Introduction to GDScript in Godot 4 Half 2

Earlier than beginning with this a part of the tutorial, be sure you completed the primary half as this half will construct upon the basics laid down there.
On this second a part of the tutorial, you’re going to study in regards to the following:

  • The fundamentals of state machines.
  • Including and eradicating nodes with code.
  • Making a digital camera that follows a node.
  • Utilizing UI components to tell the participant.

With out additional ado, it’s time to get again to scripting!

Getting Began

Obtain the initiatives by clicking Obtain Supplies on the high or backside of the tutorial. Subsequent, unzip the file and import the starter folder into Godot. Alternatively, you’ll be able to proceed with the mission you used within the earlier half.

On the finish of the earlier a part of this tutorial, gravity was continuously being utilized on the participant avatar, permitting it to leap and fall again down. This had the facet impact of the avatar by no means having the ability to stand on the bottom beneath, so it’s important to constantly leap now.

Robot constantly jumping and falling

Ideally, the avatar ought to keep on the bottom and may solely fall down as soon as he’s within the air. A method of maintaining observe of those states is utilizing a finite state machine.

Finite State Machines

A finite state machine (FSM) is a technique to break down a recreation or utility into completely different states. Take a easy journey recreation for example: you might need a recreation state for strolling round, a state for preventing and a state for when the recreation menu is open. Whereas the participant is exploring, you may disguise the UI for full immersion, whereas in battle you need to present well being bars, expertise and so forth. In the meantime, you need to pause the sport within the background when the menu is open so the participant can handle his stock and alter settings.

Programming what ought to occur in every state of affairs and not using a FSM results in messy code with lots of if-statements strewn about. It’s additionally liable to errors and tougher to debug. With a FSM, you create three states:

The present state is saved in a variable and relying on the energetic state, a special code path is adopted. You’ll be able to even add transitions between states the place UI components fade in or out for instance.

For this recreation, there are two doable states: on the bottom and within the air. The sport begins with the avatar on the bottom, the place it will probably do a handbook leap and isn’t effected by gravity. As soon as the avatar has jumped up, it’s within the air and gravity will get utilized to it. So as to add this to the script, begin by including the next line on the high of the script, beneath var velocity : Vector2 = Vector2.ZERO:

enum AvatarState {ON_GROUND, IN_AIR}

AvatarState isn’t a variable, however an enum, which is a set of constants. Enums are helpful as you’ll be able to entry their worth by their key, that are ON_GROUND and IN_AIR on this case. Behind the scenes, the values of those keys are integers ranging from 0. You should use an enum as a sort as you’ll see beneath.
To maintain observe of the energetic state, add this variable declaration proper above the enum you added:

var state : AvatarState = AvatarState.ON_GROUND

The state variable makes use of AvatarState as its kind and units its default worth to AvatarState.ON_GROUND. This variable will are available in use to maintain observe of the avatar’s state and react accordingly. To use the finite state machine idea to the remainder of the script, you’ll must make a number of modifications to its construction. To begin with, add these two capabilities beneath the _process operate:

func _process_on_ground() -> void:

func _process_in_air(delta) -> void:

Relying on the state, the corresponding operate shall be known as each body. This splits up the logic in response to the state, which is the idea of each FSM.
Now add this block of code to _process, proper beneath var cursor_right:

match state: # 1
    AvatarState.ON_GROUND: # 2
    AvatarState.IN_AIR: # 3

Right here’s what this code does:

  1. This match assertion reads the worth of state and branches the additional execution stream relying on its worth. This could change if-statements the place the one distinction is a single worth and ends in a cleaner, extra readable outcome. Should you’re conversant in different programming languages, the match assertion is much like a change assertion, albeit with some further options.
  2. In case the worth of state is AvatarState.ON_GROUND, name _process_on_ground.
  3. In case the worth of state is AvatarState.IN_AIR, name _process_in_air.

Be aware that the match assertion, its branches and the logic for every department wants its personal indentation.
With the finite state machine in place, it’s time to maneuver the method code to their acceptable capabilities. To begin off, transfer the decision to _process_input from _process to _process_on_ground, changing the cross key phrase. This ensures the avatar can’t manually leap if it’s not on the bottom. The _process_on_ground operate ought to appear like this now:

func _process_on_ground() -> void:

Subsequent, the gravity ought to solely be utilized when the avatar is within the air, so transfer the road velocity.y += delta * gravity from _process to _process_in_air, changing the cross key phrase. The _process_in_air operate now appears like this:

func _process_in_air(delta) -> void:
    velocity.y += delta * gravity

Should you run the mission now and make the avatar leap, you’ll discover the avatar is again to his house rocket methods as gravity isn’t being utilized. This is sensible, as gravity is now solely utilized within the IN_AIR state, whereas the avatar by no means switches to that state. To repair that, add the next line to _jump operate:

state = AvatarState.IN_AIR

This modifications the state to IN_AIR after a leap, so gravity will begin getting utilized. Run the mission once more and check out leaping, the avatar will now leap and fall down and… retains falling down. Hey, it’s progress!

Robot jumps and falls down through ground

As with all the opposite points you’ve confronted all through the tutorial, this too might be mounted with some code. The present downside is the avatar has no concept the place the bottom is, and in consequence, has no technique to react to falling on the bottom. Fortunately, it’s straightforward to determine the place the bottom is, as that’s the avatar’s beginning place. You simply want to save lots of that place someplace, if solely there was some form of container to retailer values into. :]

Sure, you want one other variable! Add this line to the highest of the script, proper beneath var state:

var start_height : float

This can retailer the Y place of the avatar at the beginning of its lifetime, its beginning peak. You don’t have to offer it a default worth on this case, as its worth shall be set within the _ready operate. Talking of which, add this line to _ready, changing the print assertion that’s in there:

start_height = global_position.y

This units start_height to the preliminary Y place of the avatar. To make use of this beginning peak to detect the bottom when falling, add the next to the _process_in_air operate:

if velocity.y > 0: # 1 (falling)
    if global_position.y >= start_height: # 2
        var _result = get_tree().reload_current_scene() # 3
else:  # 4 (going up)

For simplicity’s sake, the scene will get reloaded if the avatar hits the bottom after falling. This resets the sport state with out having to reset any variables. Right here’s a breakdown of the completely different elements:

  1. If the avatar’s vertical velocity is constructive, meaning it’s falling down.
  2. If the Y place of the avatar is the same as the beginning peak or strikes previous it whereas falling…
  3. Restart the present scene utilizing get_tree().reload_current_scene(). The get_tree() name returns an occasion of SceneTree, which is a node supervisor class that comprises helpful strategies for working with scenes and nodes. A kind of strategies is reload_current_scene(), which reloads the energetic scene and returns a outcome code. The outcome code is ignored for this instance.
  4. If the avatar is shifting up, do nothing for now.

Run the mission once more, this time the scene will reset as soon as the avatar hits the bottom, permitting you to maintain “enjoying” indefinitely. There’s now a recreation loop, even when it’s not essentially the most thrilling one.

Robot jumping up and down

Now is an effective time to make the avatar leap up when hitting jumpers, in spite of everything, that’s what they’re for!
To take action, you simply want to attach the Area2D‘s area_entered sign to the player_avatar script such as you did with the jumpers. To recap, choose Area2D within the Scene dock, open the Node tab on the best facet of the editor and double click on the area_entered sign. Lastly, click on the Join button to create the brand new _on_area_2d_area_entered operate.
Add this line to the newly created _on_area_2d_area_entered operate, changing its cross key phrase:


This makes the avatar routinely leap when hitting jumpers. Guess what? It’s time for an additional check run! Run the mission and see if you happen to can hit all three jumpers earlier than hitting the bottom once more.

Robot jumping on orbs

I hope you agree that this begins to really feel like a recreation now. It would even already slot in with WarioWare‘s microgames. :]

Avatar Ending Touches

As a ultimate addition to the avatar script, the animation and route of the sprite ought to change relying on the state and motion route. Step one to do this is getting a reference to the kid node AnimatedSprite2D. Keep in mind the drag-and-drop trick so as to add node references: drag AnimatedSprite2D onto the player_avatar script and maintain CTRL/CMD earlier than releasing.

This can add the next code:

@onready var animated_sprite_2d: AnimatedSprite2D = $AnimatedSprite2D

Rename animated_sprite_2d to sprite as the unique identify is a bit wordy. Subsequent, add the next if-statement to the _process_on_ground operate:

if velocity.x == 0:
    sprite.animation = "idle"
    sprite.animation = "run"

This can change the avatar’s animation when it’s on the bottom. If there’s no horizontal velocity, the idle animation is performed, whereas run is performed if the avatar is shifting. As with the jumpers, yow will discover these animations by clicking the AnimatedSprite2D node and looking on the backside of the editor.

robot animations, falling, idle, jump, run

Check the sport once more to see the outcomes. Discover the avatar isn’t switching to his idle animation, why is that?

GIF of robot stuck in walking animation

To research the issue, add this print name proper above the if-statement you added in _process_on_ground:


This can print out the avatar’s present velocity, which needs to be (0, 0) when the avatar is on the identical horizontal place because the cursor. Run the mission as soon as once more and keep watch over the console within the editor.

Console never reads zero zero

Discover how the avatar’s X velocity isn’t zero. It is because there are solely two methods the avatar can transfer in the intervening time: left or proper. That is as a result of approach the motion code is ready up in _process:

var cursor_right : bool = (mouse_pos.x - global_position.x) > 0


if cursor_right:
    if global_position.x < viewport_size.x - viewport_border:
        velocity.x = move_speed
    if global_position.x > viewport_border:
        velocity.x = -move_speed

Mainly, the avatar could have a constructive X velocity if the cursor is correct and in all different circumstances it’ll have a destructive X velocity. You’ll be able to add a case the place the X velocity shall be zero if the cursor is already near the avatar. For this, you’ll want to maintain observe of the gap to the cursor, which is already executed by the cursor_right variable with mouse_pos.x - global_position.x.

To retailer this calculation in a variable, change the cursor_right variable declaration with the next two traces:

var cursor_x_pos_relative_to_avatar : float = mouse_pos.x - global_position.x
var cursor_right : bool = cursor_x_pos_relative_to_avatar > 0

This provides a descriptive variable named cursor_x_pos_relative_to_avatar that replaces the relative place calculation cursor_right was utilizing. As earlier than, the worth of this calculation is the gap between the avatar and the cursor, with a constructive worth that means the cursor is to the proper of the avatar.
Now you want a variable that units the minimal distance to the cursor earlier than the avatar strikes horizontally, so add this on the high of the script, beneath var gravity:

@export var min_distance_before_move : float = 10.0

This units the gap in pixels to the cursor earlier than the avatar will transfer. To make use of the variables you added, change the if-statement in _process with the next:

if abs(cursor_x_pos_relative_to_avatar) > min_distance_before_move: # Added this line
    if cursor_right:
        if global_position.x < viewport_size.x - viewport_border:
            velocity.x = move_speed
        if global_position.x > viewport_border:
            velocity.x = -move_speed

Solely the primary line is new code right here, which does the next:

  • abs is brief for absolute and returns absolutely the worth of any given parameter, which suggests the worth turns into constructive. -1 turns into 1 for instance.
  • cursor_x_pos_relative_to_avatar, the gap to the avatar, is now at all times constructive. If this distance is larger than the minimal transfer distance, proceed with the motion logic.

Now run the mission once more and also you’ll see the avatar lastly stands idle when the cursor is close to.

GIF of robot walking and standing still correctly

Go forward and take away the print line from _process_on_ground now, as that’s not wanted anymore.
To make the avatar flip in the best route, add this one-liner to _process, proper beneath var cursor_right:

sprite.flip_h = !cursor_right

This units the flip_h property on the avatar’s Sprite2D node to true if the cursor is to the proper, and false if it’s to the left. The exclamation level inverts the worth of cursor_right, altering true into false and vice-versa.
Check out the modifications by urgent F5 and making the avatar transfer round, it ought to now rotate as anticipated.

GIF of robot facing cursor left and right

As a ultimate cherry on high, the animations for leaping and falling needs to be set as effectively. To do that, add the next line to the _process_in_air operate, contained in the if velocity.y > 0 case:

sprite.animation = "falling"

Subsequent, add this line to the else case of the identical if-statement, changing the cross:

sprite.animation = "leap"

These two traces change the energetic animation like they did for the idle and run animations.
The complete _process_in_air operate ought to appear like this now:

func _process_in_air(delta) -> void:
    velocity.y += delta * gravity

    if velocity.y > 0:
        sprite.animation = "falling"
        if global_position.y >= start_height:
            var _result = get_tree().reload_current_scene()
        sprite.animation = "leap"

Run the mission as soon as extra to check the leap and fall animations.

GIF of robot jumping and falling

That completes the participant avatar for now!
With the jumpers and avatar absolutely working, it’s time so as to add a complete bunch extra jumpers so the avatar can get to new heights.

Instantiating Scenes With Code

The subsequent step on this little recreation is routinely spawning a bunch of jumpers by way of code. To begin off, delete all Jumper nodes from the recreation scene by deciding on all of them and hitting Delete in your keyboard.

Jumper, Jumper2, Jumper3 highlighted

Subsequent, create a brand new baby node for the Recreation node by right-clicking it and deciding on Add Little one Node. Within the Create New Node window, choose Node2D for its kind and click on the Create button on the backside.

GIF of node creation process

This new node will act as a dad or mum node for the jumpers you’ll be producing, so identify it Jumpers. You are able to do this by urgent F2, or by right-clicking the node and deciding on Rename within the context menu. Now that you just ready the sport scene, it’s time so as to add one other script! Choose the Recreation node and click on the Add Script button so as to add a brand new script, go away it at its default identify and ensure to create it within the scripts folder.

New script window

Godot will now open the brand new recreation script within the script editor, prepared so that you can add logic. Firstly, you’ll want a reference to the jumper scene to have the ability to create new situations of it. Probably the most versatile approach to do that is by exporting a PackedScene variable, so you’ll be able to change what scene to spawn by way of the editor. To do this, add the next line beneath extends Node2D:

@export var jumper_scene : PackedScene

PackedScene is an interface to a scene file which lets you instantiate nodes in your scene in a while. Save the script and reselect the Recreation node within the Scene dock. You’ll now see a brand new property showing within the Inspector named Jumper Scene.

Jumper Scene empty

To assign a scene, drag the jumper.tscn scene file from the FileSystem dock onto the property or click on the property and choose Fast Load ▸ scenes/jumper.tscn.

GIF of selecting jumper scene

Subsequent, you want a reference to the Jumpers node, so drag that node onto the script editor whereas holding CTRL/CMD so as to add this line:

@onready var jumpers: Node2D = $Jumpers

Rename this variable to jumpers_parent to keep away from confusion in a while. With each references in place, now you can create new jumpers. For a fast check, add the next to the _ready operate, changing the cross key phrase:

var new_jumper = jumper_scene.instantiate() # 1
jumpers_parent.add_child(new_jumper) # 2

This can instantiate a brand new jumper and add it as a toddler of the Jumpers node:

  1. Instantiate an occasion of the jumper scene and retailer its reference in a new_jumper variable.
  2. Make the brand new jumper a toddler of jumpers_parent, the Jumpers node within the Scene dock.

Now run the mission by urgent F5 and have a look round. Can you see the jumper?

Partially hidden orb at top left of screen

It’s on the high left of the window, largely hidden. This isn’t as a result of it’s shy, however as a result of its default place is at (X:0, Y:0), which occurs to be the highest left of the window.
The code works although, which is the essential half! To randomly spawn the jumpers, you’ll want to consider what number of and the place to spawn them first. Think about the next parameters:

  • Quantity of jumpers
  • Top of first jumper
  • Y-spacing between jumpers
  • Random X-position vary

Illustration showing blue orb with arrows and text

The illustration above is a visible illustration of most of those parameters. With this in thoughts, add the next variables proper beneath @export var jumper_scene:

@export var jumpers_to_spawn : int = 50 # 1
@export var first_jumper_height : float = 400.0 # 2
@export var spacing_between_jumpers : float = 350.0 # 3
@export var jumper_x_pos_spawn_range : Vector2 = Vector2(80, 930) # 4

These will let you tweak the parameters within the editor till the gameplay feels good. The defaults I present right here felt proper to me, however be at liberty to alter them in a while.
Right here’s a fast rundown:

  1. I feel this one speaks for itself, it’s the quantity of jumpers to spawn.
  2. That is the Y-position of the primary jumper.
  3. The vertical quantity of pixels between every jumper. Smaller values make the sport simpler, whereas greater values present extra problem.
  4. The minimal and most X-position of every jumper, represented with a Vector2. Each new jumper could have a random place inside this vary.

Now for the enjoyable half: coding the logic that can use these parameters to generate a load of jumpers. Create this new operate beneath _ready:

func _create_jumpers(start_pos : float) -> void: # 1
    for y in vary(0, jumpers_to_spawn): # 2
        var new_jumper = jumper_scene.instantiate() # 3
        jumpers_parent.add_child(new_jumper) # 4
        var jumper_x_pos = randf_range(jumper_x_pos_spawn_range.x, jumper_x_pos_spawn_range.y) # 5
        var jumper_y_pos = -y * spacing_between_jumpers + start_pos # 6
        new_jumper.global_position = Vector2(jumper_x_pos, jumper_y_pos) # 7

At first look, this may look a bit daunting. By wanting on the separate items although, you’ll see it’s not too difficult:

  1. The _create_jumpers operate takes a single parameter: start_pos, which is the place of the primary jumper.
  2. This can be a for-loop, it’ll execute the code beneath it a certain quantity of occasions and maintain observe of the occasions it has ran. On this case, vary is used to make it run from 0 to the quantity of jumpers to spawn. The quantity of occasions it has looped is saved within the y variable.
  3. Instantiate a brand new jumper and retailer a reference to it in new_jumper.
  4. Make the brand new jumper a toddler of jumpers_parent.
  5. The randf_range methodology accepts two numbers and returns a random quantity between the 2. The X and Y values of jumper_x_pos_spawn_range are handed into it, as these are the minimal and most X-positions for the jumpers. The output is saved in jumper_x_pos.
  6. Right here, the y variable from the loop is negated and multiplied with the spacing between the jumpers. Keep in mind, destructive Y is up in Godot, which is why the worth is negated. The beginning place is used as an offset, so it’s added as effectively. The result’s the Y-position for the jumper, which is saved in jumper_y_pos.
  7. Set the place of the brand new jumper to the X and Y-position calculated within the earlier two steps.

I hope that cleared up how this operate works. It makes use of among the mostly utilized strategies like vary and randf_range, that are invaluable instruments when creating your personal video games.
Now you simply must name it to really create the jumpers, so change all the things in _ready with this line:


This calls the operate you created and passes the peak of the primary jumper it ought to create. Time for an additional check run! Play the mission and examine if the jumpers are created. If all went effectively, try to be seeing two jumpers on the display.

Two orbs in sky

Should you leap on them, you may get the avatar to super heights and… Oh proper, the digital camera is stationary so the avatar vanishes within the air while you hit the jumpers.

GIF of robot jumping against orb and flying up

Digicam Observe and Background Scrolling

Up till now this wasn’t a problem because the avatar couldn’t leap excessive. Now although, it’s clear the digital camera must comply with the avatar. For this you’ll must create one other script.
Choose Camera2D and create a brand new script named within the scripts folder. Take away its _ready operate and add these variables as a replacement:

@export var node_to_follow : Node2D # 1
@export var follow_speed : float = 10.0 # 2
@export var y_offset : float = -650.0 # 3

These are all variables you want for a digital camera to comply with a node round:

  1. The Node2D to comply with. You’ll assign the avatar node to this.
  2. The pace in pixels per second at which the digital camera will transfer in the direction of its goal.
  3. An offset of digital camera’s Y-position relative to the goal. This transfer the digital camera up vertically so the avatar on the backside of the view.

Now save the script and reselect Camera2D within the Scene dock. Drag the PlayerAvatar node from the Scene dock onto the Node to Observe property within the Inspector to set it because the digital camera’s goal.

Note to Follow, PlayerAvatar

Subsequent, add this to the _process operate, changing the cross:

var target_position = Vector2(global_position.x, # 1
    node_to_follow.global_position.y + y_offset)
global_position = global_position.lerp(target_position, delta * follow_speed) # 2

This makes the digital camera comply with its goal easily:

  1. Calculate the place the digital camera needs to be. It’s X-position will at all times keep the identical, however its desired Y-position is the same as that of the node it’s following plus the Y-offset. Retailer this worth in target_position.
  2. This modifications the digital camera’s place by utilizing the lerp methodology, which stands for linear interpolation. lerp means that you can easily transition from one place to a different. Its first parameter is the ultimate place and the second parameter is the quantity of pixels to maneuver in a body to achieve that place. The digital camera will transfer nearer to its objective a tiny bit each body.

Play the mission to check the digital camera out. It ought to now comply with the avatar round when leaping and falling.

Robot jumping from orb to orb

Superior! The fundamental gameplay is now full, if you happen to needed this recreation to final lower than a minute anyway. Right here’s a problem for you if you happen to really feel prefer it: attempt to attain the highest of the jumpers. This will provide you with a really feel for the stability of the sport, so you’ll be able to tweak the gap between jumpers, the avatar’s leap peak, gravity and so forth.

Whereas enjoying round, you might need seen the background doesn’t transfer. This isn’t an enormous difficulty, however if you wish to add that further splash of polish, comply with alongside the subsequent optionally available steps to make it scroll. Alternatively, you’ll be able to skip to the Creating Infinite Jumpers part to complete up the sport.

The background is a Sprite2D with a seamless background as its texture. This implies it may be scrolled alongside its Y-axis with none gaps or noticeable modifications. You can also make it scroll alongside based mostly on the digital camera’s place with a number of traces of code.
Choose Background and create a brand new script named within the scripts folder. Add the next variables beneath extends Sprite2D:

@export var starting_position_offset : Vector2 = Vector2(0, 1024) # 1
@export var texture_size : Vector2 = Vector2(1024, 2048) # 2
@export var scroll_multiplier : float = 0.25  # 3

Right here’s what these are used for:

  1. That is an offset that shall be utilized to the background’s place at the beginning. That is wanted to maneuver the sprite up a bit, so it fills the window.
  2. The scale of the ultimate texture. The background texture’s dimension is 1024×1024 pixels, however you want extra vertical house so no gaps will seem on the edges. For regular textures, this is able to stretch the feel and make it look horrendous. The background texture is ready to repeat although, so it merely provides extra of the identical texture vertically.
  3. This worth will get multiplied with the digital camera’s place for a parallax-like impact because the background strikes slower than the digital camera.

Subsequent, add this to _ready to set the preliminary place for the background:

global_position = get_parent().global_position - starting_position_offset

This modifications the background’s place to that of its dad or mum, Camera2D and subtracts the place offset from it.
Lastly, add this to _process to finish the script:

region_rect = Rect2(0, global_position.y * scroll_multiplier, texture_size.x, texture_size.y)

A Rect2 represents a rectangle utilizing 4 parameters: X-position, Y-position, width and peak. By adjusting the background’s region_rect, the rectangle that units what a part of the feel needs to be displayed, the feel will get scrolled. Extra particularly, by shifting the Y-position up and down together with the digital camera’s place, you get a pleasant scrolling impact.
Now run the mission to see what impact this has on the sport.

Robot jumping, background scrolls

Now that appears cool! It’s a small contact, but it surely provides lots to the texture of the sport, don’t you assume?
Subsequent up is spawning and eradicating jumpers infinitely to maintain the sport going so long as the participant can sustain, or offers up. :]

Creating Infinite Jumpers

The plan is to maintain spawning new jumpers in every time the avatar will get to a sure peak. To realize this, you’ll want to maintain observe of the highest level the avatar reached and the place of the final spawned jumper. It can save you the latter as you recognize the place of all spawned jumpers whereas instantiating them. To retailer the Y-position of the final jumper spawned, add the next variable beneath the others within the recreation script:

var last_jumper_y_position : float

You’ll be able to assign this worth by including this to the _create_jumpers operate, on the finish of the for-loop:

last_jumper_y_position = new_jumper.global_position.y

This set the worth of last_jumper_y_position to the Y-position of each new jumper. Every time the for-loop finishes operating, this worth shall be set to the very best jumper.
Cool, however how is the recreation script imagined to know what the avatar’s highest leap is? Why, with alerts in fact!

The participant avatar must maintain observe of its present peak and highest achieved peak. Then, every time it reaches a brand new excessive level, it ought to emit a sign which might be related to the sport script. To retailer the very best level reached, open the player_avatar script and add this variable above the _ready operate:

var highest_point_reached : float

This can retailer the very best Y-position that the avatar has reached.
Subsequent is the sign that must be emitted every time a brand new peak is reached. Add it by including this line beneath the variable you simply added:

sign new_height(peak : float)

Not like the alerts you’ve seen up, this sign accepts a parameter: the brand new peak that was reached. That is tremendous helpful as this fashion you’ll be able to notify the sport script of the brand new peak and cross the worth in a single go.
To replace highest_point_reached and emit this sign, add the next on the finish of the _process_in_air operate:

Be aware: Should you’re having bother discovering a particular operate in a rising script, bear in mind to make use of the operate checklist on the left facet of the script editor to leap to a operate.

function list

if global_position.y < highest_point_reached: # 1
    highest_point_reached = global_position.y # 2
    new_height.emit(highest_point_reached - start_height) # 3

This checks if the present place is greater than the one recorded, then updates the variable and emits a sign if that’s the case:

  1. Test if the present Y-position is decrease than the one saved in highest_point_reached. Keep in mind, destructive Y is up in Godot, so the decrease the destructive worth within the Y-position, the upper up the avatar is.
  2. Set the worth of highest_point_reached to the present Y-position.
  3. Emit the new_height sign and cross the very best level reached minus the beginning peak. By subtracting start_height, the emitted peak will begin at 0.

Now you can join the new_height sign to the recreation script by opening the recreation scene, deciding on PlayerAvatar and double-clicking the new_height sign within the Node menu on the best.

GIF of signal connecting process

Be certain Recreation is chosen and click on the Join button within the sign connection window.

Connect Button

This can add a brand new _on_player_avatar_new_height operate to the recreation script. Now the recreation script is conscious of the avatar’s high peak, it will probably react to it by spawning in additional jumpers. Exchange the cross within the operate that was simply added with the next:

if peak < last_jumper_y_position: # 1
    _create_jumpers(peak) # 2

Right here’s what this does:

  1. If the peak handed by the avatar is decrease than the final created jumper…
  2. Create a batch of jumpers, beginning on the handed peak.

Time to take the sport for an additional spin! Decrease the quantity of jumpers to spawn without delay from 50 to 10 by altering the Jumpers to Spawn property of the Recreation node and urgent Enter. This can make it simpler to check if all the things is working. Now run the mission, maintain leaping up and see if the jumpers maintain showing.

GIF of robot jumping from orb to orb

The sport is getting near being executed now, with only a few tidbits remaining. Within the ultimate part beneath, you’ll discover ways to replace UI components utilizing scripting.

Holding Rating

To make it straightforward for the participant to trace how excessive the avatar has gotten and what number of factors have been earned, you’ll must replace the labels on the backside of the window to mirror these values. The consumer interface has its personal scene to which you’ll be able to add logic, so open the ui scene and add a brand new script to its root aspect, UI. Title this new script and reserve it to the scripts folder. As typical, this opens the script within the script editor.

The scene comprises two labels you’ll want references to in your script: HeightLabel and ScoreLabel. I’ll share a fast tip with you, choose each Label nodes within the Scene dock, right-click and choose Entry as Distinctive Title within the context menu.

Access as Unique Name

This can add a p.c signal subsequent to their names. By marking nodes as having distinctive names, you don’t want to offer a full path for them when creating references. Extra importantly, you’ll be able to freely transfer the nodes wherever within the node tree with out having to alter any paths in your scripts! When creating your personal video games and initiatives, it is best to use this liberally as it will probably save an enormous period of time.

Now drag the nodes to your ui script whereas holding CTRL/CMD so as to add the references. This can add these two traces:

@onready var height_label : Label = $"%HeightLabel"
@onready var score_label : Label = $"%ScoreLabel"

Discover how the trail comprises a p.c signal at the beginning, that’s the way you reference nodes with an distinctive identify.
To replace the labels, add these two capabilities:

func update_height(peak : float) -> void: # 1
    height_label.textual content = str(spherical(peak)) + "m" # 2

func update_score(rating : int) -> void: # 3
    score_label.textual content = str(rating) # 4

Right here’s a abstract of the traces:

  1. The update_height operate accepts a peak parameter, which is the very best level the avatar reached.
  2. Spherical peak to the closest integer utilizing the spherical methodology and convert the outcome to a string utilizing str. Replace the textual content of the height_label with this new worth.
  3. This operate takes a rating parameter. I’ll clarify how the scoring works beneath.
  4. Convert the rating to a string and replace the score_label textual content.

There’s one ultimate essential line so as to add to the script: its class identify. Up till now, the communication between completely different scripts occurred by way of alerts, which emit an replace up the node tree. On this case although, the recreation script will name the ui script, which is decrease down the node tree. In eventualities like this, it’s finest to assign the script that’s going to be known as a class identify to make autocompletion work.
A well-liked line to recollect when to make use of a sign versus a operate name among the many Godot group is: “Sign up, name down”.

So as to add a category identify, add this line proper beneath extends CanvasLayer:

class_name UserInterface

This makes it so the ui script might be accessed as a kind by the identify UserInterface.
With the ui script executed, it’s time to maneuver on to the recreation script once more, because it wants a reference to the UI node and its UserInterface class. This time, you received’t be capable of depend on the drag-and-drop methodology as Godot received’t routinely add the right kind you created. As an alternative, add this line beneath @onready var jumpers_parent within the recreation script:

@onready var ui := $"UI" as UserInterface

There are some things this node reference does completely different than those you’ve seen so far:

  • The := operator, additionally known as the “walrus operator”, is used to let Godot guess the kind of the UI node, which is CanvasLayer.
  • as UserInterface casts the node because the UserInterface kind. This makes ui the right kind and allows autocompletion.
Be aware: The rationale for this unusual syntax as a substitute of utilizing @onready var ui: UserInterface = $UI is due to a bug in Godot involving customized lessons which prevents autocompletion from working with the standard syntax. This may not be an issue for this tutorial as you’ll be able to copy the code with out counting on autocompletion, however watch out for this in your personal initiatives if you happen to discover that the autocompletion isn’t working as anticipated.

Subsequent, to replace the peak label, add this to the tip of _on_player_avatar_new_height:

var height_in_metres = -height/100.0 # 1
ui.update_height(height_in_metres) # 2

This converts the peak in pixels to an arbitrary decrease quantity and calls the ui script to replace its peak label:

  1. Negate the peak so it’s a constructive quantity and divide it by 100. That is purely to have a decrease quantity as a substitute of utilizing the pixel worth. The calculated worth is saved in height_in_metres.
  2. Name the ui script’s update_height operate and cross the brand new peak quantity.

With that, the peak label ought to now replace routinely to mirror the peak of the avatar. Run the mission and leap as much as check if this works.

Robot jumping, label at bottom left showing height

Nice! That leaves simply the rating label to hook up.
At any time when the avatar hits a jumper, the rating ought to go up by 100 factors. To make this work, the avatar ought to let the recreation script know when it hit a jumper, which in flip can name the ui script to replace the rating label.

With a view to inform the recreation script of the avatar’s jumper hits you’ll must create a brand new sign. Add this to the player_avatar script beneath sign new_height:

sign hit_jumper

To make the avatar emit that sign every time it hit a jumper, add this line to the _on_area_2d_area_entered operate:


Good, now you simply want to attach the hit_jumper sign to the recreation script. As typical, you do that by opening the recreation scene, deciding on PlayerAvatar and double-clicking the hit_jumper sign within the Node menu on the best. Go away the receiver methodology at its default worth and click on Join, this may create the _on_player_avatar_hit_jumper operate within the recreation script.
To maintain observe of the rating, add this variable simply above the _ready operate within the recreation script:

var rating : int

The final code so as to add on this tutorial is updating the rating and making the ui script replace the related label. To do this, add this to the _on_player_avatar_hit_jumper operate:

rating += 100

The += operator takes the present worth of rating and provides 100 to it. The rating then will get handed to the ui script by way of the update_score operate to replace the rating label.
Alright, time for a ultimate run of the mission to see all of it come collectively! Play the sport and examine if the rating label is updating.

Robot jumping, label at bottom right showing score

That finally ends up this tutorial and the small recreation you constructed up alongside the best way. I hope you loved this journey by the land of scripts, alerts and nodes.

The place to Go From Right here?

Thanks for studying this tutorial to the tip! You’ll be able to obtain the mission recordsdata utilizing the hyperlink on the high and backside of this web page.
You’ve realized all the things you’ll want to know to get began with GDScript 2.0 on this tutorial:

  • The completely different sorts of variables declaration and numerous sorts
  • Referencing nodes in numerous methods
  • How and when to make use of alerts and capabilities
  • Studying participant enter
  • Creating and utilizing state machines
  • Node manipulation

To study much more about Godot, check out its official documentation.
In order for you a enjoyable problem, listed here are some solutions to enhance the sport additional to make it a extra full expertise:

  • Finish the sport if the avatar is falling for a very long time
  • Present an finish recreation display with the achieved peak and rating
  • Hold observe of excessive scores and present them within the UI
  • Add a title display
  • Add obstacles to keep away from whereas leaping
  • Add shifting objects that award further factors when hit
  • Change the background when sure heights are reached
  • Add juicy results like display shake and lightweight results when a jumper is hit

We hope you loved this tutorial. Go away a remark beneath or be part of the discussion board dialogue to share your ideas and ask any questions you might need!

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