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diff --git a/APEX_1.4/common/src/variable_oscillator.cpp b/APEX_1.4/common/src/variable_oscillator.cpp
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+++ b/APEX_1.4/common/src/variable_oscillator.cpp
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+/*
+ * Copyright (c) 2008-2015, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * NVIDIA CORPORATION and its licensors retain all intellectual property
+ * and proprietary rights in and to this software, related documentation
+ * and any modifications thereto.  Any use, reproduction, disclosure or
+ * distribution of this software and related documentation without an express
+ * license agreement from NVIDIA CORPORATION is strictly prohibited.
+ */
+
+
+#include "Apex.h"
+#include "variable_oscillator.h"
+#include "PxMath.h"
+
+namespace nvidia
+{
+namespace apex
+{
+
+variableOscillator::variableOscillator(float min, float max, float initial, float period) :
+	mMin(min),
+	mMax(max),
+	mPeriod(period),
+	mStartVal(initial),
+	mLastVal(initial)
+{
+	mCumTime = 0.0f;
+	mGoingUp = true;
+	mEndVal = computeEndVal(mMin, mMax);
+}
+
+
+variableOscillator::~variableOscillator()
+{
+}
+
+float variableOscillator::computeEndVal(float current, float maxOrMin)
+{
+	float target;
+	float maxDelta;
+	float quarterVal;
+
+	// compute the max range of the oscillator
+	maxDelta = maxOrMin - current;
+	// find the 'lower bound' of the oscillator peak
+	quarterVal = current + (maxDelta / 4.0f);
+	// get a rand between 0 and 1
+	target = (float) ::rand() / (float) RAND_MAX;
+	// scale the rand to the range we want
+	target = target * PxAbs(quarterVal - maxOrMin);
+	// add the offset to the scaled random number.
+	if (current < maxOrMin)
+	{
+		target = target + quarterVal;
+	}
+	else
+	{
+		target = quarterVal - target;
+	}
+	return(target);
+}
+
+float variableOscillator::updateVariableOscillator(float deltaTime)
+{
+	float returnVal;
+	float halfRange;
+
+	mCumTime += deltaTime;
+
+	// has the function crossed a max or a min?
+	if ((mGoingUp  && (mCumTime > (mPeriod / 2.0f))) ||
+	        (!mGoingUp && (mCumTime > mPeriod)))
+	{
+		mStartVal = mLastVal;
+		if (mGoingUp)
+		{
+			mEndVal = computeEndVal(mStartVal, mMin);
+		}
+		else
+		{
+			mEndVal = computeEndVal(mStartVal, mMax);
+			mCumTime = mCumTime - mPeriod;
+		}
+		mGoingUp = !mGoingUp;
+	}
+	halfRange = 0.5f * PxAbs(mEndVal - mStartVal);
+	returnVal = -halfRange * PxCos(mCumTime * PxTwoPi / mPeriod) + halfRange + PxMin(mStartVal, mEndVal);
+	mLastVal = returnVal;
+
+	return(returnVal);
+}
+
+}
+} // namespace nvidia::apex