Quick Ruby script to convert Minecraft schematics to BOB objects

bobuilder.rb

# Convert a Minecraft schematic to a BO2 object template
# Usage: ruby bobuilder.rb [-f, --force] <path to schematic> <path to bob output> [z offset]
# See: http://www.minecraftwiki.net/wiki/Schematic_File_Format
#      https://github.com/Wickth/TerrainControll/blob/master/bo2spec.txt
#
# Copyright (c) 2011 Ross Paffett
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

require "nbtfile"

# Needy blocks are items like torches and doors, which require other blocks to
# be in place -- otherwise they'll simply fall to the ground as entities. We
# defer them to the end of the BOB output to ensure they're "built" last.
NEEDY_BLOCKS = [26, 27, 28, 31, 32, 37, 38, 39, 40, 50, 55, 59, 63, 64, 65,
  66, 68, 69, 70, 71, 72, 75, 76, 77, 81, 83, 85, 96, 104, 105, 106, 111, 115]

@options = ARGV.select { |arg| arg =~ /^\-+[a-z]+/ }
@args = ARGV - @options

if @args.size >= 2 && !(@args.include?("-h") || @args.include?("--help"))
  @schematic_path = File.expand_path(@args[0])
  @bob_path = File.expand_path(@args[1])
  @z_offset = (@args[2] || 0).to_i
else
  STDERR.puts "usage: ruby bobuilder.rb [-f, --force] <path to schematic> <path to bob output> [z offset]"
  STDERR.puts "       -f, --force will overwrite existing files"
  exit 1
end

if !(@options.include?("-f") || @options.include?("--force")) && File.exists?(@bob_path)
  STDERR.puts "error: #{@bob_path} already exists or cannot be written to"
  exit 1
end

open(@schematic_path, "r") do |io|
  @schematic = NBTFile.load(io)[1]
end

# Slice blocks and block metadata by the size of the schematic's axes, then
# zip the slices up into pairs of [id, metadata] for convenient consumption.
blocks = @schematic["Blocks"].bytes.each_slice(@schematic["Width"]).to_a
blocks = blocks.each_slice(@schematic["Length"]).to_a
data = @schematic["Data"].bytes.each_slice(@schematic["Width"]).to_a
data = data.each_slice(@schematic["Length"]).to_a
layers = blocks.zip(data).map { |blocks, data| blocks.zip(data).map { |blocks, data| blocks.zip(data) } }
deferred = []

open(@bob_path, "w") do |io|
  io.write(DATA.read)
  
  layers.each_with_index do |rows, z|
    z += @z_offset
    rows.each_with_index do |columns, x|
      x -= @schematic["Width"] / 2 # Center the object on the X axis
      columns.each_with_index do |(block, data), y|
        y -= @schematic["Length"] / 2 # Center the object on the Y axis
        line = "#{y},#{x},#{z}:#{block}.#{data}"
        if NEEDY_BLOCKS.include?(block)
          deferred << line
        else
          io.puts(line)
        end
      end
    end
  end
  
  # Write needy blocks to the end of the BOB file, respecting the order of
  # NEEDY_BLOCKS, in case some blocks are needier than others.
  deferred.sort! { |a, b| NEEDY_BLOCKS.index(a) <=> NEEDY_BLOCKS.index(b) }
  deferred.reverse.each { |line| io.puts(line) }
end

__END__
[META]
version=2.0
randomRotation=False
[DATA]

LICENSE

Copyright (c) 2011 Ross Paffett

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.