So I'm trying to make a game about soccer. In this program, I'd created 2 objects called (in Hierarchy): Ball and goal_line_1. In this code, I'm trying to check if the ball collides with the goal line or not, and if it does collide, I will return (Lerp) the ball to the point in the middle (0,0.3,0). But somehow when I drag the ball to the position that the ball collides with the goal line and then press play, the ball just stay there and don't return to the middle point.
public var smooth : float;
private var newPosition : Vector3;
function Awake ()
{
newPosition = transform.position;
}
function OnTriggerEnter (ball : Collider)
{
var positionA : Vector3 = new Vector3(0, 0.3, 0);
newPosition = positionA;
ball.transform.position = Vector3.Lerp(ball.transform.position, newPosition, smooth * Time.deltaTime);
}
That is because you used OnTriggerEnter() function. This function is called when a collider enters a collision with another collider. What you do by dragging the ball into the line and then pressing play is actually skipping the 'Trigger Enter' event. There are three main events when it comes to collisions: TriggerEnter, TriggerStay and TriggerExit.
Although I'm not sure, if you change your function to OnTriggerStay(), you might get your function work. However for a safer testing method, I suggest you add a script to the ball so you can manually move it with your keyboard and see if the OnTriggerEnter() function works because by doing that, you will be simulating a more realistic situation (ball being kicked/moving towards the line rather than "suddenly existing" on the line).
If you are using 2D, you need to change your OnTriggerEnter function to OnTriggerEnter2D.
Related
I'm creating a top down 2D game, where the player has to break down trees. I made it so the player casts a ray toward the mouse, and when the ray hits a tree, it should lower the tree's health. I don't get any errors when I run the game or click, but it seems like the tree isn't detecting the hits.
void Update()
{
...
if (Input.GetMouseButtonDown(0))
{
RaycastHit2D hit = Physics2D.Raycast(playerRb.transform.position, mousePosition - playerRb.transform.position, 2.0f);
if (hit.collider != null)
{
if (hit.collider == GameObject.FindWithTag("Tree"))
{
hit.collider.GetComponent<TreeScript>().treeHealth--;
}
}
}
}
Still pretty new to coding and I'm teaching myself, so please make your answer easy to understand to help me learn.
Input.mousePosition is equal to the pixel your mouse is on. This is very different than the location your mouse is pointing at in the scene. To explain further, Input.mousePosition is where the mouse is. Think about it. If the camera was facing up, the mouse positon would be the same, but where they are clicking is different.
Instead of using Input.mousePosition, You should pass this into a function called Ray Camera.ScreenPointToRay();
You just input the mouse position and then use this new ray to do the raycast.
ANOTHER EXTREMELY IMPORTANT THING 1: Do not use Camera.main in Update(), as it uses a GetComponet call, which can cause perormance decreases. Store a reference of it in your script and use that.
Extremely important thing 2: I notice you are using GetComponent to change the tree's health. This is fine, but do not use GetComponent if you don't have to.
Like this:
Camera cam;
void Start()
{
cam = Camera.main; //it is fine to use this in start,
//because it is only being called once.
}
void Update()
{
...
if (Input.GetMouseButtonDown(0))
{
Ray ray = cam.ScreenPointToRay(Input.mousePosition);
RaycastHit2D hit = Physics2D.Raycast(ray);
...
}
}
You need to convert your mouse position from screen point to world point with Z value same as the other 2D objects.
Vector3 Worldpos=Camera.main.ScreenToWorldPoint(mousePos);
Also use a Debug.DrawRay to check the Raycast
Debug.DrawRay(ray.origin, ray.direction*10000f,Color.red);
Source
I want to make sure that various objects moving at high speed cannot pass through walls or other objects. My thought process was to check via Raycast if a collision has occurred between two moments of movement.
So the script should remember the previous position and check via Raycast for collisions between previous and current position.
If a collision has occurred, the object should be positioned at the meeting point and moved slightly in the direction of the previous position.
My problem is that works outside the map not inside. If I go from inside to outside, I can go through the walls. From outside to inside not.
Obviously I have misunderstood something regarding the application with raycasts.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ObsticalControll : MonoBehaviour
{
private Vector3 positionBefore;
public LayerMask collisionLayer = 9;
private Vector3 lastHit = new Vector3(0, 0, -20);
// Start is called before the first frame update
void Start()
{
positionBefore = transform.position;
}
private void OnDrawGizmos()
{
Gizmos.DrawCube(lastHit, new Vector3(.2f,.2f,.2f));
}
// Update is called once per frame
void Update()
{
Vector3 curruentMovement = transform.position;
Vector2 dVector = (Vector2)transform.position - (Vector2)positionBefore;
float distance = Vector2.Distance((Vector2)positionBefore, (Vector2)curruentMovement);
RaycastHit2D[] hits = Physics2D.RaycastAll((Vector2)positionBefore, dVector, distance, collisionLayer);
if(hits.Length > 0)
{
Debug.Log(hits.Length);
for (int i = hits.Length -1 ; i >= 0 ; i--)
{
RaycastHit2D hit = hits[i];
if (hit.collider != null)
{
Debug.Log("hit");
lastHit.x = hit.point.x;
lastHit.y = hit.point.y;
Vector3 resetPos = new Vector3(hit.point.x, hit.point.y, transform.position.z) + positionBefore.normalized * 0.1f;
transform.position = new Vector3(resetPos.x, resetPos.y, transform.position.z);
}
}
}
positionBefore = transform.position;
}
}
Theres a better way to deal with this that unity has built in.
Assuming the object thats moving at a high speed has a RigidBody(2d in your case) you can set its Collision Detection to Continuous instead of Discrete.
This will help collisions with high speed collision, assuming that its moving at high speed and the wall is not moving.
If for some reason you cannot apply this to your scenario, Ill try to help with the raycast solution.
However, I am still wondering about the collision behavior of my raycast script. That would be surely interesting, if you want to calculate shots or similar via raycast
Alright, so your initial idea was to check if a collision had occurred, By checking its current position and its previous position. And checking if anything is between them, that means a collision has occurred. And you would teleport it back to where it was suppose to have hit.
A better way todo this would be to check where the GameObject would be in the next frame, by raycasting ahead of it, by the distance that it will travel. If it does hit something that means that within the next frame, it would have collided with it. So you could stop it at the collision hit point, and get what it has hit. (This means you wouldn't have to teleport it back, So there wouldn't be a frame where it goes through then goes back)
Almost the same idea but slightly less complicated.
Problem would be that if another object were to appear between them within the next frame aswell, it could not account for that. Which is where the rigidbody.movePosition shines, And with OnCollisionEnter you can detect when and what it collided with correctly. Aswell as without the need to teleport it back
I'm making a simple character that follows the player's cursor. What I also want is for when the game object "enemy" appears the character then goes to that location to alert the player. Once the enemy is gone the character continues to follow the cursor like normal. Is there a reason why my script won't work. How else can I paraphrase it?
public class FollowCursor : MonoBehaviour
{
void Update ()
{
//transform.position = Camera.main.ScreenToWorldPoint( new Vector3(Input.mousePosition.x,Input.mousePosition.y,8.75f));
if (gameObject.FindWithTag == "Enemy")
{
GameObject.FindWithTag("Enemy").transform.position
}
if (gameObject.FindWithTag != "Enemy")
{
transform.position = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x,Input.mousePosition.y,8.75f));
}
}
}
You are not using FindWithTag correctly, as it is a method that takes a string as parameter you need to use it like this:
GameObject.FindwithTag("Something") as stated in the Unity scripting API
Now to apply this to your code you would need to do the following to set your players position based on wether or not an enemy is found (assuming this script is on your actual player object):
if(GameObject.FindWithTag("Enemy"))
{
//If an enemy is found with the tag "Enemy", set the position of the object this script is attatched to to be the same as that of the found GameObject.
transform.position = GameObject.FindWithTag("Enemy").transform.position;
}
else
{
//when no enemy with the tag "Enemy" is found, set this GameObject its position to the the same as that of the cursor
transform.position = Camera.main.ScreenToWorldPoint( new Vector3(Input.mousePosition.x,Input.mousePosition.y,8.75f));
}
However this code will just snap your player instantly to the position of the found Enemy. If this is not the desired behaviour you could use a function like Vector3.MoveTowards instead to make the player move to it gradually.
This code also has room for optimisation as searching for a GameObject every update frame is not the ideal solution. But for now it should work.
I'm going to code coding all the function for you, I'm not pretty sure about the beavihour of your code, I understand a gameobject will be attached to the mouse position, so not really following....
Vector3 targetPosition;
public float step = 0.01f;
void Update()
{
//if there is any enemy "near"/close
//targetPosition = enemy.position;
//else
//targetPosition = MouseInput;
transform.position = Vector3.MoveTowards(transform.position, targetPosition , step);
}
For the f you can use a SphereCast and from the enemies returned get the closest one.
So, as the title implies, my OnCollisionEnter is not being called. I'm not sure why. The objects are bouncing off surfaces they contact.
Here's the relevant code:
static Rigidbody m_ProjectileRigidbody;
internal void FireProjectile(GameObject projectile, float speed)
{
projectile.transform.position =
State.PlayerTransform.position + State.PlayerTransform.forward;
projectile.transform.rotation = State.PlayerTransform.rotation;
m_ProjectileRigidbody = projectile.GetComponent<Rigidbody>();
m_ProjectileRigidbody.AddForce
(State.PlayerTransform.forward * speed, ForceMode.Impulse);
if (State.PlayerState.Consumes)
{
State.PlayerState.ConsumeCellEnergy(EnergyConsumption);
State.PlayerState.GenerateCellHeat(HeatProduction);
}
}
void OnCollisionEnter(Collision collision)
{
Debug.Log("Collided With: " + collision.gameObject.name);
}
If you are working with 2D colliders and rigidbodies, use OnCollisionEnter2D instead of OnCollisionEnter.
And make sure in Edit -> Project Settings -> Physics the collision matrix is properly set.
And also, double check that:
Both objects have collider, rigidbody properly set up.
Both objects are active.
You do not accidentally disable collider, rigidbody or set
isKinematic, isTrigger from your script.
I'm trying to implement a tower defense game in Unity, and I can't figure out how can I assign a velocity or a force to a new instantiated object (in the creator object's script)
I have a tower which is supposed to shoot a bullet towards the enemy which triggered its collider. This is the script of the towers:
function OnTriggerEnter(other:Collider){
if(other.name=="Enemy")
{
ShootBulletTo(other.transform);
}
}
function ShootBulletTo(target:Transform)
{//public var Bullet:Transform
var BulletClone = Instantiate(Bullet,transform.position, Quaternion.identity); // ok
BulletClone.AddForce(target.position); //does not compile since Transform.AddForce() does not exist.
}
I guess the problem is I have to use a Transform variable for instantiate but I need a GameObject variable for velocity, force etc. So how can I instantiate the bullet with initial velocity?
Thanks for help.
You have to acces the rigidbody component of your bullet clone to change the force, not the transform.
Here's how your code should look:
function OnTriggerEnter(other:Collider)
{
if(other.name=="Enemy")
{
ShootBulletTo(other.transform);
}
}
function ShootBulletTo(target:Transform)
{
var Bullet : Rigidbody;
BulletClone = Instantiate(Bullet, transform.position, Quaternion.identity);
BulletClone.AddForce(target.position);
}
There's also a good example in the unity script reference
http://docs.unity3d.com/Documentation/ScriptReference/Object.Instantiate.html
[EDIT] I'm pretty sure, that you don't want to add the enemies position as a force, instead you should add a direction that goes towards the enemies position.
You subtract two positions to gain a direction vector between them, so the ShootBulletTo function should look like this:
function ShootBulletTo(target:Transform)
{
// Calculate shoot direction
var direction : Vector3;
direction = (target.position - transform.position).normalized;
// Instantiate the bullet
var Bullet : Rigidbody;
BulletClone = Instantiate(Bullet, transform.position, Quaternion.identity);
// Add force to our bullet
BulletClone.AddForce(direction);
}