How to convert JavaScript(UnityScript) to C# and implement a low pass filter?

Question

I've been trying to implement a low-pass filter code sample that I found In the Unity Manual into my game but I am having some issues.

Here is the original JavaScript sample found in the Unity Manual:

var AccelerometerUpdateInterval : float = 1.0 / 60.0;
var LowPassKernelWidthInSeconds : float = 1.0;

private var LowPassFilterFactor : float = AccelerometerUpdateInterval /    LowPassKernelWidthInSeconds; // tweakable
private var lowPassValue : Vector3 = Vector3.zero;

function Start () 
{
    lowPassValue = Input.acceleration;
}

function LowPassFilterAccelerometer() : Vector3 
{
    lowPassValue = Mathf.Lerp(lowPassValue, Input.acceleration, LowPassFilterFactor);
    return lowPassValue;
}

Here is my conversion to C#:

float AccelerometerUpdateInterval = 1.0f / 60.0f;
float LowPassKernelWidthInSeconds = 1.0f;

private float LowPassFilterFactor = AccelerometerUpdateInterval / LowPassKernelWidthInSeconds; // tweakable
private Vector3 lowPassValue = Vector3.zero;

void  Start ()
{
    lowPassValue = Input.acceleration;
}

Vector3 LowPassFilterAccelerometer ()
{
    lowPassValue = Mathf.Lerp(lowPassValue, Input.acceleration, LowPassFilterFactor);
    return lowPassValue;
}

My original code to move my character using the accelerometer was this(no low pass filter):

float speed = 30.0f;
Vector2 dir;
private float accel;

void Start () 
{
    accel = Input.acceleration.x;
}

// Update is called once per frame
void Update () 
{  
    accel = Mathf.MoveTowards (accel, Input.acceleration.x, speed * Time.deltaTime);
    dir = new Vector3(accel, 0);

    // move the object at the velocity defined in speed:
    transform.Translate(dir * speed * Time.deltaTime, 0);
}

This is my attempt to implement the low pass filter to reduce the noise/jerkiness:

float AccelerometerUpdateInterval = 1.0f / 60.0f;
float LowPassKernelWidthInSeconds = 1.0f;

private float LowPassFilterFactor;
private Vector3 lowPassValue = Vector3.zero;

public float speed = 30.0f;

void Start () 
{
    lowPassValue = Input.acceleration;
    LowPassFilterFactor = AccelerometerUpdateInterval / LowPassKernelWidthInSeconds; 
}

Vector3 LowPassFilterAccelerometer() 
{
    lowPassValue = Mathf.Lerp(lowPassValue, Input.acceleration, LowPassFilterFactor);
    return lowPassValue;
}

// Update is called once per frame
void Update () 
{  
    // move the object at the velocity defined in speed:
    transform.Translate(LowPassFilterAccelerometer() * speed * Time.deltaTime, 0);
}

I am getting some errors when I try to compile the script:

error CS1502: The best overloaded method match for `UnityEngine.Mathf.Lerp(float, float, float)' has some invalid arguments

error CS1503: Argument #1' cannot convertUnityEngine.Vector3' expression to type `float'

Answer 1

The example code may be wrong. Use Vector3.Lerp() instead. A full list of Lerps is here.