CODEWITHSUNDEEP
c#objectcameraunity-game-engine
chesnutcase
chesnutcase

Reputation: 522

How do I make a camera follow an object in unity3d C#?

I have an object called Ball, and I added keyboard interactivity to it(WASD to move the ball) I need the camera to stay behind and follow the ball, but I am getting errors.

using UnityEngine;
using System.Collections;
public class ballmain : MonoBehaviour {
    public bool isMoving = false;
    public string direction;
    public float camX;
    public float camY;
    public float camZ;
    // Use this for initialization
    void Start () {
        Debug.Log("Can this run!!!");
    }

    // Update is called once per frame
    void Update () {
        camX = rigidbody.transform.position.x -=10;
        camY = rigidbody.transform.position.y -=10;
        camZ = rigidbody.transform.position.z;
        camera.transform.position = new Vector3(camX, camY, camZ);
            //followed by code that makes ball move
    }
}

I get error "Assets/ballmain.cs(18,44): error CS1612: Cannot modify a value type return value of 'UnityEngine.Transform.position'. Consider storing the value in a temporary variable" Does anyone know the answer? If I comment out the code about the camera the ball can move around.

Upvotes: 7

Views: 69627

Answers (6)

Dilmer
Dilmer

Reputation: 169

Here're one script I found useful during my game development. I didn't create them so I give credit to wiki.unity3d.com for providing this amazing script.

Smooth Follow:

using UnityEngine;
using System.Collections;

        public class SmoothFollow2 : MonoBehaviour {
        public Transform target;
        public float distance = 3.0f;
        public float height = 3.0f;
        public float damping = 5.0f;
        public bool smoothRotation = true;
        public bool followBehind = true;
        public float rotationDamping = 10.0f;

        void Update () {
               Vector3 wantedPosition;
               if(followBehind)
                       wantedPosition = target.TransformPoint(0, height, -distance);
               else
                       wantedPosition = target.TransformPoint(0, height, distance);

               transform.position = Vector3.Lerp (transform.position, wantedPosition, Time.deltaTime * damping);

               if (smoothRotation) {
                       Quaternion wantedRotation = Quaternion.LookRotation(target.position - transform.position, target.up);
                       transform.rotation = Quaternion.Slerp (transform.rotation, wantedRotation, Time.deltaTime * rotationDamping);
               }
               else transform.LookAt (target, target.up);
         }
}

More information about my work

Upvotes: 3

NabeelSaleem
NabeelSaleem

Reputation: 879

I found this simple and useful unity 2d camera follow script. 

using UnityEngine;
using System.Collections;

public class FollowCamera : MonoBehaviour {

public float interpVelocity;
public float minDistance;
public float followDistance;
public GameObject target;
public Vector3 offset;
Vector3 targetPos;
// Use this for initialization
void Start () {
    targetPos = transform.position;
}

// Update is called once per frame
void FixedUpdate () {
    if (target)
    {
        Vector3 posNoZ = transform.position;
        posNoZ.z = target.transform.position.z;

        Vector3 targetDirection = (target.transform.position - posNoZ);

        interpVelocity = targetDirection.magnitude * 5f;

        targetPos = transform.position + (targetDirection.normalized * interpVelocity * Time.deltaTime); 

        transform.position = Vector3.Lerp( transform.position, targetPos + offset, 0.25f);

    }
   }
}

source unity2d camera follow script

Upvotes: 1

Sourav Kondapaka
Sourav Kondapaka

Reputation: 53

If you just simply want to follow the target object align the position of the camera the way you want it and make the camera the child of the target object and the rest will do

Upvotes: 5

Reaz Murshed
Reaz Murshed

Reputation: 24211

Include Standard Mobile Asset to your project. It contains a SmoothFollow2D.js code in its script section. Attach this code with the gameobject and initialize public variables. This will simply do the job for you.

Upvotes: 1

user2423014
user2423014

Reputation:

here you go . a full code.

Simple Following

using UnityEngine;
using System.Collections;

public class Follow: MonoBehaviour {
public Transform target;
public float smooth= 5.0f;
void  Update (){
    transform.position = Vector3.Lerp (
        transform.position, target.position,
        Time.deltaTime * smooth);
} 

    }

Advanced Following

using UnityEngine;
using System.Collections;

public class SmoothFollowScript: MonoBehaviour {

// The target we are following
public  Transform target;
// The distance in the x-z plane to the target
public int distance = 10.0;
// the height we want the camera to be above the target
public int height = 10.0;
// How much we 
public heightDamping = 2.0;
public rotationDamping = 0.6;


void  LateUpdate (){
    // Early out if we don't have a target
    if (TargetScript.russ == true){
    if (!target)
        return;

    // Calculate the current rotation angles
    wantedRotationAngle = target.eulerAngles.y;
    wantedHeight = target.position.y + height;

    currentRotationAngle = transform.eulerAngles.y;
    currentHeight = transform.position.y;

    // Damp the rotation around the y-axis
    currentRotationAngle = Mathf.LerpAngle (currentRotationAngle, wantedRotationAngle, rotationDamping * Time.deltaTime);

    // Damp the height
    currentHeight = Mathf.Lerp (currentHeight, wantedHeight, heightDamping * Time.deltaTime);

    // Convert the angle into a rotation
    currentRotation = Quaternion.Euler (0, currentRotationAngle, 0);

    // Set the position of the camera on the x-z plane to:
    // distance meters behind the target
    transform.position = target.position;
    transform.position -= currentRotation * Vector3.forward * distance;

    // Set the height of the camera
    transform.position.y = currentHeight;

    // Always look at the target
    transform.LookAt (target);
}
}
}

Upvotes: 6

Skizz
Skizz

Reputation: 71060

The -= in these lines:

   camX = rigidbody.transform.position.x -=10;
   camY = rigidbody.transform.position.y -=10;

is wrong. The -= will attempt to modify the rigidbody.transform.position. You just want -.

However, as it stands, the camera won't track changes in the target's Z position, nor will it track properly if the camera is rotated. To get the correct position you need (in vectors):-

cam_pos = target_pos - dist_to_target * cam_look_at

Upvotes: 0

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