added a simple kd-tree performance benchmark

SConstruct

@@ -487,6 +487,7 @@ plugins = []
 
 # Build the plugins -- utilities
 plugins += env.SharedLibrary('plugins/addimages', ['src/utils/addimages.cpp'])
+plugins += env.SharedLibrary('plugins/kdbench', ['src/utils/kdbench.cpp'])
 
 # BSDFs
 plugins += env.SharedLibrary('plugins/lambertian', ['src/bsdfs/lambertian.cpp'])

src/utils/kdbench.cpp

@@ -0,0 +1,71 @@
+/*
+    This file is part of Mitsuba, a physically based rendering system.
+
+    Copyright (c) 2007-2010 by Wenzel Jakob and others.
+
+    Mitsuba is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License Version 3
+    as published by the Free Software Foundation.
+
+    Mitsuba 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <mitsuba/render/util.h>
+#include <mitsuba/core/timer.h>
+
+MTS_NAMESPACE_BEGIN
+
+class KDBench : public Utility {
+public:
+	int run(int argc, char **argv) {
+		if (argc != 2) {
+			cout << "Test the kd-Tree performance using a specified scene" << endl;
+			cout << "Syntax: mtsutil kdbench <scene.xml>" << endl;
+			return -1;
+		}
+
+		ref<Scene> scene = loadScene(argv[1]);
+		Thread::getThread()->getLogger()->setLogLevel(EDebug);
+		scene->initialize();
+		BSphere bsphere(scene->getBSphere());
+
+		for (int j=0; j<3; ++j) {
+			ref<Random> random = new Random();
+			ref<Timer> timer = new Timer();
+			size_t nRays = 5000000, nIntersections = 0;
+
+			Log(EInfo, "Bounding sphere: %s", bsphere.toString().c_str());
+			Log(EInfo, "Shooting " SIZE_T_FMT " rays ..", nRays);
+
+			for (size_t i=0; i<nRays; ++i) {
+				Point2 sample1(random->nextFloat(), random->nextFloat()),
+					sample2(random->nextFloat(), random->nextFloat());
+				Point p1 = bsphere.center + squareToSphere(sample1) * bsphere.radius;
+				Point p2 = bsphere.center + squareToSphere(sample2) * bsphere.radius;
+				Ray r(p1, normalize(p2-p1));
+
+				Intersection its;
+				if (scene->rayIntersect(r, its))
+					nIntersections++;
+			}
+
+			Log(EInfo, "Found " SIZE_T_FMT " intersections in %i ms",
+				nIntersections, timer->getMilliseconds());
+			Log(EInfo, "%.3f MRays/s", 
+				nRays / (timer->getMilliseconds() * (Float) 1000));
+		}
+
+		return 0;
+	}
+
+	MTS_DECLARE_UTILITY()
+};
+
+MTS_EXPORT_UTILITY(KDBench, "kd-tree performance benchmark")
+MTS_NAMESPACE_END