Spawning Bullets - c#

So i am really, really new to Unity and C# and i just want to try a few things like a shooting script. The way i want it to work is that i have a game object, in my case it's called "Glock" and as a child of that game object i have an empty called "bulletSpawn". I now want to assign a script to "bulletSpawn" that spawns in an predefined object whenever i hit the left mouse button.
What i tried:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class spawnBullet : MonoBehaviour
{
public GameObject bullet;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
if (Input.GetButtonDown("Fire1"))
{
GameObject newBullet = Instantiate(bullet, new Vector3(0, 0, 0), Quaternion.identity);
}
}
}
And it kinda works. Whatever, it clones everything in an exponential way, so when i hit the left mouse button it spawns in the object but it also spawns in an object called "Glock(Clone)" and if i hit it again, it spawns: "Glock(Clone)","Glock(Clone)(Clone)","bullet(Clone)" and "bullet(Clone)(Clone)". And that doubles each time i click. My second problem is, that it spawns every object at the global coordinates [0,0,0] and not the local ones of the empty.

As Helmi say are you using a bullet prefab and not the Glock prefab?
This code under should fix your position problem.
if (Input.GetButtonDown("Fire1"))
{
GameObject newBullet = Instantiate(bullet, transform.position, Quaternion.identity);
}

Related

Referencing Instantiated objects after their creation in Unity

Hi!
After the discussion with Ruzihm in the comments. I've now created a simple version of my game to better ask the question I'm having.
The question now is, since I'm not able to manually create a connection to the testObject field in the inspector. How do I now tell Unity to use my instantiated objects while the game is running?
And is this a good solution for a RTS game that may have 100s of Units active at a time? The end goal here is to apply this force to a radius around the cursor. Which I was thinking of using Physics.OverlapSphere
Here's the minimal scenario of what I have:
New Unity scene
Attached the InputManager to the main camera.
Created a capsule and a plane.
Added ApplyForce to the Capsule
Created a prefab from the capsule and deleted it from the scene.
In the InputManager I added the ability to press space to Instantiate a capsule with the ApplyForce script attached..
Drag the capsule prefab to the InputManager "objectToGenerate"
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace GL.RTS.Mites
{
public class InputManager : MonoBehaviour
{
public GameObject testObject;
public ApplyForce onSpawnTest;
public GameObject objectToGenerate;
void Start()
{
onSpawnTest = testObject.GetComponent<ApplyForce>();
}
void Update()
{
if(Input.GetKeyDown(KeyCode.Space))
{
Instantiate(objectToGenerate);
}
if (Input.GetMouseButton(0))
{
onSpawnTest.PushForward();
}
}
}
}
The ApplyForce script that I attach to the Capsule:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace GL.RTS.Mites
{
public class ApplyForce : MonoBehaviour
{
public float moveSpeed;
Rigidbody rb;
void Start()
{
rb = GetComponent<Rigidbody>();
Debug.Log("A Mite has spawned!");
}
public void PushForward()
{
rb.AddRelativeForce(Vector3.up * moveSpeed * Time.deltaTime);
Debug.Log("A force of: " + moveSpeed + " is being added.");
}
}
}
Well, you are creating your new instances of your object, but your input manager immediately forgets about them (note that you do nothing with the return value). The InputManager only knows about the ApplyForce that was created in its Start (and then interacts with it depending on mouse input) and your ApplyForce script knows nothing about any InputManager. So, it should come as no surprise that only the first instance reacts to the mouse input.
So, something has to be done to your InputManager and/or your ApplyForce. Your InputManager could remember the instances it creates (which isn't enough, because what if for example, a map trigger creates new player controllable units) or it could go looking for units each time.
Your ApplyForce could register with the InputManager when they are created, but then you would need to loop through the units and find out which ones are under the mouse, anyway.
Since you only want to select ones based on what is near or under your cursor and only when input occurs and not like every frame, I would go with the simplest approach, just letting your InputManager find the units when it needs them. Something like below, explanation in comments:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace GL.RTS.Mites
{
public class InputManager : MonoBehaviour
{
public GameObject testObject;
public ApplyForce onSpawnTest;
public GameObject objectToGenerate;
private Camera mainCam;
// which layers to consider for cursor detection
[SerializeField] LayerMask cursorLayerMask;
// how big for cursor detection
[SerializeField] float cursorRadius;
void Awake()
{
// cache main camera
mainCam = Camera.main;
}
void Update()
{
if(Input.GetKeyDown(KeyCode.Space))
{
Instantiate(objectToGenerate);
}
if (Input.GetMouseButton(0))
{
Collider[] colls = FindCollidersUnderCursor();
// check each collider for an applyforce and use it if present
foreach( Collider coll in colls)
{
ApplyForce af = coll.GetComponent<ApplyForce>();
if (af != null)
{
af.PushForward();
}
}
}
}
Collider[] FindCollidersUnderCursor()
{
// find ray represented by cursor position on screen
// and find where it intersects with ground
// This technique is great for if your camera can change
// angle or distance from the playing field.
// It uses mathematical rays and plane, no physics
// calculations needed for this step. Very performant.
Ray cursorRay = mainCam.ScreenPointToRay(Input.mousePosition);
Plane groundPlane = new Plane(Vector3.up, Vector3.zero);
if (groundPlane.Raycast(cursorRay, out float cursorDist))
{
Vector3 worldPos = cursorRay.GetPoint(cursorDist);
// Check for triggers inside sphere that match layer mask
return Physics.OverlapSphere(worldPos, cursorRadius,
cursorLayerMask.value, QueryTriggerInteraction.Collide);
}
// if doesn't intersect with ground, return nothing
return new Collider[0];
}
}
}
Of course, this will require that every unit you're interested in manipulating has a trigger collider.

How to spawn objects in Unity?

I am trying to build a flappy bird like game and I am trying to spawn enemy birds and gold coins so I have written the C# code and the made the prefabs, but when I run the bird and the coins are not respawning.
This is the respawn code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SpawnPlayer : MonoBehaviour
{
public GameObject GameObjectToSpawn;
private GameObject Clone;
public float timeToSpawn = 4f;
public float FirstSpawn = 10f;
// Update is called once per frame
void Update()
{
FirstSpawn -= Time.deltaTime;
if (FirstSpawn <= 0f)
{
Clone = Instantiate(GameObjectToSpawn, gameObject.transform.localPosition, Quaternion.identity) as GameObject;
FirstSpawn = timeToSpawn;
}
}
}
screenshot of unity:
This where i am respawning the first enemy bird:
From your second screenshot it seems to be spawned but way off the screen! You can still see the tiny little island in the bottom left corner.
You thought seems to be that you have to spawn it in the Canvas pixel space using the spawn point's localPosition. But this is not the case since Instantiate places it into the scene root (without any parent) with absolute world-space position into the scene.
You should rather actually place the spawn point to the absolute world position where the spawn should happen and rather use
Clone = Instantiate(GameObjectToSpawn, transform.position, Quaternion.identity);
Btw no need for the as GameObject since Instantiate already returns the type of the given prefab.

Untiy Health System

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class MoveProjectile : MonoBehaviour
{
public Rigidbody2D projectile;
public float moveSpeed = 10.0f;
// Start is called before the first frame update
void Start()
{
projectile = this.gameObject.GetComponent<Rigidbody2D>();
}
// Update is called once per frame
void Update()
{
projectile.velocity = new Vector2(0,1) * moveSpeed;
}
void OnCollisionEnter2D(Collision2D col){
if(col.gameObject.name == "Enemy"){
gameObject.name == "EnemyHeart5".SetActive(false);
}
if(col.gameObject.name == "Top"){
DestroyObject (this.gameObject);
}
}
}
This is the code to my player projectile. On collision i tried to reference it to a game object i have called playerheart and it doesnt seem to work out the way i wanted it to.
Im trying to make a health system where if my bullet collides with the enemy game object the health would decrease by one. Im pretty new to Unity and im confused on how to target the hearts when the bullets collide.
I'm assuming "EnemyHeart5" is a GameObject inside Enemy as child gameobject. Correct?
Issue here is when the collision takes place, it recognize "Enemy" gameobject and won't have access to "EnemyHeart5" for disabling it. I'd suggest you to add simple EnemyManager script into your enemy which manages your enemy health and health related gameobject (ie. EnemyHearts which you are displaying). When collision takes place, access that EnemyManager component and change health value.
void OnCollisionEnter2D(Collision2D col){
if(col.gameObject.tag == "Enemy"){
col.gameObject.GetComponent<EnemyManager>().health =-1;
}
Now, in the update method of EnemyManager you check the health value and disable EnemyHealth5 component.
Also, use "tag" in collision instead of "name". name will create issues when you have multiple enemies in the game. Make sure you add tag in enemy gameobject if you are using it.
Hope this helps, let me know how it goes.

Unity c# - unable to Spawn Prefabs on a NavMesh

I am trying to make a zombie wave game and current have a Prefab for my enemies. If I have the prefab be in the scene when I hit run, they are attached to the NavMesh and track the player perfectly. I want to achieve this but with the enemy being spawned from an empty GameObject so I can get the waves spawning in. I have achieved them Spawning but they have the error,
"SetDestination" can only be called on an active agent that has been placed on a NavMesh.
UnityEngine.AI.NavMeshAgent:SetDestination(Vector3)
EnemyAI:Update() (at Assets/Scripts/EnemyAI.cs:25)
Here is my EnemyAI Script
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;
public class EnemyAI : MonoBehaviour
{
public float lookRadius = 10f;
Transform target;
NavMeshAgent agent;
public GameObject Player;
void Start()
{
agent = GetComponent<NavMeshAgent>();
}
// Update is called once per frame
void Update()
{
float distance = Vector3.Distance(Player.transform.position, transform.position);
if (distance <= lookRadius)
{
agent.SetDestination(Player.transform.position);
}
}
}
And my spawning script, which is attached to an empty game object,
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Spawning : MonoBehaviour
{
public GameObject prefab;
public int CountofCubes;
private IEnumerator coroutine;
public float spawnRate;
IEnumerator Start()
{
while (true)
{
for (int i = 0; i < CountofCubes; i++)
{
Instantiate(prefab, new Vector3(Random.Range(-25.0f, 25.0f), 0.5f, Random.Range(-25.0f, 25.0f)), Quaternion.identity);
}
yield return new WaitForSeconds(spawnRate);
}
}
}
Any help would be great thanks!
I had the same issue and I don't have an explanation but only a workaround:
In the Start fucntion, I added:
navAgent = GetComponent<NavMeshAgent>();
navAgent.enabled = false;
// Invoke is used as a workaround for enabling NavMeshAgent on NavMeshSurface
Invoke("EnableNavMeshAgent", 0.025f);
And the EnableNavMeshAgent function is just :
private void EnableNavMeshAgent ()
{
navAgent.enabled = true;
}
If I set the invoke delay to a value less than 0.025 second the error keep going but for 0.025 I only have it twice and the behaviour is the one I wanted after that.
Some reasons this might happen:
The agent is not on level with any navmesh i.e. can be too far above or below. You want it to be "close to the NavMesh surface". Use raycasting on the floor to position the agent or add a rigidbody and drop it from above the floor. After you do this you might need to disable and enable the agent.
Moving the transform yourself rather than using Wrap function. There's property where you can check if the simulated and actual position are in sync.
Corrupted navmesh so you might need to re-bake it.
It is essentially trying to tell you your agent is not on the mesh so it cannot find a path. Try playing with where you're placing the agent.
I kind of remember running into a similar problem a while back and problem was I forgot to bake the NavMesh in Window > AI > Navigation. Just in case.

Why cant I move my camera in (Unity)C#?

camera transform
I am trying to move my camera based on the players' movements on Y axis in Unity.
However, it does not work...
What did I do wrong? I have attached image of my script (C#) here.
and, Yes, I did attach this script with Main Camera.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CameraController : MonoBehaviour {
GameObject player;
// Use this for initialization
void Start () {
this.player = GameObject.Find("cat");
}
// Update is called once per frame
void Update () {
Vector3 playerPos = this.player.transform.position;
transform.position = new Vector3(
transform.position.x, playerPos.y, transform.position.z);
}
}
Make the player GameObject public and just drag and drop your player in the inspector in unity see if that works? Are you getting any exceptions? Also add Debug.Log (player.transform.position.ToString ()) to see if it is showing the right values. Are you sure you player object name is cat and not Cat, it is case sensitive. Check on those things and let me know if you figured it out!

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