- removed some fixed point functions that are no longer needed.

- fixed: Visplane checks should only compare the plane flags that are relevant for rendering and mask out the rest.
- floatified FTransform and made the visplane checks a bit less verbose by moving the comparison as an operator into FTransform.

Note that this operator needs forceinline on Visual Studio so that it won't get called as a function.

src/r_plane.h

@@ -100,11 +100,7 @@ visplane_t *R_FindPlane
   int			lightlevel,
   fixed_t		alpha,
   bool			additive,
-  fixed_t		xoffs,		// killough 2/28/98: add x-y offsets
-  fixed_t		yoffs,
-  fixed_t		xscale,
-  fixed_t		yscale,
-  angle_t		angle,
+  const FTransform &xform,
   int			sky,
   FSectorPortal *portal);