Palm Desktop

License: GPL
Download: source and executable .zip archive
To run: Microsoft Windows 95/NT or later with DirectX 3+
To compile: Microsoft Visual C++ 2005 Express Edition, Microsoft Platform SDK for Microsoft Visual C++ 2005 Express, DirectX 9 SDK
Technologies: C++, DirectDraw, Direct3DRM, DirectShow, image compositing

Real-time software compositing algorithms were used for everything that DirectDraw didn't support at the time: alpha blending, procedural shadows/glows for arbitrary shapes, procedural lens effect, etc. The mouse cursor is also an arbitrary object with color-keying for transparency and procedural shadow.

All the objects are draggable or clickable. Moving the lens around is fun; it will even work above dynamic objects.