Spark is a shading language for real-time graphics pipelines that improves support for good software engineering practices; in particular, separation of concerns.

Spark: Modular, Composable Shaders for Graphics Hardware (SIGGRAPH 2011)

Together with Jeremy Sugerman I developed a GPU-based ray tracer that used a k-d tree acceleration structure. Previously, efficient GPU ray tracers were limited to simple acceleration structures like uniform grids.

KD-Tree Acceleration Structures for a GPU Raytracer (Graphics Hardware 2005)

I helped to implement the compiler and runtime for the BrookGPU system, a framework for abstracting a GPU as a stream processor for numerical computing.

Brook for GPUs: Stream Computing on Graphics Hardware (SIGGRAPH 2004)