[PATCH 6/6] wined3d: Set z = 0.0 via the projection matrix instead of depth clamping.

Thu Feb 12 01:45:57 CST 2015

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Am 2015-02-11 um 23:56 schrieb Matteo Bruni:
> It's probably hard to measure and not going to really matter in 
> practice but toggling the depth clamping (where supported) might
> be slightly faster than updating the projection matrix.
I'll try to patch my drawprim overhead tester to test this.

I don't expect it to be faster though. At very least it depends on the
game's behavior. One of two switches that needs to be toggled to
disable depth clipping is switching to POSITIONT vertices, in which
case we update the projection matrix anyway.

Even if there's a minor performance advantage of depth clamping in
cases where an application constantly uses POSITIONT and switches
ZENABLE on an off I prefer to always use the projection matrix to have
only one codepath that does this. If there's a huge difference we may
think about two alternating codepaths.