Method and apparatus for rendering shadows

Details Method and apparatus for rendering shadows Method and apparatus for rendering shadows

2007-06-19

2007-06-19

Nguyen, Kimbinh T. (Department: 2628)

Computer graphics processing and selective visual display system

Computer graphics processing

Three-dimension

C345S421000, C345S422000, C345S424000, C345S427000, C345S581000, C345S582000, C345S586000, C345S589000, C345S629000

Reexamination Certificate

active

11274883

ABSTRACT:
A method and apparatus for rendering shadows. A pre-rendering process implements a two dimensional array or map of depth-based functions, such as a visibility function in z. During rendering of an object scene, these functions are accessed via lookup operations to efficiently determine the function value for a sample point at a given depth. The use of visibility functions allows for partial light attenuation effects. Each visibility function is computed by filtering multiple transmittance functions obtained by casting sample rays from a light source onto an object scene. The visibility function is implemented as a sequence of vertices. Colored shadows are modeled by vertices comprising a depth value and separate visibility function values for red, green, and blue light at a given depth value. Compression is achieved by minimizing the number of vertices needed to represent a visibility function within a desired error tolerance.

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