Patent attributes
Surfaces without a global surface coordinate system are divided into surface regions having local surface coordinate systems to enable the caching of surface attribute values. A surface attribute value for a surface region may include contributions from two or more adjacent surfaces. Sample points may be arranged at the corners, rather than centers, of surface regions and include prefiltered values based on two or more surfaces. A renderer may sample the surface attribute function using these prefiltered values without accessing any adjacent surfaces, even if the renderer's filter crosses a surface boundary. A multiresolution cache stores surface attribute values at different resolution levels for surface regions of one or more surfaces, which may be discontiguous. Two or more resolution levels may have the same number of sample points but have values based on filters with different areas and spatial frequency limits. Resolution levels may be selected based on geodesic distance on a surface.
