Brahma is a 3D game engine with a rather retrofuturistic design, intended for small studios and solo developers. It's being written from scratch in C++ using standard Windows API and no third-party libraries. This technology introduces an entirely new class of low-latency real-time engines that make special timing requirements, treating frames as video fields with a target time budget of 2-4 ms each, down from 16-33 ms frame budgets normally seen in game engines. It evolves in a different way than other modern engines, rejecting conventional BSP, Z-buffer, floating-point coordinates, and most of the lame screen-space effects in favor of innovative and efficient techniques. The engine is non-Euclidean capable to some degree; also it supports true displacement mapping for sectors as a means to virtualize geometry that affects collisions. The engine is also carefully designed to be easy and convenient to develop for, yet versatile and adaptive to any needs.
The depth of field effect has been supported for a while, although it's still in a prototype state. My engine has an implementation of depth of field that works without shader post-processing, just by means of sampling multiple frames with projection offsets, so it can correctly draw sharp background objects behind a blurred foreground (other game engines always fail in such cases). The sampling quality can be vastly improved if temporal multisampling is used like on these screenshots. In this mode, the engine emulates double display refresh rate by averaging consecutive fields together.
Further iterations of this effect will be able to additionally blur the background and thus reduce the sampling artifacts. The renderer will have to support arbitrary scene clipping planes in order to do that. The same technique could also be used to render rough reflections.