Abstract: One embodiment of the present invention includes techniques for pre-computing ambient shadowing parameters for a computer-generated scene. A processing unit retrieves a reference object associated with the computer-generated scene and comprising a plurality of vertices. For each vertex in the plurality of vertices, the processing unit computes a local ambient shadowing parameter, and stores the local ambient shadowing parameter in a memory. For each instance of the reference object included in the computer-generated scene, the processing unit computes a first global ambient shadowing parameter based on the position of the instance within the computer-generated scene, and stores the first global ambient shadowing parameter in the memory. One advantage of the disclosed embodiments is that ambient obscurance is applied to instance objects in a scene in real time while reducing memory space dedicated to storing the AO parameters.

Abstract: One embodiment of the present invention includes techniques for pre-computing ambient shadowing parameters for a computer-generated scene. A processing unit retrieves a reference object associated with the computer-generated scene and comprising a plurality of vertices. For each vertex in the plurality of vertices, the processing unit computes a local ambient shadowing parameter, and stores the local ambient shadowing parameter in a memory. For each instance of the reference object included in the computer-generated scene, the processing unit computes a first global ambient shadowing parameter based on the position of the instance within the computer-generated scene, and stores the first global ambient shadowing parameter in the memory. One advantage of the disclosed embodiments is that ambient obscurance is applied to instance objects in a scene in real time while reducing memory space dedicated to storing the AO parameters.

Abstract: Embodiments of the invention provide techniques for calculating volumetric obscurance. Volumetric obscurance is an alternative approach to screen-space ambient occlusion that can be efficiently evaluated on graphics processing units (GPUs). In one embodiment, to calculate the volumetric obscurance at a particular pixel location, an integral is calculated that sums distances between depth values in a depth buffer relative to a surface of a sphere centered at the pixel location. In alternative embodiments, a statistical model of the depth buffer can be used to calculate the volumetric obscurance.

Abstract: Modular radiance transfer pre-computes a spectral decomposition of a one bounce transport operator for each of a set of shapes and replaces a scene dependent direct-to-indirect transfer lighting computation with an art-directable mapping step. Modular radiance transfer provides an approach for rendering an approximate indirect lighting which requires small amounts of data, can be used to model very large (or even random scenes), and propagates much of the indirect lighting using a small number of spectral coefficients, so that rendering scales well to large scenes.

Abstract: The present invention is directed to a enhanced Precomputed Radiance Transfer (PRT) system employing an algorithm to compute a PRT signal over a surface mesh and subdividing facets of the mesh to increase the number of surface vertices such that the spatial variation of the transfer signal is resolved sufficiently everywhere on the surface. The method of this system ensures that radiance transfer shading produces colors of sufficient accuracy all over the surface. In certain embodiments, transfer is computed only at surface vertices, although this does result in a certain amount of acceptable aliasing and blurring of surface lighting detail in regions where the tessellation is too coarse. Furthermore, the method comprises a spatial and density sampling techniques that measures the transfer signal to a desirable appropriate resolution while minimizing aliasing. Once computed, the signal is represented as compactly as possible to minimize storage and runtime computation requirements.

Abstract: Computer graphics systems and methods for all-frequency relighting are described. In one described embodiment, all-frequency relighting is achieved by representing low frequencies of lighting with spherical harmonics and approximating the residual high-frequency energy with point lights. In another embodiment low-frequencies are rendered with precomputed radiance transfer (PRT) techniques while the higher-frequencies are rendered with on-the-fly techniques.