SmallLuxGPU v1.0 is a test on how to introduce GPGPU rendering in Luxrender (http://www.luxrender.net). The test has been written using the ATI OpenCL SDK 2.0 on Linux with a Q6600 as CPU and an ATI HD4870 as GPU.
The idea is to use the GPGPU only for ray intersections in order to minimize the amount of the brand new code to write and to not loose any of the functionality already available in Luxrender. In order to test this idea, I wrote a very simplified path tracer and ported Luxrender's BVH accelerator to OpenCL.
The path integrator has the particularity to work on a huge set (i.e. 300,000+) of paths at the same time in order to generate a large amount of rays to trace and to keep the GPGPU feed.
The sources and binaries are available at http://davibu.interfree.it/opencl/smallluxgpu/smallluxGPU.html