copy_shape.rb

#!/usr/bin/env ruby -W

require 'yaml'
require 'fileutils'


#
# Copies a physics shape from a sprite (reading it's .meta file)
# and aplies the same shape to other sprites.
# Tested only with .meta files created with Unity 2019.1.0f2 and MY
# use case. I'm sure it will break in any other case!
# MAKE A BACKUP BEFORE USING!
#


def read_meta(path)
	YAML.load_file(path)
end

IMPORTER_KEY = 'TextureImporter'

src_sprite = ARGV.shift
if src_sprite.nil?
	puts "usage: #{$0} sprite_with_shape dst_1[ dst_2[ ..]]"
	exit 1
end

meta = read_meta(src_sprite)
shape = meta[IMPORTER_KEY]['spriteSheet']['physicsShape']

shape_as_s = '    - - ' + shape.map do |item|
	item.map { |subitem| '{x: %d, y: %d}' % [subitem['x'], subitem['y']] }
end.join("\n      - ")

puts "copying shape:\n["
#puts shape
puts shape_as_s
puts "]"

while (dst=ARGV.shift) do
	print '.'

	# to_yaml produces something like the original but not the same
	# so it changes it as a string
	# meta = read_meta(dst)
	# meta[IMPORTER_KEY]['spriteTessellationDetail'] = 0
	# meta[IMPORTER_KEY]['spriteSheet']['physicsShape'] = shape

	meta = IO.read(dst)
	unless meta.gsub!(%r{(?<=spriteTessellationDetail: )[\d-]+}, '0')
		raise "couldn't replace tesselation detail in #{dst}"
	end
	unless meta.gsub!(%r{(?<=physicsShape:) \[\]}, "\n" + shape_as_s)
		raise "couldn't replace physicsShape detail in #{dst}"
	end

	tmp_path = dst + '.tmp'
	File.open(tmp_path, 'w') do |io|
		io.write(meta)
		#YAML.dump(meta, io)
	end
	FileUtils.mv(tmp_path, dst)
end
puts