Cycles render engine, initial commit. This is the engine itself, blender modifications and build instructions will follow later.

Cycles uses code from some great open source projects, many thanks them:

* BVH building and traversal code from NVidia's "Understanding the Efficiency of Ray Traversal on GPUs":
http://code.google.com/p/understanding-the-efficiency-of-ray-traversal-on-gpus/
* Open Shading Language for a large part of the shading system:
http://code.google.com/p/openshadinglanguage/
* Blender for procedural textures and a few other nodes.
* Approximate Catmull Clark subdivision from NVidia Mesh tools:
http://code.google.com/p/nvidia-mesh-tools/
* Sobol direction vectors from:
http://web.maths.unsw.edu.au/~fkuo/sobol/
* Film response functions from:
http://www.cs.columbia.edu/CAVE/software/softlib/dorf.php

intern/cycles/util/util_path.cpp

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2011, Blender Foundation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "util_debug.h"
+#include "util_path.h"
+#include "util_string.h"
+
+#include <OpenImageIO/sysutil.h>
+OIIO_NAMESPACE_USING
+
+#include <boost/filesystem.hpp> 
+
+CCL_NAMESPACE_BEGIN
+
+static string cached_path = "";
+
+void path_init(const string& path)
+{
+	cached_path = path;
+}
+
+string path_get(const string& sub)
+{
+	if(cached_path == "")
+		cached_path = path_dirname(Sysutil::this_program_path());
+
+	return path_join(cached_path, sub);
+}
+
+string path_filename(const string& path)
+{
+	return boost::filesystem::path(path).filename();
+}
+
+string path_dirname(const string& path)
+{
+	return boost::filesystem::path(path).parent_path().string();
+}
+
+string path_join(const string& dir, const string& file)
+{
+	return (boost::filesystem::path(dir) / boost::filesystem::path(file)).string();
+}
+
+CCL_NAMESPACE_END
+