Cornell University Program of Computer Graphics
Interactive direct lighting in dynamic scenes.Sebastian Fernandez, Kavita Bala, Moreno A. Piccolotto, and Donald P. Greenberg.
Technical report PCG-00-2, Program of Computer Graphics, Cornell University, Jan 2000.
This paper presents an interactive renderer that computes direct illumination in dynamic scenes with soft shadows and complex BRDFs. The renderer permits the user to both navigate the scene interactively and modify the scene by moving objects, changing materials, and changing lighting conditions.
To support interactive viewing, we introduce a visibility caching technique in which the illumination of each patch in the scene is captured by a local illumination environment. This simplified environment enables interactive rendering by accelerating visibility computations. Since this is an object-space technique, local illumination environments can be reused from frame to frame.
To support interactive modification of the scene, we introduce a dynamic visibility algorithm that rapidly identifies which local illumination environments to update when the scene is modified. A 5D hierarchy stores illumination dependencies, and permits efficient identification of affected local illumination environments.
These techniques have been implemented in a parallel rendering system that uses a cluster of Intel processors connected on a fast network. The renderer produces images at interactive rates, achieving speedups of 10 times to 20 times over a standard parallelized ray tracer.
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