2d acceleration and deceleration | Official Unity Discord | Page 1

jolly crown Sep 12, 2022, 12:11 PM

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thread create

muted shard Sep 12, 2022, 12:12 PM

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👋

jolly crown Sep 12, 2022, 12:12 PM

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you mean this one?

muted shard Sep 12, 2022, 12:12 PM

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Yes

jolly crown Sep 12, 2022, 12:12 PM

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so the movedirection is from Input.GetAxis

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and if it's over 1 a button is pressed

muted shard Sep 12, 2022, 12:13 PM

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Yes, yes

jolly crown Sep 12, 2022, 12:13 PM

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mathf.abs makes it 1 so the number from input.getAxis is always 1 or 0

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i think

muted shard Sep 12, 2022, 12:13 PM

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Ohh, that is the input, not the speed

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Ok

jolly crown Sep 12, 2022, 12:14 PM

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yes

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the problem is now that when I change direction the "currentSpeedX" stays on 500 .. so no acceleration when changing direction

muted shard Sep 12, 2022, 12:16 PM

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I see

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Shouldn't currentSpeedX be clamped between -speedMax and speedMax?

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Instead of 0 and speedMax

jolly crown Sep 12, 2022, 12:19 PM

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ok.. I 'll try

muted shard Sep 12, 2022, 12:20 PM

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And maybe you should check the velocity on the Rigidbody2D as you test, not only on the script

muted shard Sep 12, 2022, 12:21 PM

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muted shard Shouldn't currentSpeedX be clamped between -speedMax and speedMax?

You are actually using the input to determine the direction so this might not be the solution

jolly crown Sep 12, 2022, 12:22 PM

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yeah the player moves to the opposite direction from key press now and keeps moving

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no way to stop it

muted shard Sep 12, 2022, 12:23 PM

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By the way, I think decceleration should be higher than acceleration. Can you try this?

jolly crown Sep 12, 2022, 12:25 PM

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ok I set acceleration to 1500 and deceleration to 2000 but still the same problem ..

jolly crown Sep 12, 2022, 12:25 PM

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muted shard You are actually using the input to determine the direction so this might not be...

should I not use the input to determine the direction?

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in another way?

muted shard Sep 12, 2022, 12:26 PM

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The changeSpeed() part doesn't convice me🤔

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Because if the player is going left at 200 units/s and then the next frame turns right, the speed will increase and the player will change direction right away, instead of deccelerating and then accelerating to the other direction.

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Decceleration shouldn't be applied only when the player releases the buttons but also when changing directions (these are 2 different types of decceleration)

jolly crown Sep 12, 2022, 12:30 PM

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oof do you know how to apply deceleration when changing directions.. I can't find any helpful tutorials online /:

muted shard Sep 12, 2022, 12:34 PM

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So, in changeSpeed() you should:

if(turtle.speed > 0){
   if(moveDirection.x > 0){
   currentSpeed += acc * Time.deltaTime;
   }else{
   currentSpeed -= dec * Time.deltaTime;
}
//Then the opposite if turtle.speed < 0

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It's a bit annoying with lots of nested if-s but this approach has worked for me

jolly crown Sep 12, 2022, 12:37 PM

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ew the turtle.speed gives n error do I have to set sth up for that?

muted shard Sep 12, 2022, 12:38 PM

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Sorry, turtle.speed.x

jolly crown Sep 12, 2022, 12:39 PM

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mmh it says the rigidbody doesn't have a definition for speed 😱

muted shard Sep 12, 2022, 12:40 PM

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Soooorry

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turtle.velocity.x

jolly crown Sep 12, 2022, 12:40 PM

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everthing fine (;

muted shard Sep 12, 2022, 12:40 PM

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😅

jolly crown Sep 12, 2022, 12:45 PM

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ok just to go sure again
I will remove that and put the other code in?

muted shard Sep 12, 2022, 12:46 PM

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Remove just the upper half, for velocity x. Then you'll have to do the same for velocity y but finish this first

jolly crown Sep 12, 2022, 12:47 PM

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so like this?

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I've tried around with that but there the turtle can't move in x

muted shard Sep 12, 2022, 12:52 PM

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Add even the rest. So below what you added, add:

...
else{
   if(moveDirection.x < 0){
   currentSpeedX -= acc * Time.deltaTime;}
   else{
   currentSpeedX += dex * Time.deltaTime;
}
}

jolly crown Sep 12, 2022, 12:56 PM

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Ahhhh the currentspeedX doesn't stop increasing now ;D

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this should be right?

muted shard Sep 12, 2022, 12:58 PM

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Just remove movedirectionforcalculatingX in the multiplication

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Aaand, you shouldn't have removed the clamping

jolly crown Sep 12, 2022, 1:03 PM

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owww it's working to 99% now 😃

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but the turtle is always moving a bit

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is it possible to stop that?

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lol now both work

muted shard Sep 12, 2022, 1:05 PM

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So is it working?

jolly crown Sep 12, 2022, 1:06 PM

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Yes only the player always moves slightly

muted shard Sep 12, 2022, 1:06 PM

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Can you show a screenshot of the code with the line numbers? I want to show you how to add the 2nd type of decceleration

jolly crown Sep 12, 2022, 1:07 PM

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like this?

muted shard Sep 12, 2022, 1:10 PM

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Below line 69 add:

...
else if(moveDirection.x == 0){
currentSpeed -= acc *time;
}
...

and below line 80 add:

...
else if(moveDirection.x == 0){
currentSpeed += acc *time;
}
...

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To sum up the code so that you understand what is happening:

if the object is moving right:

if the player keeps pressing right, add speed by acceleration;
if the player doesn't press, slow down little by little (in this case by acceleration but if you want you can have another variable);
if the player is pressing left, slow down by decceleration.

The opposite happens when the player is moving left.

jolly crown Sep 12, 2022, 1:17 PM

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everything sounds very logical and also works
but I do not know why but the player still moves and always in the direction in which I last moved

muted shard Sep 12, 2022, 1:17 PM

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Maybe due to the huge values of acceleration and decceleration?

jolly crown Sep 12, 2022, 1:18 PM

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I will try

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if that fixes it

muted shard Sep 12, 2022, 1:18 PM

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muted shard Below line 69 add: ```cs ... else if(moveDirection.x == 0){ currentSpeed -= acc ...

Did you add this ^ ?

jolly crown Sep 12, 2022, 1:19 PM

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yes

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it's always blinking between some numbers

muted shard Sep 12, 2022, 1:20 PM

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That happened to me as well, but e-07 is super small so no big deal

jolly crown Sep 12, 2022, 1:20 PM

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OK

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(;

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Thank's a lot

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that should be it

muted shard Sep 12, 2022, 1:21 PM

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Can you show a video of the turtle moving?

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And also, if you want the same movement for y, the code should be the same.

jolly crown Sep 12, 2022, 1:23 PM

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just realised that the turtle is jiggling

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when I use small numbers for acceleration and decceleration it's fixed but bc of they're so small it takes forever until the turtle is moving

muted shard Sep 12, 2022, 1:26 PM

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I think decceleration should be higher than acceleration. (Doesn't fix the jiggling, it did happen to me at times as well but at other times it didn't. I think it happens when the player reaches max speed. Try also checking the velocity value in Rigidbody2D)

jolly crown Sep 12, 2022, 1:28 PM

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A velocity value in this rigidbody2d?

muted shard Sep 12, 2022, 1:36 PM

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Yes, under Info I think

jolly crown Sep 12, 2022, 1:38 PM

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can't change anything there.. but should be on 0 anyway right?

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well for now it's working I will leave it as it is rn
THANK YOU FOR YOUR TIME AND HELP 🤩

muted shard Sep 12, 2022, 2:04 PM

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I mean that you can check as it jiggles what is actually happening to the velocity to find out why it might be happening.

#2d acceleration and deceleration