⚙️ Building a Physics Engine for HTML5 Games

A physics engine makes your games feel real. Objects fall, bounce, collide, and interact naturally. Here's how to build one from scratch for HTML5 games.

Core Concepts

Velocity, acceleration, gravity, friction, and collision response. These are the building blocks of any physics simulation.

Implementing Gravity

Every frame, add a gravity constant to the object's vertical velocity. Update position by velocity. Simple math, realistic results.

Collision Detection

Axis-Aligned Bounding Box (AABB) is the simplest approach. Check if two rectangles overlap on both axes. For circles, check distance between centers.

Collision Response

When objects collide, separate them and reverse their velocity (with energy loss for bounciness). This prevents objects from overlapping.

Optimization

Don't check every object against every other object. Use spatial partitioning (quad trees, grid cells) to only check nearby objects.