This document discusses implementing Minecraft in Python using the Pyglet library. It explains that Pyglet is a 3D gaming library that provides a simple OpenGL wrapper. The document outlines the key components of the Python Minecraft code, including a Window class that handles user interaction and rendering, and a Model class that represents the game world as blocks in a 3D grid stored in a dictionary. It also describes techniques like sectorization to speed up rendering by only drawing nearby regions of the world.

1. Minecraft in 500 lines of Python
Richard Donkin
@rdonkin
cloudfindhq.com

2. http://xkcd.com/353/

3. Why Python?
Easy to write
Great community
Fast enough
Compilers (Cython)
JIT (PyPy)
3D and Game
Libraries
http://xkcd.com/353/

4. Demo

5. github.com/fogleman/Minecraft
- Michael Fogleman
Early version:

6. Minecraft Essentials
Objects are blocks, in 3D grid
Operations
Move: W, S, A, D
Look around: move mouse
Add or remove blocks: click mouse
Textures

7. How Pyglet Helps
3D gaming library - pyglet.org
Simple wrapper for OpenGL
Pure Python
Library not a framework
This is a quick Minecraft code walkthrough,
not a Pyglet tutorial
Tutorial based on Asteroids: steveasleep.com

8. Overview of Structure
Window class
Subclass of Pyglet window class
User interaction, movement, rendering
Model class
Models the world as blocks in 3D grid
“The Whole World is an (x, y, z) Dictionary”
Dictionary world[position]
Where position is tuple (x, y, z)
Each entry contains texture such as

9. Window & Startup Code

10. Building stuff
Mouse locking, sight vector, hit testing
Remove Block – STONE is special

11. Look around
Motion matters (dx, dy), not absolute position
Get ‘look vector’ rotation (as x, y degrees) &
add proportion of motion
Mouse left/right is x (look left/right)
And forward/back is y (look up/down) – max ±90°

12. Highlighting ‘target block’
Hit-test from player position to target block
Draw line around visible edges of block, using
Pyglet

13. Model

14. Adding a Block
Remove any existing block at (x, y, z) position from the
‘world dictionary’
Set texture for this block at position
Update sectors (16x16 2D grid) to record this block
Enables speedup by only rendering some sectors
Show the block, and check if any neighbours now visible

15. 1100 commits later…
github.com/boskee/Minecraft
Major fork
8,000 lines
19 contributors
Multi-player
Cython

16. Pyglet and More
2D game toolkits:
Cocos2D: http://cocos2d.org/ - uses Pyglet
Fife: http://www.fifengine.net/ - esp. RTSs and RPGs
Add-on libraries that can work with Pyglet:
Rabbyt – sprites:
http://arcticpaint.com/projects/rabbyt/
Pymunk – physics: http://pymunk.org
Alternative frameworks:
Pygame – larger community, more game-specific, open
source book at http://inventwithpython.com/

17. Wrap Up
Concise, elegant code
You can do a lot in 500 lines!

18. Thank You
Download slides:
https://www.slideshare.net/rdonkin/minecraft-in-500-lines-with-pyglet-pycon-uk
Richard Donkin
@rdonkin
cloudfindhq.com

19. Sect0rization
Technique used to speed up rendering of
world – only render nearby sectors
Sector = 16x16 2D region of world
In Model, dictionary sectors[sector]
maps from sector to list of positions in that
sector
Track player position in sector
If player moves between sectors, determine
which adjacent sectors to show – see
change_sectors()