c# Unity Jump Issue

Question

I'm new to programming in C#.

I have a sphere rigid body on a plane in unity.

I want to make this sphere jump when the spacebar is pressed and then bounce twice before coming to rest again when the key is released.

This will not always be on the plane it will sometimes be on an object and I would like the height of the bounce to reflect the distance dropped from the initial jump.

I currently have a camera facing onto the sphere from a side and have it following the ball from a set distance. The sphere can move in any direction but the camera always stays on the same side and distance from the sphere.

The issue is that my code currently says (to my knowledge) IF the spacebar is not pressed try to move the sphere's Y position down, then if the spacebar is pressed make the sphere jump and then come back down on spacebar release.

The way this code is written makes my plane jump as the ball is constantly bouncing into it when spacebar is not being pressed but if I take that part out the ball refuses to drop.

Example Code :

public class RollAdvancedScript : MonoBehaviour 
{   
    public Transform camera;
    public float posY;

    void lol()
    {
        posY =  transform.position.y;
    }

    void Update() 
    {
       if (Input.GetKey(KeyCode.D))
        { 
            Vector3 vectorToUse = camera.right;
            vectorToUse.y = 0;
            transform.position += vectorToUse * Time.deltaTime * 5;
        }
        if (Input.GetKey(KeyCode.A))
        { 
            Vector3 vectorToUse = -camera.right;
            vectorToUse.y = 0;
            transform.position += vectorToUse * Time.deltaTime * 5;
        }
        if (Input.GetKey(KeyCode.S))
        { 
            Vector3 vectorToUse = -camera.forward;
            vectorToUse.y = 0;
            transform.position += vectorToUse * Time.deltaTime * 5;
        }
        if (Input.GetKey(KeyCode.W))
        { 
            Vector3 vectorToUse = camera.forward;
            vectorToUse.y = 0;
            transform.position += vectorToUse * Time.deltaTime * 5;
        }
        if (Input.GetKey(KeyCode.Space))
        {
            Vector3 vectorToUse = camera.up;
            transform.position += vectorToUse * Time.deltaTime * 10;    
        }
        else
        {   
            if ( posY >= 0) 
                {Vector3 vectorToUse = camera.up;
                transform.position -= vectorToUse * Time.deltaTime * 10;
                }
                else
            {
                Vector3 vectorToUse = camera.up;
                vectorToUse.y = 0;
                transform.position -= vectorToUse * Time.deltaTime * 10;
            }
        }
    }
}

Example Image:

Please ignore the shadow as it's not working correctly just now.

TLDR; The best way to make an object jump and fall with a bounce on Keypress when moving in relation to a fixed camera position?

Answer 1

This is my code, hope it can help you:

public class Player : MonoBehaviour
{ 
    public float m_gravity=10f;          
    void Jump()
    {
        if (m_ch.isGrounded) //this is the point
        {
            m_Gravity = 10;
            if (Input.GetKeyDown(KeyCode.Space))
            {
                m_Gravity = -8;
            }
        }
        else
        {
            m_Gravity += 10f * Time.deltaTime;
            if (m_Gravity >= 10) { m_Gravity = 10; }
        }
    }
}

Answer 2

Are you trying to handle this in animation or in physics? Looking at the code it looks like pure controller animation, so I'd suggest that you track your jump state explicitly instead of just using the y > 0 check every update. It's a lot easier to see what's going on if you know the state of the object.

Your code makes it look like you pop up by (10 * deltaTime) when you hit space and then immediately pop down by 10 until you are below zero. Are you expecting the player to hold down space to fly, jetpack-style? Otherwise you should give an initial impulse up and then subtract from it to give a smooth fall.

Here's a very simple example. The up vector is world up (not Camera up as in your example) but if you're camera is not rolling the result would be the same.

public class DoJump : MonoBehaviour {

    public float JumpSpeed = .25f;
    public bool Jumping;
    Vector3 jumpVec;

    void Start () {
    Jumping = false;
    }

    void Update () {

        if (Jumping)
        {
            transform.position += jumpVec * Time.deltaTime;
            jumpVec += (Vector3.down * Time.deltaTime);
            //accelerate downward one unit per second per second                           
        }
        else
        {
            if (Input.anyKeyDown)
            {
                Jumping = true;
                jumpVec = Vector3.up * (JumpSpeed * Time.SmoothDeltaTime);
                // impulse up @ jumpSpeed units per second
            }
        }
    }

    void LateUpdate()
    {
        if (transform.position.y < 0)
        {
            transform.position = new Vector3(transform.position.x, 0, transform.position.z);
            Jumping = false;
        }
    }
}

If you're going to have uneven terrain, you should probably use physics colliders or raycast to know when to stop falling.