Develop Reference

rb.AddForce() is launching my player in the opposite direction of the vector 2 value I assigned

Im making a game where you click and drag with the mouse then release to launch the player. But sometimes the player gets launched in the opposite direction of where it should go. I made a debug output to show you the different values. Here is the output
In that image for example you can see that the Vector2 of force * power is positive on the y axis, but the player launched downwards, and the same happens Viceversa. I think its also worth to note that this happens inconsistantly for some reason. Here is my code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Movement : MonoBehaviour
{
public GameObject player;
public float power = 10f;
public Rigidbody2D rb;
public float maxSpeed;
public Vector2 minPower;
public Vector2 maxPower;
TragectoryLine tl;
Camera cam;
public Vector2 force;
public Vector3 startPoint;
public Vector3 endPoint;
public Vector3 currentPoint;
public Vector3 startPointMouse;
public bool isPulling = false;
float distance;
private void Start()
{
cam = Camera.main;
tl = GetComponent<TragectoryLine>();
}
private void Update()
{
if (Input.GetMouseButtonDown(0))
{
startPointMouse = cam.ScreenToWorldPoint(Input.mousePosition);
startPointMouse.z = 15;
}
if (Input.GetMouseButton(0))
{
startPoint = player.transform.position;
startPoint.z = 15;
isPulling = true;
Vector3 currentPoint = cam.ScreenToWorldPoint(Input.mousePosition);
currentPoint.z = 15;
tl.RenderLine(startPoint, currentPoint);
}
if (Input.GetMouseButtonUp(0))
{
endPoint = cam.ScreenToWorldPoint(Input.mousePosition);
endPoint.z = 15;
isPulling = false;
tl.EndLine();
distance = startPointMouse.magnitude - endPoint.magnitude;
if (distance < 0)
{
distance = -distance;
}
if (distance >= 1)
{
rb.AddForce(force * power, ForceMode2D.Impulse);
}
force = new Vector2(Mathf.Clamp(startPoint.x - endPoint.x, minPower.x, maxPower.x), Mathf.Clamp(startPoint.y - endPoint.y, minPower.y, maxPower.y));
Debug.Log("distance" + distance);
Debug.Log("start" + startPoint);
Debug.Log("end" + endPoint);
Debug.Log("force" +force);
Debug.Log("force * power" + force * power);
}
}
private void FixedUpdate()
{
rb.velocity = Vector3.ClampMagnitude(rb.velocity, maxSpeed);
}
}
Here I added the force using rb.AddForce(force * power, ForceMode2D.Impulse); when the force * power value was positive on the y axis. So why did it go to the opposite direction???
This was working perfectly fine before i tried implementing a feature where the player has to move the mouse a certain distance or else it wont launch. I have tried removing it but it doesnt seem to make a difference. I think I changed something in the code that ruined it but I cant figure out what! Please help!

Converting 2D position / rotation to 3D

I have a player-object, and a player and a camera attached to it as childs.
I would like to rotate the camera in a circle around the player so that it always faces the player (which is centered at 0,0,0).
I have a 2D approach which I need to convert 3D.
What would this script look like for 3D?
Thank you.
using UnityEngine;
using System.Collections;
public class circularMotion : MonoBehaviour {
public float RotateSpeed;
public float Radius;
public Vector2 centre;
public float angle;
private void Start()
{
centre = transform.localPosition;
}
private void Update()
{
angle += RotateSpeed * Time.deltaTime;
var offset = new Vector2(Mathf.Sin(angle), Mathf.Cos(angle)) * Radius;
transform.localPosition = centre + offset;
}
}

Well, one approach could be to define an upwards vector and then rotate around the corresponding axis.
using UnityEngine;
public class circularMotion : MonoBehaviour
{
public float RotateSpeed = 1;
public float Radius = 1;
public Vector3 centre;
public float angle;
public Vector3 upDirection = Vector3.up; // upwards direction of the axis to rotate around
private void Start()
{
centre = transform.localPosition;
}
private void Update()
{
transform.up = Vector3.up;
angle += RotateSpeed * Time.deltaTime;
Quaternion axisRotation = Quaternion.FromToRotation(Vector3.up, upDirection);
// position camera
Vector3 offset = axisRotation * new Vector3(Mathf.Sin(angle), 0, Mathf.Cos(angle)) * Radius;
transform.localPosition = centre + offset;
// look towards center
transform.localRotation = axisRotation * Quaternion.Euler(0, 180 + angle * 180 / Mathf.PI, 0);
}
}

How do i make it into a smooth camera? (unity C# programming)

This is what i got and why does this website want me to put more explaining when i clarified above well i want to achieve a smooth camera control where the player is in the middle of the camera if the mouse is in the middle but as it moves toward a direction i want the camera to move just a little bit to reveal terrain (here i have 2 problems:
1.The camera doesnt move if the mouse is at the point 0,0 of the screen and i want it to be the center of the camera
2. the camera drifts away in that direction, it doesnt stop like i want to make it):
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CameraController : MonoBehaviour {
// Camera cam = Camera.main.orthographicSize;
//Vector2 camcenter = new Vector2(cam * 2, camheight);
public GameObject mage;
private Vector3 offset;
public float mincam = 30f;
public float maxcam = 120f;
public bool mouse_smooth_cam = false;
// Update is called once per frame
void LateUpdate ()
{
offset = Input.mousePosition / 100 + transform.position - mage.transform.position;
transform.position = mage.transform.position + offset;
}
void Update()
{
HandleZoom();
}
private void HandleZoom()
{
float scrollValue = Input.mouseScrollDelta.y;
float newCamSize = Camera.main.orthographicSize - scrollValue*4;
Camera.main.orthographicSize = Mathf.Clamp(newCamSize, mincam, maxcam);
}
}

Instead of Input.mousePosition / 100 use Camera.main.ScreenToWorldPoint(Input.mousePosition)
also always use Time.deltaTime in Update methods
var PAN_SPEED = 30f;
var mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
offset = mousePos + transform.position - mage.transform.position;
transform.position = mage.transform.position + offset * Time.deltaTime * PAN_SPEED;

Unity3d - Camera rotation smoothing 'bug'

I made a simple racing game. The camera follows the car (player) and its position and rotation is based on car's Y rotation. I want to smooth the camera rotation, but when it crosses 0 degree point, it rotates 360 degrees.
Here's the code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Camera : MonoBehaviour {
public Transform camera, player;
void Update() {
Vector3 cameraPosition = camera.transform.position;
float cameraRotation = camera.eulerAngles.y;
float playerRotation = player.eulerAngles.y;
Vector3 playerPosition = player.transform.position;
cameraPosition.x = (Mathf.Sin((playerRotation / 180) * Mathf.PI) * -6 + player.position.x);
cameraPosition.y = playerPosition.y + 2.5f;
cameraPosition.z = (Mathf.Cos((playerRotation / 180) * Mathf.PI) * -6 + player.position.z);
camera.transform.position = cameraPosition;
cameraRotation = cameraRotation + (playerRotation-cameraRotation)/2;
camera.localRotation = Quaternion.Euler(20f, cameraRotation, 0f);
}
}
I figured out that this rotation is caused by smoothing script:
cameraRotation = cameraRotation + (playerRotation-cameraRotation)/2;
How to prevent this unwanted rotation?

This is how I would do it:
public int smoothSpeed = 1f; // Change accordingly to increase/decrease smooth speed.
Then in update:
Vector3 directionToCar = player.position - camera.position;
Quaternion desiredRotation = Quaternion.LookRotation(directionToCar);
camera.rotation = Quaternion.Slerp(camera.rotation, desiredRotation, Time.deltaTime * smoothSpeed);
On a side node, if this camera script is attached to the camera, you don't have to make a field referencing the camera's transform. You can simply do transform.position instead of camera.transform.position.

A simpler solution to using the Slerp is to use Mathf.SmoothDamp, which has a variant called Mathf.SmoothDampAngle which handles the looping correctly. I've also had success doing the wraparound by hand but its not a very rewarding experience
using UnityEngine;
public class RotFollow : MonoBehaviour
{
[SerializeField] Transform carTransform;
[SerializeField] float smoothTime = .4f;
float currentYAngle;
float targetYAngle;
float angleVel;
void Update()
{
targetYAngle = carTransform.rotation.eulerAngles.y;
currentYAngle = Mathf.SmoothDampAngle(currentYAngle, targetYAngle, ref angleVel, smoothTime);
transform.rotation = Quaternion.Euler(
transform.rotation.eulerAngles.x,
currentYAngle,
transform.rotation.eulerAngles.z);
}
}

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.

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);
}
}
}

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

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

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.

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

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