How do I make the player jump at a fixed height?

Question

I've been tinkering with the code, but I can't find anything that works. I'm making a 3D game, and writing in C#. Here's the code that I have now.

 public class PlayerController : MonoBehaviour {
 
     public float speed;
 
     public float jumpHeight;
 
     private Rigidbody rb;
 
     void Start ()
     {
         //Got too lazy, so added this in.
         rb = GetComponent<Rigidbody>();
     }
 
     void FixedUpdate ()
     {
         //Movement on the X and Z axes
         float moveHorizontal = Input.GetAxis ("Horizontal");
         float moveVertical = Input.GetAxis ("Vertical");
 
         Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);
 
         rb.AddForce (movement * speed);
 
         // The Jump Code
         if (Input.GetKeyDown (KeyCode.Space))
         {
             Vector3 jump =new Vector3 (moveHorizontal, jumpHeight, moveVertical);
 
             rb.AddForce (jump);
         }
     }
 }

Now what? I want to do this in the shortest and the most efficient way possible, without using too many variables.

Answer 1

Answer by toddisarockstar · Apr 02, 2017 at 06:15 PM

if your game is 3d and Y is up, this should get you moving:

      public class PlayerController : MonoBehaviour {
      
          public float speed;
      
          public float jumpHeight;
      
          private Rigidbody rb;
      
          void Start ()
          {
              //Got too lazy, so added this in.
              rb = GetComponent<Rigidbody>();
          }
      
          void FixedUpdate ()
          {
              //Movement on the X and Z axes
              float moveHorizontal = Input.GetAxis ("Horizontal");
              float moveVertical = Input.GetAxis ("Vertical");
      
              Vector3 movement = new Vector3 (moveHorizontal, rb.velocity.y, moveVertical);
      
              rb.velocity=movement*speed;
      
              // The Jump Code
              if (Input.GetKeyDown (KeyCode.Space))
              {
 
      
                  rb.AddForce (Vector3.up*jumpHeight);
              }
          }
      }

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Swagology · Apr 17, 2017 at 10:17 PM 0

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The movement is good, but when I jump, it seems to teleport to a higher location and descend slowly, as if there was no gravity at all.

Answer 2

Answer by RobAnthem · Apr 02, 2017 at 11:02 AM

First suggestion, don't use AddForce for movement, it's basically the worst thing you can do to move a player. Use Velocity. After that, you can literally just AddForce to jump like this.

 rb.AddForce(transform.up * jumpHeight);

Or you can incorporate it into your velocity mechanism and scale or lerp the height over time to smooth it out. Also you need to smooth your movement out a bit. I wrote a tutorial on this, you can find it here. Proper Velocity-Based Movement 101

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How do I make the player jump at a fixed height?

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