I'm currently developing a game in unity using c# scripts and I have a small problem. I'm trying to give one of my game objects a constant speed/velocity without it being affected by other gravity, drag or any other type of physics characteristic except velocity. I looked through the Unity manual to find any classes that would be able to help me with this and I seemed to have found one class that would do the job:
https://docs.unity3d.com/ScriptReference/Rigidbody-velocity.html
I edited it in order to make it fit my game since this is a game object that doesn't have its velocity affected by the player but every time I run the game in the test screen nothing happens(The object stays static). I was wondering if anyone knows of a class in Unity or C# that deals with this problem or generally knows how I can make this happen. Both by having it affect all the game objects appearing on the screen at the same time or only a select few? And secondly, I was also wondering how I could convert the rigidbody velocity vector2 into from a world point into a screen point?
Thanks alot.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class BallSpeed : MonoBehaviour
{
public Rigidbody rb;
void Start()
{
rb = GetComponent<Rigidbody>();
}
void Update()
{
rb.velocity = new Vector2(0, 100);
}
}
Expected result: The game object moves upwards with a speed of 100.
Actual result: Nothing happens.
If you are trying to make your object move at a constant speed, there is no need for a rigidbody reference.
public float upSpeedPerSecond = 100f;
void Update() {
transform.translate(new Vector3(0, upSpeedPerSecond*time.deltaTime, 0));
}
Be sure to check that your Rigidbody2D is set to dynamic in the inspector, as Kinematic and Static rigidbodies do not have physics. If you don't want it to be dynamic, just use rb.Translate() instead. However, NEVER translate a static rigidbody, as it messes with the optimizations the engine does to them, use kinematic rigidbodies for transforming instead.
Related
novice to intermediate Unity developer here. I've been hitting a pretty significant roadblock the past ~2 days concerning the raycast detection of objects with specific layers. I've been researching this issue quite a lot, and all the solutions I've found don't seem to reflect the strange issue I'm facing.
Basically, the problem follows this sequence of events:
My player character has a vision cone shaped trigger mesh called 'InSightBox' which detects all objects with the tag 'Mob' and adds them to a List of colliders called 'MobsInRange'.
public List<Collider> mobsInRange;
public List<Collider> GetColliders()
{
return mobsInRange;
}
// Start is called before the first frame update
void Start()
{
mobsInRange = new List<Collider>();
}
// Update is called once per frame
void Update()
{
}
//add enemy with tag 'mob' to list
private void OnTriggerEnter(Collider other)
{
if(!mobsInRange.Contains(other) && other.tag == "Mob")
{
mobsInRange.Add(other);
}
}
//remove enemy with tag 'mob' to list
private void OnTriggerExit(Collider other)
{
if (mobsInRange.Contains(other) && other.tag == "Mob")
{
mobsInRange.Remove(other);
}
}
This list is then fed up to the root/parent player game object containing everything relating to the player.
public Transform closestMob;
public List<Collider> mobs;
public Transform GetClosestEnemy()
{
Transform tMin = null;
float minDist = Mathf.Infinity;
Vector3 currentPos = transform.position;
foreach(Collider trans in mobs)
{
//find enemy with closest distance and set tMin to it. Method returns tMin
float dist = Vector3.Distance(trans.transform.position, currentPos);
if(dist < minDist)
{
tMin = trans.transform;
minDist = dist;
}
}
//Debug.Log(tMin);
return tMin;
}
The player then uses a 'Look at' method to find the closest of all 'mobs' to the player. The player will set their forward transform to look at the closest mob.
Problem Step ---> 4) When the player raises their gun and attempts to shoot the closest enemy, a ray is cast with a layermask that looks only for objects on the layer 'Enemy', the 8th layer. When the ray detects the enemy, the enemy script should fire its 'TakeDamage' method which decreases the 'curHealth' variable by 8. Only problem is, the cast doesn't seem to detect the enemy object on the 'Enemy' layer.
LayerMask layerMask = 1 << 8;
void Fire()
{
//play the audio of the gunshot
StartCoroutine("SetPlaying");
RaycastHit hit;
//cast a ray from the player forward and check if the hit object is on layer 'Enemy'
if (Physics.Raycast(transform.position, transform.forward, out hit, Mathf.Infinity, layerMask))
{
//if hit object is an enemy, set its 'gotShot' bool to true
print("hit enemy");
closestMob.GetComponent<EnemyBase>().gotShot = true;
}
//play gunshot sound and stop player from turning
source.clip = fireSound;
source.PlayOneShot(fireSound, gunshotVolumeScale);
turnSpeed = 0;
}
I'll also note that all the solutions I've seen to this issue are not working for me. I declared an int variable called 'layerMask' and initialized it in Awake() by bit shifting layer 8 into it (i.e. int layerMask = 1 << 8), but it still isn't detecting it. The enemy contains all that I belive it should need for this to work, including a rigidbody, a capsule collider, the associated scripts, as well as being on the 'Enemy' layer.
This is where it gets weird (at least to my knowledge), when I invert the mask in the cast (~layerMask), it does exactly what I'd expect, and begins firing the code within the raycasts if statement when the player 'shoots' anything that doesn't have the 'Enemy' layer.
Any help would be suuuper appreciated as I'm getting to the point of slamming my face into the desk :/
Side Note: I'm getting to the point where I may just attach a 'fire range' cube trigger to my player and enabled it when the Fire() event is triggered, then have that check for game objects with the tag 'mob' as that kind of detection works most consistent to me.
First, be sure that you didn't confuse layers with tags. They are different.
Second, get rid of any implicit actions and references, i.e. don't use bitshifting, layer indices, or any non-straightforward reference. Instead, create something like this:
[SerializedField] private LayerMask _layerMask;
Use inspector to assign needed layer(s).
This way you will explicitly see, which layer you are using. This is useful not only for you, but for you in future, when you forget layers' indices. Also, for anyone who aren't familiar with the project.
Third is for debug. Be sure that your raycasting works as intended at other aspects:
Try remove layerMask and see if the ray goes where you want it to
Use custom gizmos to check if you cast the ray in a right direction
Try using RaycastAll. Maybe some objects catch (block) your ray earlier than you think
Looks like the issue was that I had my 'Enemy' prefab which contained the necessary components (RigidBody, Collider, scripts, NavmeshAgent) nested inside an empty game object. I thought at first to make something a prefab you needed to have it inside an Empty. I see now that is rather redundant and not necessary (at least in my case).
Physics.RaycastAll solved this issue as it no longer got 'halted' by the parent empty's collider and also hit the child.
I actually got it working just using a regular Physics.Raycast by rebuilding the Enemy prefab as just a single Capsule object (which I'll replace with character meshes later on).
Side Note
Before I got this new method working, I also used a different one that achieves the same goal in a pretty lightweight manner.
I added a long and thin box trigger to the front of my player so that it has enough distance to collide with any enemies within the shooting range.
I then enable the trigger any time the player enters their 'Aiming' state. If the trigger collides with any mesh that has the tag "Mob', it sets a bool on the player that indicates if the enemy is in range.
Then if the enemy is in range && the player enters the 'Firing Gun' state, a method in the Enemy Base script is fired that decrements the enemy health by a publicly decided variable called damagetaken.
Both the Raycast method and the box trigger method work equally well for me, but the box trigger one just took less time to figure out and gave me less headache haha.
Hope this helps anyone else in a bind!!!!!
I have a simple project where I spawn multiple asteroids and they tend to gravitate over a planet. I wanted to add a simple trail to enhance the visual effects. It's very simple when I add the asteroid manually and then add component "trail renderer" and select desired material. But I can't work it out on how to add it to a script. This is my code for now:
using System.Collections;
using UnityEngine;
[RequireComponent(typeof(Rigidbody))]
[RequireComponent(typeof(FauxGravityBody))]
public class Spawner : MonoBehaviour {
public GameObject meteorPrefab;
public float distance = 20f;
public float time = 10f;
private GameObject meteor;
public TrailRenderer trail;
void Start ()
{
StartCoroutine(SpawnMeteor());
}
IEnumerator SpawnMeteor()
{
Vector3 pos = Random.onUnitSphere * distance;
meteor = Instantiate(meteorPrefab, pos, Quaternion.identity);
meteor.AddComponent<FauxGravityBody>();
meteor.AddComponent<DestroyMeteor>();
meteor.AddComponent<SphereCollider>();
meteor.AddComponent<TrailRenderer>();
yield return new WaitForSeconds(time);
StartCoroutine(SpawnMeteor());
}
}
Which indeed adds the trail to the spawned objects, but it's using the default pink trail. My desired trail material is located in folder "Assets/Effects/Trail.mat". How can I specify in the script that I want to use that specific material?
Kind regards.
Note if you need these components -- TrailRenderer, SphereCollider etc. -- on all meteors, you can simply add them to the Prefab itself manually (by dragging them over it). Then they will already be there, right materials and all, once you Instantiate the main prefab.
You can then still adjust specific settings (or disable components) by using getting them via GetComponent<TrailRenderer>() etc. Good luck!
The best way to do it is....
create Prefab and attach you needed component to your Prefab
and Instatiate it when and where you need it
and using GetComponent<>() method you can get attached component
GameObject bullets = Instantiate(yourPrefab, yourtransform.position, Quaternion.identity) as GameObject;
bullets.GetComponent<Rigidbody>().AddForce(transform.forward * 100, ForceMode.Impulse);
I am trying to move a gameobject but I found these two most popular functions to move the object. The difference I know between these two is that there is a rigidbody needed in using AddForce but no Rigidbody needed in Transform.translate. I just wanted to make sure that I am using right function for game. Is there anny difference in the functionality of these two function? I am moving a cube over an infinite plane with obstacles in the way. I think rigidbody is needed ofcourse but I want to know what is the use of Transform.translate?
transform.translate:
With this method you basically teletransport the GameObject, not taking in account
physics nor colliders. This one is pretty expensive if you have a RigidBody attached.
AddForce:
With this one you are adding force to the RigidBody of the GameObject, so all the
movement will be taking physics and colliders into account.
If you need to move a RigidBody (like a Player) I recommend using MovePosition.
It's more precise than AddForce and use the physics motor.
EDIT:
Example:
public float movementSpeed= 5f; //for instance
void FixedUpdate()
{
Vector3 direction = new Vector3(Input.GetAxisRaw("Horizontal"), 0 , Input.GetAxisRaw("Vertical"));
rigidbody.MovePosition(transform.position + direction * movementSpeed * Time.fixedDeltaTime);
}
Tweak movementSpeed to go faster or slower.
Didn't test the code but it should work.
Sometimes you don't want to use physics in your game cause it uses a lot of calculating power, also there are a lot of other use cases that the developer does not need to use physics to move the object or the collision with other objects is not important.
So in my game, there's a gun that sprays bullets, and I'm trying to make a gameObject destroy on collision with the bullets. The bullets are based off of one gameObject (Capsule). I've tried these two scripts so far:
using UnityEngine;
using System.Collections;
public class whenshot : MonoBehaviour {
void OnCollisionEnter(Collision col)
{
if (col.gameObject.name == "Bullet")
{
Destroy(col.gameObject);
}
}
}
and:
using UnityEngine;
using System.Collections;
public class whenshot : MonoBehaviour {
void OnCollisionEnter(Collision col)
{
if (col.gameObject.name == "Bullet")
{
Destroy(this); //the difference between the two is that I changed "col.gameObject" to "this"
}
}
}
I'm shooting the object but it's not disappearing/destroying itself. How can I fix this?
Here's a visual if it helps:
this refers to the object instance of the caller (this is basic OOP), i.e., whenshot, and not gameObject. So the second sample is effectively Destroying the instance of the script from the gameObject it is attached to.
The first script is technically fine, and should work, provided these conditions are met:
Either the projectile (bullet) or the target (or both) have a non-kinematic rigidbody component attached. (Unity docs.)
Both have 3D Collider components.
The name of every single bullet gameObject that collides with the target is exactly "Bullet".
All projectile objects have this script as a component.
Some suggestions
Use prefabs and tags: take your bullet primitive and store it as a prefab. Add a tag to the prefab called "Bullet". Do the same for the target and tag it as "Target". Tag the player as "Player". In the "gunController", set a reference to the bullet prefab and make it Instantiate bullets on whatever trigger you're using. In the bullet's script, use CompareTag("Target") instead of == and Destroy both the target gameObject and this.gameObject.
It seems to me that the above is the behaviour you want. If that is the case, there is no delay between collision and destruction, and hence no need to simulate physics whatsoever. Unless you have some other physics interactions with bullets/targets, mark the one without a rigidbody as a Trigger.
A Strong Suggestion
Go through Unity tutorials.
This is an example from a 2D Game I made a while back, but i think it might help.
void OnTriggerEnter2D(Collider2D other)
{
if (other.tag == "Destroyable")
{
Destroy(other.gameObject);
}
}
I used this to destroy certain blocks when the player would shoot them so many times, just switch them to the 3D Collider and Trigger, but it should do the trick for ya (i hope ^^).
edit: this script should be attached to your bullet prefab
Ok so I figured it out, it's kind of weird but apparently I was making the bullets move too fast... I had to slow down the "Bullet_Forward_Force" float to about 150f to make it work. Thanks to everyone who answered though.
I can't comment so I will make an answer:
You can make the bullet go fast, just set the collision detection to continious dynamic.
It has an almost %100 success rate.
I am trying to make a game where you drag different types of spheres and put them together to form a figure (without any gravity). For dragging the objects I use this script:
using UnityEngine;
using System.Collections;
public class Test : MonoBehaviour {
void OnMouseDrag()
{
float distance_to_screen = Camera.main.WorldToScreenPoint(gameObject.transform.position).z;
transform.position = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, distance_to_screen ));
}
}
When I drag two spheres to eachother they go trough eachother. I added a rigibody to the objects, tried a LOT of different things with it, but nothing seemed to work. They always seem to bounce off eachother OR they just don't collide at all. Any sollution to this? Imagine this like a person running in to a wall. The person doesn't bounce off the wall, he just stops moving.
The reason why you're getting some strange behaviour (objects clipping through/ignoring each other) is that you're setting transform.position directly, rather than manipulating the Rigidbody component of the object. Use Rigidbody.MovePosition() to also take into account physics when positioning an object.
Now, seeing objects bounce off each other is not an abnormal physics behaviour - this is because when objects clip into each other (as they will often do with your code), they exert a repulsing force on each other (a bit like Newton's third law). If you want to freeze them as soon as they collide, try setting Rigidbody.isKinematic = true in the OnCollisionEnter() event.
Bringing this all together, your class might look like:
public class Test : MonoBehaviour {
Rigidbody rb;
void Start()
{
// Store reference to attached Rigidbody
rb = GetComponent<Rigidbody>();
}
void OnMouseDrag()
{
float distance_to_screen = Camera.main.WorldToScreenPoint(gameObject.transform.position).z;
// Move by Rigidbody rather than transform directly
rb.MovePosition(Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, distance_to_screen )));
}
void OnCollisionEnter(Collision col)
{
// Freeze on collision
rb.isKinematic = true;
}
}
Hope this helps! Let me know if you have any questions.
When directly giving the position variable coordinates in a non-incremental way, the object is "phasing" into existence at the next location fooling the collision system.
You have to code it by having some sort of other system move the object in incremental ways:
Instead of moving the object directly like this:
position =
position = lerp(oldPosition,new position,Time.deltaTime)