Serious Sam (one of my favorite games) has always been an OpenGL game. The new 1.05 patch adds DX8 support as well as ATI Truform and other enhancements. I'm downloading the patch now and will check it out.
<< Direct3D 8
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Support for D3D is finished, but there might be some issues with different hardware. Generally D3D is ~10% slower than OpenGL, but on some systems you might experience moderate speedups and/or compatiblity fixes. Feel free to experiment. It is recommended to install DirectX 8.1 version, but 8.0 will be sufficient, too. >>
<< Direct3D 8
----------
Support for D3D is finished, but there might be some issues with different hardware. Generally D3D is ~10% slower than OpenGL, but on some systems you might experience moderate speedups and/or compatiblity fixes. Feel free to experiment. It is recommended to install DirectX 8.1 version, but 8.0 will be sufficient, too. >>