You might as well just set the initial value to 1.0. Note that this seems to succeed on at least some setups though: http://test.winehq.org/data/4d3aec55ea41cb0f47a9da82de1665ad1b16f3de/win7_Win7-x86/d3d9:visual.html Also, does this work for the d3d8 version of the test?