Blockbuster: Minecraft Movies

01 Jul 2014 henrygarner.com

Taking the current obsession for 3D film to its illogical conclusion. I demonstrate the Redstone Clojure interface to Minecraft via pixels, voxels, obsolete image formats and coloured wool.

Blockbuster: Minecraft Movies

Blockbuster Presentation

I gave a talk at the London Clojurians July 2014 meetup about the work I'd been doing on Blockbuster, a command-line tool for rendering images and movies in Minecraft using coloured wool blocks. This was also an opportunity to introduce Redstone, the library that handles communication with the Minecraft server.

A video of the talk was recorded, or you can read the slides as an .org file.

Prerequisites

You will need to have imageMagick and ffmpeg installed, and you will need to be running a Craftbukkit server with the RaspberryJuice plugin.

On OS X imageMagick and ffmpeg can be installed through homebrew in the following way:

brew install imagemagick
brew install ffmpeg

Download

You'll need to have Leiningen installed to compile the code. Download Blockbuster and run lein compile in the project directory.

Usage

The following will draw movie.mov on a screen 50 blocks wide. The height will be determined by the aspect ratio of the file.

bin/blockbuster -f [path/to/movie.mov] -w 50

Options

The application accepts the following arguments:

-f "The movie file to play"
-w "The width of the screen"
-p "The x,y,z coordinates of the screen"
-n "Draw every n frames"
-m "The number of milliseconds to wait between frames"
-c "Whether space should be cleared for the screen"

How does it work?

The application uses ffmpeg to separate movie files into sequences of still images. Each image is then resized and interpreted as a .ppm file using imageMagick's convert utility. A .ppm file is a text-based format that's easy to parse into a stream of r,g,b pixel values. Each of these pixels is compared against the 16 available wool block colours to find the closest match and then drawn in the specified location using the redstone library.