950GX2 card. Experiments show that the algorithm can render subdivision surfaces and their shadows in real-time under dynamic lighting. Source code is available online