Continuous Jumping using gravity

Questions & Answers
1

I can’t understand why this code changes the player’s speed when standing on a platform (so the speed should be 0). As a result, gravity also changes:

178856-untitled.png
178856-untitled.png289×665 63.4 KB

This is velocity.y:

178857-untitled-1.png
178857-untitled-1.png285×617 66.7 KB

The problematic function is this (if I remove it, velocity.y becomes 0 when the player is on a floor):

private void setJumpGravity()
    {
        if(playerRb.velocity.y < 0)
        {
            playerRb.gravityScale = fallJumpGravity;
        }
        else if(playerRb.velocity.y > 0 && Input.GetKey(KeyCode.Space) == false)
        {
            playerRb.gravityScale = spaceJumpGravity;
        }
        else
        {
            playerRb.gravityScale = defaultGravity;
        }
    }

The whole class is:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerMovement : MonoBehaviour
{
    private float horizontalInput;
    [SerializeField] private float horizontalSpeed;
    private Rigidbody2D playerRb;

    private bool isGetSpaceDown;
    [SerializeField] private float jumpForce;
    [SerializeField] private float fallJumpGravity;
    [SerializeField] private float spaceJumpGravity;
    private float defaultGravity;

    // Start is called before the first frame update
    void Awake()
    {
        playerRb = gameObject.GetComponent<Rigidbody2D>();
        defaultGravity = playerRb.gravityScale;
    }

    void Update()
    {
        horizontalInput = Input.GetAxisRaw("Horizontal");

        if(Input.GetKeyDown(KeyCode.Space))
        {
            isGetSpaceDown = true;
        }
    }

    // Update is called once per frame
    void FixedUpdate()
    {
        playerRb.velocity = new Vector2(horizontalSpeed * horizontalInput, playerRb.velocity.y);

        if(isGetSpaceDown == true)
        {
            playerRb.AddForce(Vector2.up * jumpForce, ForceMode2D.Impulse);
            isGetSpaceDown = false;
        }

        setJumpGravity();

        //Debug.Log(playerRb.velocity.y);
        Debug.Log(playerRb.gravityScale);
    }

    private void setJumpGravity()
    {
        if(playerRb.velocity.y < 0)
        {
            playerRb.gravityScale = fallJumpGravity;
        }
        else if(playerRb.velocity.y > 0 && Input.GetKey(KeyCode.Space) == false)
        {
            playerRb.gravityScale = spaceJumpGravity;
        }
        else
        {
            playerRb.gravityScale = defaultGravity;
        }
    }    
}
3

Easy fix is to add a bool for whether or not the player is jumping. Add a private bool isJumping = false to your initializers.

    if (isGetSpaceDown == true)
    {
        playerRb.AddForce(Vector2.up * jumpForce, ForceMode2D.Impulse);
        isJumping = true; //after adding upward force set isJumping to true
        isGetSpaceDown = false;
    }

Then change the section of code where you find the issue to:

private void setJumpGravity()
{
    if (isJumping)  //this will ensure gravity is only changed when in the air
    {
        if (playerRb.velocity.y < 0)
        {
            playerRb.gravityScale = fallJumpGravity;
        }
        else if (playerRb.velocity.y > 0 && Input.GetKey(KeyCode.Space) == false)
        {
            playerRb.gravityScale = spaceJumpGravity;
        }
    }
    else
    {
        playerRb.gravityScale = defaultGravity;  //now gravity will remain at it's default when not in the air
    }
    if(playerRb.velocity.y == 0)  //set isJumping back to false when the player hits the ground
    {
        isJumping = false;
    }
}
2

Ignore everything and use Physics material for jumping like bouncing ball :slight_smile: