Last October the WINE developers began working on Direct3D 10.0 support and then earlier this year CodeWeavers, the company that puts out CrossOver Office and CrossOver Games, confirmed their interest in DirectX 10 support for WINE. In WINE 1.1.21 is just the initial work in supporting Shader Model 4.0 with its vertex, pixel, and geometry shaders and high-level shader language, but obviously more is coming in WINE's bi-weekly development releases.
Besides starting on the Shader Model 4.0 support, WINE 1.1.21 introduces support for copying and pasting images from X11 applications, offers GDIPlus improvements, various ListView fixes, and 64-bit support in winemaker. While Mac OS X 10.6 "Snow Leopard" will not be released until late this summer, this is the first WINE release that as support for building on Mac OS X Snow Leopard.
Besides these changes there is also the usual assortment of bug-fixes. The release announcement can be read at WINE HQ.