diff --git a/indra/llmath/llcamera.cpp b/indra/llmath/llcamera.cpp
index e37c97b13894f262f81a5d832075ecfed5b08afe..70b716d8dc060f90cf24927b47c8f4c06c343ef9 100644
--- a/indra/llmath/llcamera.cpp
+++ b/indra/llmath/llcamera.cpp
@@ -95,7 +95,7 @@ LLPlane LLCamera::getUserClipPlane()
 
 // ---------------- LLCamera::setFoo() member functions ----------------
 
-void LLCamera::setUserClipPlane(LLPlane& plane)
+void LLCamera::setUserClipPlane(const LLPlane& plane)
 {
 	mPlaneCount = AGENT_PLANE_USER_CLIP_NUM;
 	mAgentPlanes[AGENT_PLANE_USER_CLIP] = plane;
diff --git a/indra/llmath/llcamera.h b/indra/llmath/llcamera.h
index a8d13f698ff8122cb9961ade18ab458674cef35f..2e0dd2067b5d1f544926048ec8b26bc7721d2637 100644
--- a/indra/llmath/llcamera.h
+++ b/indra/llmath/llcamera.h
@@ -155,7 +155,7 @@ class LLCamera
 	bool isChanged(); //check if mAgentPlanes changed since last frame.
 
     LLPlane getUserClipPlane();
-	void setUserClipPlane(LLPlane& plane);
+	void setUserClipPlane(const LLPlane& plane);
 	void disableUserClipPlane();
 	virtual void setView(F32 vertical_fov_rads);
 	void setViewHeightInPixels(S32 height);
diff --git a/indra/llmath/llplane.h b/indra/llmath/llplane.h
index a43bcfc862cc2fff7f2d240cfddb89bd03d91752..c4068533c626a068b297b752bc7ca42cc49946be 100644
--- a/indra/llmath/llplane.h
+++ b/indra/llmath/llplane.h
@@ -89,7 +89,7 @@ class LLPlane
 	inline void getVector3(LLVector3& vec) const { vec.set(mV[0], mV[1], mV[2]); }
 	
 	// Retrieve the mask indicating which of the x, y, or z axis are greater or equal to zero.
-	inline U8 calcPlaneMask() 
+	inline U8 calcPlaneMask() const
 	{ 
 		return mV.greaterEqual(LLVector4a::getZero()).getGatheredBits() & LLVector4Logical::MASK_XYZ;
 	}