This is a dielectric sphere and a Coca-Cola bottle model in a diffuse box.
The global illumination and the caustics are rendered with the photon mapping algorithm (200000 for the global map & 500000 for the caustic map)
This is the same scene without photon mapping, but with an area light, which produces the soft shadows.
I created a simple configuration file to describe the scenes using the JSON format. Mesh object models are loaded using Assimp.