add Obj2D builder, skeleton obj2d.rb script

Rakefile.rb

@@ -6,9 +6,17 @@ rescue Bundler::BundlerError => e
 end
 require "rscons"
 
+class Obj2D < Rscons::Builder
+  def run(target, sources, cache, env, vars)
+    command = ["ruby", "obj2d.rb", sources.first, target]
+    standard_build("Obj2D #{target}", target, command, sources + ["obj2d.rb"], env, cache)
+  end
+end
+
 desc "Build ScreenSaver"
 task :default do
   Rscons::Environment.new do |env|
+    env.add_builder(Obj2D.new)
     sources = []
     dirs = [
       "src",
@@ -20,16 +28,19 @@ task :default do
     ].each do |dir|
       sources += Dir["#{dir}/**/*.d"]
     end
+    sources << "build/obj2d/logo.d"
     env["D_IMPORT_PATH"] += [
       "modules/DerelictUtil/source",
       "modules/DerelictSDL2/source",
       "modules/DerelictGL3/source",
       "modules/gl3n",
       "modules/glamour",
+      "build/obj2d",
     ]
     env["DFLAGS"] += ["-fversion=Derelict3", "-fversion=gl3n", "-fversion=SDLImage"]
     env["LDFLAGS"] += ["-static-libgcc"]
     env.build_root = "build"
+    env.Obj2D("build/obj2d/logo.d", "model/gentex-logo.obj")
     env.Program("gss", sources)
   end
 end

obj2d.rb

@@ -0,0 +1,8 @@
+#!/usr/bin/env ruby
+
+def main(obj_fname, d_fname)
+  File.open(d_fname, "w") do |fh|
+  end
+end
+
+main(*ARGV)