Rubyを使ってWavefront(.obj)形式の3Dモデルデータを読み込んでみる

wavefrontobj.rb

#!ruby -Ku
# -*- mode: ruby; coding: utf-8 -*-
# Last updated: <2017/03/10 14:53:55 +0900>
#
# wavefront(.obj) read and parse
#
# use : Ruby 2.2.6 p396 mingw32
# License : CC0 / Public Domain

require "pp"

# wavefront(.obj) read and parse class
class WaveFrontObj

  # @return [String] .obj file path
  attr_reader :objpath

  # @return [String] Directory where .obj is stored
  attr_reader :objdir

  # @return [String] .mtl filename (material file)
  attr_reader :material_filename

  # @return [Array<Array>] vertex (x, y, z, w)
  attr_reader :vertexs

  # @return [Array<Array>] uv (u, v, w)
  attr_reader :uvs

  # @return [Array<Array>] normal (x, y, z)
  attr_reader :normals

  # @return [Array<Array>] vp ( u or u, v or u, v, w)
  attr_reader :vps

  # @return [Hash<Array>] face
  attr_reader :faces

  # @return [Hash] material
  attr_reader :mtls

  # @return [Array] textures
  attr_reader :texs

  def initialize(objpath)
    @objpath = File.expand_path(objpath)
    @objdir = File.dirname(@objpath)
    @mtlname = ""
    @vertexs = []
    @uvs = []
    @normals = []
    @vps = []
    @faces = {}
    @mtls = {}
    @texs = []

    read_geometry(@objpath)

    @mtlpath = File.join(@objdir, @mtlname)
    read_material(@mtlpath)
    @texs = get_texture_list
  end

  def read_geometry(objpath)
    dbg = false
    mat = "none"
    smooth = false
    objgroup = ""
    File.open(objpath) do |file|
      file.each_line do |l|
        next if l =~ /^#/
        next if l =~ /^$/

        s = l.split(" ")
        case s[0]
        when "mtllib"
          @mtlname = s[1]
          puts ".mtl = #{@mtlname}" if dbg
        when "o"
          objgroup = s[1]
          puts "objgroup #{objgroup}" if dbg
        when "v"
          # vertex
          if s.size == 4
            x, y, z, w = s[1].to_f, s[2].to_f, s[3].to_f, 1.0
            @vertexs.push([x, y, z, w])
          elsif s.size == 5
            x, y, z, w = s[1].to_f, s[2].to_f, s[3].to_f, s[4].to_f
            @vertexs.push([x, y, z, w])
          end
        when "vt"
          # texture u v
          if s.size == 3
            u, v, w = s[1].to_f, s[2].to_f, 0.0
            @uvs.push([u, v, w])
          elsif s.size == 4
            u, v, w = s[1].to_f, s[2].to_f, s[3].to_f
            @uvs.push([u, v, w])
          end
        when "vn"
          # normal
          x, y, z = s[1].to_f, s[2].to_f, s[3].to_f
          @normals.push([x, y, z])
        when "vp"
          if s.size == 2
            u = s[1].to_f
            @vps.push([u])
          elsif s.size == 3
            u, v = s[1].to_f, s[2].to_f
            @vps.push([u, v])
          elsif s.size == 4
            u, v, w = s[1].to_f, s[2].to_f, s[3].to_f
            @vps.push([u, v, w])
          end
        when "usemtl"
          # use material
          mat = s[1]
          puts "material #{mat}" if dbg
          unless @faces.key?(mat)
            @faces[mat] = []
          end
        when "s"
          # Smooth
          if s[1] == "off"
            smooth = false
          else
            smooth = true
          end
          puts "smooth #{smooth}" if dbg
        when "f"
          # face
          finfo = []
          s.each do |n|
            if n =~ %r|^(\d+)/(\d+)/(\d+)$|
              vi, vti, vni = ($1.to_i - 1), ($2.to_i - 1), ($3.to_i - 1)
              finfo.push([vi, vti, vni])
            elsif n =~ %r|^(\d+)//(\d+)$|
              vi, vti, vni = ($1.to_i - 1), nil, ($2.to_i - 1)
              finfo.push([vi, vti, vni])
            elsif n =~ %r|^(\d+)/(\d+)$|
              vi, vti, vni = ($1.to_i - 1), ($2.to_i - 1), nil
              finfo.push([vi, vti, vni])
            elsif n =~ %r|^(\d+)$|
              vi, vti, vni = ($1.to_i - 1), nil, nil
              finfo.push([vi, vti, vni])
            end
          end
          unless finfo.empty?
            dt = { :mat => mat, :smooth => smooth, :vertexs => finfo }
            @faces[mat].push(dt)
          end
        end
      end
    end
  end

  def read_material(mtlpath)
    mtlname = ""
    File.open(mtlpath) do |f|
      f.each_line do |l|
        next if l=~ /^#/
        next if l=~ /^$/

        s = l.split(" ")
        case s[0]
        when "newmtl"
          mtlname = s[1]
          @mtls[mtlname] = {}
        when "Ka"
          # Ambient
          r, g, b = s[1].to_f, s[2].to_f, s[3].to_f
          @mtls[mtlname][:ambient] = [r, g, b, 1.0]
        when "Kd"
          # Diffuse
          r, g, b = s[1].to_f, s[2].to_f, s[3].to_f
          @mtls[mtlname][:diffuse] = [r, g, b, 1.0]
        when "Ks"
          # Specular
          r, g, b = s[1].to_f, s[2].to_f, s[3].to_f
          @mtls[mtlname][:specular] = [r, g, b, 1.0]
        when "Ns"
          # Shininess
          @mtls[mtlname][:shininess] = s[1].to_f
        when "Ke"
          # Emission ?
          r, g, b = s[1].to_f, s[2].to_f, s[3].to_f
          @mtls[mtlname][:emission] = [r, g, b, 1.0]
        when "Ni"
          # Optical density
          @mtls[mtlname][:optical_density] = s[1].to_f
        when "d"
          # Dissolve
          @mtls[mtlname][:dissolve] = s[1].to_f
        when "illum"
          # Lighting model
          @mtls[mtlname][:illum] = s[1].to_i
        when "map_Ka"
          # Ambient texture
          @mtls[mtlname][:ambient_tex] = s[1]
        when "map_Kd"
          # Diffuse texture
          @mtls[mtlname][:diffuse_tex] = s[1]
        when "map_Ks"
          # Specular texture
          @mtls[mtlname][:specular_tex] = s[1]
        when "map_Ns"
          # Specular highlight texture
          @mtls[mtlname][:specular_high_tex] = s[1]
        when "map_d"
          # Dissolve texture
          @mtls[mtlname][:dissolve_tex] = s[1]
        when "map_bump"
          # Bump mapping texture
          @mtls[mtlname][:map_bump_tex] = s[1]
        when "bump"
          # Bump mapping texture
          @mtls[mtlname][:bump_tex] = s[1]
        when "disp"
          # Displacement texture
          @mtls[mtlname][:displacement_tex] = s[1]
        when "decal"
          # Stencil decal texture
          @mtls[mtlname][:decal_tex] = s[1]
        end
      end
    end
  end

  # get texture list
  # @return [Array<String>] texture name
  def get_texture_list
    lst = {}
    @mtls.each_value do |mat|
      [
        :ambient_tex,
        :diffuse_tex,
        :specular_tex,
        :specular_high_tex,
        :dissolve_tex,
        :map_bump_tex,
        :bump_tex,
        :displacement_tex,
        :decal_tex
      ].each do |k|
        lst[mat[k]] = 1 if mat.key?(k)
      end
    end
    return lst.keys
  end

  def dump_info_size
    puts "vertex = #{@vertexs.size}"
    puts "uv     = #{@uvs.size}"
    puts "normal = #{@normals.size}"

    cnt = 0
    @faces.each { |k, v| cnt += v.size }
    puts "face   = #{cnt}"
    puts "material = #{@faces.size}"
  end

  def dump_faces
    @faces.each do |key, value|
      puts "material : #{key}"
      value.each_with_index do |f, i|
        puts "face #{i} : "
        pp f
      end
    end
  end

  def dump_mtl
    @mtls.each do |key, value|
      puts "#{key} :"
      pp value
    end
  end

  def dump_texs
    @texs.each { |tn| puts tn }
  end
end

if $0 == __FILE__
  # o = WaveFrontObj.new("wavefront/airplane.obj")
  # o = WaveFrontObj.new("wavefront/airplane_metaseq.obj")
  o = WaveFrontObj.new("wavefront/suzanne.obj")
  # o = WaveFrontObj.new("wavefront/robo_01.obj")

  if false
    o.dump_info_size
    o.dump_faces
    o.dump_mtl
    o.dump_texs
  end
end