http://perfume-dev.github.com/ から得られるBVHの数値を適当に色にした

frame__aachan.bvh.png

frame_png.rb

# -*- coding: utf-8 -*-
require "zlib"
require "pathname"

class PNG
  def initialize(width, height, pixel_lines)
    @width = width
    @height = height
    @depth = 8
    @color_type = 2
    @pixel_lines = pixel_lines
  end

  def lines
  end

  def save(path)
    open(Pathname.new(path).expand_path, "w") do |f|
      # ファイルシグニチャ
      f.write "\x89PNG\r\n\x1a\n"
      
      # ヘッダ
      f.write chunk("IHDR", [@width, @height, 8, 2, 0, 0, 0].pack("NNCCCCC"))
      
      # 画像データ
      img_data = @pixel_lines.map {|line| ([0] + line.flatten).pack("C*")}.join
      f.write chunk("IDAT", Zlib::Deflate.deflate(img_data))
      
      # 終端
      f.write chunk("IEND", "")
    end
  end

  private
  def chunk(type, data)
    [data.bytesize, type, data, Zlib.crc32(type + data)].pack("NA4A*N")
  end
end

tet = <<-TEST
width = 200
height = 100
pixel_lines = []
0.upto(height -1) do |y|
  line = []
  0.upto(width - 1) do |x|
    line.push([(255 / width.to_f) * x, 0, 0])
  end
  pixel_lines.push(line)
end

png = PNG.new(width, height, pixel_lines)
png.save("./test.png")
TEST

module KludgyBVHParser
  class << self
    def parse(path, proc)
      pixel_lines = []
      open(Pathname.new(path).expand_path, "r") do |f|
        skip = true

        f.each do |line|
          if line.match(/^Frame Time:.*/)
            skip = false
            next
          end
          unless skip
            values = line.split(" ").map{|v| v.to_f}
            pixel_lines.push(proc.call(values))
          end
        end
      end
      pixel_lines
    end
  end
end

$last_values = []
frame_proc = Proc.new do |values|
  pixels = []
  if $last_values.length == 0
    values.each_with_index do |v,i|
      rgb = [0, 0, 0]
      pixels.push(rgb)
    end
  else
    value_range = values.max - values.min
    values.each_with_index do |v,i|
      corrected_value = ((v + (-values.min)) / value_range * 255).to_i
      rgb = [corrected_value, 0, 0]
      pixels.push(rgb)
    end
  end
  $last_values = values
  pixels
end

path = "../data.org/bvhfiles/aachan.bvh"
pixel_lines = KludgyBVHParser.parse(path, frame_proc)
height = pixel_lines.length
width = pixel_lines[0].length
png = PNG.new(width, height, pixel_lines)
file_id = path.split("/")[-1]
png.save("./frame__#{file_id}.png")