Develop Reference

Unity: Enemy objects passing through box collider on edges of background

I'm developing a simple 2D Unity game (which I'm very new to so sorry if this is a silly question!) in which my player can eat its enemies by colliding with them. This works fine as I'm just selecting the "is trigger" component for the enemies and using this code in my Player class:
private void OnTriggerEnter2D(Collider2D other)
{
Debug.Log("Hit detected");
Destroy(other.gameObject);
transform.localScale += new Vector3(x, y, z);
}
However, this means the colliders placed around the border of my background image aren't stopping the enemies. What's the best fix for this?

I don't understand very well your question. However it seems that your collisions are not working. So, remember that for have collisions actually taking place in your game you need to use colliders and that one of the two elements participating in the collision need to have the rigidbody component.
That will make the physics work in the engine, which triggers dont.
To check if that works you can debug with:
// called on collision
void OnCollisionEnter2D(Collision2D col)
{
Debug.Log("OnCollisionEnter2D");
}

From what I understood, you want only to detect triggers between the player and the enemies, but you still want these to collide with physic objects in your scene, such as background colliders.
One possible way to achieve this is to create a child object for the player object with a collider component with the trigger option set, and attaching a script to it to handle the triggers. Then, with the use of layers to group your player and enemy objects, you can uncheck the collision between them following: Edit -> Project Settings -> Physics 2D: "Layer Collision Matrix".

You can assign a script to any enemy, checking the distance with the player in each frame. Then you can Uncheck "is trigger"
Vector2.Distance

Why does my script, which aims to remove gravity when the game starts, not work?

I'm trying to create a script in Unity wherein the gravity will go to zero when the game starts. The problem is, the gravity was still there after I launched the game.
This is for a Unity3D game. I've already tried to change the variable name, add using System; and moved my script to the top of the Rigidbody component, but none of these things worked.
public class PlayerGrav : MonoBehaviour
{
public Rigidbody rb;
void Start()
{
rb.useGravity = false;
}
void Update()
{
}
}
I expected the gravity to be removed when the game launches, but in the actual output the gravity still remained, and the cube still fell downwards.

create a new scene
create a new cube
add rb = this.GetComponent<Rigidbody>() to your start function in your PlayerGrav script
attach your PlayerGrav script to the new cube
Hit play, and take look at the "use gravity" property from your new cube's inspector window (make sure the inspector isn't locked to other game object)
If the above tryout succeeds, then you need to check the other code/objects in your original scene. If there are massive other objects in your original scene, then I will suggest disable other objects first, and re-enable them back group by group to see which object/monobhevaiour is causing the issue.

I know this is an old question but I looked forever trying to find an answer to this. I am new to unity so it took me a long time to figure this out but I am using a Rigidbody 2d so this is what worked for me
gameObject.GetComponent<Rigidbody2D>().gravityScale = 0;

Changing player rotation to a camera rotation

I'm new to unity and I'm currently working on a portal-like game.
I did the whole teleportation script and it works, but the problem comes that I didn't implement the player camera correction and actually I don't have any ideas how to do it. The concept is that when you're jumping through a portal, the player (or player camera) rotation should be changed to the portal/portal camera rotation from you've come so the final effect is more 'realistic'.
I've tried some lines in teleportation script like player.transform.rotation = portal.transform.rotation but in the end it didn't work and now I end up with nothing, deleting previous scripts and trying to write it all over and over again.
I'll be glad if someone could guide me how to start coding it. Should I do it in onTriggerEnter (when you're jump through portal), or in onTriggerExit? Should the script be attached to a player or to a portals? Should I gather rotation only from camera or from the whole gameobject (portal/player)? I'm posting also couple of screens (with a video how it currently works, and also an entire teleportation script. If I missed something just ask me and I'll post it here.
https://imgur.com/a/pbqYnLD - screens with portals inspector
https://streamable.com/b14hk - video how it works
teleportation script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Teleportation : MonoBehaviour {
[SerializeField] private GameObject otherPortal;
[SerializeField] private GameObject player;
void OnTriggerEnter(Collider col) {
if(col.tag == "Player") {
col.transform.position = new Vector3(otherPortal.transform.position.x+1, otherPortal.transform.position.y+1, otherPortal.transform.position.z+1);
Debug.Log("wszedłem w portal");
}
}
void Update() {
}
}
some informations how it is coded right now:
portals are currently in game behind 'the box', i didnt instantiate them anywhere; just changing position on lpm (blue portal) and ppm (orange portal)
portals are sticking to the walls, just like in the original game
portals have a camera attached to it and right now the cameras are static. (offtop: i have a script to move them exactly when player is moving and it quite works but also have some problems, like camera can get too far away from portal and start rendering only that green outer side of the box, and i also dont know how to fix it, so currently i didnt use this script)
the player movement im using is that from unity standard assets (if it somehow matters)
the player have a rigidbody but the portals dont; not sure if i should attach this component to them
teleportation script is attached to the both of portals - the 'otherPortal' variable is moved from inspector, like in orange portal the 'otherPortal' variable is blue portal and the other way

What you did is correct (setting the player rotation to the portal.
You can do it in onTriggerEnter after setting the position, then it should look like
player.transform.rotation = otherPortal.transform.rotation
If you do that, the player will have the same rotation. You already have something that make the camera follow the player, so it is likely that you don't need to set the camera rotation. I don't know how you did your camera follow, so I can't be sure, though. If the camera has not the proper orientation, doing Camera.main.transform.rotation = otherPortal.transform.rotation will do it.
The remaining thing that might be wring, could be that your player (and camera) is not facing the right axis. On your video, I can see that the portal faces the x-axis (the red axis in Unity editor). Check that when going forward, your player has the red axis looking forward.
It is likely that your player has the z-axis (blue) facing forward, which is (by convention) more correct and fits the names Unity uses (z-axis is also called forward-axis)
I would recomand to create the portal object (and all other objects, including the player) so that the forward-axis is the blue one. It might require editing the objects. Anycase, check that the player forward axis is that same as the portal, otherwise setting the rotation won't work

On-collision script not working?

in advanced I would like to say if this is a really simple question with a simple answer, I apologize as I have just now gotten into programming.Basically, I'm trying to create a script that a block named blue(picture below) on collision with the FPSController, will get destroyed, here is my script:
using UnityEngine;
using System.Collections;
public class Cube : MonoBehaviour {
void OnCollisionEnter (Collision col) {
if(col.gameObject.name == "Blue") {
Destroy(col.gameObject);
print ("collison detected");
}
}
}
for some reason, though, whenever the fps controller collides with the object known as "Blue" nothing happens, the print() function is not triggered nor is the destroy() function
Thank you in advaned ;)

Rigidbody` is missing from your Cubes.
1.Attach Rigidbody component to both cubes.
2.Also,set both Cubes Rigidbody to Is-kinematic. You must set both Cubes Rigidbody to Is-kinematic so that the Character Controller wont be able to move it. Note that if your cube is falling down after adding Rigidbody, simply disable Use Graivty on the Rigidbody.
Important:
3.Delete FPSController. Since you will be interacting with other Rigidbody GameObjects, use RigidBodyFPSController. It can be found in Assets\Standard Assets\Characters\FirstPersonCharacter\Prefabs. Drag RigidBodyFPSController to the Scene then attach Cube script to it.
You will notice there is a Rigidbody attached to RigidBodyFPSController. Don't modify the settings of it.
That's it. Everything should be working as expected.
Cube settings:
RigidBodyFPSController Settings:

Magnet script issues in Unity

I'm trying to make a magnet PowerUp in Unity. I used this script, which I attached to the coin GameObject:
public GameObject attractedTo;
private float strengthOfAttraction = 3f;
void FixedUpdate ()
{
Vector3 direction = attractedTo.transform.position - transform.position;
gameObject.GetComponent<Rigidbody>().AddForce (strengthOfAttraction * direction);
}
I have two problems :
1. Only newly spawn coins are attracted to the player
2. For some reason, the coins move only in straight lines, so most of them goes past the player
Anyone knows how this can be fixed?
Any help will be appreciated!

Major issue on your code. You have to recreate your procedure logic on how you make the coins get closer to the Player.
First Major problem is this.
void FixedUpdate() So on a fix amount of time per frame. You are trying to
Declare a Variable Vector3 : Vector3 direction = attractedTo.transform.position - transform.position;
So frame will recalculate and create a new pointer name direction then you try to find gameObject.GetComponent<Rigidbody>().AddForce (strengthOfAttraction * direction);
your Own Component in your gameObject. Then Call Addforce. AddForce. And you didn't even use time.deltatime.
Addforce Will push the rigidbody depending on the direction you input. So it will go straight. And you are doing this Every Fix amount of frame per sec.
First fix your procedure. My recommendation is this.
Use the Smooth Follow script. Made by Unity3D get your Reference there. It is also installed already in the script section in your Editor. If you are having problem finding it, go to this link and check he script.
Smooth Follow Script
[Update Answer]
For the 2nd Problem that only new coins is getting attracted.
Check all of this situations.
Your Player is newly spawned and your attractedTo variable is blank.
Non newly spawned coins should have referenced to the Player already, if not you have to tell all the coins that if you spawn the Player, they needed to be attracted to Player. -> Assign attractedTo when Player Spawned.
You can either Achieve that on Instantiate then find all GameObjects with TAG. Then getcomponent then assign attractedTo
Your non Spawned coins, doesn't have the Script Component.
Your non Spawned coins, is disabled.