Photosphere downloader and stitcher

sphere.rb

module Enumerable
  # inside the block you can use Thread.exit to stop this execution and Thread.exclusive{...} to synchronize stuff
  def parallel_map
    map{|e| Thread.new{ Thread.current[:result] = yield(e) } }.map{|t| t.join; t[:result]}
  end

  def parallel_map_in_chunks(chunk_size=8, &block)
    chunks = each_slice(chunk_size).each_with_index
    chunks.map{|chunk,i|
      puts "chunk #{i+1}/#{chunks.size}. chunk_size=#{chunk.size}"
      chunk.parallel_map(&block)
    }.flatten(1)
  end
end

def get(url, out) `wget -q -O #{out} #{url}` end

def download(sphere_base_url)
  packets = []
  (0..27).each do |x|
    (0..13).each do |y|
      packets << [x,y]
    end
  end

  packets.parallel_map_in_chunks(8) do |x,y|
    get("#{sphere_base_url}/x#{x}-y#{y}-z5/p", "sphere/#{y.to_s.rjust(2,'0')}_#{x.to_s.rjust(2,'0')}.jpg")
    puts "#{x} #{y}"
  end
end

def stitch
  `montage sphere/*.jpg -tile 28x14 -mode Concatenate sphere.jpg`
end

download('https://lh3.ggpht.com/-F8poV1Q5x7w/VlzTerU51oI/AAAAAAAAArY/2btnk9d72s8')
stitch