Moving collision box manually based on collisions

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Moving collision box manually based on collisions

Jerry7

Let's say I want:
1) The player object to detect a tile below while somersault jumping like in contra (= shorter collisionbox)
2) When a tile is detected, change the player to using a taller, standing collisionbox. This would probably mean that player is now colliding with the tile.
3) move the player up until it is standing on said tile and no longer colliding

How would you do this?

My current approach has an Area2D+CollisionShape2d, if the Area2d detects a body it sends a signal:

func _on_FloorDetect_body_shape_entered(body_rid, body, body_shape_index, local_shape_index):
var coordinate: Vector2 = Physics2DServer.body_get_shape_metadata(body_rid, body_shape_index)
var tileid = tilemap.get_cellv(coordinate)
var shapes = tilemap.tile_set.tile_get_shapes(tileid)
var shape = shapes[0]["shape"]
var otherTrans = shapes[0]["shape_transform"]
var contacts = FloorDetectShape.get_shape().collide_and_get_contacts(FloorDetectShape.transform, shape, otherTrans)

I don't get any contacts like this, it's something about the transforms most likely.
But even if I get the contacts, I'm not sure how I'd proceed with them.
here's some hints here how to use them, but I don't think I quite get it yet.
https://docs.godotengine.org/en/stable/classes/class_shape2d.html#class-shape2d-method-collide-and-get-contacts

The other idea would be to use 16 downward Raycast2ds (Width of the player collisionboxes) and determine player vertical position based on those, but this seems like a non-optimal approach.

Any better ideas or improvements on this?

SnapCracklins

Jerry7 you should be able to save a CollisionShape as a resource, preload it, then change it when needed during the physics process.

Just a note: if you change physics elements, only change them in the physics_process function or you'll get errors, often, usually null pointers because physics will not load until the first frame loads, usually right after ready (more experienced devs, please correct me if I am wrong here).

Assuming your player is called $PlayerObject with a CollisionShape2D child called '$Collision':

var _defaultPhysicsBox = preload("insert filepath here")
var _somersaultPhysicsBox = preload("insert filepath here")
var _isSomersault = false

func _physics_process(_delta):
      if _isSomersault:
           $Collision.shape = _somersaultPhysicsBox
      else:
           $Collision.shape = _defaultPhysicsBox

You likely won't use "else" as if it's Contra style you likely have some other player states. But that should work? Alternatively, you could even just change the radius as long as its centered on the player object.

Jerry7

Thanks for the input.

In my current setup I have a CollisionShape2D for both standing and somersaulting, which are enabled based on the player state. So I believe I'm doing what you are suggesting already, although a bit differently.

What I wish to do is to:
1) Use the somersaulting collisionbox while jumping, so it can be used like a crouch jump to reach platforms that you couldn't while using the standing collisionbox.
2) While somersaulting, detect the floor well below the actual somersaulting hitbox, switch to standing collisionbox and move it upwards until it no longer collides with floor.

So as an example, there's an obstacle that the player is unable to jump over normally. He then does a somersaulting jump and is able to go over the obstacle. Instantly after the obstacle is detected X units below the somersaulting hitbox, we switch to the standing hitbox and the player is left standing on top of the obstacle.

I'm able to detect the floor and change the collisionshape, but the result of the collision with the obstacle is that the player is not pushed upwards, but backwards, resulting in the player not being able to go over the obstacle.