Question - C# move steady speed

Unity Engine
1

So Ive written some basic left/right movement object code, with some increase and decrease in speed, I’m having trouble trying to figure out how to maintain the speed of the object once it reaches maximum speed.
As it stands, the object reaches maximum speed then slows down because of the way my code is written.
I want the object to reach max and stay there until the key is released.

using UnityEngine;
using System.Collections;

public class move : MonoBehaviour
{
    public float speed = 3.0f;
    private float maxspeed = 4.0f;
    private float minspeed = 3.0f;

    void Update ()
    {
         if (Input.GetKey (KeyCode.LeftArrow) && (speed < maxspeed))
        {
            this.transform.Translate (new Vector3 (-speed * Time.deltaTime, 0, 0));
            speed += Time.deltaTime; //increase speed until maximum speed
        }
        else if (Input.GetKey (KeyCode.RightArrow) && (speed < maxspeed))
        {
            this.transform.Translate (new Vector3 (speed * Time.deltaTime, 0, 0));
            speed += Time.deltaTime;
        }
        else if (speed > minspeed ) {
            speed -= Time.deltaTime; //reduce speed until minimum speed
        }
    }

}
2

Check out mathf clamp to clamp the values.

3

Line 22 above:

        else if (speed > minspeed ) {

Should be something like this:

else if(!Input.GetKey(KeyCode.LeftArrow) && !Input.GetKey(KeyCode.RightArrow) && speed > minspeed)

Or you have to rearrange these if-else statements to exclude the case when you push the left/right keys but it’s already on top speed from the slow down section.

4

Thanks, that looks very useful.

5 
else if(!Input.GetKey(KeyCode.LeftArrow) && !Input.GetKey(KeyCode.RightArrow) && speed > minspeed)

It seems that line of code stops the object once reaching max

6

Okay, what’s your goal here, do you want to move the object all the time, regardless of the keypress with at least minimumspeed? Or do you want to stop moving the object if the key is released and the speed reached minspeed?

Because your solution is depending on it.

7

The goal is to make speed = maxspeed once maxspeed is hit, until the key is realeased. If that makes sense. Once maxspeed is reached, stay at that speed until realease

8

Maybe like this…

float h = Input.GetAxis("Horizontal");
if(h != 0) {
   this.transform.Translate (new Vector3 (Mathf.Sign(h) * speed * Time.deltaTime, 0, 0));
   speed += Time.deltaTime; //increase speed until maximum speed
  }
else speed -= Time.deltaTime;
speed = Mathf.Clamp(speed, minspeed, maxspeed);

Edit: I wasn’t 100% sure if the translate should be happening when no key is pressed, at whatever the current speed is, or not. This only lowers the speed, but does not translate.

9

But when you release the button, it should slow down. Should it stop when it reach minspeed or maintain the movement with at least minspeed all the time?

10

yeah it should stop once it reaches min speed also, which it does at the moment

11

Then something like this:

float h = Input.GetAxis("Horizontal");
if(h != 0) {
   speed += Time.deltaTime; //increase speed until maximum speed
  }
else speed -= Time.deltaTime;
speed = Mathf.Clamp(speed, minspeed, maxspeed);
if (speed > minspeed) {
       this.transform.Translate (new Vector3(Mathf.Sign(h) * speed * Time.deltaTime, 0, 0));
}

Using @methos5k 's example. But keep in mind, that we don’t have any means to test it, so just try to grasp the idea of our suggestions.

12

That’s great thank you LurkingNinjaDev, methos5k and NiceBischoff, I will work from these.
Would it be a good idea to look at velocity as well?

13

velocity is for rigidbody movement. I think, generally speaking it’s good to know about both, because you might want one, the other, or both in a game. However, use the one that’s right for your situation. :slight_smile:

Maybe for now: do what your doing, learn what velocity is and keep it in mind, if you ever need it? :slight_smile: