Environment Lighting for Point Sampled Geometry

Point sampled geometry has recently gained significant interest due to the tremendous advances in the technology of 3D scanning and the representational simplicity afforded by avoiding any need for explicit connectivity information. Their use in creating highquality rendered images is however still limited. Till date, most renderings of point sampled surfaces use the Phong illumination model. In this paper we consider the rendering of point sampled surfaces with both diffuse and specular material properties under distant illumination, as specified using an environment map. For this, we have combined two of the earlier works for continuous surfaces, spherical harmonic representations of irradiance environment maps and glossy reflection, and programmed it on the GPU using vertex and fragment shaders. This hardware accelerated implementation has been incorporated into a public domain point based renderer enabling us to efficiently produce high quality images of point sampled geometry.