diff --git a/src/gl/scene/gl_drawinfo.cpp b/src/gl/scene/gl_drawinfo.cpp
index abcdbe70b..c7e02314c 100644
--- a/src/gl/scene/gl_drawinfo.cpp
+++ b/src/gl/scene/gl_drawinfo.cpp
@@ -201,6 +201,7 @@ FDrawInfo *FDrawInfo::StartDrawInfo(GLSceneDrawer *drawer)
 	di->mDrawer = drawer;
 	di->mVBO = GLRenderer->mVBO;
 	di->mClipper = &staticClipper;
+    di->mClipper->SetViewpoint(r_viewpoint);
 	staticClipper.Clear();
     di->FixedColormap = drawer->FixedColormap;
 	di->StartScene();
diff --git a/src/gl/scene/gl_portal.cpp b/src/gl/scene/gl_portal.cpp
index 3f8ede410..bb0d09adb 100644
--- a/src/gl/scene/gl_portal.cpp
+++ b/src/gl/scene/gl_portal.cpp
@@ -941,9 +941,7 @@ void GLMirrorPortal::DrawContents(FDrawInfo *di)
 	angle_t af = drawer->FrustumAngle();
 	if (af<ANGLE_180) di->mClipper->SafeAddClipRangeRealAngles(r_viewpoint.Angles.Yaw.BAMs()+af, r_viewpoint.Angles.Yaw.BAMs()-af);
 
-	angle_t a2 = linedef->v1->GetClipAngle();
-	angle_t a1 = linedef->v2->GetClipAngle();
-	di->mClipper->SafeAddClipRange(a1,a2);
+    di->mClipper->SafeAddClipRange(linedef->v1, linedef->v2);
 
 	gl_RenderState.SetClipLine(linedef);
 	gl_RenderState.EnableClipLine(true);
diff --git a/src/hwrenderer/scene/hw_clipper.cpp b/src/hwrenderer/scene/hw_clipper.cpp
index e1811dd8c..85646f84c 100644
--- a/src/hwrenderer/scene/hw_clipper.cpp
+++ b/src/hwrenderer/scene/hw_clipper.cpp
@@ -373,10 +373,10 @@ angle_t Clipper::AngleToPseudo(angle_t ang)
 //
 //-----------------------------------------------------------------------------
 
-angle_t R_PointToPseudoAngle(double x, double y)
+angle_t Clipper::PointToPseudoAngle(double x, double y)
 {
-	double vecx = x - r_viewpoint.Pos.X;
-	double vecy = y - r_viewpoint.Pos.Y;
+	double vecx = x - viewpoint->Pos.X;
+	double vecy = y - viewpoint->Pos.Y;
 
 	if (vecx == 0 && vecy == 0)
 	{
@@ -427,14 +427,15 @@ bool Clipper::CheckBox(const float *bspcoord)
 	
 	// Find the corners of the box
 	// that define the edges from current viewpoint.
-	boxpos = (r_viewpoint.Pos.X <= bspcoord[BOXLEFT] ? 0 : r_viewpoint.Pos.X < bspcoord[BOXRIGHT ] ? 1 : 2) +
-		(r_viewpoint.Pos.Y >= bspcoord[BOXTOP ] ? 0 : r_viewpoint.Pos.Y > bspcoord[BOXBOTTOM] ? 4 : 8);
+    auto &vp = viewpoint;
+	boxpos = (vp->Pos.X <= bspcoord[BOXLEFT] ? 0 : vp->Pos.X < bspcoord[BOXRIGHT ] ? 1 : 2) +
+		(vp->Pos.Y >= bspcoord[BOXTOP ] ? 0 : vp->Pos.Y > bspcoord[BOXBOTTOM] ? 4 : 8);
 	
 	if (boxpos == 5) return true;
 	
 	check = checkcoord[boxpos];
-	angle1 = R_PointToPseudoAngle (bspcoord[check[0]], bspcoord[check[1]]);
-	angle2 = R_PointToPseudoAngle (bspcoord[check[2]], bspcoord[check[3]]);
+	angle1 = PointToPseudoAngle (bspcoord[check[0]], bspcoord[check[1]]);
+	angle2 = PointToPseudoAngle (bspcoord[check[2]], bspcoord[check[3]]);
 	
 	return SafeCheckRange(angle2, angle1);
 }
diff --git a/src/hwrenderer/scene/hw_clipper.h b/src/hwrenderer/scene/hw_clipper.h
index c3897bd56..e8da8172c 100644
--- a/src/hwrenderer/scene/hw_clipper.h
+++ b/src/hwrenderer/scene/hw_clipper.h
@@ -6,14 +6,6 @@
 #include "r_utility.h"
 #include "memarena.h"
 
-angle_t R_PointToPseudoAngle(double x, double y);
-
-// Used to speed up angle calculations during clipping
-inline angle_t vertex_t::GetClipAngle()
-{
-	return  R_PointToPseudoAngle(p.X, p.Y);
-}
-
 class ClipNode
 {
 	friend class Clipper;
@@ -37,6 +29,7 @@ class Clipper
 	ClipNode * clipnodes = nullptr;
 	ClipNode * cliphead = nullptr;
 	ClipNode * silhouette = nullptr;	// will be preserved even when RemoveClipRange is called
+    const FRenderViewpoint *viewpoint = nullptr;
 	bool blocked = false;
 
 	static angle_t AngleToPseudo(angle_t ang);
@@ -78,6 +71,11 @@ public:
 		c->next = c->prev = NULL;
 		return c;
 	}
+    
+    void SetViewpoint(const FRenderViewpoint &vp)
+    {
+        viewpoint = &vp;
+    }
 
 	void SetSilhouette();
 
@@ -105,6 +103,13 @@ public:
 			AddClipRange(startangle, endangle);
 		}
 	}
+    
+    void SafeAddClipRange(const vertex_t *v1, const vertex_t *v2)
+    {
+        angle_t a2 = PointToPseudoAngle(v1->p.X, v1->p.Y);
+        angle_t a1 = PointToPseudoAngle(v2->p.X, v2->p.Y);
+        SafeAddClipRange(a1,a2);
+    }
 
 	void SafeAddClipRangeRealAngles(angle_t startangle, angle_t endangle)
 	{
@@ -141,13 +146,15 @@ public:
 	{
 		return blocked;
 	}
+    
+    angle_t PointToPseudoAngle(double x, double y);
 
 	bool CheckBox(const float *bspcoord);
 
 	// Used to speed up angle calculations during clipping
 	inline angle_t GetClipAngle(vertex_t *v)
 	{
-		return unsigned(v->angletime) == starttime ? v->viewangle : (v->angletime = starttime, v->viewangle = R_PointToPseudoAngle(v->p.X, v->p.Y));
+		return unsigned(v->angletime) == starttime ? v->viewangle : (v->angletime = starttime, v->viewangle = PointToPseudoAngle(v->p.X, v->p.Y));
 	}
 
 };
diff --git a/src/r_defs.h b/src/r_defs.h
index 4ba0d45d3..4422fbf8d 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -180,8 +180,6 @@ struct vertex_t
 	{
 		p.Zero();
 	}
-
-	angle_t GetClipAngle();
 };
 
 // Forward of LineDefs, for Sectors.