OpenGL is the cross-platform alternative to Microsoft's DirectX. The problem with OpenGL is, especially during the mid 2000s, OEMs became ultra-lazy in updating the drvers for graphics cards regarding OpenGL. Likewise, they also skimped on lower end graphics cards by loading them up with older OpenGL tech despite later versions being available. in essence, there are a LOT of computers out there that could run OpenGL 2.0, but cannot because the drivers do not exist. Blizzard is finding this out the hard way with their last Starcraft ptach, which has taken eight iterations to reintegrate DirectX 9.0c again to un-break a 20-year-old game.