zeplar-exe / basic-physics-engine

A C# class library to simulate physics in a modular way.

This project is discontinued, see PhySim for a completely different continuation of the project.

Basic Physics Engine

A lightweight physics engine built in C# to simulate multiple environments.

NuGet Package: https://www.nuget.org/packages/BasicPhysicsEngine/

Installation

99% of the time, you'll find the class library DLL under releases.

Download that, then add it's reference in whatever IDE you use.

Physics Simulator

Class used to create instances of physics simulations. Each simulation has a unique timescale and physics settings. Through the usage of threads, each can be analyzed side-by-side.

Usage (C#):

PhysicsSimulator simulator = new PhysicsSimulator();

simulator.SetPhysicsStep(new Milliseconds(10));
simulator.ApplyGravitySettings(Gravity.Earth()); // 'Gravity.Earth()' is an alternative to 'new Gravity(-9.81f)'
simulator.ApplyTimeSettings(Time.Default()); // 'Time.Default()' is an alternative to 'new Time(1)'

simulator.Start(); // Keep in mind that a simulation will automatically stop if there are no PhysicsObjects

To start a simulation with a real-time display, call simulator.StartWithVisuals() instead.

A simulation can be successfully started when Gravity and Time settings have been applied. It will automatically stop if all PhysicsObjects have been destroyed.

Physics Object

Object that can be manipulated by physics.

PhysicsObjects can be constructed using a BoundsType or a ObjectBounds instance directly. Unhandled BoundsTypes wil redirect to a Rectangle.

Usage (C#)

PhysicsObject physObject = new PhysicsObject(BoundsType.Rectangle);

physObject.SetObjectType(ObjectType.Dynamic | ObjectType.Kinematic);
// Dynamic objects are affected by physics.
// Kinematic objects can affect other non-static objects.
// Non-Kinematic objects are not affected by any forces and must be moved directly through their ObjectBounds.

physObject.Resize(new Vector2(5, 5));
physObject.AddToSimulation(simulator);

PhysicsObject ground = new PhysicsObject(Bounds.Rectangle);

ground.SetObjectType(ObjectType.Static);
// Static objects cannot be moved and are not affected by physics.

ground.Resize(new Vector3(30, 1));
ground.AddToSimulation(simulator);

// Object type 'ObjectType.Dynamic | ObjectType.Kinematic' can also be written as 'ObjectType.Default'

The PhysicsObject class cannot be subclassed.

Physics Object Configuration

Used to configure the properties of a PhysicsObject.

physicsObject.SetConfiguration(new PhysicsObjectConfiguration()
{
  Name = "MyObjectName",
  Mass = 15,
  Elasticity = 0,
  Color = ColorWrapper.Blue
});

By default, a physics object has the following properties: Name = "", Mass = 1, Elasticity = 1, and Color = ColorWrapper.White

Mass controls how much an object is affected by gravity. Elasticity controls how bouncy an object is. Color defines what color the object is when using simulator.StartWithVisuals(...)

Note that ColorWrapper wraps SFML.Graphics.Color

Object Bounds

The ObjectBounds class defines a template for collision boundaries of all Physics Objects. ObjectBounds are publicly exposed, allowing for custom shapes.

Pre-made shapes can be accessed using the BoundsType enum.

public enum BoundsType { Rectangle }

Creating your own BoundsType will require the following class attributes

public abstract Vector2 Center { get; set; }

public abstract Vector2 Top { get; set; }

public abstract Vector2 Bottom { get; set; }

public abstract Vector2 Left { get; set; }

public abstract Vector2 Right { get; set; }

public abstract void Resize(Vector2 size);

public abstract bool IsOverlapping(PhysicsObject other);

public abstract Shape ToShape();

public abstract override string ToString();