Set rigidbody.velocity to direction of mouse in Unity2d: Updated Version - c#

Yes I know this question was asked before by SuperSonyk! That post is here:
Set rigidbody.velocity to direction of mouse in Unity2d
However- the link referenced in the answer to that post is now legacy material, and I can't bring myself to understand it in Unity's current version.
My Problem: In short, I want to make my player accelerate in the direction of my cursor. My game is currently a TOP-DOWN Space Shooter in 2D. My player already looks at my mouse correctly, using cam.ScreenToWorldPoint. But relentlessly trying to add force seems futile for me, since I am fairly new to coding.
If I have any other issues in my code, It would be great if anyone could point them out!
Here's my code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour
{
//================= MOVEMENT =====================
private float thrust = 0.5f;
private float maxSpeed = 10f;
public Rigidbody2D rb;
//================= AIMING =======================
public Camera cam;
Vector2 mousePos;
// Update is called once per frame: Good for INPUTS
void Update()
{
//aiming
mousePos = cam.ScreenToWorldPoint(Input.mousePosition);
}
// Called Set amount of times. Good for PHYSICS CALCULATIONS
void FixedUpdate()
{
Move();
speedLimiter();
//aim
Vector2 lookDirection = mousePos - rb.position;
float angle = Mathf.Atan2(lookDirection.y, lookDirection.x) * Mathf.Rad2Deg - 90f;
rb.rotation = angle;
}
//======= MY MOVE FUNCTION DOES NOT WORK. HELP? ======
void Move()
{
if (Input.GetButtonDown("Accelerate"))
{
rb.velocity = new Vector3(0, thrust, 0) * Time.deltaTime;
}
}
void speedLimiter()
{
if (rb.velocity.magnitude > maxSpeed)
{
rb.velocity = Vector3.ClampMagnitude(rb.velocity, maxSpeed);
}
}
}
Please summarize the edits clearly, thank you!

In general since this is a 2D rigidbody also the velocity is a Vector2 and you should probably rather use Vector2.ClampMagnitude
and then in
rb.velocity = new Vector3(0, thrust, 0) * Time.deltaTime;
do you only want to move in global Y direction? Also a velocity is already a "per second" value -> it makes no sense to multiply by Time.deltaTime if you reassign a new velocity. Since it says thrust I guess you rather wanted to add to the existing velocity.
What you would rather do is save your mouse direction you already have and do
public class PlayerController : MonoBehaviour
{
...
void FixedUpdate()
{
// I would update the aim BEFORE moving
// Use a NORMALIZED direction! Makes things easier later
Vector2 moveDirection = (mousePos - rb.position).normalized;
float angle = Mathf.Atan2(moveDirection.y, moveDirection.x) * Mathf.Rad2Deg - 90f;
rb.rotation = angle;
// OPTIONAL: Redirect the existing velocity into the new up direction
// without this after rotating you would still continue to move into the same global direction
rb.velocity = rb.velocity.magnitude * moveDirection;
Move(moveDirection);
speedLimiter();
}
void Move(Vector2 moveDirection)
{
if (Input.GetButtonDown("Accelerate"))
{
// Instead of re-assigning you would probably add to the existing velocity
// otherwise remove the "+" again
rb.velocity += moveDirection * thrust * Time.deltaTime;
}
}
void speedLimiter()
{
if (rb.velocity.magnitude > maxSpeed)
{
// You are working with Vector2 so use the correct method right away
rb.velocity = Vector2.ClampMagnitude(rb.velocity, maxSpeed);
}
}
}

You already have half of the work by having your player looking at the mouse. We will be using the vector lookDirection as the direction of the movement for the player, normalize it so its length is 1 and multiply it by thrust. This way, we have a vector in the direction of the mouse and of length thrust as intended.
void Move()
{
if (Input.GetButtonDown("Accelerate"))
{
Vector2 lookDirection = (mousePos - rb.position);
rb.AddForce(lookDirection.normalized * thrust);
}
}
Note that we work here with Vector2 since you are using a Rigidbody2D.
Also, I don't think that using Time.DeltaTime is relevant here. When you apply force to a physic object, you don't need to use it, by definition, the function FixedUpdate() has a fixed frequency. If you look at one of Unity's tutorial, you can see that they don't multiply it by Time.DeltaTime
Last tip: you may want to be playing around with the drag property of your Rigidbody2D to have your player slow down over time when not accelerating, otherwise, it will be sliding out of control and the player won't be able to stop it.
Don't hesitate to tell me if my answer is not clear for you or does not entirely satisfy you, it's my first answer here!
EDIT: I forgot to tell you but as derHugo mentioned, since you are using Rigidbody2D, you must use Vector2.ClampMagnitude to limit your speed in your speedLimiter function. Also, I don't think that you need your if since the function Vector2.ClampMagnitude will only change the value of the velocity if it exceeds the maximum.

Thanks to everyone who responded!
With the help of Brackeys community, I managed to solve this by using this method:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour
{
//================= MOVEMENT =====================
private float thrust = 10f;
private float maxSpeed = 100f;
public Rigidbody2D rb;
//================= AIMING =======================
public Camera cam;
Vector2 mousePos;
// Update is called once per frame: Good for INPUTS
void Update()
{
//aiming
mousePos = cam.ScreenToWorldPoint(Input.mousePosition);
}
// Called Set amount of times. Good for PHYSICS CALCULATIONS
void FixedUpdate()
{
Move();
speedLimiter();
//aim
Vector2 lookDirection = mousePos - rb.position;
float angle = Mathf.Atan2(lookDirection.y, lookDirection.x) * Mathf.Rad2Deg - 90f;
rb.rotation = angle;
}
void Move()
{
if (Input.GetKey("up"))
{
rb.AddRelativeForce(Vector2.up*thrust);
}
}
void speedLimiter()
{
if (rb.velocity.magnitude > maxSpeed)
{
rb.velocity = Vector3.ClampMagnitude(rb.velocity, maxSpeed);
}
}
//rb.AddForce(new Vector3(0, thrust, 0));
}

Related

Player moves at a very slow speed in Unity

I'm making a first-person movement script for the player, and everything movement-wise seems to work fine (other than an unrelated issue of the player not moving in the camera's direction), however when running in the game, the player moves at a very slow speed.
Here's the movement script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerMovement : MonoBehaviour
{
private Rigidbody RB;
[SerializeField] private GameObject cam;
private float walkVel; // Forward & backward movement
private float strafeVel; // Sideways movement
[SerializeField] public float walkSpeed = 5f;
private void Start()
{
RB = GetComponent<Rigidbody>();
}
private void Update()
{
walkVel = Input.GetAxis("Vertical");
strafeVel = Input.GetAxis("Horizontal");
}
private void FixedUpdate()
{
transform.localRotation = Quaternion.Euler(0f, cam.transform.rotation.y * Time.deltaTime, 0f);
Vector3 Up = new Vector3(RB.velocity.x, RB.velocity.y, RB.velocity.z);
RB.velocity = (transform.forward * strafeVel + transform.right * walkVel).normalized * walkSpeed * Time.deltaTime;
}
}
I'm pretty sure the issue is not related to the camera script, but here it is:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerCamPositioning : MonoBehaviour
{
private Vector2 camTurn;
[SerializeField] public float camSensitivity = 5f;
private void Start()
{
Cursor.lockState = CursorLockMode.Locked;
}
private void Update()
{
camTurn.x += Input.GetAxis("Mouse X") * camSensitivity;
camTurn.y -= Input.GetAxis("Mouse Y") * camSensitivity;
transform.localRotation = Quaternion.Euler(camTurn.y, camTurn.x, 0);
}
}
I tried to implement a very basic velocity script, and alternatively RB.AddVelocity to the Rigidbody, however it did not solve my problem.
I also tried simply increasing the walkSpeed variable to increase player speed, which actually solves my problem, HOWEVER I want to refrain from using this solution as previously the player moved at a relatively normal speed with walkSpeed set to 5f.
Sounds like you just need to tweak your values. Try splitting your equation into pieces and logging the individual and multiplied value so you can understand what values you see versus what values you're expecting.
I see many variables in your code that can be less than 1. strafeVel, walkVel and Time.deltaTime. In fact, in my experience, Time.deltaTime is always a very small float.
Perhaps you would prefer to use RB.velocity with += or *= along with a Mathf.Clamp() to gradually increase your speed.
All I had to do to solve my problem was remove Time.deltaTime from the RB.Velocity vector. The vector already runs in the FixedUpdate function, so I think it should work as intended now.

How to make a game object move to the opposite direction of a constantly moving object? Unity 2D

I have a game object that constantly rotates around another one:
What I am trying to achieve is to have the circle move in the opposite direction of the square when I press the space key, the square will simulate a propeller, for example:
This is the code I have, which kinda works:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour
{
[SerializeField] GameObject rotatingPropellant;
[SerializeField] float rotationSpeed;
[SerializeField] float impulseForce;
Rigidbody2D playerRb;
void Start()
{
playerRb = GetComponent<Rigidbody2D>();
}
void Update()
{
RotatePropellant();
Move();
}
void RotatePropellant()
{
rotatingPropellant.transform.RotateAround(transform.position, new Vector3(0f, 0f, 1f), rotationSpeed * Time.deltaTime);
}
void Move()
{
if (Input.GetButtonDown("Jump"))
{
playerRb.velocity = -rotatingPropellant.transform.position * impulseForce * Time.deltaTime;
}
}
}
But sometimes the circle moves up even if the square is up (meaning that the circle should be pushed down), not sure if maybe the signs are not correct or if I should be approaching this with a different method
So this:
playerRb.velocity = -rotatingPropellant.transform.position * impulseForce * Time.deltaTime;
relies on rotatingPropellant position relative to World's zero position (Vector3.zero), which might work only if the propellant revolves around this zero point.
What you should probably do instead is get the difference:
Vector3 dir = (rotatingPropellant.transform.position - transform.position).normalized;
playerRb.velocity = dir * impulseForce * Time.deltaTime;
Also, instead of changing velocity, you can add force instead:
Vector3 dir = (rotatingPropellant.transform.position - transform.position).normalized;
playerRb.AddForce(dir * impulseForce, ForceMode2D.Impulse);
To get movement direction, you can use this vector formula AB = B - A. This formula will give you the position vector of A Related to B space and if you normalize this vector you will get the movement direction
A is sphere and B is Square at here. Check Vector Addition and Substraction.

Dashing in Unity 2D using the Rigidbody Component

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Movement : MonoBehaviour
{
public float movementSpeed;
public Rigidbody2D Rigidbody;
private Vector2 moveDirection;
public Transform Player;
void Start()
{
}
void Update()
{
ProcessInputs();
} void FixedUpdate()
{
move();
}
void ProcessInputs()
{
float moveX = Input.GetAxisRaw("Horizontal");
float moveY = Input.GetAxisRaw("Vertical");
moveDirection = new Vector2(moveX, moveY).normalized;
}
void move()
{
Rigidbody.velocity = new Vector2(moveDirection.x * movementSpeed, moveDirection.y * movementSpeed);
}
}
So i needed some tips so i thoght id ask here, i wanted to implement dashing in my Top-Down-Shooter but i didnt find any code on Youtube that would properly work with my code i have also tried moveing the players position +2 to the wanted direction but i couldnt work it out.
id be happy if yall could help me.
Nice that you are using FixedUpdate() for physics - many beginners use that wrong.
However do not set velocity manually. Use AddForce.
It will effectively set the velocity but automatically takes the objects mass into account and allows to speed up instead of instantly being at speed.
That is the more logical approach since you move in a direction by applying forces to your body.
For Dashing, you could add a significantly higher force for a small number of Physics frames (aka small number of FixedUpdate calls). You can use a countdown which you set to a number when the chaarcter hsould start dashing.
In the FixedUpdate you decrement the counter and as long as it is >0 you apply the dashing force.

Relative input but global movement in Unity

I'm working on a spaceflight game in unity and stumbled across this simple logical error. I want to be able to add relative movement to my spaceship, but also for it to keep the momentum in that direction when you turn. I've sot a separate script for looking around and movement. Here is my movement source code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerMovement : MonoBehaviour
{
public CharacterController ship;
public float speed = 0.001f;
float momentum = 0f;
Vector3 velocity;
void Start()
{
Cursor.lockState = CursorLockMode.Locked;
}
void Update()
{
momentum = momentum + Input.GetAxis("Vertical");
Vector3 move = transform.forward * momentum * 0.001f;
ship.Move(move);
}
}
I know this is a simple question, my brain is just kind of stuck right now. Thanks! ~OwenPT
Do I understand correctly that you want the spaceship fly forward and when it turns right or left it must continue flying forward?
Your spaceship must have component rigidbody (I think it does) and you get mode him using function GetComponent().AddForce. There you can choose the ForceMode. There are 4 kinds of force_mode:
Force - Add a continuous force to the rigidbody, using its mass.
Acceleration - Add a continuous acceleration to the rigidbody, ignoring its mass.
Impulse - Add an instant force impulse to the rigidbody, using its mass.
VelocityChange - Add an instant velocity change to the rigidbody, ignoring its mass.
So, choose the one you need and the spaceship must continue flying forward after turning
You've neglected your velocity variable. You're applying a scalar speed (momentum) in the direction of facing (transform.forward).
If you want to have a feel of momentum, you need to deal with Acceleration:
public CharacterController Ship;
public float AccelerationFactor = 1.0f;
public float BrakingFactor = 0.1f;
public float MaxSpeed = 20.0f;
private Vector3 Velocity;
void Update()
{
var totalBraking = Velocity.normalized * BrakingFactor;
var totalAcceleration = transform.forward * AccelerationFactor * Input.GetAxis("Vertical");
Velocity = Velocity + (totalAcceleration + totalBraking) * Time.deltaTime;
Velocity = Vector3.ClampMagnitude(Velocity, MaxSpeed);
Ship.Move(Velocity * Time.deltaTime);
}

Make an enemy walk around a rectangular platform, like in Metroid

I'm new to Unity, so probably this is a dumb question but I have several days trying to figure it out. I have an enemy walking from one side of a platform to the other. I'm using Raycasting to check if there´s no ground below and turn to the other way.
What I want is for the enemy to walk AROUND the platform (Just like the enemies in Metroid). I set the gravity of the enemy to 0 so it will not fall down, but I don´t know how to make it rotate and keep walking around the platform. I know it could be done with raycasting but I have not clue how to do it.
I will enormously appreciated if anyone can help me with the piece of code I'm missing. Thanks in advance!
public class BlobController : MonoBehaviour {
private Rigidbody2D myRigidBody;
public float moveSpeed;
public LayerMask groundMask;
float myWidth;
// Use this for initialization
void Start ()
{
myRigidBody = GetComponent<Rigidbody2D>();
myWidth = GetComponent<SpriteRenderer> ().bounds.extents.x;
}
// Update is called once per frame
void Update ()
{
}
void FixedUpdate()
{
//Check to see if there's ground in front before moving forward
Vector2 lineCasPos = transform.position - transform.right * myWidth;
Debug.DrawRay (lineCasPos, Vector2.down,Color.red);
bool isGrounded = Physics2D.Raycast (lineCasPos, Vector2.down, 2, groundMask);
//If there's no ground, turn around
if (!isGrounded)
{
Vector3 currRot = transform.eulerAngles;
currRot.y += 180;
transform.eulerAngles = currRot;
}
//Always move forward
Vector2 myVel = myRigidBody.velocity;
myVel.x = -transform.right.x * moveSpeed;
myRigidBody.velocity = myVel;
}
}

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