# Mathfx

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## Description

The following snippet provides short functions for floating point numbers. See the usage section for individualized information.

## Usage

• Hermite - This method will interpolate while easing in and out at the limits.
• Sinerp - Short for 'sinusoidal interpolation', this method will interpolate while easing around the end, when value is near one.
• Berp - Short for 'boing-like interpolation', this method will first overshoot, then waver back and forth around the end value before coming to a rest.
• Bounce - Returns a value between 0 and 1 that can be used to easily make bouncing GUI items (a la OS X's Dock)
• SmoothStep - Works like Lerp, but has ease-in and ease-out of the values.
• Lerp - Short for 'linearly interpolate', this method is equivalent to Unity's Mathf.Lerp, included for comparison.
• NearestPoint - Will return the nearest point on a line to a point. Useful for making an object follow a track.
• NearestPointStrict - Works like NearestPoint except the end of the line is clamped.

## History

• Added Approx function for testing float value within an offset range. All thanks to Opless for this!
• Clerp added by Jeffcraighead 10:51, 2 May 2008 (PDT)

## C# - Mathfx.cs

<csharp> using UnityEngine; using System;

public class Mathfx {

```   public static float Hermite(float start, float end, float value)
{
return Mathf.Lerp(start, end, value * value * (3.0f - 2.0f * value));
}

public static float Sinerp(float start, float end, float value)
{
return Mathf.Lerp(start, end, Mathf.Sin(value * Mathf.PI * 0.5f));
}

public static float Berp(float start, float end, float value)
{
value = Mathf.Clamp01(value);
value = (Mathf.Sin(value * Mathf.PI * (0.2f + 2.5f * value * value * value)) * Mathf.Pow(1f - value, 2.2f) + value) * (1f + (1.2f * (1f - value)));
return start + (end - start) * value;
}

public static float SmoothStep (float x, float min, float max)
{
x = Mathf.Clamp (x, min, max);
float v1 = (x-min)/(max-min);
float v2 = (x-min)/(max-min);
return -2*v1 * v1 *v1 + 3*v2 * v2;
}

public static float Lerp(float start, float end, float value)
{
return ((1.0f - value) * start) + (value * end);
}

public static Vector3 NearestPoint(Vector3 lineStart, Vector3 lineEnd, Vector3 point)
{
Vector3 lineDirection = Vector3.Normalize(lineEnd-lineStart);
float closestPoint = Vector3.Dot((point-lineStart),lineDirection)/Vector3.Dot(lineDirection,lineDirection);
return lineStart+(closestPoint*lineDirection);
}

public static Vector3 NearestPointStrict(Vector3 lineStart, Vector3 lineEnd, Vector3 point)
{
Vector3 fullDirection = lineEnd-lineStart;
Vector3 lineDirection = Vector3.Normalize(fullDirection);
float closestPoint = Vector3.Dot((point-lineStart),lineDirection)/Vector3.Dot(lineDirection,lineDirection);
return lineStart+(Mathf.Clamp(closestPoint,0.0f,Vector3.Magnitude(fullDirection))*lineDirection);
}
public static float Bounce(float x) {
return Mathf.Abs(Mathf.Sin(6.28f*(x+1f)*(x+1f)) * (1f-x));
}

// test for value that is near specified float (due to floating point inprecision)
// all thanks to Opless for this!
public static bool Approx(float val, float about, float range) {
return ( ( Mathf.Abs(val - about) < range) );
}
```
```   // test if a Vector3 is close to another Vector3 (due to floating point inprecision)
// compares the square of the distance to the square of the range as this
// avoids calculating a square root which is much slower than squaring the range
public static bool Approx(Vector3 val, Vector3 about, float range) {
return ( (val - about).sqrMagnitude < range*range);
}
```
```  /*
* CLerp - Circular Lerp - is like lerp but handles the wraparound from 0 to 360.
* This is useful when interpolating eulerAngles and the object
* crosses the 0/360 boundary.  The standard Lerp funciton causes the object
* to rotate in the wrong direction and looks stupid. Clerp fixes that.
*/
public static float Clerp(float start , float end, float value){
float min = 0.0f;
float max = 360.0f;
float half = Mathf.Abs((max - min)/2.0f);//half the distance between min and max
float retval = 0.0f;
float diff = 0.0f;
```
```       if((end - start) < -half){
diff = ((max - start)+end)*value;
```

retval = start+diff;

```           }
else if((end - start) > half){
diff = -((max - end)+start)*value;
retval =  start+diff;
}
else retval =  start+(end-start)*value;
```
```           // Debug.Log("Start: "  + start + "   End: " + end + "  Value: " + value + "  Half: " + half + "  Diff: " + diff + "  Retval: " + retval);
return retval;
}
```

} </csharp>