Unity 2d game movement script issue - unable to jump - c#

So basically, after hours of torment trying to create basic movement script for simple platformer game I succeeded, but not quite. Square character is able to move around and jump just ok, but sometimes it won't jump, usually while moving on short distances or, rarely, standing in place and trying to jump. I can't figure out how to fix that. Here is entire script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerMovement : MonoBehaviour {
private Rigidbody2D rgdb2;
public float movementSpeed;
public float jumpHeight;
private bool isJumping = false;
// Use this for initialization
void Start ()
{
rgdb2 = GetComponent<Rigidbody2D>();
}
// Update is called once per frame
void FixedUpdate ()
{
float moveHorizontal = Input.GetAxis("Horizontal");
HandleMovement(moveHorizontal);
if (Input.GetKeyDown(KeyCode.Space) && isJumping == false)//by typing Space player jumps, cant double-jump
{
rgdb2.AddForce(new Vector2(rgdb2.velocity.x, 1 * jumpHeight), ForceMode2D.Impulse);
isJumping = true;
Debug.Log("jumped");
}
}
private void HandleMovement(float moveHorizontal)//applying player horizontal controls and customing player's speed by movementSpeed variable
{
rgdb2.velocity = new Vector2(moveHorizontal * movementSpeed, rgdb2.velocity.y);
}
private void OnCollisionEnter2D(Collision2D coll)
{
if (coll.transform.tag == "Platform") //if player is touching object with Platform tag, he can jump
{
Debug.Log("on ground bitch");
isJumping = false;
}
}
}
It may not be that important, but I want to polish this game as much as possilble, even if I don't need to, since it's basically my first game made in Unity3d with C#.

An important thing to keep in mind: Unity3D Engine's inputs are only updated during the time the engine calls Update() methods for your GameObjects.
What this means is that you should not read any type of input in the FixedUpdate() method. Methods like GetKeyDown() and other methods from the Input class which read keyboard/mouse/axis buttons/values should not be called during FixedUpdate(), as their returned values are unreliable.
Due to this, what is probably causing your jump implementation to fail is that the GetKeyDown() method you're calling in FixedUpdate() is returning inconsistent/invalid (false) results, when the user presses the jump key.
Fixing this can be quite simple. I suggest you keeping a boolean variable which keeps track of whether the jump key has been pressed, and gets its value updated during Update(). This should fix your problem.
bool jumpKeyPressed;
private void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
jumpKeyPressed = true;
else if (Input.GetKeyUp(KeyCode.Space))
jumpKeyPressed = false;
}
private void FixedUpdate()
{
/* Update "moveHorizontal", call HandleMovement(...) here, as you've already done. */
if (jumpKeyPressed && isJumping == false)
{
// IMPORTANT: this prevents the "jump force" from being applied multiple times, while the user holds the Space key
jumpKeyPressed = false;
/* Remaining jumping logic goes here (AddForce, set "isJumping", etc) */
}
}

It's because your logic for jumping is inside FixedUpdate()
When you use GetKeyDown to register input make sure to use Update instead because if you press the key using FixedUpdate it may or may not run during that frame, test it with Update instead.
You already have in comments how Update works, it is called every frame but FixedUpdate according to Unity documentation: This function is called every fixed framerate frame
void Update ()
{
float moveHorizontal = Input.GetAxis("Horizontal");
HandleMovement(moveHorizontal);
if (Input.GetKeyDown(KeyCode.Space) && isJumping == false)//by typing Space player jumps, cant double-jump
{
rgdb2.AddForce(new Vector2(rgdb2.velocity.x, 1 * jumpHeight), ForceMode2D.Impulse);
isJumping = true;
Debug.Log("jumped");
}
}

Related

OnCollisionStay not working in 2D movement script

So, I'm still not the best at this but I'm trying to use this script for 2D movement but the jumping isn't working for some reason. It keeps saying that the OnCollisionEnter function "is declared but never used". Can someone tell me what im doing wrong? Thanks
If I remove the (Collision col) part it says that "void cannot be used in this context".
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class RonyWalking : MonoBehaviour
{
Rigidbody2D rigid;
SpriteRenderer sprite;
public bool isJumping;
public float spd = 2.0f;
// Start is called before the first frame update
void Start()
{
rigid = GetComponent<Rigidbody2D>();
sprite = GetComponent<SpriteRenderer>();
}
// Update is called once per frame
void Update()
{
if(Input.GetKey("d")){rigid.velocity = new Vector2(spd, 0);}
else if(Input.GetKey("a")){rigid.velocity = new Vector2(-spd, 0);}
if(Input.GetKeyDown("w") && isJumping == false)
{
rigid.velocity = new Vector2(0, 5);
isJumping = true;
}
void OnCollisionStay(Collision col)
{
isJumping = false;
}
}
}
When using 2D physics, you need to use the 2D lifecycle methods;
void OnCollisionStay2D(Collision2D col)
{
isJumping = false;
}
And you shouldn't put this method inside your Update method... It should be on class level:
public class RonyWalking
{
void Update()
{
// ...
}
void OnCollisionStay2D(Collision2D col)
{
// ...
}
}
Don't worry about "Is declared but never used", this may be because you don't have specific code referencing the method, but Unity will raise events that calls it, "automagically"
Another thing that I can see while reading your code, that may be unintentional behaviour for you, is that when clicking left/right, you set velocity UP to 0, and when clicking up you set LEFT/RIGHT velocity to 0; this will result in freezing the movement mid-air if you jump, then move while in air:
Click D; velocity = 2, 0
Click W; velocity = 0, 5
Character will now move upwards until another input is given
Click D; velocity = 2, 0 and the character will continue moving while in air because when moving sideways the up/down velocity is set to 0
To solve this, either set the other to existing velocity or make the inputs manipulate a Vector that you then apply at the end of the movement code:
Vector2 existingMovement = rigid.velocity;
if (Input.GetKey(KeyCode.D))
existningMovement.x = spd;
else if (Input.GetKey(KeyCode.A))
existningMovement.x = -spd;
if (Input.GeyKeyDown(KeyCode.W) && !isJumping)
{
existningMovement.y = 5f;
isJumping = true;
}
Furthermore, I think you may have some unexpected behaviour with OnCollisionStay; it will fire every frame that you're colliding with the ground, I assume. But I think it may also fire a frame or two AFTER you've jumped since the physics of your character will not INSTANTLY leave the collision, so isJumping will be set to false even after your jump, letting you jump while in the air one more time.
I would recommend that you use OnCollisionExit2D(Collision2D col) to set isJumping = true instead, or OnCollisionEnter2D(Collision2D col) and set it to isJumping = false, depending on the functionality you desire (if you want the ability to jump after walking out of a cliff)

Rigidbody velocity is zero sometimes while the rigidbody is moving

I'm trying to add sound to my pushable object and just have a simple if statement for checking if the pushable object is moving. The concept is quite simple, if the object is moving the sound should play and when it's not moving it shouldn't. The problem however is, that when I debug the value there is a 0 every 5 frames or so. This causes the sound to work inconsistently. The script I have is really simple, and I have tried changing to fixedupdate, but it didn't work. I had read somewhere that physics calculations are done in fixedUpdate.
public class PushableObject : MonoBehaviour
{
Rigidbody rb;
AudioSource audioS;
bool rbIsMoving = false;
// Start is called before the first frame update
void Start()
{
rb = GetComponent<Rigidbody>();
audioS = GetComponent<AudioSource>();
}
// Update is called once per frame
void FixedUpdate()
{
if (rb.velocity == Vector3.zero)
{
Debug.Log("Not moving");
audioS.volume = 0f;
}
else
{
Debug.Log("Moving");
audioS.volume = 0.1f;
}
}
}
Edit: I have just figured out that if the player pushes the pushable object into the wall the sound is still playing, for this reason I think I have to change the way too determine if the object is moving or not.
This happens due to single precision floating point.
You never (should) compare two float values directly since they might logically be equal (e.g. 1 = 5*0.2) but for the computer they might be different by a small "epsilon"
So Unity decides that Vector3 simply uses only a precision of 0.00001 for equality for ==
Rather use Mathf.Approximately which uses a very small Epsilon instead.
Than easier than comparing each component of the rb.velocity against 0 what you actually want is the rb.velocity.magnitude which is actually the overall speed.
if (Mathf.Approximately(rb.velocity.magnitude, 0))
Update
Alternatively store the last position and compare it to the current one using Vector3.Distance either again with Mathf.Approximately
private Vector3 lastPosition;
private void LateUpdate()
{
if(Mathf.Approximately(Vector3.Distance(lastPosition, transform.position), 0))
{
//...
}
else
{
//...
lastPosition = transform.positiom;
}
}
Or with a custom threshold
if(Vector3.Distance(lastPosition, transform.position) <= someThreshold)
or this time you actually can use == if a threshold of 0.00001 is what you want
if(lastPosition == transform.position)
You can check if the RigidBody is sleeping:
if (!rb.IsSleeping()
{
//it's moving
}
else
{
//it's not
}
Or check if the transform position has moved since last frame:
Vector3 lastposition;
Gameobject go = somegameobject;
function Update()
{
if (lastposition == go.transform.position)
{
//not moving
}
else
{
//moving
}
lastposition = go.transform.position;
}
You can use Transform.hasChanged to check if the player position has changed on the last update
if (!this.transform.hasChanged)
{
print("Player is not moving");
}
transform.hasChanged = false;

Unity Jump function issue

I've been working on this script for the past day. For some reason my character will not jump as long as it's animator is active. I've got into the animation (there is only one) and removed all references to the animation placing a position anywhere and still the issue presides.
I have discovered that I can make my player jump if I use Co-routine which I'm using. However, I'm still new to using them and I can't work out why my player won't fall to the ground once a force has been added to it. And my player only moves up when the button is clicked. Could someone please take a look at my script and tell me what I'm doing wrong?
public float jumpSpeed = 100.0f;
public float jumpHeight = 2.0f;
public AudioClip jumpSound;
private GameObject pos;
private bool moving;
private bool isJumping;
void Start()
{
}
// Update is called once per frame
void Update ()
{
if(Input.GetMouseButtonDown(0))// && !moving)
{
isJumping = true;
StartCoroutine(JumpPlayer(gameObject.transform.localPosition));
}
else
{
isJumping = false;
}
}
IEnumerator JumpPlayer(Vector3 startPos)
{
Vector3 jump = new Vector3(transform.localPosition.x, jumpHeight, transform.localPosition.z);
float t = 0f;
t += Time.deltaTime / jumpSpeed;
rigidbody.AddForce(Vector3.up * jumpSpeed);
//gameObject.transform.localPosition = Vector3.Lerp(startPos, jump, 0.5f);
//isJumping = false;
yield return null;
}
Firstly, your use of coroutine isn't doing anything in particular - because it only does yield return null at the end, it'll run in a single frame and then exit. You could make it a regular void function and you shouldn't see any change in behaviour.
Removing other redundant code and you have just this:
if(Input.GetMouseButtonDown(0))
{
rigidbody.AddForce(Vector3.up * jumpSpeed);
}
This force is added for only a single frame: the frame where the mouse button is pressed down (if you used Input.GetMouseButton instead, you'd see the force applied for multiple frames).
You say "my player only moves up when the button is clicked" but I'm not clear why that's a problem - perhaps you mean that the player should continue to move up for as long as the button is held, in which case you should refer to my previous paragraph.
The most obvious reasons for the player not falling again are related to the RigidBody component: do you have weight & drag set to suitable values? An easy way to test this would be to position your player some distance from the ground at the start of the scene, and ensure that they fall to the ground when you start the scene.
Another reason might be that you're using the default override of .AddForce in an Update cycle. The default behaviour of this method applies force during the FixedUpdate calls, and you might find that using ForceMode.Impulse or ForceMode.VelocityChange gives you the result you're looking for.

Adding velocity to 2d sprite in c# unity

hi i was wondering if someone could help me fix practice code (i make practice codes before i make the real thing because its just how i roll) it is basically an object that requires the user to click on the screen in order for it to not touch the ground much like flappy bird however although i have applied gravity correctly to the sprite i cannot fix the velocity section (i coded is to every time the user clicks with his mouse or taps the space key the object will move up like flappy bird)
using UnityEngine;
using System.Collections;
public class BirdMovment : MonoBehaviour {
Vector3 Velocity = Vector3.zero;
public Vector3 gravity;
public Vector3 flapVelocity;
public float maxSpeed = 5f;
bool didFlap = false;
// Use this for initialization
void Start () {
}
void update (){
if (Input.GetKeyDown (KeyCode.Mouse0))
{
didFlap = true;
}
}
// Update is called once per frame
void FixedUpdate () {
Velocity += gravity* Time.deltaTime;
if (didFlap) {
didFlap = false;
Velocity += flapVelocity;
}
Velocity = Vector3.ClampMagnitude (Velocity, maxSpeed);
transform.position += Velocity * Time.deltaTime;
}
}
can you please fix the error as every time i set the velocity in unity for the sprite ad run the program the sprite just keeps on falling and no matter how much i click or tap the space key the sprite does not stop falling even if i increase the velocity
First of all, the correct Update function is with a capital U, so Update() instead of update(). Then, since you're not doing anything with physics, you can do everything in Update and not use FixedUpdate at all. So you can remove the didFlap variable and add to Velocity directly inside the if (Input.GetKeyDown ...) block. Furthermore, regarding gravity, you're multiplying it twice with Time.deltaTimethere, so remove the first one. That should get you started.

My character sometimes fails to jump - Unity2D

So, I've set up a basic script in Unity to move around a 2D sprite, and it works pretty well, except for the fact that occasionally the player-character will not jump when told to. It seems to only happen while or shortly after the character moves horizontally. I really have no idea why this is happening. Hopefully someone else can shed some light on this. Here is the controller script. Any feedback is helpful, even if it's unrelated to the question, I'm doing this as a learning exercise.
using UnityEngine;
using System.Collections;
public class PlayerControlsCs : MonoBehaviour {
public KeyCode walkLeft;
public KeyCode walkRight;
public KeyCode jumpUp;
public float speed = 5;
public float jumpForce = 750;
public int jumpCapacity = 1;
public int extraJumps = 0;
public bool facingRight = true;
public bool grounded = false;
private Transform groundCheck;
private Animator anim;
void Awake () {
groundCheck = transform.Find("GroundCheck");
anim = GetComponent<Animator>();
}
void Update () {
grounded = Physics2D.Linecast(transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Terrain"));
if(grounded){
anim.SetTrigger("Grounded");
anim.ResetTrigger("Falling");
extraJumps = jumpCapacity;
}
else {
anim.ResetTrigger("Grounded");
anim.SetTrigger("Falling");
}
}
void FixedUpdate () {
anim.SetFloat("Speed", Mathf.Abs(rigidbody2D.velocity.x));
anim.SetFloat("Ascent", rigidbody2D.velocity.y);
if(Input.GetKey(walkLeft))
{
if(facingRight){
Flip();
}
rigidbody2D.velocity = new Vector2(-speed, rigidbody2D.velocity.y);
}
else if(Input.GetKey(walkRight))
{
if(!facingRight){
Flip();
}
rigidbody2D.velocity = new Vector2(speed, rigidbody2D.velocity.y);
}
else
{
rigidbody2D.velocity = new Vector2(0, rigidbody2D.velocity.y);
}
if(Input.GetKeyDown(jumpUp) && grounded)
{
anim.SetTrigger("Jump");
rigidbody2D.velocity = new Vector2(rigidbody2D.velocity.x, 0);
rigidbody2D.AddForce(new Vector2(0f, jumpForce));
}
else if(Input.GetKeyDown(jumpUp) && extraJumps > 0)
{
anim.SetTrigger("Jump");
rigidbody2D.velocity = new Vector2(rigidbody2D.velocity.x, 0);
rigidbody2D.AddForce(new Vector2(0f, jumpForce));
extraJumps -= 1;
}
}
void Flip ()
{
// Switch the way the player is labelled as facing.
facingRight = !facingRight;
// Multiply the player's x local scale by -1.
Vector3 theScale = transform.localScale;
theScale.x *= -1;
transform.localScale = theScale;
}
}
If it helps at all, here is what I have made:
https://www.dropbox.com/s/ka4vgc0s0205sbd/test.html
https://www.dropbox.com/s/40i8kltwfz1jgyu/test.unity3d
Building on Max's answer...
You should use FixedUpdate() for physics stuff like applying a force to a RigidBody as it runs 50 times a second regardless of how fast the game is running. This makes it frame rate independent.
See the documentation.
Update() runs once per frame, so is frame rate dependent. In here is where most of your non-physics stuff should go, checking for inputs for example.
This video is a good explanation of the difference.
The link in the comment is also correct:
You need to call this function from the Update function, since the
state gets reset each frame
So check if is grounded only when the player presses jump as ray/linecasts are computationally expensive, apply the physics in FixedUpdate(), and check for input in Update().
Update and FixedUpdate aren't guaranteed to happen every time one after another. I haven't ran into this kind of bugs, so I can't say for sure, but you may experience a situation where your grounded state is incorrect. Instead of saving this value as a field, try checking for it every time you need it — at least a separate check in Update and FixedUpdate.
Input should be handeled in Update, because update runs every frame, while fixed update isn't like update and it doesn't run every frame so when input is handeled in fixed update it might miss the input and it won't jump !
I suggest you cut and paste all the input code from fixed update to update !

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