unity smooth movement lerp code example
Example: unity smooth movement lerp
using UnityEngine;
using System.Collections;
public class LerpOnSpacebarScript : MonoBehaviour
{
///
/// The time taken to move from the start to finish positions
///
public float timeTakenDuringLerp = 1f;
///
/// How far the object should move when 'space' is pressed
///
public float distanceToMove = 10;
//Whether we are currently interpolating or not
private bool _isLerping;
//The start and finish positions for the interpolation
private Vector3 _startPosition;
private Vector3 _endPosition;
//The Time.time value when we started the interpolation
private float _timeStartedLerping;
///
/// Called to begin the linear interpolation
///
void StartLerping()
{
_isLerping = true;
_timeStartedLerping = Time.time;
//We set the start position to the current position, and the finish to 10 spaces in the 'forward' direction
_startPosition = transform.position;
_endPosition = transform.position + Vector3.forward*distanceToMove;
}
void Update()
{
//When the user hits the spacebar, we start lerping
if(Input.GetKey(KeyCode.Space))
{
StartLerping();
}
}
//We do the actual interpolation in FixedUpdate(), since we're dealing with a rigidbody
void FixedUpdate()
{
if(_isLerping)
{
//We want percentage = 0.0 when Time.time = _timeStartedLerping
//and percentage = 1.0 when Time.time = _timeStartedLerping + timeTakenDuringLerp
//In other words, we want to know what percentage of "timeTakenDuringLerp" the value
//"Time.time - _timeStartedLerping" is.
float timeSinceStarted = Time.time - _timeStartedLerping;
float percentageComplete = timeSinceStarted / timeTakenDuringLerp;
//Perform the actual lerping. Notice that the first two parameters will always be the same
//throughout a single lerp-processs (ie. they won't change until we hit the space-bar again
//to start another lerp)
transform.position = Vector3.Lerp (_startPosition, _endPosition, percentageComplete);
//When we've completed the lerp, we set _isLerping to false
if(percentageComplete >= 1.0f)
{
_isLerping = false;
}
}
}
}