ordoor/scripts/try-uncompress

#!/usr/bin/env ruby

require 'pp'

module Obj
  class Header
    SIZE = 5*4 # 5x 32-bit little-endian integers

    attr_reader(
      :num_sprites, # Number of entries in the directory. Always dir_size/8?
      :dir_offset,  # Offset of the sprite directory. Also the size of the main header
      :dir_size,    # Number of bytes allocated to the sprite directory. Always num_sprites*8?
      :data_offset, # Number of bytes allocated to the sprites themselves
      :data_size    # Total size of the sprite data
      # JUNGTIL.obj has 0x0000 0x0000 0x0000 following. Probably just padding to
      # allow the sprite directory to start at a word boundary.
    )

    def self.parse(data)
      hdr = new(*data[0..SIZE - 1].unpack("V*"))
      pp hdr
      hdr.validate!(data.bytes.size)
      hdr
    end

    def initialize(*entries)
      @num_sprites, @dir_offset, @dir_size, @data_offset, @data_size = *entries
    end

    def validate!(overall_size)
      raise "Directory overlaps EOF" if overall_size < dir_size + dir_offset
      raise "Data overlaps EOF" if overall_size < data_offset + data_size
      raise "Bad dir_size or num_sprites" if num_sprites * DirEntry::SIZE != dir_size
      raise "Directory overlaps data" if data_range.cover?(dir_offset+1)
      raise "Data overlaps directory" if dir_range.cover?(data_offset+1)

      true
    end

    def dir_range
      dir_offset...(dir_offset+dir_size)
    end

    def data_range
      data_offset...(data_offset+data_size)
    end
  end

  class DirEntry
    SIZE = 8

    attr_reader :rel_offset # Relative to the main header's data_offset
    attr_reader :sprite_size

    def self.parse(rel_data)
      new(*rel_data.unpack("VV"))
    end

    def initialize(rel_offset, sprite_size)
      @rel_offset = rel_offset
      @sprite_size = sprite_size
    end

    def sprite_range
      rel_offset...(rel_offset+sprite_size)
    end
  end

  class SpriteDir
    attr_reader :entries

    def self.parse(rel_data)
      count = rel_data.bytes.size
      num_entries = count / DirEntry::SIZE
      trailing = count%DirEntry::SIZE

      raise "SpriteDir block has #{trailing} trailing bytes" unless trailing == 0

      entries = 0.upto(num_entries-1).map do |n|
        rel_offset = n * DirEntry::SIZE
        DirEntry.parse(rel_data.byteslice(rel_offset, DirEntry::SIZE))
      end

      pp entries

      new(entries)
    end
    
    def initialize(entries)
      @entries = entries
    end

    # Convert the directory into an Array of bytes. Until we work out how to
    # parse sprites, anyway...
    def realize(rel_data)
      entries.map { |entry| rel_data[entry.sprite_range] }
    end
  end

=begin
  SpriteHeader = Struct.new(
    :unknown0,        # Possibly magic data? It's the same for every sprite in jungtil.obj
    :maybe_dimension, # Low nibble comes to 63 in jungtil.obj which would work for a 64x64 tile
    :size,            # Number of bytes of pixel data following this header
  ) do
    SIZE = 4*6        # Seems to be, anyway. Based on 

    def self.parse(rel_data)
      new(*sprite_data[0..SIZE-1]).unpack("V*")
    end

    def pixel_range
      SIZE...size # maybe,anyway
    end
  end

  Sprite = Struct.new(
    :header, :data
  ) do
    def self.parse(rel_data)
      hdr = SpriteHeader.parse(rel_data)
      sprite_pixels = rel_data[hdr.pixel_range]

      Sprite.new(hdr, sprite_pixels)
    end
  end
=end

  class Parsed
    attr_reader :header
    attr_reader :directory
    attr_reader :sprites

    def initialize(header, directory, sprites)
      @header = header
      @directory = directory
      @sprites = sprites
    end
  end

  def self.parse(data)
    hdr = Header.parse(data)
    dir = SpriteDir.parse(data[hdr.dir_range])
    sprites = dir.realize(data[hdr.data_range])

    Parsed.new(hdr, dir, sprites)
  end
end

parsed = Obj.parse(File.read("orig/Obj/jungtil.obj").force_encoding("BINARY"))

def hex(num, leading=0)
  "%0#{leading}x"%num
end

def display(data, blocksize=8, skip=0)
  bytes = data.bytes
  nrows = (bytes.count / blocksize)

  skip.upto(nrows) do |i|
    block = bytes[(i*blocksize)...(i*blocksize+blocksize)]
    out = [
      "0x#{hex(i*blocksize, 4)}",
      block.map { |b| hex(b, 2) },
    ]

    puts out.flatten.join(' ')
  end
end


puts "Dumping blank sprite"
display(parsed.sprites[0], 8, 0)

# The per-sprite data in jungtil.obj is too small to represent a 64x64 block,
# even at 1bpp, so try some decompression algorithms to see what comes out.
# Step through every byte of each sprite so we manage if some header is present
#
# Tried so far, with no success:
#   * LZO

puts "\nAttempting decompression..."

require 'lzo'

parsed.sprites.each_with_index do |sprite, i|
  print "Sprite %02d..."%i

  (0...sprite.size).each do |offset|
    block = sprite.byteslice(offset, sprite.size-offset)

    begin
      decompressed = LZO.decompress(block)
      puts "succeeded! sprite=#{i} offset=#{offset} decompressed_size=#{decompressed.size}"
      puts "data:"
      puts decompressed.inspect
      exit 0
    rescue => err
    end
  end

  puts "failed"
end