en Matter

Matter.js

2D Physics Engine

Matter.js is an open source 2D physics engine written in JavaScript:

Website: https://brm.io/matter-js/

Github repository: https://github.com/liabru/matter-js

You can enable and use Matter.js in your microStudio project, whichever language you picked: microScript, JavaScript, Python, Lua.

Basics

Enable Matter.js

After creating your project, open the settings tab and click "Show advanced options". Check "Matter.js" to enable the library for your project. The Matter.js API will be exposed to your code as a global variable Matter.

Initializing the engine

You can create a Matter engine with this line:

engine = Matter.Engine.create()

To get the engine's default gravity to be downwards, set

engine.world.gravity.y = -1

Adding shapes

The API sometimes requires you to pass JavaScript objects as arguments, for example { isStatic: true }. From microScript, you will pass the equivalent microScript object: object isStatic = true end. This is how you can add a fixed ground object to your Matter world:

ground = Matter.Bodies.rectangle(0,-50,200,10,object isStatic=true end)
Matter.Composite.add(engine.world,ground)

You can then add a moving box as follows:

box = Matter.Bodies.rectangle(0,50,20,20)
Matter.Composite.add(engine.world,box)

Running the simulation

In the body of your function update(), simply call Matter.Engine.update:

update = function()
  Matter.Engine.update(engine,1000/60)
end

Drawing your shapes

In the course of your function draw(), you can draw all the shapes you have added to the world. Here is an example:

draw = function()
  screen.clear()
  screen.drawRect(ground.position.x,ground.position.y,200,10,"rgb(255,0,0)")
  screen.setDrawRotation(box.angle/PI*180)
  screen.drawRect(box.position.x,box.position.y,20,20,"#FF0")
  screen.setDrawRotation(0)
end

Bodies

The Matter.Bodies module contains factory methods for creating rigid body models with commonly used body configurations (such as rectangles, circles and other polygons).

Creating a circle body

Matter.Bodies.circle(x, y, radius, [options])

This methods creates a new rigidbody with circle as its shape, centered around the x and y coordinates. The radius parameter determine how big the circle is and [options] is a javascript object which can contain angle, angularSpeed, isStatic, and many more

Example:

baloon = Matter.Bodies.circle(0, 0, 5, object isStatic = true end)

Creating a rectangle body

Matter.Bodies.rectangle(x, y, width, height, [options])

This methods creates a new rigidbody with rectangle as its shape, centered around the x and y coordinates. The width and height parameters determine how wide or tall the rectangle is

Example:

ground = Matter.Bodies.rectangle(0, -90, 200, 10, object isStatic=true end)

Creating a regular polygon body

Matter.Bodies.polygon(x, y, sides, radius, [options])

This methods creates a new rigidbody with any regular polygon with the given number of sides as its shape, centered around the x and y coordinates. The radius also determine how big the polygon is going to be

Example:

spike = Matter.Bodies.polygon(0, 0, 3, 5)

This will create an equilateral triangle (a 3-sided regular polygon) body with the radius of 5

Body

The Matter.Body module contains methods for creating and manipulating body models. A Matter.Body is a rigid body that can be simulated by a Matter.Engine. This is diffrent from Matter.Bodies (used for creating primitive objects such as circle, rectangle, and other polygons).

Creating a new body

Matter.Body.create([options])

Creates a new rigid body model. The options parameter is an object that specifies any properties you wish to override the defaults. All properties have default values, and many are pre-calculated automatically based on other properties. Vertices must be specified in clockwise order. See the properties section below for detailed information on what you can pass via the options object.

Applying force to a body

Matter.Body.applyForce(body, position, force)

Applies a force to a body from a given world-space position, including resulting torque. The parameter body is passed to specifies which body will be affected by the force, the parameter position will determine the torque along with force to determine how much force are being applied to the given body

Rotating a body

Matter.Body.rotate(body, rotation, [point])

Rotate the given body along the point (optional) parameter based on the rotation given. This will not change the angular velocity, position, or force applied to the body

Documentation

Official documentation

Reference: https://brm.io/matter-js/docs/

Wiki: https://github.com/liabru/matter-js/wiki

Example projects

https://microstudio.dev/i/gilles/matterjstest/