[PATCH 4/5] wined3d: Don't use the depth range clipping hack when we have ARB_depth_clamp.

[Chris Robinson]

On Tuesday 19 January 2010 2:52:28 pm Henri Verbeet wrote:
> ARB_depth_clamp should give pretty much the desired behaviour by clamping
> instead of clipping depth values outside the depth range.

I think you need to make sure glEnable(GL_DEPTH_CLAMP) gets called in 
state_clipping if you're going to bypass the depth range hack with it. 
Currently it's only called if WINED3DRS_CLIPPING is off.