- use locally stored viewpoint variables in the hardware renderer.

- move a few variables from SceneDrawer to FRenderViewpoint.

The global r_viewpoint variable is left alone now to always represent the current viewpoint to the play code.
The main reason behind this change is to reduce the amount of global variables being used by the hardware renderer's scene processing code.

src/r_utility.cpp

@@ -598,7 +598,8 @@ void R_ResetViewInterpolation ()
 
 //==========================================================================
 //
-// R_SetViewAngle
+// R_SetViewAngle 
+// sets all values derived from the view angle.
 //
 //==========================================================================
 
@@ -609,6 +610,12 @@ void FRenderViewpoint::SetViewAngle (const FViewWindow &viewwindow)
 
 	TanSin = viewwindow.FocalTangent * Sin;
 	TanCos = viewwindow.FocalTangent * Cos;
+
+	DVector2 v = Angles.Yaw.ToVector();
+	ViewVector.X = v.X;
+	ViewVector.Y = v.Y;
+	HWAngles.Yaw = float(270.0 - Angles.Yaw.Degrees);
+
 }
 
 //==========================================================================