So, my jumping is inconsistent, basically, every time i press space the character jumps different heihgts, even when standing still (not moving left, and right), why is that?
here is my code:
public bool onGround = false;
public float JumpHeight;
public Rigidbody2D gravidade;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
if (onGround == true)
{
if (Input.GetKey(KeyCode.Space))
{
gravidade.AddForce(new Vector2(0, JumpHeight * Time.deltaTime), ForceMode2D.Impulse);
}
}
}
void OnCollisionEnter2D(Collision2D outro)
{
if (outro.gameObject.CompareTag("ground"))
{
onGround = true;
}
}
void OnCollisionExit2D(Collision2D outro)
{
if (outro.gameObject.CompareTag("ground"))
{
onGround = false;
}
}
You shouldn't multiply by delta time when applying a one-time force.
Time.deltaTime is the time completion time in seconds since the last frame. Check the documetation
This time is not constant. MonoBehaviour.FixedUpdate uses fixedDeltaTime instead of deltaTime, this fixedDeltaTime and the FixedUpdate is usually used for physics and it is quite an advanced topic.
Use a constant value instead of the Time.deltaTime to have always the same jump height.
It is different becuase it's calculated off of deltaTime, which is incosistent (time between two rendered frames if i'm not wrong), and it yields a slightly different value every time, which combined with multiplication has a bigger deviation from an average.
Hope i helped to clarify this, cheers!
Related
I want to move a rigidBody2D for a fixed amount of time with a fixed amount of velocity, when the player presses a button. I am calling the method in FixedUpdate() and the results are not consistent. Sometimes the rigidBody will travel more and sometimes less (Here is a relevant part of my code how i went about do this)
void Update()
{
GetPlayerInput();
}
private void FixedUpdate()
{
GroundCheck();
ApplayNormalPlayerMovement();
ApplyMove(); // This is the method of interest - I tried calling this in Update() with Time.DeltaTime - still inconsistent results.
MoveCooldownCounter(); // I tried calling this in Update() - inconsistent results also
}
IEnumerator MoveRB()
{
savedVelocityX = rb.velocity.x;
rb.gravityScale = 0;
savedXinput = xInput;
while (moveTimer >= 0)
{
if (xInput != 0)
xInput = 0;
cc.sharedMaterial = noFriction;
if (facingRight)
{
rb.velocity = new Vector2(moveSpeed, .0f); // I tried multiplying the moveSpeed by Time.DeltaTime and FixedDeltaTime - still inconsistent results.
} else
{
rb.velocity = new Vector2(-moveSpeed, .0f);
}
moveTimer -= Time.fixedDeltaTime;
yield return null;
}
moveTimer= moveDuration;
rb.gravityScale = gravity;
rb.velocity = new Vector2 (savedVelocityX, .0f);
xInput = savedXinput;
moveCooldownInternal -= Time.deltaTime; // I tried changing this to a specific float - still inconsistent results in physics..
}
private void MoveCooldownCounter()
{
if (moveCooldownInternal != moveCooldown)
{
moveCooldownInternal -= Time.deltaTime;
if (moveCooldownInternal <= 0)
{
moveCooldownInternal = moveCooldown;
}
if (moveCooldownInternal == moveCooldown && isGrounded)
canMove = true;
}
}
private void ApplyMove()
{
if (b_Fire3 && canMove)
{
StartCoroutine("MoveRB");
canMove= false;
}
}
Side note: right now i experience player input loss on occasions because i call this ApplyMove() in FixedUpdate() (will have to find a workaround for that as well - naturally if I can call the ApplyMove in Update() and get consistent results than this issue would be fixed).
Pleas excise my newbiness, i am trying to learn :)
Thank you in advance!
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Unity is a game engine. All game engines are based on the game loop - however Unity somewhat hides if from you, behind the 3 Update functions.
Not all parts are equally important. Drawing is generally skipped when the GPU is not ready or the FPS are capped. And Drawing and physics are generally calculated independantly of one another (unless you really messed up the development).
With Physics and Animations, you generally want to stuff to be consistent to the Game Tick Counter, not real time. All movement of game pieces and all animation should count in game ticks. Real Time is a nice figure and all, but ticks can have wildly different processing times. Especially since the CPU side drawing work also has to run in the same thread.
Just figure out your maximum ticks/second. And if you want to run something to run for "roughly" 10 ingame seconds, you multiply that value. It does not mater if the game on this machine needs 2 seconds for 200 ticks or 2 minutes for 200 ticks - with the number of ticks, the results will be consistent (unless the math itself is inprecise, like floating point math).
If it's not multiplayer game, it does not have to be hackproof and thus easiest fix is to capture the first frame of the button pressed and apply the force only on that frame, because of that we have to capture input on the Update function and also there immadietly apply the force even though it's suggested to do physics stuff in fixed update, but if you use delta time in update function for calculation it should be fine!
Now I think you know how to do that but I'll write it anyway we can either use apply force or set the velocity,
void Update()
{
if(Input.GetKeyDown("w"))
rb.velocity = new Vector2(rb.velocity.x, rb.velocity.y + 5f*Time.deltaTime);
}
Note: I didn't test it but it should be allright since GetKeyDown returns true only on the first frame when the button was pressed,
If it was just GetKey and in case of jump we would check the grounding of player, we could be during jump and still be grounded on the second frame even if we jumped because of not really precise ground checking.
PS. Use fixedDeltaTime in fixedUpdate method!
I have the following code
public Rigidbody2D rb;
public float speed = 5f;
void FixedUpdate()
{
if (Input.GetKeyDown("w"))
{
Fire();
}
}
void Fire()
{
rb.MovePosition(rb.position + Vector2.down * speed * Time.deltaTime);
}
but every time I play the game, the ball does not move according to the fire function, it only goes down by 1 on the y-axis.
How can I edit my code, so that the Rigidbody moves according to the Fire() function?
There could be a couple things going wrong here. The first thing that stands out to me is that you're using Input.GetKeyDown instead of Input.GetKey-- GetKeyDown only returns true on the first frame that the key is pressed (so it's useful for things like shooting once per keypress), whereas GetKey returns true for the entire time that the key is down (so it's useful for things like movement). Changing that should give you the behavior that you're expecting.
Another issue is that you're doing input checking in FixedUpdate. It runs on a separate game loop from Update, and you can find more details about that here: Is it really wrong to use Input.GetKey() on FixedUpdate?
I would use Input and GetKey to store the input state in a Vector2 in the Update loop, and then use that data in FixedUpdate to do the actual movement:
public Rigidbody2D rb;
public float speed = 5f;
private Vector2 velocity = Vector2.zero;
void Update()
{
if (Input.GetKey("w"))
{
velocity = Vector2.down * speed;
}
else {
velocity = Vector2.zero;
}
}
void FixedUpdate()
{
MoveBall();
}
void MoveBall()
{
rb.MovePosition(rb.position * velocity * Time.deltaTime);
}
This way, you also have a stronger separation between the input code and movement code, and it will be easier to handle once you start trying to implement more complexity. Good luck!
I'm having this problem with my enemy shooting, you see I'm using raycasting to detected where my player is and once detected I want the enemy to shoot, so far I have accomplished that but however there's not delay between each Instantiated bullet!So the bullet is being constantly spawn rather than a delay in between each spawn. I've tried a whole lot of different solutions to fix this problem but nothing worked! I've tried IEnumerator, object pooling, creating a count down timer and invoke & invokerepeating but still my bullets are still being instantiated instantly without no delay. Does any one knows how to have a delay between each instantiated bullet?? Thank you!
This is my script:
public GameObject bulletPrefab;
public Transform bulletSpawn;
public Transform sightStart, sightEnd;
public bool spotted = false;
void Update()
{
RayCasting ();
Behaviours ();
}
void RayCasting()
{
Debug.DrawLine (sightStart.position, sightEnd.position, Color.red);
spotted = Physics2D.Linecast (sightStart.position, sightEnd.position, 1 << LayerMask.NameToLayer("Player"));
}
void Behaviours()
{
if (spotted == true) {
//Invoke("Fire", cooldownTimer);
Fire ();
} else if (spotted == false) {
//CancelInvoke ();
}
}
void Fire()
{
GameObject bullet = (GameObject)Instantiate (bulletPrefab);
//GameObject bullet = objectPool.GetPooledObject ();
bullet.transform.position = transform.position;
bullet.GetComponent<Rigidbody2D> ().velocity = bullet.transform.up * 14;
Destroy (bullet, 2.0f);
}
You need to throttle the rate at which bullets are spawned. You could base it on number of frames but that's a bad approach as fire rate will vary with game performance.
A better approach is to use a variable to track how much time must elapse before we can fire again. I'll call this "Time To Next Shot" (TTNS)
Decrement TTNS by the time that has elasped.
Check if TTNS is 0 or less
If so:
Set TTNS as appropriate for our desired rate of fire.
Fire a shot
Something like..
private float fireRate = 3f; // Bullets/second
private float timeToNextShot; // How much longer we have to wait.
// [Starts at zero so our first shot is instant]
void Fire() {
// Subtract the time elapsed (since the last frame) from TTNS .
timeToNextShot -= time.deltaTime;
if(timeToNextShot <= 0) {
// Reset the timer to next shot
timeToNextShot = 1/fireRate;
//.... Your code
GameObject bullet = (GameObject)Instantiate (bulletPrefab);
//GameObject bullet = objectPool.GetPooledObject ();
bullet.transform.position = transform.position;
bullet.GetComponent<Rigidbody2D> ().velocity = bullet.transform.up * 14;
Destroy (bullet, 2.0f);
}
}
This does assume that you only call Fire() once per frame (Otherwise the elapsed time will be subtracted from nextShot multiple times).
I opted to do it this way (subtracting slices from a time span) rather than defining an absolute time (wait until time.elapsedTime > x) as the resolution of elapsedTime decreases over time and that approach will result in glitches after a few hours of gameplay.
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.
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 !