Free 2d dash ability script!

Question

I have a dashing mechanic in my game. I was using Transform, but since transform doesn't account for physics I was going through walls on occasion. I'm trying to use addforce, but it doesn't have the quick burst of speed effect as previously.

how can I use addforce to make the dash seem more like a dash?

I think my dash's cooldown is messed up too, allowing the player to spam the button, instead of using it once, then having to wait. If someone could check that out it would help me alot too.

         if(Input.GetKey(KeyCode.LeftShift) && canIDash == true){
             if(direction == true)
                 {
                 dashTimer += Time.deltaTime*3;
                 rigidbody.AddForce(Vector3.right*50);
                 
             }
             if (direction == false)
                 {
                 dashTimer += Time.deltaTime*3;
                 rigidbody.AddForce(Vector3.left*50);
                     }
             }
         
             if(dashTimer > .5f)
                 {
                 canIDash = false;
                 dashCooldown = true;
                 }
             if(dashTimer < .5f && dashCooldown == false)
             {
                 canIDash = true;
             }
             if(dashTimer <= 0)
             {
                 dashCooldown = false;
             }
             
         }

EDIT:

This is what the script currently looks like, it still doesn't work perfect. If anyone can help it would be awesome.

  public class DashAbility : MonoBehaviour {
 
  public float dashCooldown;
  public bool canIDash = true;
  public Vector2 savedVelocity;
 
  void Update () 
  {
      if(dashCooldown > 0)
      {
          canIDash = false;
          dashCooldown -= Time.deltaTime;
                //if I put saved velocity here, it will continue to move at savedVelocity until dashCooldown = 0? so it can't go here? right?
      }
      if(dashCooldown <= 0)
      {
          canIDash = true;
               //if I put savedVelocity here it doesn't return to savedVelocity until dashCooldown <=0 so... it doesn't go here either right...?
      }
      if(Input.GetKeyDown(KeyCode.LeftShift) && canIDash == true)
      {
          //saves velocity prior to dashing
          savedVelocity = rigidbody.velocity;
          //this part is the actual dash itself
          rigidbody.velocity =  new Vector2(rigidbody.velocity.x*3f, rigidbody.velocity.y);
          //sets up a cooldown so you have to wait to dash again
          dashCooldown = 2;
      }
  }

Answer 1

Best Answer

Answer by Alanisaac · Feb 04, 2015 at 01:48 PM

Ok, I'm pulling this out of the comment thread. From a technical perspective, your dash mechanic may be modeled as a state machine.

We really don't need to get that complicated or formal in our implementation, but it might be helpful to think of dashing as a set of states (Ready, Dashing, Cooldown), with specific conditions that transition from state to state (is the dash key down?, is max dash hit?, is cooldown time over?).

Try out something like the following script. It uses an enum to represent the three states. Notes:

Dash can only be activated when you're in the Ready state, and activating it sets the Dashing state. This prevents the dash button continuously attempting to save previous velocity.
For the other two cases, I added a bit of value coercion so the timer never goes outside of 0 or the max.

Let me know if you have any questions!

 public class DashAbility : MonoBehaviour {
     
     public DashState dashState;
     public float dashTimer;
     public float maxDash = 20f;
 
     public Vector2 savedVelocity;
     
     void Update () 
     {
         switch (dashState) 
         {
         case DashState.Ready:
             var isDashKeyDown = Input.GetKeyDown (KeyCode.LeftShift);
             if(isDashKeyDown)
             {
                 savedVelocity = rigidbody.velocity;
                 rigidbody.velocity =  new Vector2(rigidbody.velocity.x * 3f, rigidbody.velocity.y);
                 dashState = DashState.Dashing;
             }
             break;
         case DashState.Dashing:
             dashTimer += Time.deltaTime * 3;
             if(dashTimer >= maxDash)
             {
                 dashTimer = maxDash;
                 rigidbody.velocity = savedVelocity;
                 dashState = DashState.Cooldown;
             }
             break;
         case DashState.Cooldown:
             dashTimer -= Time.deltaTime;
             if(dashTimer <= 0)
             {
                 dashTimer = 0;
                 dashState = DashState.Ready;
             }
             break;
         }
     }
 }
 
 public enum DashState 
 {
     Ready,
     Dashing,
     Cooldown
 }

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Razputin · Feb 04, 2015 at 04:59 PM 0

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I just made a slight change and decided to only save the x velocity ins$$anonymous$$d of the x and y velocity. this way when we return to savedVelocity the character doesn't continue moving up/down for a second(Unless you can think of a better way to stop that). Thank you very much for your help with this it works perfectly and exactly how I wanted it to!

I also changed the questions title so if anyone in the future needs this script they can find it easier :)

j_masters Razputin · Jan 26, 2017 at 05:20 AM 0

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Any chance you can share how you saved just the x velocity?

meiousei · Jul 23, 2019 at 03:28 AM 0

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Hi Alanisaac, I've tried your code with my project but it doesn't seem to do anything with my movement. I've created the needed .cs file and attached to the object (player) with the correct variables like the rigidbody and so on. I see the Dash State, Dash Timer and $$anonymous$$axDash in the inspector in Unity but when I test it out, it detects the button presses, changes to dashing, and when it reaches $$anonymous$$axDash it cools down to 0. Unfortunately it doesn't alter the movement in my character.

I could post my code but it is essentially a copy-paste of what you provided. I would be really glad... like... REALLY GLAD if you help me out. Dash is quite tricky sometimes. I attach a screenshot of what you would expect from my project and the values of the .cs of my PlayerController, as well as the physics of my Rigidbody 2D. alt text

Thanks a lot in advance. I want to progress with my project :)

anotacion-2019-07-22-222300.png (226.2 kB)

OnlyAskarek meiousei · Mar 24 at 12:40 PM 0

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I litlebit corrected code and that code will work try to play with "dashForce" in Unity

 public class ScriptName : MonoBehaviour
 {
     private Rigidbody2D rb;
 
     public DashState dashState;
     public float dashForce;
     public float dashTimer;
     public float maxDash = 20f;
 
     public Vector2 savedVelocity;
 
     private void Start()
     {
         rb = GetComponent<Rigidbody2D>();
     }
 
     void Update()
     {
         switch (dashState)
         {
             case DashState.Ready:
                 var isDashKeyDown = Input.GetKeyDown(KeyCode.LeftShift);
                 if (isDashKeyDown)
                 {
                     savedVelocity = rb.velocity;
                     rb.AddForce(new Vector2(rb.velocity.x * dashForce, rb.velocity.y));
                     dashState = DashState.Dashing;
                 }
                 break;
             case DashState.Dashing:
                 dashTimer += Time.deltaTime * 3;
                 if (dashTimer >= maxDash)
                 {
                     dashTimer = maxDash;
                     rb.velocity = savedVelocity;
                     dashState = DashState.Cooldown;
                 }
                 break;
             case DashState.Cooldown:
                 dashTimer -= Time.deltaTime;
                 if (dashTimer <= 0)
                 {
                     dashTimer = 0;
                     dashState = DashState.Ready;
                 }
                 break;
         }
     }
 }
 
 public enum DashState
 {
     Ready,
     Dashing,
     Cooldown
 }

unity_143462 · Feb 08, 2020 at 11:19 AM 0

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Very useful, helped me make my group project dash ability in school, would recommend to others looking for the same script, only note, makes the player character abruptly stop, without a smooth stopping phase, if there could be one implemented, that would be nice to know.

Answer 2

Answer by VOTRUBEC · Feb 04, 2015 at 05:20 AM

Give this a shot:

 rigidbody.AddForce(Vector3.right*50,  ForceMode.VelocityChange);

Check Force here at the Docs.

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Razputin · Feb 04, 2015 at 05:26 AM 0

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Not really looking to use AddForce anymore, sorry i'll change the title.

Free 2d dash ability script!

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