Category Archives: high dynamic range

Box Projected Cubemap Environment Mapping

I have added a new technique called … I’d rather not write  it down again…. So, the great thing is that it mimics reflections on shiny surfaces using a simple, but yet quite accurate approximation based on environment cubemap textures.

For more details, see

The hard part was to find a hidden bug in the engine that prevented me to render in-scene cubemap snapshots using a dedicated off-screen compositor chain. But eventually I have managed to find it and it seems that it worth the effort.

The engine automatically places light probes in each room in the level at load time, then it renders a fully lit HDR cubemap texture for each of them. The engine uses these cubemaps and some extra parameters assigned to the probes, to calculate the reflections with the aforementioned method.

First I have experimented with a similar idea that uses spheres to distort the cubemap look-up coordinates, but it was inaccurate. BPCEM gives a more accurate results in box-shaped rooms.

There are some images with the results:

A demo video: