Spritz

Spritz is a tool for working with raw 2D assets to generate packed ones.

Spritz can take a bunch of images and create tiled atlas texture bitmaps (also known as sprite sheets) for drawing many sprites from a single, packed bitmap image.

• Easily integrates into makefiles.
• Writes easily readable JSON.
• Supports all image formats supported by ImageMagick (ie., a lot).
• Supports outputting to PNG and iOS pvrtc (includ gzipped) formats.
• Can generates setup code for Moai.

gem install spritz

rake install

• Ruby 1.8.7 or later.
• ImageMagick 6.x.
• textiletool from iOS SDK, if you want to generate pvrtc textures.

This will generate a dungeon package:

spritz pack sheets/dungeon dungeon/*.png

The command will generate:

• sheets/dungeon.0.png, sheets/dungeon.1.png etc. — the texture bitmaps.
• sheets/dungeon.json.gz — a gzipped JSON file describing the necessary vertex and texture coordinates for each image, ready to be used with drawing functions.

For more options:

spritz pack --help

To generate a quad deck for Moai, use the option:

--moai:quad-decks myfile.lua

For texture-mapping applications, you will want to specify --padding 1 in order to ensure that texture coordinates round evenly to pixel coordinates.

The default texture size is 2048x2048, which corresponds to the largest texture size allowed on the current generation of iOS devices.

If an image does not fit within a single texture, it will be split across multiple textures. In other words, there is no upper limit on the dimensions of any image.

The format of the package JSON file is:

• version: File format version. Currently 1.
• textures: A hash of textures, indexed by a numeric key.
• images: A hash of image slices for each file. (An image will have multiple slices if its dimensions exceed the maximum texture dimensions.)

Each texture hash has the following format:

• file: File name, relative to the JSON file.
• format: The format, eg. png.

Each image hash has the following format:

• i: The index of the texture, which can be looked up in the textures key.
• v: The vertex coordinates for this slice.
• t: The texture coordinates for this slice.
• w: The width of the slice.
• h: The haight of the slice.
• r: Will be true if rotated -90 degrees.

The "MaxRects" algorithm was ported from C++ code originally by Jukka Jylänki.

See accompanying LICENSE file.