My problem looks like this:
I have one stationary object wall and second object that is moving projectile. I want projectile to stop when it collides with wall. But ewery my attempt ended with projectile passing through wall.
Only script that affects movement of projectile:
public Transform trans;
void Update()
{
trans.Translate(0, 0, speed * Time.deltaTime, Space.Self);
}
All compomponents of projectile:
All components of wall:
Note: I have correctly set up layers in project settings.
I have tried many combinations of rigit boddies, colliders, layers and so on, but projectile always passed through wall.
In general, your presented setup is right. The contacting object have a Rigidbody component, and the objects you can collide have at least a collider (not a trigger).
First possible problem: your Rigidbody is set to Kinematic. Did you enable all collision modes in Project Settings > Physics > Contact Pairs Mode?
Second problem is the use of transform.Translate in the Update. Translate will ignore physic and just move the object when you tell it to do, and Update may be out of sync with the physic loop, where it would be recommended to use FixedUpdate. Even using FixedUpdate, Translate will not do the right job. It will force the object to move and the physic can complain or not about that (it can move the object back, glitching, or it can just ignore and let the object pass).
The right way to move a Kinematic rigidbody is through rigidbody.MovePosition, as stated in the Unity docs. For non-kinematic objects, you can use AddForce. Some tutorials also teach to set velocity of Rigidbody, which is not recommended because it can have undesired effects. Do it if you know the side effects and really want them.
I had a similar issue before. May I suggest destroying the projectile instead? You will then have to use OnCollisionEnter().
First, create a script and attach it to your projectile game object. After that, give your wall a tag, like 'wall'. Then, do something like this:
void OnCollisionEnter(Collision collision)
{
// Gets information about the game object the projectile collided with
GameObject objectCollided = collision.gameObject;
if (objectCollided.tag == "wall'){
// Do something with either the wall/enemy
}
// Destroy the projectile
Destroy(gameObject);
}
Note: If the intent was not to destroy the projectile but rather sticking to the wall, I suggest you to use detect collision using Raycast. Raycast has a hitInfo parameter and stores information about a gameObject that it hit, as well as the where did the Ray hit the gameObject.
Thus you can use this to move your projectile accordingly. In my previous projects, I used the Rigidbody component of my projectile and used .AddForce() to shoot it out, then detect collision with OnCollisionEnter().
Maybe you could do the same, but have a separate function to remove that force on entering a collision. I never tried it so I do not know if it will work.
Transform.Translate overrides the physics engine of unity. If you want to take advantage of the rigidbody and collider components of your gameObjects, you need to use rigidbody.Velocity or (as unity recommends in the docs) rigidbody.AddForce, and make sure you set IsKinematic to False on both rigidbodies, so that they can interact with one another physically.
Related
I know you can use rigid body on two objects for collision and so on. I can do that just fine but I’m trying to do this without needing one on my player object.
But if I have a player object that is using only a character controller, is there any way to “push” them around when colliding with other objects?
As the CharacterController inherits from Collider you could do this if the other objects have a (kinematic) Rigidbody - at least one Rigidbody is required so the collision itself is detected (not sure on this though, might work without, the CharacterController is a special case) - and then use Physics.ComputePenetration in order to calculate the distance and direction you have to move your player in order to move it out of the hit collider => pushing it away.
[RequireComponent(typeof(Rigidbody))]
public class PushCharacter : MonoBehaviour
{
[SerializeField] Collider ownCollider;
void Awake ()
{
if(! ownCollider) ownCollider = GetComponentInChildren<Collider>();
}
void OnCollisionStay(Collision collision)
{
if(collision.collider is CharacterController character)
{
Physics.ComputePenetration(ownCollider, ownCollider.transform.position, ownCollider.transform.rotation, character, character.transform.position, character.transform.rotation, out var direction, out var distance);
character.Move(direction * distance);
}
}
}
Note also
One of the colliders has to be BoxCollider, SphereCollider CapsuleCollider or a convex MeshCollider. The other one can be any type.
Which limits the objects you can use as the pushing objects since the CharacterController is none of those (even though it kinda acts like a Capsule).
However - just as a heads-up - as soon as there are multiple pushing objects involved this could get quite complex!
Yes, of course it is possible to do it without using built in colliders and rigid bodies. They are just script after all.
One way to do this, is to see if one of the outer bounds of the player object are within Vector3-radius and Vector3+radius then apply force to the RigidBody or move the players Vector3.
There are countless possibilities for how to do this but the easiest way is definitely using colliders and RigidBodies..
Thank you in advance for any input.
What is essentially happening is this: When the player shoots, the scene resets
What I interpret as happening:
Player shoots a laser beam
Laserbeam prefab collides immediately with player (so far as I can tell)
SceneManager resets scene
I suspect two possible causes:
Either the origin of my laserbeam is causing the created projectilePrefab to trigger the player's collision in this piece of code:
private void OnCollisionEnter2D(Collision2D collision)
{
SceneManager.LoadScene(0);
//if collider is projectile.Prefab, don't run this piece of code
}
More generally that my laserbeam collision doesn't exclude the player gameobject:
void Update()
{
if (Input.GetButtonDown("Fire1"))
{
var projectile = Instantiate(
projectilePrefab,
transform.position,
projectilePrefab.transform.rotation);
}
}
The typical solutions then would likely look like this:
Ensure the laserbeam spawns away from the player, so they do not collide.
or, ideally,
The collider on my player would be able to simply exclude contact with a laserbeam as cause for SceneManager to reset the scene.
Where I get stuck when it comes to testing these solutions is the exact syntax. I was hoping someone might be willing to give some insight that is adept at conditional statements and the like. I'm still super new, so while I can largely comprehend what I'm reading and being shown, I'm still stuck before that hump of really being able to dissect it all myself.
Essentially what my ideal might look like (so far as I can tell) is: "If collider is projectilePrefab, do not run SceneManager.LoadScene"
Cheers and thank you in advance!
As the title suggests, I've literally just started learning Unity recently and I'm practising by making a side scrolling shooter. I've been following a Udemy course about it and (to my knowledge) I've been following the tutor's instructions to the letter, but at the point where he tests his and it works fine, by projectiles go straight through my enemies.
I'm a bit stumped at this point and so I thought I'd post here to see what you guys thought. I bet it's something really simple I've not done.
Please see my projectile code below:
using UnityEngine; using System.Collections;
public class DestroyEnemyAndProjectile : MonoBehaviour {
public GameObject WhiteExplosion;
public GameObject OrangeExplosion;
void Start()
{
}
void Update()
{
}
void OnCollisionEnter2D (Collision2D tempCollision)
{
if (tempCollision.gameObject.tag == "Collision")
{
spawnParticles(tempCollision.transform.position);
Destroy(tempCollision.gameObject);
}
}
void spawnParticles(Vector2 tempPosition)
{
Instantiate(WhiteExplosion, tempPosition, Quaternion.identity);
Instantiate(OrangeExplosion, tempPosition, Quaternion.identity);
}
}
Thanks for your help!
I did post a question to them which got a response, they suggested that perhaps the projectile is going too fast and check there was a Rigidbody 2D attached - both of which were already collect
make sure that the object you're colliding with has the tag "Collision", with the same capitalisation.
If it's not, you can do this by:
1. Selecting the GameObject to be collided with
2. In the top-right, select the Tag property
3. Add tag, click the plus and type in "Collision"
4. Select the GameObject again, and select the "Collision" tag from the Tag property dropdown
Otherwise, if that's not the issue. Make sure the projectile has a type of Collider2D component, and that the projectile, or the object being collided with, has a Rigidbody2D.
First I would like to know what the behaviour of this script curently is. Is the collision method being called, and the projectile goes through the enemy anyway? Or the collision method is not being called at all?
That being said, these are things that you should check in order for collision to work:
Make sure that the projectile and the enemy have Collider2D components attached to them.
Make sure that the projectile and/or the enemy (at least one of them must) have a Rigidbody2D attached to it.
Make sure that the layer of the projectiles and the layer of the enemies are set to collide in the collision matrix (You can find the collision matrix in Edit->ProjectSettings->Physics)
Make sure that the enemy GameObject has its tag set to "Collision".
P.S: Welcome to Unity where issues like this are, in fact, usually caused by something super simple that you probably missed.
I have an issue that I've not been able to solve for a few days now and without it working I can't move on with my project, so your help would be greatly appreciated!
What I'm trying to do is 'find' the velocity of an object that is directly below my 2D sprite (that also contains a Rigidbody and 2D box collider) and then add that velocity (in the same direction) to the object that is 'looking' for it.
I feel like ray-casting might be part of the answer but I'm not sure how to use that, especially in this context.
The idea behind this is I have a platform that can carry objects stacked on top of each other, so you move the mouse, it manipulates the platforms velocity, but this causes the objects on-top to fly backwards, no mater how high the friction is.
Here is the platform code:
void Update()
{
float distance_to_screen = Camera.main.WorldToScreenPoint(gameObject.transform.position).z;
Vector3 pos_move = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, distance_to_screen));
mouseDelta = pos_move - lastMousePosition;
acceleration = mouseDelta.x * 0.4f;
platformVelocity += acceleration;
platform.velocity = new Vector2(platformVelocity, 0) * speed;
lastMousePosition = pos_move;
}
Thank you for taking the time to read this, I would very much appreciate any help you can give!
Is it necessary to 'find' that object? 'Finding' may be difficult & costing.
Can you hold the 'below-thing' reference and pass it to 'above-thing'?
I'm assuming you have some method on objects that checks whether it's on a moving platform. One option is to add an IsOnMovingPlatform flag on those objects. Then use a similar method to check if any object is on top of the "IsOnMovingPlatform == true" objects. Keep doing passes on that method until you don't come up with any more flags set to true.
So, i'm trying to understand your question and I think I might know what you're talking about.
Are you saying that you want your game object (2d sprite) to stay on the platform as its moving? I have had the same problem, where a platform is moving and my player (game object) slides off- and this is how I fixed it.
Add a box collider to the platform (trigger). When the player enters the platform, make the player's transform the platform. That way, when the platform moves- the player moves with it no matter what the speed is.
For example:
void OnTriggerEnter2D(Collider2d collider){
if(collider.tag.equals("Player")){ // you only want the player to work
// attach script to platform for "this.transform" to work
collider.transform.SetParent(this.transform);
}
}
then, to unparent the transform "otherwise, even when the player is off the platform, it will move with the platform.
void OnTriggerExit(Collider2d collider){
// assuming your player isn't supposed to have a parent!
collider.transform.parent = null;
}
Sorry if I misunderstood your question! If this is what you were going for, finding the velocity of the platform is not necessary. Also, this is uncompiled code- if you have issues let me know.
EDIT:
To add a bit of a give, for the entire duration that the player is in contact with the platform, we can add a little bit of a negative force to shove the player a little bit!
We do this by using OnTriggerStay2D (assuming your game is 2d, otherwise use OnTriggerStay).
For example:
void OnTriggerStay2D(Collider2d collider){
if(collider.tag.equals("Player")){
collider.getComponent<Rigidbody2D>().addForce(new vector2(forceToAdd, 0));
}
}
now, that "forceToAdd" variable should be based on the speed and direction that your platform is going. Does your platform have a rigid body on it? if so you can get your force variable by retrieving the rigid body from the platform (getcomponent()) and get the X velocity from it. With this velocity, experiment with dividing it by numbers until you find a good fit, multiply it by -1 (because you want to push the player in the opposite direction of the platform travel), then this will be your forceToAdd!
However, if your platform is not using a Rigidbody, then a way you can do this is record the x positions in your script (just two positions, and subtract these to find the distance in an update method), multiply by -1, try dividing by a number (experiment with this) and that can be your force to add variable.
Also, my code for the OnTriggerStay2d is rough, the spelling could be a bit wrong- but this will give you a rough idea for a solution! ALSO.. I don't think getting the component of a rigid body should be done in every frame, a way around this would to have your rigid body component as a global variable in the script, then set your rigid body on OnTriggerEnter2d, this way it will only retrieve it once (instead of every frame) which I assume would be more efficient!
Good luck! and if you have any questions il try to help!
This is a raycast2d version, I tested it and it works much better than the trigger collider version :).
using UnityEngine;
using System.Collections;
public class RaycastFeetDeleteLater : MonoBehaviour {
[SerializeField] private float raycastDist = 0.1f;
[SerializeField] Transform feet;
[SerializeField] private float xForceDampener = 0.1f;
private Rigidbody2D rb2d;
// Use this for initialization
void Start () {
rb2d = GetComponent<Rigidbody2D> ();
}
// Update is called once per frame
void FixedUpdate () {
RaycastDown ();
}
private void RaycastDown(){
RaycastHit2D hit = Physics2D.Raycast (feet.position, Vector2.down, raycastDist);
if (hit.collider != null) {
print (hit.transform.tag);
if (hit.collider.tag.Equals ("Platform")) {
transform.SetParent (hit.transform);
Vector2 force = new Vector2 ((hit.transform.gameObject.GetComponent<Rigidbody2D> ().velocity.x * xForceDampener) * -1, 0);
print (force);
rb2d.AddForce (force);
} else if (transform.parent != null) {
print ("UNPARENT");
transform.parent = null;
}
} else {
if (transform.parent != null) {
transform.parent = null;
}
}
Debug.DrawRay (feet.position, Vector3.down, Color.green, raycastDist);
}
}
This script is attached to the player! No need to have scripts on the platforms, which was the main reason my previous method was a pain :P
Basically this script does the following:
- Gets rigidbody2d of the player on start (we will be adding forces to the player with it soon, so might as well store it in a variable!
On FixedUpdate (Different than Update, FixedUpdate is called on Physics update, where as Update is called every frame) I have read that raycast should use FixedUpdate, I suppose because it is a Physics method!
RaycastDown shoots a 2D raycast directly down from the feet position (to get the feet, create a child object of the player, put the position of the feet a tiny bit below the player, NOT ON THE PLAYER- I will explain why in a second why that will mess up everything! Then drag the feet GameObject on to the "feet" slot of the script.)
Raycast shoots from feet directly down at a distance that is changeable in the editor (raycastDist) I found a distance of 0.1f was perfect for my needs, but play around with it for yours! You can actually see a drawing of your Ray by using Debug.DrawRay as seen in the code, the ray is only visible in the editor- not game view! But this will help, especially with positioning the feet.
Checks if it hit an object with a collider, if so check if the objects tag is a Platform (set the platforms to a new tag and call it Platform).
If it hits a platform set the parent of the player to the platform (like the last script) and start applying a little force to the player in the negative direction that the platform is traveling (we get the rigid body of the platform to find its velocity).
If the raycast does not hit a platform, unparent it so the player can move freely.
Thats basically it, however...
Please note:
This script needs to be on the player, not any of the players child objects, since this script will unparent the player from any platforms- if you have the script on a child object of the player it will unparent from the player- which is horrible. So The script MUST be on the root game object of the player. There are ways around this if for some reason you can't.
As mentioned before, the "feet" child object must be a little bit under the player- this is because when the Raycast2d "fires" it will find the FIRST object with a collider it hits- so if you have the start of the raycast hit a collider on the player then it will always show the raycast hitting the player, not a platform. So to get around this have the raycast fire from the feet- and have the feet position a tiny bit below the player. To help with this I added a print statement that will print to the console which object the raycast is hitting, if it doesn't say "Platform" then you need to lower the feet! :)
Furthermore, I'm not sure how you are moving your platforms- but if the Velocity of the platform always prints "0,0" then its because you are moving the platforms position directly, instead of moving it by forces (this happened to me when I was testing this script). I got around this by moving the platform by "AddForce". Also depending on the "Mass" of your platforms, you may need to drastically increase the "xForceDampener" which I should of actually labeled "xForceMultiplier" as I found while testing I needed to set it much higher- like at 60, instead of 0.25 which I previously thought would be okay..
Hope this helped :D
EDIT: Linking the unity docs for 2D Raycasts in case you need
http://docs.unity3d.com/ScriptReference/Physics2D.Raycast.html
I have a very weird issue in my 2D Unity game, which I was able to reduce to the following core problem/minimal reproducing test case. Follow these steps to reproduce (Unity 5.1.1f1):
Create a player object (Cube) at location (0,0,0).
Remove the BoxCollider Component.
Attach the following C# script, Unity will automatically add the required Components and thereby make it a Rigidbody Collider.
Set the isKinematic flag.
Add another Cube to the scene at location (2,0,0).
Remove the BoxCollider Component and add a BoxCollider2D. This makes this cube a static Collider.
Set the isTrigger flag.
Run the scene.
Expected behavior:
The player cube accelerates towards the other cube and stops moving once it touches it.
Observed behavior:
The player cube accelerates towards the other cube, then continues moving at constant speed.
Additional implementation details:
I originally moved all objects by translating their transform and didn't use Rigidbodies at all because I didn't need collision detection. Now I do, so I want Rigidbodies. I dived into online resources and found out I'm supposed to use rigidbody.MovePosition() rather than transform.Translate() or transform.position. I changed my script, and the above error appeared.
Going back to transform.position fixes the issue, but that's not a good solution, as it involves bad practice which, according to what I read, produces significant CPU loads.
Failed attempts to solve:
Switching to Update() and Time.deltaTime didn't make any difference.
I tried not returning in the Update() and instead simply resetting the timestep to 0 while stop is set. No change.
Fiddling with the Inspector and doing stuff like freezing position on the rigidbody or setting the player objects to also be a trigger had no effect at all. Changing anything on the Rigidbody component while the game is running (after the collision) makes the cube stop immediately. Literally anything, even setting its mass to 0.
I also tried setting velocity to 0, resulting in no change. Which does make sense since Update() is skipped entirely (I also checked that with a Debug.Log() by the way).
So at this point, I'm down to barely 30 lines of code and I still have no idea what's causing this. Since the involved objects are a static Trigger collider and a kinematic rigidbody collider, both with no physics materials, there should be nothing that makes this thing move once the flag is set. But it does move.
SimpleController2D.cs
using UnityEngine;
using System.Collections;
[RequireComponent (typeof (BoxCollider2D), typeof (Rigidbody2D))]
public class SimpleController2D : MonoBehaviour {
public Vector3 velocity = Vector3.zero;
private Transform thisTransform;
private Rigidbody2D thisRigidbody;
public bool stop = false;
void Awake () {
thisTransform = GetComponent<Transform> ();
thisRigidbody = GetComponent<Rigidbody2D> ();
}
void FixedUpdate() {
float timestep = Time.fixedDeltaTime; // temporarily stored for ease of access
if (stop) {
return; // freeze on hit
}
velocity.x += timestep; // accelerate
/* add a second slash (/) to toggle between transform and rigidbody
thisTransform.position += velocity * timestep; /*/
thisRigidbody.MovePosition ((Vector3)thisRigidbody.position + velocity*timestep); //*/
}
void OnTriggerEnter2D(Collider2D col) {
stop = true;
}
}
Solution
This is a bug in Unity 5.1.1f1 and was fixed in the patch release 5.1.1p2 and later.
Get it here:
http://unity3d.com/unity/qa/patch-releases?version=5.1
What happened?
You can even reduce the problem to a single MovePosition call. MovePosition uses the physics engine to move the object. Therefore Unity calculates the velocity necessary to reach the target position within the next physics update. Version 5.1.1f1 fails to reset the velocity to zero after reaching the position, so the object will just continue moving with the calculated velocity.