Unity Platform 04 Wall Jump & Hop
===
2020.08.08

###### tags: `platform`

## List
1. [Side Wall Check](#SWC)
2. [Side Wall Sliding](#SWS)
3. [Move in Air](#MA)
4. [Cut Jump Height](#CJH)
5. [Wall Jump & Hop](#WJH)

## Content
### Side Wall Check<a id="SWC"/>
Like grounding, use obj for check side wall.<br>Linear check using method `Physics2D.RayCast()`.

isTouchingWall = Physics2D.Raycast(wallCheck.position, transform.right, wallCheckDistance, WhatIsGround);

### Side Wall Sliding<a id="SWS"/>
If player attaching wall, slide with wall line.<br>Check Wall Slide state in update.<br>Move control(velocity control) in FixedUpdate.

// In Update()
private void CheckIfWallSliding()
{
    if (isTouchingWall && !isGrounded && rb2D.velocity.y < 0)
        isWallSliding = true;
    else
        isWallSliding = false;
}

// In FixedUpdate()
privte coid applyMovement()
{
    ~~~
    if (isWallSliding)
    {
        if (rb2D.velocity.y < -wallSlidingSpeed)
            rb2D.velocity = new Vector2(rb2D.velocity.x, -wallSlidingSpeed);
    }
    ~~~
}

And `Flip()` must be changed.<br>Now, not correct work when direction is other way of wall.

protected void Flip()
{
    if (!isWallSliding) // This condition for right position for wallSliding.
    {
        isFacingRight = !isFacingRight;
        transform.Rotate(0.0f, 100.0f, 0.0f);
    }
}

### Move in Air<a id="MA"/>
Player in air can move a little bit.<br>Conditions are below.

else if (!isGrounded && !isWallSliding && moveDirection != 0)
{
    Vector2 forceToAdd = new Vector2(movementForceInAir * moveDirection, 0);
    rb2D.AddForce(forceToAdd);

    if (Mathf.Abs(rb2D.velocity.x) > velocity)
        rb2D.velocity = new Vector2(velocity * moveDirection, rb2D.velocity.y);
}

Now, move little in air, but don't stop when you tab off button.<br>So write below for velocity slow down.

else if (!isGrounded && !isWallSliding && moveDirection == 0)
{
    rb2D.velocity = new Vector2(rb2D.velocity.x * airDragMultiplier, rb2D.velocity.y);
}

### Cut Jump Height<a id="CJH"/>
You can push jump button long or short.<br>Jump height is different when this.

if (Input.GetButtonUp("Jump"))
    rb2D.velocity = new Vector2(rb2D.velocity.x, rb2D.velocity.y * jumpHighierMultiplier);

### Wall Jump & Hop<a id="WJH"/>
Hop is off to wall, wall_jump is jump at wall_slide.<br>This 3 Step.
1. Hop and WallJump Force Setting / Direction

public float wallHopForce;
public float wallJumpForce;

public Vector2 wallHopDirection;
public Vector2 wallJumpDirection;

2. Jump setting when wall_slide

protected void Jump()
{
    if (canJump && !isWallSliding) // !isWallSliding is wall jump
    {
        rb2D.velocity = new Vector2(rb2D.velocity.x, jumpForce);
        amountOfJumpsLeft--;
    }
    // Below is for Hopping Wall(Just down ward(not jump))
    else if (isWallSliding && moveDirection == 0 && canJump)
    {
        isWallSliding = false;
        amountOfJumpsLeft--;
        Vector2 forceToAdd = new Vector2(wallHopForce * wallHopDirection.x * -facingDirection, wallHopForce * wallHopDirection.y);
        rb2D.AddForce(forceToAdd, ForceMode2D.Impulse);
    }
    // Below is for Jump at Wall
    else if ((isWallSliding || isTouchingWall) && moveDirection != 0 && canJump)
    {
        isWallSliding = false;
        amountOfJumpsLeft--;
        Vector2 forceToAdd = new Vector2(wallJumpForce * wallJumpDirection.x * moveDirection, wallJumpForce * wallJumpDirection.y);
        rb2D.AddForce(forceToAdd, ForceMode2D.Impulse);
    }
}

3. Set JumpIf Condition

private void CheckIfJump()
{
    //  isWallSlipding => canJump state
    if ((isGrounded && rb2D.velocity.y <= 0) || isWallSliding)
        amountOfJumpsLeft = amountOfJumps;
    ~~~

4. Wall Face Direction setting(For Hop)

private int facingDirection = 1;

protected void Flip()
{
    if (!isWallSliding) // This condition for right position for wallSliding.
    {
        facingDirection *= -1;
        isFacingRight = !isFacingRight;
        transform.Rotate(0.0f, 100.0f, 0.0f);
    }
}