high performance computing on graphics processing units: hgpu.org

Radiosity is a popular global illumination algorithm capable of achieving photorealistic rendering results. However, its use in interactive environments is limited by its computational complexity. This paper presents a GPGPU-based implementation of the gathering radiosity approach using texture-based discretisation and the OpenCL framework. Hemicubes are rendered to a texture array and processed by OpenCL kernels in parallel to compute the output radiance of the patches. Results show that even with the high synchronisation overhead of the OpenGL-OpenCL interoperability, the proposed method is an order of magnitude faster than a CPU-based implementation, and that it approaches interactive speeds. Investigation of the influence of different parameters shows that an increase in hemicube size results in a linear increase in computation time, while an increase in the number of layers in the texture array dimensions results in a logarithmic decrease in computation time.