Develop Reference

Is There a Way to Flip a Sprite in Unity?

I'm working on a 2D Unity project where it's a platformer but you controller the character with gravity. For the game, I need to make it so that when you turn the gravity say, up, it should flip the sprite upside down. This is my code so far in the C# script I have that is attached to the character game object.
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class GravityController2d : MonoBehaviour
{
enum GravityDirection { Down, Left, Up, Right };
public Animator animator;
public GameObject Game_object;
private Vector3 chestPos = new Vector3(6.69f, 1.45f, 0.0f);
void Start()
{
Physics2D.gravity = new Vector2(0f, -9.8f);
}
void FixedUpdate()
{
if (Input.GetKeyDown(KeyCode.DownArrow))
{
Physics2D.gravity = new Vector2(0f, -9.8f);
//flip
}
if (Input.GetKeyDown(KeyCode.LeftArrow))
{
Physics2D.gravity = new Vector2(-9.8f, 0f);
//flip
}
if (Input.GetKeyDown(KeyCode.UpArrow))
{
Physics2D.gravity = new Vector2(0f, 9.8f);
//flip
}
if (Input.GetKeyDown(KeyCode.RightArrow))
{
Physics2D.gravity = new Vector2(9.8f, 0f);
//flip
}
}
}
Edit: The tag I used was Unity2D but it auto corrected it to unity3d so thats my excuse for that.
Also: It needs to also be able to flip 90 degrees in case the player switches the gravity to go to the left/right

Assuming you are referring to a SpriteRenderer you can use SpriteRenderer.flipX and SpriteRenderer.flipY and check in which direction your gravity goes like e.g.
// Link in the Inspector
[SerializeField] SpriteRenderer spriteRenderer;
and then
private void UpdateSpriteFlip()
{
// The conditions according to your needs of course
spriteRenderer.flipX = Physics2D.gravity.x < 0;
spriteRenderer.flipY = Physics2D.gravity.y > 0;
}

Ball Breaker Game - Ball is getting stuck to paddle after certain bounces - Unity

I have created a block breaker game using Unity. Everything works fine except sometimes, the ball gets stuck to the paddle and then gets released after bit of time, causing it's speed to decrease. Please help as I am on the verge of completing my project :)
Here is the code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Ball : MonoBehaviour
{
private Paddle paddle;
private Vector3 paddleToBallVector;
private bool hasStarted = false;
// Start is called before the first frame update
void Start()
{
paddle = GameObject.FindObjectOfType<Paddle>();
paddleToBallVector = this.transform.position - paddle.transform.position;
}
// Update is called once per frame
void Update()
{
if (!hasStarted)
{
//Lock the ball relative to paddle..
this.transform.position = paddle.transform.position + paddleToBallVector;
if (Input.GetMouseButtonDown(0))
{
print("Mouse Clicked, Ball Launched!!");
hasStarted = true;
this.GetComponent<Rigidbody2D>().velocity = new Vector2(2f, 10f);
}
}
}
void OnCollisionEnter2D(Collision2D c)
{
Vector2 tweak = new Vector2(Random.Range(0f,0.2f),Random.Range(0,0.2f));
if (hasStarted)
{
// GetComponent<AudioSource>().Play();
Rigidbody2D rigidbody = gameObject.GetComponent<Rigidbody2D>();
rigidbody.velocity += tweak;
}
}
}

How do I change a GameObject's rotation equal to my player camera's rotation?

Im working on a first person shooter. I have an aim function, which puts the pistol right in front of the camera, to make it look like your holding it in front of you. Im trying to make it so the pistol will also rotate with the camera on the Z axis, so that way the pistol wont stay still, because that looks odd and gets in the way. To do this, I tried this:
GPR.gun.transform.rotation = Quaternion.Euler(0, 0, plrCam.transform.rotation.z);, however this ends up rotating the gun very slightly around the z axis, and mainly rotating it around the y axis whenever I move my camera. I am a beginner programmer in Unity so please try to make answers more digestible to beginners so I can understand it. Here is my full script:
using System.Collections.Generic;
using UnityEngine;
public class PistolFire : MonoBehaviour
{
//Gun Properties
public float range = 50f;
public float damage = 10f;
//Sensitivity decrease for looking down the sights
public float downSights = 5f;
//Other vars
private playerGunControls playerGun;
private GameObject plrCam;
private Camera fpsCam;
private ParticleSystem muzzleFlash;
private GameObject impactEffect;
private bool aimed = false;
private GameObject aimPos;
private GunPickupRaycast GPR;
private GameObject handPos;
private GameObject Player;
// Start is called before the first frame update
void Start()
{
//Getting objects because gun is instantiated, so this is necessary
plrCam = GameObject.Find("Player Camera");
playerGun = plrCam.GetComponent<playerGunControls>();
fpsCam = plrCam.GetComponent<Camera>();
muzzleFlash = GetComponentInChildren<ParticleSystem>();
impactEffect = GameObject.Find("Impact Effect");
aimPos = GameObject.Find("aimPos");
GPR = plrCam.GetComponent<GunPickupRaycast>();
handPos = GameObject.Find("Hand Pos");
Player = GameObject.Find("Player");
}
// Update is called once per frame
void Update()
{
//Check for shoot button down
if (Input.GetButtonDown("Fire1"))
{
if (playerGun.holding == "Pistol")
{
Shoot();
}
}
//Check if aim button down
if (Input.GetButton("Fire2"))
{
if (playerGun.holding == "Pistol")
{
Aim();
}
}
//Check if no longer aiming to reset to normal
if (aimed == true && !(Input.GetButton("Fire2")))
{
Unaim();
}
}
void Shoot()
{
muzzleFlash.Play();
RaycastHit hit;
if(Physics.Raycast(plrCam.transform.position, plrCam.transform.forward, out hit, range))
{
Debug.Log(hit.transform.name);
Health health = hit.transform.GetComponent<Health>();
if (health != null)
{
health.TakeDamage(damage);
}
//Instantiate the Impact Effect
GameObject IE = Instantiate(impactEffect, hit.point, Quaternion.identity);
Destroy(IE, 1.5f);
}
}
void Aim()
{
aimed = true;
Debug.Log("Aiming");
GPR.gun.transform.position = aimPos.transform.position;
GPR.gun.transform.rotation = Quaternion.Euler(0, 0, plrCam.transform.rotation.z);
}
void Unaim()
{
GPR.gun.transform.position = handPos.transform.position;
Debug.Log("No longer aiming");
aimed = false;
}
}

I fixed my problem by making the gun a child of my camera instead of a child of my player.

Collider does not always detect OnTriggerEnter

I stumbled across a problem while working with the book "Unity in Action". At the end of chapter 3 you'd end up with the basics for a simple fps game. It's basically a player (camera attached to it) in a simple and small level which only exists out of a number of cubes forming walls and the floor etc. These cubes all have box collider on them. Now the player is also able to shoot at moving enemies which are also able to shoot. This was done by Raycast/RaycastHit. All this worked perfectly so I wanted to add something that reassembles bullet holes, simply by instantiating a black sphere object on the wall where the fireball (this is the object the enemy and the player shoot) hits it. This works BUT sometimes the fireball object just goes through the wall. In case there is another wall behind it, the fireball object gets destroyed by this second wall and the desired sphere is created on the second wall instead of on the first wall.
I changed the speed in the fireball from 20 to 10 and then back to 20 and at a speed of 10, the success rate is around 19/20, while at a speed of 20 it's around 6/10.
Here is the code of the fireball which is supposed to check whether it hits the player (then health is deducted, that works fine) or hits the enemy (then the enemy falls over, also works fine) or hits the wall in which case the sphere should be created.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Fireball : MonoBehaviour {
public float speed = 10.0f;
public int damage = 1;
[SerializeField] private GameObject wallHit;
private GameObject _wallHit;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
transform.Translate(0,0, speed * Time.deltaTime);
}
void OnTriggerEnter(Collider other){
RaycastHit hit;
PlayerCharacter player = other.GetComponent<PlayerCharacter>();
ReactiveTarget target = other.GetComponent<ReactiveTarget>();
WallBehavior wall = other.GetComponent<WallBehavior>();
if(player != null){
player.Hurt(damage);
}
if(target != null){
target.ReactToHit();
}
if(wall != null){
if(Physics.Raycast(transform.position, transform.forward, out hit)){
wall.WallWasHit(hit);
}
}
Destroy(this.gameObject);
}
}
As you can see one thing I tried was to give each wall a WallBehavior script, which looks like this:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class WallBehavior : MonoBehaviour {
[SerializeField] private GameObject wallHit;
private GameObject _wallHit;
static int count = 0;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
}
public void WallWasHit(RaycastHit hit){
count++;
Debug.Log("Wall was hit: " + count);
_wallHit = Instantiate(wallHit) as GameObject;
_wallHit.transform.position = hit.point;
}
}
But none of my attempts to understand why this happens so infrequently was successful so far and I hope someone can help me with this because I feel like might be crucial for my learning before I continue with the book! Thanks in advance. if further information are needed, I am happy to provide them. See the following picture for a better visualization of the issue.
EDIT:
As mentioned in the answers, I replaced the fireball script accordingly but I am not sure how to change the following script likewise. This script is on my camera which is on my player object. In the Update function the Fireball is instantiated and also given a movement, so I guess this causes the problems?
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class RayShooter : MonoBehaviour {
private Camera _camera;
[SerializeField] private GameObject fireballPrefab;
private GameObject _fireball;
void Start () {
_camera = GetComponent<Camera>();
Cursor.lockState = CursorLockMode.Locked;
Cursor.visible = false;
}
void OnGUI(){
int size = 12;
float posX = _camera.pixelWidth/2 - size/4;
float posY = _camera.pixelHeight/2 - size/2;
GUI.Label(new Rect(posX, posY, size, size), "X");
}
// Update is called once per frame
void Update () {
if(Input.GetMouseButtonDown(0)){
Vector3 point = new Vector3(_camera.pixelWidth/2, _camera.pixelHeight/2, 0);
_fireball = Instantiate(fireballPrefab) as GameObject;
_fireball.transform.position = transform.TransformPoint(Vector3.forward * 1.5f);
_fireball.transform.rotation = transform.rotation;
Ray ray2 = _camera.ScreenPointToRay(point);
RaycastHit hit;
if(Physics.Raycast(ray2, out hit)){
GameObject hitObject = hit.transform.gameObject;
ReactiveTarget target = hitObject.GetComponent<ReactiveTarget>();
if(target !=null){
target.ReactToHit();
}
}
}
}
}

This is not how to move a Rigidbody Object and moving it like this could cause so many issues including the one mentioned in your question. Objects with Rigidbody should be moved with the Rigidbody component and with the functions like Rigidbody.MovePosition, Rigidbody.AddForce and Rigidbody.velocity not by the transform or transform.Translate.
Also, you should move the Rigidbody Object in the FixedUpdate function instead of the Update function. If you are moving your other Rigidbody Objects by their transform then you must fix them too. The example below replaces transform.Translate with Rigidbody.MovePosition in the Fireball script:
public float speed = 10.0f;
public int damage = 1;
[SerializeField]
private GameObject wallHit;
private GameObject _wallHit;
public Rigidbody rb;
// Use this for initialization
void Start()
{
rb = GetComponent<Rigidbody>();
}
// Update is called once per frame
void FixedUpdate()
{
//Move to towards Z-axis
Vector3 pos = new Vector3(0, 0, 1);
pos = pos.normalized * speed * Time.deltaTime;
rb.MovePosition(rb.transform.position + pos);
}
void OnTriggerEnter(Collider other)
{
RaycastHit hit;
PlayerCharacter player = other.GetComponent<PlayerCharacter>();
ReactiveTarget target = other.GetComponent<ReactiveTarget>();
WallBehavior wall = other.GetComponent<WallBehavior>();
if (player != null)
{
player.Hurt(damage);
}
if (target != null)
{
target.ReactToHit();
}
if (wall != null)
{
if (Physics.Raycast(transform.position, transform.forward, out hit))
{
wall.WallWasHit(hit);
}
}
Destroy(this.gameObject);
}
If you still run into issues, use Rigidbody.velocity instead:
void FixedUpdate()
{
Vector3 pos = Vector3.zero;
pos.z = speed * Time.deltaTime;
rb.velocity = pos;
}
Sometimes, depending on the size of the object and the speed it is moving by, you many need to set its Rigidbody Interpolate from None to Interpolate and Collision Detection to Continuous.
Don't forget to remove the code in the Update function.
EDIT:
I looked at your project and found new problems:
1.You enabled IsTrigger on your "Fireball" GameObject. Please uncheck the IsTrigger on the collider.
2.You just want to shoot a bullet. The force should be added once only not every FixedUpdate. Add the force in the Start function instead of the FixedUpdate function. Use Rigidbody.velocity instead of Rigidbody.MovePosition.
Remove the FixedUpdate function and the code inside it.
This should be your new Start function:
void Start()
{
rb = GetComponent<Rigidbody>();
Vector3 pos = transform.forward * speed * Time.deltaTime;
rb.velocity = pos;
}

Mouse clicks aren't recognized when I build Unity game

EDIT : Apparently when I select Windowed, the buttons work. Why is this? Why doesn't it work without that box selected?
I created a game in Unity and everything works fine in Unity itself. When I build and run the game, my buttons no longer recognize my mouse clicks. Why is this?
This is a basic pong game. I don't know why it would work in Unity and not outside of Unity if it was the code but here is the code.
Code :
paddle script:
using UnityEngine;
using System.Collections;
public class paddle : MonoBehaviour {
public float paddleSpeed = 1;
public Vector3 playerPos = new Vector3(0,0,0);
// Update is called once per frame
void Update () {
float yPos = gameObject.transform.position.y + (Input.GetAxis ("Vertical") * paddleSpeed);
playerPos = new Vector3 (-20,Mathf.Clamp(yPos, -13F,13F),0);
gameObject.transform.position = playerPos;
}
}
ball script:
using UnityEngine;
using System.Collections;
public class Ball : MonoBehaviour {
public float ballVelocity = 1500;
private Rigidbody rb;
private bool isPlay; //false by default
int randInt; //random ball directon when game begins
// Use this for initialization
void Awake () {
rb = gameObject.GetComponent<Rigidbody> ();
randInt = Random.Range (1,3);
}
// Update is called once per frame
void Update () {
if(Input.GetMouseButton(0) == true && isPlay == false){
transform.parent = null;
isPlay = true;
rb.isKinematic = false;
if(randInt == 1){
rb.AddForce(new Vector3(ballVelocity,ballVelocity,0));
}
if(randInt == 2){
rb.AddForce(new Vector3(-ballVelocity,-ballVelocity,0));
}
}
}
}
enemy script:
using UnityEngine;
using System.Collections;
public class Enemy : MonoBehaviour {
public float speed = 8;
private Vector3 targetPos;
private Vector3 playerPos;
private GameObject ballObj;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
ballObj = GameObject.FindGameObjectWithTag ("ball");
if (ballObj != null) {
targetPos = Vector3.Lerp (gameObject.transform.position, ballObj.transform.position, Time.deltaTime * speed);
playerPos = new Vector3 (-20, Mathf.Clamp (targetPos.y, -13F, 13F), 0);
gameObject.transform.position = new Vector3 (20, playerPos.y, 0);
}
}
}
score script:
using UnityEngine;
using System.Collections;
public class Score : MonoBehaviour {
public TextMesh currScore;
public GameObject ballPref;
public Transform paddleObj;
GameObject ball;
private int score;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
ball = GameObject.FindGameObjectWithTag("ball");
currScore.text = "" + score;
}
void OnTriggerEnter(Collider other) {
if(other.tag == "ball"){
score += 1;
Destroy(ball);
(Instantiate(ballPref, new Vector3(paddleObj.transform.position.x + 1, paddleObj.transform.position.y,0), Quaternion.identity) as GameObject).transform.parent = paddleObj;
}
}
}
title screen script:
#pragma strict
function Start () {
}
function Update () {
}
function StartGame () {
Application.LoadLevel("Main");
}
function ExitGame () {
Application.Quit();
}

From what I am understanding, you want Unity to recognize your mouse button event even when the mouse pointer is not inside the game Window.
There could be 2 ways to achieve this:
1. The easy way, make your game full screen.
2. If you want your game in a window box, you must check "Run In Background" option in Player settings -> Resolution. And then, learn how to hook mouse event: http://www.codeproject.com/Articles/7294/Processing-Global-Mouse-and-Keyboard-Hooks-in-C
Please note that the hooking mouse event tutorial only works on Windows, not Mac nor Linux. I do not know how to do it with Mac or Linux.