The Irrlicht Engine is an open source high performance realtime 3D engine written and usable in C++. It is completely cross-platform, using D3D, OpenGL and its own software renderers.
CoolReader is fast and small cross-platform XML/CSS based eBook reader for desktops and handheld devices. Supported formats: FB2, TXT, RTF, DOC, TCR, HTML, EPUB, CHM, PDB, MOBI. Platforms: Win32, Linux, Android. Ported on some eInk based devices.