#Collisions between 2 CharacterBody2Ds pushing the other

1 messages · Page 1 of 1 (latest)

tulip gale
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I am making a puzzle game, where all of the blocks are CharacterBody2Ds. Once a match is made the blocks blast off in the x direction only. I want to add a velocity to the matching set and the player is trying to push the blocks to the right. So the more the match the more velocity is added.

I have them setup as CharacterBody2Ds in order to allow the new blocks to move in and collides. If a new block is falling and collides with a stack that is shooting it will collide and go for the ride.

I am not sure how to apply a velocity.x to the stack that are on top of the matched blocks.

game.png
urban bronze
tulip gale
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Basically, I want to apply a force going in the positive X direction.

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I had an x velocity, and changed it to velocity.x and deleted apply somehow.

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@urban bronze right now I was trying changing them from CharacterBody2Ds to RigidBody2Ds and use Gravity instead of move_and_collide (The F in the photo is falling from the right and landing on the stack. The game is played left to right and not top to bottom like a normal match 3)

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Unfortunately, with my Gravity attempt, when they collide, all of the blocks under it collide and shake the entire tower of blocks.

urban bronze
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with CharacterBody2D you need to use the move_and_slide() function

tulip gale
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This was my attempt at that.

urban bronze
# 
            var direction = Vector2(X,Y)
            velocity = direction * speed_float
            move_and_slide()
tulip gale
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#if matched:
#velocity.x += 200
#
#
#for index in get_slide_collision_count():
#var collision = get_slide_collision(index)
#if collision:
#print(collision)
#velocity.x += 200
#
#if velocity.x:
#move_and_slide()

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(How do I paste code like you have?)

urban bronze
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did you do that in _phyiscs_process(delta)?

tulip gale
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yes it's in the physics process, but I was not using delta because I was trying to get it to move period

urban bronze
urban bronze
tulip gale
# 
    if to_pos:
        if move_and_collide((to_pos - position).normalized() * speed * delta):
            to_pos = 0
            check_match.emit()
        
    if matched:
        velocity.x += 200
    
    
    for index in get_slide_collision_count():
        var collision = get_slide_collision(index)
        if collision:
            print(collision)
            velocity.x += 200
            
    if velocity.x:
        move_and_slide()```
urban bronze
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so you don't have to worry about it, as long as it's in process

tulip gale
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That was my entire physics process for that attempt

urban bronze
tulip gale
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It will absolutely print, I had it printing the word matched

urban bronze
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can you print velocity?

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WAIT

tulip gale
urban bronze
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so first remove the += lmao

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that's going to set some wonky numbers

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make it just = 200

tulip gale
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makes no different.

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One sec

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(I don't have one shot installed or I'd send you a screenshot of the console and the game)

urban bronze
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are you able to take a short video?

tulip gale
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Let me get it installed.

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I had just reformatted recently.

urban bronze
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basically I'd like to see what the behavior currently is, and then you tell me what you want it to do instead of what it shows

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unfortunately movement and physics debugging requires a bit of visuals :x

tulip gale
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nothing moves sadly.

urban bronze
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hmm

tulip gale
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It appears to very slightly shake, but none of the blocks move

urban bronze
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do you have gravity affecting them entirely

tulip gale
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Does gravity work on CharacterBody2D?

urban bronze
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it "can"

tulip gale
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No

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I didn't know it can. I was trying to use Gravity because I know I can push RigidBody2Ds

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My next solution is to go though the game loop and add the force to every block on top of the match, I was hoping I could use the matched blocks to push the other characterBody2ds

urban bronze
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how pixel perfect is your collision

tulip gale
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relatively close, top and bottom I had to remove a pixel from the collision on both sides or the game would think they would sometimes collide when falling in.

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This is what I am trying to do ultimately.

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This game functions top down, and I want to make it similiar just function left right

urban bronze
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so a tetris-like

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but from the side

tulip gale
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It's a match 3.

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When you match, a "rocket" is applied to the blocks and they fire off at the opponent.

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The more "booster" blocks in a row the higher the rocket goes.

urban bronze
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I would turn off any collision when that happens before applying velocity, so that they fly off without friction

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right now my belief is everything's "catching"

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then you'd have an Area2D to detect when they "hit" something

tulip gale
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I sadly need things to collid though

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Okay.

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I can do 90% of that in my head, my one hang up is how would I then make the blocks land ontop.

urban bronze
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new blocks, after it launches?

tulip gale
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Basically, block is falling in, I start to launch off the "rocket" and the falling block needs to land on the stack and fly with the stack

urban bronze
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oh. hmmmm

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actually i think i may see an issue

tulip gale
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Thats why I am using move_and_collide because I need to detect the collision

urban bronze
tulip gale
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yes, it is trying to move and vibrates

urban bronze
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does the collision match the sprite exactly

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are all the sprites "the same size"

tulip gale
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Inherited object, all are the same

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I am using filler images, I don't make the art, my wife does that.

urban bronze
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what's your Safe Margin set to

image.png
tulip gale
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Some are PNGs and some are JPGs so the PNGs have transparency.

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0.08

urban bronze
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set it to 0.

tulip gale
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So, earlier you said change it away from velocity.x += 200, is there a problem with using +=?

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I wanted to use that so as other blocks "hit" in the same row it would trigger more force.

urban bronze
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that's 200 pixels/second/second

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so 200->400->600->800

tulip gale
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exactly.

urban bronze
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in 4 seconds it travels 2000 pixels

tulip gale
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I need to write code so that the velocity "turns off"

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And it only lasts a second

urban bronze
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oh. well alright :V

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set your margin to 0.0

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see if the jittering stops

tulip gale
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It did

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It doesn't move at all, but the jitterig stopped

urban bronze
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okay cool

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so now

tulip gale
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Any idea how to make them move though? lol

urban bronze
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move and collide will have them stop when they collide

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unless they have something telling them otherwise

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your code hasn't changed right?

tulip gale
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The move and collide is ONLY used when they are falling in

urban bronze
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ah gotcha

tulip gale
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Afterwards, it's all move and slide

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I just want the collide part so a falling in block will land on top of the stack if the top of the start has changed since it was calculated and set to fall.

urban bronze
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trynna think

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i would recommend

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using move_and_collide for the rocket liftoff as well

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because that returns the object it collides with

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which can then call the function to move THAT object

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right now it's move_and_sliding into objects and stopping.

tulip gale
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Okay, how do you turn them all off at the same time?

urban bronze
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wdym turn them all off

tulip gale
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All blocks are going in a positive x for a... second? And all blocks need to start falling back to their board position after that second

urban bronze
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only the blocks that are colliding should be positive x

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i may be confused about the end goal here

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Gameplay loop:

  1. Blocks fall from right
  2. You combine 3
  3. Those blocks fly to the right and explode/queue_free on colliding with [target], collecting more blocks along the way
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correct?

tulip gale
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Okay, so they CAN fly off and explode, but its not garantteed. Basically, the blocks have to reach the max height of your gameboard and then they are removed. BUT the postive X force is only applied to the blocks for a short period of time.

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Now, if you have 3 in the same row that were matched, += 200

urban bronze
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use either a timer node, or a float timer function

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build up the timer using whatever mechanic you want

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on timer complete, it falls back left

tulip gale
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I come from a web gaming background, and I think I am overthinking it.

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Javascript forces you to do a lot of.... cleanup to make sure things go smoothly, and I am thinking that the force is going to be applied not uniformly in one single delta of time.

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Oh wait, if I use move_and_collid won't the block that collids stop moving and the block on top of it would start?

urban bronze
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only if you stop applying velocity

tulip gale
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Oh.

urban bronze
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if you have move_and_collide under an if statement and it just keeps going, it won't stop

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it may reset velocity but it won't stop

tulip gale
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Yeah yeah....

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I'll play with it, if you don't mind I might mention you later and pick your brain, if that's okay.

urban bronze
urban bronze
tulip gale
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@urban bronze Really quickly, I use this all the time, is there anything wrong with doing it?

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await get_tree().create_timer(randf_range(1.7, 3.3)).timeout

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Instead of making a timer node

urban bronze
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no that's perfect

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i alternate between them depending on what im doing with it

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for my weapon cooldowns I'll use a timer node for example

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but for things like a timer for hitflash I'll just use a scenetree timer

tulip gale
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I use a timernode for anything I might need to cancel

urban bronze
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yeah

tulip gale
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If it is what it is, then it is what it is

urban bronze
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i think a good rule of thumb is, if it's going to just fire once and can't be interrupted? just use a scenetree timer

tulip gale
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I am new to godot, so I am doing a gamejam and using it.

urban bronze
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when you're done w/ the gamejam, i recommend this thorough, in depth, and easy to follow tutorial

https://youtu.be/nAh_Kx5Zh5Q?si=H0KGxxkxW_rzXSgn

YouTube
Clear Code
The ultimate introduction to Godot 4

This video is sponsored by NordPass Business: An amazing password manager that allows you to securely store and access unlimited passwords, including wifi credentials and credit card information. You can use it for yourself or for entire teams or share your own passwords easily.

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...

▶ Play video
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it's 15 hours, which is why i recommend it after the gamejam

tulip gale
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Already did it

urban bronze
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oh lmao

tulip gale
urban bronze
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then you're about where I'm at technical-wise gdchan

tulip gale
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lol

urban bronze
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i just have experience w/ more "difficult" engines, like UDK before it was Unreal 4

tulip gale
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I did a lot differnet hen he did

urban bronze
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so godot is extremely easy for me to pick up 🤷‍♀️

tulip gale
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It was, I hated Unity

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I made flashlight, and played with things while making it, best way to learn is to challenge yourself.

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He never taught inline timeout method for example.

urban bronze
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fair

tulip gale
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I made games for girls for a living since 2007, and that's been my primary source of income, covid changed things, had kids and now I want to make stand alone games.

urban bronze
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i look forward to seeing what you put out!

tulip gale
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I am going to make horror games

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lol

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Ahhh

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Okay, small question I thought it worked this way and it appears I am in error.

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var body = move_and_collide(velocity * delta)

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I thought move_and_collide would return the object I collided with?

# 
  func _physics_process(delta):
    if to_pos:
        if move_and_collide((to_pos - position).normalized() * speed * delta):
            to_pos = 0
            check_match.emit()
    
    if !flying && (matched || launched):
        flying = true
        velocity.x += 200
    
    if velocity.x:
        print(velocity.x)
        var body = move_and_collide(velocity * delta)
        if !body.launched && !body.matched:
            body.launched = true
            
        stop_launch()

func stop_launch():
    await get_tree().create_timer(1.0).timeout
    velocity.x = -speed```
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@urban bronze

urban bronze
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hang on

tulip gale
urban bronze
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func KnockbackMovement(delta):
    velocity = KnockbackDir * AdjKnockbackDis
    var CollideData = move_and_collide(velocity * delta)
    if is_instance_valid(CollideData):
        KnockbackActive = false
        SetCanMove(true)
        CollidedObj = CollideData.get_collider()
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so you move_and_collide into a variable

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then you check if it's valid

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and then you can get_collider to get the colliding object

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now it doesn't QUITE work the same way as Godot 3

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but it still works mostly like this

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the returned object has information about the collision. one of those is the collider.

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does that make sense?

tulip gale
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Absolutely, but its not working for me.

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I am trying to read to find out why

urban bronze
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show me your code

tulip gale
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Invalid get index launched

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launched should be a variable inside of the collided object, and once it does collide that object should itself fly upwards

urban bronze
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it's colliding with a staticbody

tulip gale
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Nevermind, I found why but...

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Yeah it was colliding with the floor I set when I was using the area solution

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I am going to need to add a small gap between rows, so it stops colliding with anothe row

urban bronze
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use the .has_method(string) method to check

tulip gale
urban bronze
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OH GOD LMAO

tulip gale
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yeah right

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That's horrible. lol

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I may need to go through them all manually, as it's tiggering on blocks below it.

urban bronze
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make sure your collision is pixel-perfect inside the scenes 🤷‍♀️

tulip gale
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I wish there was somewhere to type in exactly what I want it to be

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I don't have a way to set a CollisionShape2D to 64x64 and not just draw it by hand.

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I used ctrl when making it.

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Safe Margin, minimum is 0.001

urban bronze
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maybe shrink the top/bottom

tulip gale
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I already had,

urban bronze
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but have an area that checks adjacent tiles instead of checking for collision

tulip gale
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Randomly launches ones behind it

urban bronze
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WEIRD

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but at least better

tulip gale
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Tried adding a margin and the landing blocks shake like michael j fox

urban bronze
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i'll let you play with it, this is above my pay grade now

tulip gale
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lol

urban bronze
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and i have deadlines (that i set myself for myself) to hit :V

tulip gale
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mine too

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Good luck, what are you making?

urban bronze
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just a simple zelda-like

tulip gale
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Or a Zombie Survivor?

urban bronze
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no

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like uh

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the goal is to go into dungeons and kill bosses lol

tulip gale
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@urban bronze Okay, so I want to get away from using a physics process in this. Any idea how to detect a collision in move_and_slide?

urban bronze
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_physics_process(delta) is actually the recommended place to have ANY movement

tulip gale
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The phyics processes add so much vibration that this seems like the wrong hill to die on

urban bronze
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but i see what you mean

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"no but"

tulip gale
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I am trying to fix bugs, where all I really want is this to move to a pixel perfect position, with the exception of a block falling in and when it would collide with a rising block, instead just have it's... velocity become that of the rising block

urban bronze
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If the other body is a CharacterBody2D or RigidBody2D, it will also be affected by the motion of the other body. You can use this to make moving and rotating platforms, or to make nodes push other nodes.
tulip gale
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I am using a CharacterBody2D for everything, I just feel like I'd rather go back to an node2D and use a tween, if I could only get that one collision

urban bronze
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you have to use a Body™️ for collision

tulip gale
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Even if I had an area2D instead it?

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With a collision body?

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Otherwise is there a way to turn the phyics processes off?

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I want no jitter.

urban bronze
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$Door/DoorCollision/CollisionShape2D.set_deferred("disabled", true)
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apply it to the shape

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call it deferred so it happens after the tick and not during a physics process

tulip gale
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instead of instantiate?

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LOL

urban bronze
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what no lol

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instantiate does something entirely different

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you were asking how to turn physics off

tulip gale
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(game went terrible that's why lol)

urban bronze
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that's how lol

tulip gale
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I am going to eat something and see if I get an epiphany.

tulip gale
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@urban bronze So basically I went back to Node2Ds and away form physics because there is no easing on the physics settings. I detect if the block before current blocks X position is <= 64 of current and then go with that block. I am making this in Godot, but Godot is not being used as a game engine, its no different then if I had just made it in Canvas.

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If you're curious, Canvas the HTML element.

urban bronze
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fair enough

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the fact that you can do it that way is funny tho lol

tulip gale
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I've done this for years, honestly it's disappointing

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Godot isn't doing anything to help me in this game, it's just... a holding at this point

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Obviously in your game, the engine does a lot more, but in my case Physics needs something it doesn't have in the engine. I have no way to say an object once colliding can only move in the X direction and there set 0 Y physics.

urban bronze
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i mean it might, im just not that good at it :V

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im a very good "basics" kinda guy but outside of that 🤷‍♀️

tulip gale
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@urban bronze No it doesn't, I talked to a bunch of people last night. Also, do you happen to know if anyone has made bubble bobble in this engine? I have one I made in just native Javascript, I am curious to see what they used to do it.

urban bronze
tulip gale
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It is my current belief that Godot is not well suited at things like that.

tulip gale
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@urban bronze Do you know if there is an operand in GD script where I can say x = 15 or y whichever is higher

urban bronze
slim tartan
slim tartan
# tulip gale I am making a puzzle game, where all of the blocks are CharacterBody2Ds. Once ...

As for the original problem, sorry, I just got here but from a skim of the thread my advice would be to ditch the built in godot physics engine and roll your own physics where you can have absolute control over everything that's happening.

The purpose of a general physics engine is to simulate the kinds of unpredictably complex interactions you would see in a real physical space. But you're making a puzzle game, which by its nature is a highly controlled theoretical space. So the two concepts are at odds here and that's why it's giving you so much trouble.

slim tartan
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I suppose an alternative would be using rigid bodies instead of character bodies and providing a custom _integrate_forces function that keeps tiles snapped to their row's y position, but I can't say if that would address all of your problems. It should keep things from drifting up or down incorrectly though.

tulip gale
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@slim tartan I rebuilt the entire thing using node2Ds and it just checks is another block is within 64px of itself. It works, it's just no different from using javascript to make the game.

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Thank you for your suggestions though, I will look into _intergrate_forces later this week.

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@slim tartan I have also never thought of using max that way, most languages have a better Ternary functionally than GDscript does. x = (x < 1) ? x : 1

slim tartan
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I kind of like gdscript's ternary operator. It's easier to read than c++ at least, just more verbose.

tulip gale
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In most languages the agreed upon nomenclature is the x = (x < 1) ? x : 1

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I think in max() is an excellent suggestion though.

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It's just what I have been used to for years.

slim tartan
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Most c-like languages, I guess. gdscript is more in the python family so does ternaries in that way.