Clamping camera forward and backward vector in Unity3D

Question

My perspective camera is rotated on the x axis. I've implemented a zoom with the scroll wheel and it works great.

I'm trying to limit the zoom, however. My solution right now is to take the relative scale of the transform.forward y and z components and clamp the y and z position of the camera by using Mathf.Clamp and multiplying the minZoom and maxZoom floats by the corresponding transform.forward component. It works well, except it limits the y axis, so when I translate around I can't go below a given y due to my clamp with is ideally meant to affect the zoom only.

Is there a way to clamp the forward and backward movement of the camera? I've been looking everywhere but can't find a thing.

Thanks.

Edit

Here's the relevant code (my clamping occurs in LateUpdate):

public class ClickManager : MonoBehaviour

{
    public float dragSpeed = 2;
    public float minZoom = 0.5f;
    public float maxZoom = 5.0f;

    private Vector3 dragOrigin;

    private float lerpPercentBack = 0; // value between 0 and 1 representing percentage of lerp
    private float lerpPercentForward = 0;
    private bool isLerpingBack = false;
    private bool isLerpingForward = false;



    void Update()
    {
        float scroll = Input.GetAxis("Mouse ScrollWheel");

        if (Input.GetMouseButtonDown(1))
        {
            dragOrigin = Input.mousePosition;
            return;
        }

        if (scroll > 0)
        {
            isLerpingForward = true;
            lerpPercentForward = 0;
        }
        if (scroll < 0)
        {
            isLerpingBack = true;
            lerpPercentBack = 0;
        }



        if (isLerpingBack)
        {
            scrollLerperBack();
            lerpPercentBack += 0.05f;

            if (lerpPercentBack >= 1.0f)
            {
                lerpPercentBack = 0;
                isLerpingBack = false;
            }
        }


        if (isLerpingForward)
        {

            scrollLerperForward();
            lerpPercentForward += 0.05f;

            if (lerpPercentForward >= 1.0f)
            {
                lerpPercentForward = 0;
                isLerpingForward = false;
            }
        }

        //Debug.Log(lerpPercent);

        /*if (!Input.GetMouseButton(1)) return;

        Vector3 pos = Camera.main.ScreenToViewportPoint(Input.mousePosition - dragOrigin);
        Vector3 move = new Vector3(pos.x * dragSpeed, pos.y * dragSpeed, 0);

        transform.Translate(move, Space.World);

        Debug.Log(scroll);*/


    }


    void scrollLerperBack()
    {
        transform.position -= Vector3.Lerp(transform.forward, Vector3.zero, lerpPercentBack);
    }


    void scrollLerperForward()
    {
        transform.position += Vector3.Lerp(transform.forward, Vector3.zero, lerpPercentForward);
    }

    void LateUpdate()
    {
        Vector3 pos = transform.position;

        pos.y = Mathf.Clamp(pos.y, minZoom * transform.forward.y,
            maxZoom * transform.forward.y);
        pos.z = Mathf.Clamp(pos.z, minZoom * transform.forward.z, 
            maxZoom * transform.forward.z);
        transform.localPosition = pos;
    }

}

Answer 1

Working Code:

using UnityEngine;
using System.Collections;

public class ClickManager : MonoBehaviour
{
    public float dragSpeed = 2;
    public float minZoom = 0.5f;
    public float maxZoom = 5.0f;

    private Vector3 dragOrigin;

    private float lerpPercentBack = 0; 
    private float lerpPercentForward = 0;
    private bool isLerpingBack = false;
    private bool isLerpingForward = false;

    Vector3 forwardPos;
    Vector3 backwardPos;
    void Start()
    {
        forwardPos = transform.position ;
        forwardPos.z += maxZoom;

        backwardPos = transform.position ;
        backwardPos.z += minZoom;
    }


    void Update()
    {
        float scroll = Input.GetAxis("Mouse ScrollWheel");

        if (Input.GetMouseButtonDown(1))
        {
            dragOrigin = Input.mousePosition;
            return;
        }

        if (scroll > 0)
        {
            isLerpingForward = true;
            lerpPercentForward = 0;
        }
        if (scroll < 0)
        {
            isLerpingBack = true;
            lerpPercentBack = 0;
        }



        if (isLerpingBack)
        {
            scrollLerperBack();
            lerpPercentBack += 0.05f;

            if (lerpPercentBack >= 1.0f)
            {
                lerpPercentBack = 0;
                isLerpingBack = false;
            }
        }


        if (isLerpingForward)
        {

            scrollLerperForward();
            lerpPercentForward += 0.05f;

            if (lerpPercentForward >= 1.0f)
            {
                lerpPercentForward = 0;
                isLerpingForward = false;
            }
        }
    }


    void scrollLerperBack()
    {
        transform.position = Vector3.MoveTowards(transform.position, backwardPos, Time.deltaTime * dragSpeed );
    }


    void scrollLerperForward()
    {
        transform.position = Vector3.MoveTowards(transform.position, forwardPos, Time.deltaTime * dragSpeed);
    }


}