Height in 2D game

Question

I'm working on a 2D top-down game (like the picture below) and am wondering what can I do for "jumping"

So far, I've done these:

• adding two events in jumping animation (one for when the enemy is in the air and one for when it's coming back to the ground)
• the events turn enemy's colliders off and on

And it worked well, the enemy dodged the attacks and all but upon more testing, I found out some serious issues:

1. the enemy can pass objects like trees but it shouldn't
2. explosions should affect enemies even if they are on air but without any colliders, it is not possible

So what I want to know is how I can add "jumping" to my game? Is there any "standard" way to do this in top-down games? I don't want a piece of code or something like that, just an explanation of how I can achieve this is enough. Thanks in advance!

Answer 1

So, the way jumping works in Zelda is kind of unintuitive at first, but if you think about it, it makes a lot of sense.

In modern games, sprites and models ARE the game objects, so we've become used to manipulating the thing as a whole whenever we need to do something. But in older games, sprites are only a visual representation of what is going on in the background.

Whenever you jump in Zelda, a flag (bool) gets set to indicate that the player is in the air, but the collider isn't affected. Whenever that "in air" flag is set, the player collider simply ignores the effects of other colliders like pits or enemies, but the collider still moves along the ground like normal.

While that's happening in the background, the sprite is just being moved up and down in a way that looks like jumping, while still following the position of the collider underneath, but it has no actual impact on what is happening in the background.

So, what I'm saying is that you should separate the collider from the sprite, then add your jumping animation to the sprite, and an "in air" bool to your collider interactions.

Though depending on how you've set up your code it might be easier to switch the object to a different layer.

Answer 2

For prototyping purposes, you could always use a coroutine. It will get things moving, but I would try to structure your code so physics are in a fixed update, eventually.

A coroutine is basically a process that runs on the side. It gives you enough flexibility to get the jump working while you fix your enemies. Be careful with coroutines though, I have seen some get way out of hand. You don't want too many, or too much going on in one. Memory leaks can happen here.

This is not how I would handle a jump, but it works. I would consider utilizing a state pattern for your character (even a small pseudo pattern could work.) This is not a terrible approach to a jump, though.

I am not in a place where I can test this, so this is just an example off the top of my head to show you what the syntax would look like.

void Update(){
  HandleInput(this);
}

private void HandleInput(IControllable controller){
  ...
  if(controller.jump)
    StartCoroutine(HandleJump());
}

// jumpHeightVector is a vector 3 with y being your jump height applied, the rest 0
private Vector3 jumpHeightVector = (0, jumpHeight, 0);

// every 10th of a second increments current time by 1
private float jumpInterval = 0.1f; // this would be responsible for a choppy movement
[SerializeField] jumpTime; //serialize this to show in inspector


private IEnumerator HandleJump(){

  // Important: let update know that this method is off limits
  controller.jump = false;
  anim.SetBool("jump", true);
  curJumpTime = 0;

  while(curJumpTime < jumpTime)
  {
    
    // may need better validation for landing in the right spot
    if(curJumpTime * 2 < jumpTime) Transform.Translate(jumpHeightVector); // up
    else Transform.Translate(-jumpHeightVector); // down

    // this always creates a new wait for seconds, consider assigning one of these in Start()
    yield return new WaitForSeconds(jumpInterval);

    curJumpTime++;
  }
  anim.SetBool("jump", false);
}

We have a coroutine that loops through a while loop while current jump time curJumpTime is less than our allowed jump time jumpTime . if we are less than half of the way through our jump, move up. If we are less than half, move down. When our elapsed jump time is equal to our allowed jumptime, we break the while loop. We also set our animation bool (you could even just use anim.Play("jump").