Next-Gen rendering engine designed for mobile and embedded systems, API indepdent (OpenGL, OpenGL ES 2.0/3.0, DX11), the new architecture was targeted for multi-core systems and multiple contexts (i.e. multiple GPUs and/or displays).
Commands are dispatched from multiple threads (where culling is also also performed) and executed on the main thread via command buffers. The commands are sorted based on their keys, for 3D objects they also take into account their depth to make use of hardware early-z rejection and also minimize state changes.
For rendering 2D features (i.e. roads, buildings, etc.) on top of it, a projective texturing technique was used to minimize memory footprint (the elevation tiles use only 16-bit textures) and also to minimze framebuffer switches which are expensive on tiled GPU architectures.