Basic Physics Engine in about 100 lines of pure JavaScript

"The Vec class implements 2D vectors, providing essential operations like addition, subtraction, scaling, and normalization, which are fundamental for all geometric calculations in the simulation."

"The Circle class manages properties such as position, velocity, radius, and mass, and includes an integrate() method to apply gravity and update the circle's position each frame."

"Collision functions like resolveCircleCircle and resolveCircleLine handle the detection and resolution of overlaps, applying impulses to change velocities and ensuring realistic interactions."

The simulation creates moving balls affected by gravity, detecting collisions between circles and lines. It uses vector math and Euler integration for motion updates. The Vec class handles 2D vector operations, while the Circle and Line classes manage their respective properties and interactions. Collision functions resolve overlaps and apply impulses for velocity changes. The main loop integrates bodies, resolves collisions, and draws the scene. Limitations include no continuous collision detection and rotational dynamics, but the implementation remains engaging with around 100 lines of code.

Read at Slicker