require 'bundler'

Bundler::require

require 'rmagick'
include Magick

IMAGE_DIR='video/256_128'
OUTPUT_NAME='video/256_128/apple_st75256.bin'

COLOR_STEP=(Magick::QuantumRange + 1) / 4

def convert_image(filename)
    im = Image.read(filename)
    pix_ary = Array.new(8192, 0)
    im[0].each_pixel do |pix, col, row|
        color = pix.intensity / COLOR_STEP

        byte_offset = 256 * (row / 4) + col
        bit_offset = (3 - (row % 4)) * 2

        pix_ary[byte_offset] &= ~(3 << bit_offset)
        pix_ary[byte_offset] |= (color << bit_offset)
    end
    pix_ary
end

File.open(OUTPUT_NAME, "w+") do |f|
    Dir.glob("#{IMAGE_DIR}/*.bmp").each_with_index do |img, i|
        puts "#{i} image processed."
        f.write(convert_image(img).pack("C*"))
    end
end