Box2D Lite Walkthrough Part 1 | Coding a 2D Physics Engine in Java #16

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In this tutorial I begin to walk through Erin Catto's Box2D Lite source code. This will give us an idea of how to solve the problem of box vs box collision resolution. In a high level overview, all you have to do is find the axis with the smallest amount of penetration, then clip the vertices against each other to get the collision points. This will give you the collision normal (the axis), the collision depth (the penetration), and the collision points (the clipped vertices). But this is very hard to understand unless you work through an actual example which is what I begin to do in this video.

Collide.cpp: https://github.com/erincatto/box2d-lite/blob/master/src/Collide.cpp
Slides: https://github.com/erincatto/box2d-lite/blob/master/docs/GDC2006_Catto_Erin_PhysicsTutorial.pdf
Box2D Lite Source Code: https://github.com/erincatto/box2d-lite

0:00 Intro
1:22 Where to Get Source Code
1:55 Step 1 Setting Up
5:03 Step 2 Calculating Dot Products/Projections
9:39 Step 3 Creating a Local Transformation Matrix
11:17 Step 4 Projecting A/B's Vertices
16:30 Finding the Best Axis and Separation Amount

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Website: https://ambrosiogabe.github.io/
Github: https://github.com/ambrosiogabe

Here are some books I recommend if you want to learn about game engine development more thoroughly. I do not profit off any of these sales, these are just some books that have helped me out :)

My Recommended Game Engine Books:
Game Engine Architecture: https://www.gameenginebook.com/
Game Physics Cookbook (Read this before the next physics book): https://www.amazon.com/Game-Physics-Cookbook-Gabor-Szauer/dp/1787123669
Game Physics (Ian Millington): https://www.amazon.com/Game-Physics-Engine-Development-Commercial-Grade/dp/0123819768
Game Programming Patterns (Free): https://gameprogrammingpatterns.com/

My Recommended Beginning Game Programming Books:
JavaScript Game Design: https://www.apress.com/gp/book/9781430247166

My Recommended Java Books:
Data Structures/Algorithms: https://www.amazon.com/Data-Structures-Algorithms-Java-6th-ebook/dp/B00JDRQF8C
LWJGL (Free, but I haven't read this thoroughly): https://lwjglgamedev.gitbooks.io/3d-game-development-with-lwjgl/content/