A physics engine is a system helps to detect the collisions between recreation objects and simulate their motion. That is very helpful if you wish to create a recreation that has life like physics habits. Widespread video games like puzzle video games and platformers use physics engine to create their core gameplay.
One well-known instance is Indignant Birds. It makes use of the physics engine to create the projectile of the hen and the life like fall of the obstacles after destruction.
On this tutorial, you’ll be taught in regards to the fundamentals of Godot 2D physics engine and easy methods to use it to construct a Marble drop recreation.
Alongside the best way, you’ll:
- Study completely different sorts of physics node.
- Study PhysicsMaterial and the way it impacts the sport.
- Use RigidBody2D node to create a dynamic physics object.
- Use Area2D node to create a set off.
- Use StatcBody2D node to create a stationary physics object.
- Use Snap to Grid to align the nodes.
- Add sound results and background music to the sport.
The ultimate product of this tutorial is a one-click, physics-based recreation. Gamers click on the enjoying area to drop a marble with the aim to attain as many factors as potential.
On the finish of this tutorial, you’ll know perceive the fundamentals of Godot’s 2D physics engine.
Get Began
This tutorial makes use of the newest steady model of Godot 4. You may obtain it right here.
Obtain the tutorial supplies by clicking Obtain Supplies on the prime or backside of the tutorial. Subsequent, extract the zip file to your chosen challenge location.
There are two initiatives included within the supplies:
- starter: The starter challenge you’ll use to construct upon.
- closing: The ultimate model of the sport you may run and play straight.
This tutorial requires you to have fundamental data of Godot Engine. In the event you don’t really feel aware of Godot but, strive these tutorials first:
File Overview
Import and open the starter challenge in Godot Challenge Supervisor. After opening the challenge, you’ll discover the ready useful resource information, comparable to pictures, sounds, and consumer interfaces.
The challenge construction is as follows:
- fonts: Font information
- music: Background music
-
scenes: Scene information
- game_board.tscn: Sport Board Scene
- game_over_dialog.tscn: GameOver dialog
- gui.tscn: Rating and marble rely Person Interface
- main_scene.tscn: Major scene
- scripts: Script information
- sounds: Sound results
- sprites: Graphics
- credit score.txt: An inventory of attributions for the included property
Major Scene
The Major Scene is the scene the place the sport takes place. It comprises all nodes that want by the sport.
To open it, double-click main_scene.tscn within the FileSystem dock.
Then, swap to the 2D display screen to preview the sport board.
Now, you’ve a grasp of what the challenge seems like. Subsequent, you’ll find out about some fundamental ideas of the physics engine.
Understanding 2D Physics Engine
When you find yourself growing a recreation, you might want the next options to craft the gameplay:
- When two recreation objects collide with others, for instance, when a marble hits a rating set off.
- Management the motion of an object after making use of a pressure or a collision has occurred. For instance, how the marble bounces off the pegs.
A physics engine is right for this; it gives two main capabilities: Collision Detection and Object Motion Simulation.
Collision Detection
The engine repeatedly checks for overlaps between the physics objects within the scene and sends indicators after they collide.
Object Motion Simulation
The engine simulates the motion of objects based mostly on their physics attributes.
These are the physics attributes in Godot:
- Mass: Determines how forces have an effect on an object.
- Gravity: Applies a downward pressure to simulate falling.
- Friction: Resists the movement between two surfaces in touch.
- Bounce: Determines how a lot velocity is reserved when two our bodies collide.
Now the fundamental ideas of the physics engine, you may transfer on to be taught extra in regards to the completely different physics nodes supplied by Godot.
Understanding Completely different Physics Nodes
Godot presents three fundamental physics nodes: RigidBody2D, StaticBody2D and Area2D. Every node has completely different functions and behaviors and it is best to select the fitting one for every recreation factor.
-
StaticBody2D: This node doesn’t transfer below physics simulation however can have an effect on RigidBody2D nodes.
It’s used for stationary surroundings objects like pegs and partitions. - RigidBody2D: This node has mass and is actively simulated by the physics engine. It might probably reply to forces, gravity, and collisions. It might probably additionally have an effect on different RigidBody2D nodes.
- Area2D: This node gained’t trigger physics reactions, however it may possibly verify for any collisions which have occurred. It’s used for getting into or exiting zones just like the rating set off.
Right here’s a fast comparability between the physics nodes:
With all this in thoughts, it’s time to create your first physics node.
Create a RigidBody2D node
To symbolize the marble within the recreation that may fall below gravity, and bounce off pegs, you want to create a RigidBody2D node.
The Marble Scene
As a way to create the marble that can be utilized within the recreation, you want to create a brand new scene for it with RigidBody2D as the foundation node. A scene is a group of nodes. On this case, it comprises a RigidBody2D node for the physics simulation and a Sprite2D node for the look of the marble.
To create the scene, choose the scenes folder within the FileSystem dock. Now right-click and choose Create New â–¸ Scene. Whereas the scene creation dialog is open, configure it like this:
- Root Kind: Different Node â–¸ RigidBody2D
- Scene Title: marble.tscn
- Root Title: Marble
In regards to the PhysicsMaterial
Proper after creating the RigidBody2D node, you want to configure the PhysicsMaterial of the node. PhysicsMaterial is a setting that defines how the node behave within the physics simulation.
There are two fundamental group of settings within the PhysicsMaterial: Friction and Tough and Bounce and Absorbent. Every group has completely different settings that have an effect on the node’s velocity when it collides with one other node.
Friction and Tough
Friction is a quantity between 0 and 1. The upper the worth, the node has extra friction and strikes slower when collide. The decrease the worth, the node has much less friction and seem to slip extra simply.
Tough is a boolean. It controls which friction worth is used among the many two colliding nodes. Listed below are the foundations:
- Each nodes Tough worth are ON, the upper friction worth is used.
- Each nodes Tough worth are OFF, the decrease friction worth is used.
- Just one node Tough worth is ON, the physics engine takes the friction worth with tough ON.
The next demonstration exhibits how the marble behaves with completely different friction and tough setting.
