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Godot 4 · GDScript

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Module 1 · What a game engine is, and meeting Godot

A game is a loop that runs many times a second

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1 / 219 · What a game engine is, and meeting Godot

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A game is a loop that runs many times a second
, 1 to practiseEach frame has a time budget
, 1 to practiseAn engine does the work every game needs
, 1 to practiseGodot is free, open source and yours to keep
Godot makes both 2D and 3D games
, 1 to practiseYou write games in GDScript, or in C#
, 1 to practiseInstalling Godot takes one download
, 1 to practiseThe Project Manager makes and opens projects
, 1 to practiseYour first scene says hello
Recap

The editor is a viewport surrounded by docks
, 1 to practiseWorkspaces switch what the viewport shows
, 1 to practiseA node is one building block with one job
, 1 to practiseNodes form a tree, and children follow their parent
A scene is a tree of nodes saved to a file
, 1 to practiseThe Inspector edits a node’s properties
, 1 to practiseRun the whole game, or just this scene
Project settings are saved in project.godot
, 1 to practiseres:// is the project, user:// is the player’s
Recap

A script gives a node behaviour
, 1 to practiseVariables remember values
, 1 to practiseType hints let Godot catch mistakes
, 1 to practiseOperators calculate and compare
, 1 to practiseif, elif and else make decisions
, 1 to practisematch picks one branch from many values
, 1 to practisefor and while repeat work
, 1 to practiseArrays hold lists; dictionaries look things up
, 1 to practiseFunctions name a job and can give back an answer
Recap

, 1 to practiseEvery script is a class
, 1 to practiseInheritance and super reuse a parent’s code
, 1 to practiseEnums name a fixed set of choices
, 1 to practise@export shows a property in the Inspector; @onready waits for the tree
, 1 to practiseStatic typing finds bugs before you play
, 2 to practiseGodot calls your functions at set moments
Frames, physics steps and input events
, 1 to practisenull, and nodes that are gone
, 1 to practiseFunctions are values: Callables and lambdas
Recap

Actions name what the player wants to do
, 1 to practiseAsk Input whether an action is held, pressed or released
, 1 to practiseget_axis and get_vector turn input into a direction
, 1 to practisePositions and directions are Vector2s
, 1 to practiseMultiply by delta to move per second, not per frame
Moving a sprite with the keyboard
, 1 to practiseVelocity and acceleration make movement feel weighty
, 1 to practiserotation is in radians, and transform.x is forward
, 1 to practiseWrapping round the edges of the screen
Putting it together: a ship that drifts
Recap

Four kinds of physics object, for four jobs
, 1 to practiseA body collides with the shapes you give it
, 1 to practiseCharacterBody2D moves with velocity and move_and_slide
Gravity pulls, and a jump is one upward kick
, 1 to practiseThe jump’s height comes from its speed and gravity
, 1 to practiseAfter moving, ask what the body touched
, 1 to practiseA RigidBody2D is moved by the physics engine
, 1 to practiseAn Area2D notices what enters it
, 1 to practiseLayers say what you are; masks say what you look for
, 1 to practiseA raycast asks what lies along a line
Recap

A signal announces that something happened
, 1 to practiseNodes come with signals for their own events
, 1 to practiseConnecting a signal in the editor
, 1 to practiseConnecting in code: signal.connect(handler)
, 1 to practiseA handler takes the signal’s arguments
, 1 to practiseYour own signals: declare, then emit
, 1 to practiseA Timer counts down and emits timeout
, 1 to practiseawait pauses a function until a signal comes
, 1 to practiseCall down, signal up
Recap

A PackedScene is a scene you can stamp out
, 1 to practisepreload, load, or an exported slot
, 1 to practiseSpawning a bullet at the gun’s muzzle
The bullet looks after itself
, 1 to practisequeue_free deletes a node safely
, 1 to practiseInherited scenes share a base and change the details
Prefer composing small scenes over deep inheritance
, 1 to practiseGroups tag nodes so you can find them all
, 1 to practiseFinding nodes: paths and unique names
, 1 to practiseAn enemy spawner, from the parts of this module
Recap

A Sprite2D shows a texture
, 1 to practisePixel art needs the nearest filter
, 1 to practiseA sprite sheet holds frames in a grid
, 1 to practiseAnimatedSprite2D plays named animations
, 1 to practiseFlip the sprite to face where you move
, 1 to practiseAnimationPlayer animates any property over time
, 1 to practiseAnimationTree manages animations as a state machine
, 1 to practiseA tween animates a value from code
, 1 to practiseEasing decides how a motion speeds up and slows down
Recap

, 1 to practiseControl nodes are rectangles that lay themselves out
, 1 to practiseAnchors pin edges to the parent; offsets add pixels
, 1 to practiseContainers arrange their children for you
, 1 to practiseSize flags and minimum sizes guide the container
Labels, buttons, bars and friends
, 1 to practiseA HUD lives on a CanvasLayer
Menus change scenes with change_scene_to_file
, 1 to practiseFocus makes menus work with keys and gamepads
, 1 to practisePausing the tree, and what keeps running
, 1 to practiseThemes style every control at once
Recap

A level is a grid of small pictures
, 1 to practiseMaking a TileSet from a tile sheet
, 1 to practisePainting cells, in layers
, 1 to practiseTerrains pick the right edge tile for you
, 1 to practiseTiles that collide, and tiles that carry data
, 1 to practiseA camera that follows the player
, 1 to practiseKeep the camera inside the level
, 1 to practiseParallax: far things move slower
, 1 to practiseY-sort: lower on screen draws in front
, 1 to practiseMoving from one level to the next
Try it: build two connected levels
Recap

Game feel is many small reactions
, 1 to practisePlaying a sound
, 2 to practiseAudio buses: a mixing desk for your game
, 1 to practiseMusic that loops and fades
, 1 to practiseParticles: many tiny sprites at once
, 1 to practiseScreen shake, done gently
, 1 to practiseHit stop: freeze for a few frames
, 1 to practiseEasing, squash and stretch
, 1 to practiseLet players turn the juice down
Try it: juice up your game
Recap

Changing scene forgets everything in it
, 1 to practiseUsing an autoload, and not overusing it
Resources are data you can save and share
, 1 to practiseExporting resources, and the shared-copy trap
, 1 to practiseWhere a game may write: user://
, 1 to practiseSettings in a ConfigFile
, 1 to practiseA save file in JSON
, 1 to practiseSaving resources, and why not to load untrusted ones
, 1 to practiseDesigning saves that last
Try it: a game that remembers
Recap

, 1 to practiseAn enemy is always in one state
, 1 to practiseA state machine with an enum and match
, 1 to practiseDoing something once on entering a state
Bigger enemies: each state as a node
, 1 to practiseSeeing the player: an area, then a ray
, 1 to practiseSteering: seek, flee and arrive
, 1 to practiseNavigation: finding a way around walls
, 1 to practiseAvoidance: crowds that don’t pile up
, 1 to practiseCooldowns with timers
, 1 to practiseGrid pathfinding with AStarGrid2D
Try it: a guard that hunts you
Recap

, 1 to practise3D is the same tree with one more axis
, 1 to practiseY is up, and forward is minus Z
, 1 to practiseA transform is position, rotation and scale
, 1 to practiseThe basis tells you which way a node faces
, 1 to practiseMeshes: primitive shapes to start with
, 1 to practiseImporting models made in other tools
, 1 to practiseMaterials: what a surface is made of
, 1 to practiseThree kinds of light
, 1 to practiseThe environment: sky, ambient light and tone
, 1 to practiseThe camera decides what you see
Try it: a small lit room
Recap

, 1 to practiseA character is a CharacterBody3D with a shape and a look
, 1 to practiseGravity pulls velocity down, a jump sets it up
, 1 to practiseMove relative to where the camera looks
, 1 to practiseMouse look: capture the mouse, read how far it moved
, 1 to practiseA SpringArm3D keeps the camera out of walls
, 1 to practiseTurn the model to face where it runs
, 1 to practiseSlopes, steps and sticking to the floor
, 1 to practiseRigidBody3D: things physics moves for you
, 1 to practiseArea3D and raycasts in 3D
, 1 to practisePrototype levels with CSG shapes
Recap

, 1 to practiseA shader is a tiny program the graphics card runs for every pixel
, 1 to practiseYour first shader: a canvas_item that changes colours
, 1 to practiseUV: where on the texture this pixel is
, 1 to practiseTIME makes things move
, 1 to practiseUniforms: knobs your scripts can turn
, 1 to practiseA material is shared until you make it unique
, 1 to practiseDissolve: noise decides which pixels vanish first
, 1 to practiseSpatial shaders paint 3D surfaces
, 1 to practiseVisual shaders: the same thing as a graph
, 1 to practisePost-processing: a shader over the whole screen
, 1 to practiseWhat makes shaders slow
Recap

, 1 to practiseA game grows, so plan for change
Each feature is a scene that can run alone
, 1 to practiseCall down, signal up
, 1 to practiseAn event bus for news the whole game hears
, 1 to practiseComponents: behaviour as child nodes
, 1 to practiseCustom resources hold the data
, 1 to practiseThe command pattern: actions as objects
, 1 to practiseThe state pattern: one object per state
, 1 to practiseTesting GDScript with GUT or gdUnit4
Try it in the editor
Recap

, 1 to practiseThe debugger stops the game so you can look inside
, 1 to practiseThe remote scene tree shows the running game
, 1 to practisePrinting, warnings and asserts
, 1 to practiseA frame has a budget, measured in milliseconds
, 1 to practiseCommon fixes once you know what is slow
, 1 to practiseAn object pool reuses nodes instead of freeing them
, 1 to practiseExporting: presets and export templates
, 1 to practiseDesktop, web and mobile each need something different
, 1 to practisePutting it on itch.io
Try it in the editor
Recap

, 1 to practiseTool scripts run inside the editor
, 1 to practiseEditor plugins add docks and tools to Godot
, 1 to practiseCustom node types with class_name and an icon
, 1 to practiseGDExtension: native code when you need it
, 1 to practiseC# in Godot
, 1 to practiseHigh-level multiplayer: peers and a server
, 2 to practiseRPCs and authority: who may do what
, 1 to practiseMultiplayerSpawner and MultiplayerSynchronizer
, 1 to practiseUnder the nodes: the servers
, 1 to practiseReading Godot’s source and contributing
, 4 to practiseMastery: putting it all together
Recap, and where to go next