How to start Vector3.Lerp from middle point? - unity3d

Question

I have to move object from -10 to +10 x position. But I want to start my object from zero x.point to move, how can I start my lerp at the middle position?
Edit2: Object should start at x = 0 position and move to +10 x position and go to -10 x position and again +10 x, -10 x like a loop.
Vector3 pos1, pos2, pos0, pos3;
void Start()
{
pos0 = transform.position;
pos1 = pos0 + new Vector3(10, 0, 0);
pos2 = pos0 - new Vector3(10, 0, 0);
pos3 = pos1;
}
float time = 0.5f;
void FixedUpdate()
{
time += Mathf.PingPong(Time.time * 0.5f, 1.0f);
transform.position = Vector3.Lerp(pos2, pos1, time);
}

Answer 1

From Unity API documentation at https://docs.unity3d.com/ScriptReference/Vector3.Lerp.html
public static Vector3 Lerp(Vector3 a, Vector3 b, float t);
When t = 0 returns a. When t = 1 returns b. When t = 0.5 returns the
point midway between a and b.
In this symmetrical situation where x = 0 is exactly between start and end point, you could just use lerp with t starting at t = 0.5. Perhaps something like this:
Vector3 pos1, pos2, pos0, pos3;
private float t;
void Start()
{
pos0 = transform.position;
pos1 = pos0 + new Vector3(10, 0, 0);
pos2 = pos0 - new Vector3(10, 0, 0);
pos3 = pos1;
t = 0.5
}
void FixedUpdate()
{
t += Mathf.PingPong(Time.deltaTime * 0.5f, 1.0f);
transform.position = Vector3.Lerp(pos2, pos1, t);
}
And as pointed out by #BugFinder, you should probably use Time.deltaTime instead of Time.time

Answer 2

Here is how I would approach it:
Vector3 ToPos;
Vector3 FromPos;
void Start()
{
ToPos = transform.position + new Vector3(10, 0, 0);
FromPos = transform.position - new Vector3(10, 0, 0);
}
// using Update since you are setting the transform.position directly
// Which makes me think you aren't worried about physics to much.
// Also FixedUpdate can run multiple times per frame.
void Update()
{
// Using distance so it doesnt matter if it's x only, y only z only or a combination
float range = Vector3.Distance(FromPos, ToPos);
float distanceTraveled = Vector3.Distance(FromPos, transform.position);
// Doing it this way so you character can start at anypoint in the transition...
float currentRatio = Mathf.Clamp01(distanceTraveled / range + Time.deltaTime);
transform.position = Vector3.Lerp(FromPos, ToPos, currentRatio);
if (Mathf.Approximately(currentRatio, 1.0f))
{
Vector3 tempSwitch = FromPos;
FromPos = ToPos;
ToPos = tempSwitch;
}
}