add a new Scene::invalidate() function to address an issue reported by David Harmon

include/mitsuba/render/scene.h

@@ -72,6 +72,14 @@ public:
 	 */
 	void initialize();
 
+	/**
+	 *\brief Invalidate the kd-tree
+	 *
+	 * This function must be called if, after running \ref initialize(),
+	 * additional geometry is added to the scene.
+	 */
+	void invalidate();
+
 	/**
 	 * \brief Initialize the scene for bidirectional rendering algorithms.
 	 *

src/libpython/render.cpp

@@ -330,6 +330,7 @@ void export_render() {
 		.def("getPrimitiveCount", &ShapeKDTree::getPrimitiveCount)
 		.def("addShape", &ShapeKDTree::addShape)
 		.def("build", &ShapeKDTree::build)
+		.def("isBuilt", &ShapeKDTree::isBuilt)
 		.def("getAABB", &shapekdtree_getAABB, BP_RETURN_VALUE)
 		.def("getShapes", &shapekdtree_getShapes)
 		.def("rayIntersect", &shapekdtree_rayIntersect);
@@ -343,6 +344,7 @@ void export_render() {
 		.def(bp::init<Scene *>())
 		.def(bp::init<Stream *, InstanceManager *>())
 		.def("initialize", &Scene::initialize)
+		.def("invalidate", &Scene::invalidate)
 		.def("preprocess", &Scene::preprocess)
 		.def("render", &Scene::render)
 		.def("postprocess", &Scene::postprocess)

src/librender/scene.cpp

@@ -315,6 +315,10 @@ void Scene::configure() {
 	m_integrator->configureSampler(this, m_sampler);
 }
 
+void Scene::invalidate() {
+	m_kdtree = new ShapeKDTree();
+}
+
 void Scene::initialize() {
 	if (!m_kdtree->isBuilt()) {
 		/* Expand all geometry */