benbaker76 / crunch

Command line texture packer created for Celeste.

crunch

This is a command line tool that will pack a bunch of images into a single, larger image. It was designed for Celeste, but could be very helpful for other games.

It is designed using libraries with permissible licenses, so you are able to use it freely in your commercial and non-commercial projects. Please see each source file for its respective copyright and license.

Features

• Export XML, JSON, or binary data
• Trim excess transparency
• Rotate images to fit
• Control atlas size and padding
• Premultiply pixel values
• Recursively scans folders
• Remove duplicate images
• Caching to prevent redundant builds
• Multi-image atlas when the sprites don't fit
• Support for indexed pngs'
• Support for using palette file for indexed format (act, JASC, MS pal, GIMP, Paint.net and png)
• Support for Aseprite format

What does it do?

Given a folder with several images, like so:

images/
    player.png
    tree.png
    enemy.png
    mario.ase

It will output something like this:

bin/
    images.png
    images.xml
    images.hash

Where images.png is the packed image, images.xml is an xml file describing where each sub-image is located, and images.hash is used for file caching (if none of the input files have changed since the last pack, the program will terminate).

There is also an option to use a binary format instead of xml.

Usage

crunch [options] <inputFilename1,inputFilename2,inputFilename3...> <outputFilename> [paletteFilename]

For example...

crunch -a -t -v -u -r assets/characters,assets/tiles bin/atlases/atlas

This will output the following files:

bin/atlases/atlas.png
bin/atlases/atlas.json
bin/atlases/atlas.hash

Options

option	alias	description
-o <xml|bin|json>	--output <xml|bin|json>	saves the atlas data in xml, binary or json format
-f <n>	--format <n>	texture format
-a	--alpha	premultiplies the pixels of the bitmaps by their alpha channel
-t	--trim	trims excess transparency off the bitmaps
-v	--verbose	print to the debug console as the packer works
-i	--ignore	ignore caching, forcing the packer to repack
-u	--unique	remove duplicate bitmaps from the atlas
-r	--rotate	enabled rotating bitmaps 90 degrees clockwise when packing
-s <n>	--size <n>	max atlas size (<n> can be 4096, 2048, 1024, 512, 256, 128, or 64)
-w <n>	--width <n>	max atlas width (overrides --size) (<n> can be 4096, 2048, 1024, 512, 256, 128, or 64)
-h <n>	--height <n>	max atlas height (overrides --size) (<n> can be 4096, 2048, 1024, 512, 256, 128, or 64)
-p <n>	--padding <n>	padding between images (<n> can be from 0 to 16)
-b <n|p|7|f>	--binstr <n|p|7|f>	string type in binary format (n: null-terminated, p: prefixed (int16), 7: 7-bit prefixed, f' fixed 16 bytes)
-l	--last	use file's last write time instead of its contents for hashing
-d	--dirs	split output textures by subdirectories
-n	--nozero	if there's only one packed texture, then zero at the end of its name will be omitted (ex. images0.png -> images.png)

Palette Format

For indexed png's the supported palette formats supported are act, jasc, mspal, gimp, paint.net and png.

Binary Format

crch (0x68637263 in hex or 1751347811 in decimal (little endian))
[int16] version (current version is 0)
[byte] --trim enabled
[byte] --rotate enabled
[byte] string type (0: null-termainated, 1: prefixed (int16), 2: 7-bit prefixed, 3: fixed 16 bytes)
[int16] num_textures (below block is repeated this many times)
    [string] name
    [int16] tex_width
    [int16] tex_height
    [int16] tex_format
    [int16] num_images (below block is repeated this many times)
        [int16] img_frame_index
        [string] img_name
        [string] img_label
        [byte] img_loop_direction
        [int16] img_duration
        [int16] img_x
        [int16] img_y
        [int16] img_width
        [int16] img_height
        [int16] img_frame_x         (if --trim enabled)
        [int16] img_frame_y         (if --trim enabled)
        [int16] img_frame_width     (if --trim enabled)
        [int16] img_frame_height    (if --trim enabled)
        [byte] img_rotated          (if --rotate enabled)
        [byte] img_palette_slot

Splitting

If --dirs (or -d) is enabled output textures will be split by subdirectories.

For example:

crunch -b -d bin/images images with input images

images/
    chars/
        player.png
        enemy.png
    other/
        tree.png
        box.png

will output

bin/
    images_chars.png (with player.png and enemy.png)
    images_chars.hash
    images_chars.bin
    images_other.png (with tree.png and box.png)
    images_other.hash
    images_other.bin
    images.bin

If player.png is the only changed image then only images_chars.bin will be packed and images_other.bin will be reused in images.bin.

This can be used for faster packing: unchanged subdirectories will be skipped instead of packing unchanged images.

But there're some limitations:

• multiple inputs and images as inputs are not supported
• images in input directory itself will be ignored and not packed

Building on Linux

cd linux/
make

Credits

• Ben Baker - Support for indexed pngs', palette files and Aseprite support
• Chevy Ray Johnston - Original crunch
• Nebulaxin - Updated crunch
• Randy Gaul - cute_aseprite