Merge branch 'master' into boost_filesystem

Conflicts:
	openscad.pro
	src/module.h

25 files changed, 339 insertions, 95 deletions

diff --git a/doc/OpenSCAD-polygons.graffle b/doc/OpenSCAD-polygons.graffle
index 40df7ab..758d575 100644
--- a/doc/OpenSCAD-polygons.graffle
+++ b/doc/OpenSCAD-polygons.graffle
diff --git a/doc/OpenSCAD-polygons.pdf b/doc/OpenSCAD-polygons.pdf
index ac18baf..97dfd2e 100644
--- a/doc/OpenSCAD-polygons.pdf
+++ b/doc/OpenSCAD-polygons.pdf
diff --git a/openscad.pro b/openscad.pro
index 80e2b80..ffd7563 100644
--- a/openscad.pro
+++ b/openscad.pro
@@ -188,21 +188,14 @@ HEADERS += src/parsersettings.h \
            src/system-gl.h \
            src/stl-utils.h
 
-SOURCES += src/parsersettings.cc \
-           src/openscad.cc \
-           src/mainwin.cc \
+SOURCES += src/mathc99.cc \
+	   src/linalg.cc \
            src/handle_dep.cc \
-           src/renderer.cc \
-           src/rendersettings.cc \
-           src/ThrownTogetherRenderer.cc \
-           src/glview.cc \
-           src/export.cc \
            src/value.cc \
            src/expr.cc \
            src/func.cc \
            src/module.cc \
            src/node.cc \
-           src/builtin.cc \
            src/context.cc \
            src/csgterm.cc \
            src/polyset.cc \
@@ -215,28 +208,39 @@ SOURCES += src/parsersettings.cc \
            src/surface.cc \
            src/control.cc \
            src/render.cc \
-           src/import.cc \
            src/dxfdata.cc \
-           src/dxftess.cc \
-           src/dxftess-glu.cc \
-           src/dxftess-cgal.cc \
            src/dxfdim.cc \
            src/linearextrude.cc \
            src/rotateextrude.cc \
-           src/highlighter.cc \
            src/printutils.cc \
+           src/progress.cc \
+           src/parsersettings.cc \
+           \
+           src/nodedumper.cc \
+           src/traverser.cc \
+           src/PolySetEvaluator.cc \
+           src/PolySetCache.cc \
+           src/Tree.cc \
+           \
+           src/rendersettings.cc \
+           src/highlighter.cc \
            src/Preferences.cc \
            src/OpenCSGWarningDialog.cc \
-           src/progress.cc \
            src/editor.cc \
-           src/traverser.cc \
-           src/nodedumper.cc \
+           src/glview.cc \
+           \
+           src/builtin.cc \
+           src/export.cc \
+           src/import.cc \
+           src/renderer.cc \
+           src/ThrownTogetherRenderer.cc \
+           src/dxftess.cc \
+           src/dxftess-glu.cc \
+           src/dxftess-cgal.cc \
            src/CSGTermEvaluator.cc \
-           src/Tree.cc \
-	   src/mathc99.cc \
-	   src/linalg.cc \
-           src/PolySetCache.cc \
-           src/PolySetEvaluator.cc
+           \
+           src/openscad.cc \
+           src/mainwin.cc
 
 opencsg {
   HEADERS += src/OpenCSGRenderer.h
diff --git a/src/CGALEvaluator.cc b/src/CGALEvaluator.cc
index 5384cf7..a54fe02 100644
--- a/src/CGALEvaluator.cc
+++ b/src/CGALEvaluator.cc
@@ -98,7 +98,7 @@ CGAL_Nef_polyhedron CGALEvaluator::applyToChildren(const AbstractNode &node, CGA
 		const AbstractNode *chnode = item.first;
 		const CGAL_Nef_polyhedron &chN = item.second;
 		// FIXME: Don't use deep access to modinst members
-		if (chnode->modinst->tag_background) continue;
+		if (chnode->modinst->isBackground()) continue;
 
     // NB! We insert into the cache here to ensure that all children of
     // a node is a valid object. If we inserted as we created them, the 
@@ -126,7 +126,7 @@ CGAL_Nef_polyhedron CGALEvaluator::applyHull(const CgaladvNode &node)
 		const AbstractNode *chnode = item.first;
 		const CGAL_Nef_polyhedron &chN = item.second;
 		// FIXME: Don't use deep access to modinst members
-		if (chnode->modinst->tag_background) continue;
+		if (chnode->modinst->isBackground()) continue;
 		if (dim == 0) {
 			dim = chN.dim;
 		}
diff --git a/src/CSGTermEvaluator.cc b/src/CSGTermEvaluator.cc
index fc76d56..65209dd 100644
--- a/src/CSGTermEvaluator.cc
+++ b/src/CSGTermEvaluator.cc
@@ -56,10 +56,10 @@ void CSGTermEvaluator::applyToChildren(const AbstractNode &node, CSGTermEvaluato
 			}
 		}
 	}
-	if (t1 && node.modinst->tag_highlight) {
+	if (t1 && node.modinst->isHighlight()) {
 		this->highlights.push_back(t1);
 	}
-	if (t1 && node.modinst->tag_background) {
+	if (t1 && node.modinst->isBackground()) {
 		this->background.push_back(t1);
 		t1.reset(); // don't propagate background tagged nodes
 	}
@@ -94,10 +94,10 @@ static shared_ptr<CSGTerm> evaluate_csg_term_from_ps(const State &state,
 	std::stringstream stream;
 	stream << node.name() << node.index();
 	shared_ptr<CSGTerm> t(new CSGTerm(ps, state.matrix(), state.color(), stream.str()));
-	if (modinst->tag_highlight) {
+	if (modinst->isHighlight()) {
 		highlights.push_back(t);
 	}
-	if (modinst->tag_background) {
+	if (modinst->isBackground()) {
 		background.push_back(t);
 		t.reset();
 	}
diff --git a/src/PolySetCGALEvaluator.cc b/src/PolySetCGALEvaluator.cc
index 3285b46..3cd6005 100644
--- a/src/PolySetCGALEvaluator.cc
+++ b/src/PolySetCGALEvaluator.cc
@@ -26,7 +26,7 @@ PolySet *PolySetCGALEvaluator::evaluatePolySet(const ProjectionNode &node)
 	// Before projecting, union all children
 	CGAL_Nef_polyhedron sum;
 	BOOST_FOREACH (AbstractNode * v, node.getChildren()) {
-		if (v->modinst->tag_background) continue;
+		if (v->modinst->isBackground()) continue;
 		CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(*v);
 		if (N.dim == 3) {
 			if (sum.empty()) sum = N.copy();
@@ -259,7 +259,7 @@ PolySet *PolySetCGALEvaluator::evaluatePolySet(const LinearExtrudeNode &node)
 		// to a single DxfData, then tesselate this into a PolySet
 		CGAL_Nef_polyhedron sum;
 		BOOST_FOREACH (AbstractNode * v, node.getChildren()) {
-			if (v->modinst->tag_background) continue;
+			if (v->modinst->isBackground()) continue;
 			CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(*v);
 			if (N.dim != 2) {
 				PRINT("ERROR: linear_extrude() is not defined for 3D child objects!");
@@ -357,7 +357,7 @@ PolySet *PolySetCGALEvaluator::evaluatePolySet(const RotateExtrudeNode &node)
 		// to a single DxfData, then tesselate this into a PolySet
 		CGAL_Nef_polyhedron sum;
 		BOOST_FOREACH (AbstractNode * v, node.getChildren()) {
-			if (v->modinst->tag_background) continue;
+			if (v->modinst->isBackground()) continue;
 			CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(*v);
 			if (N.dim != 2) {
 				PRINT("ERROR: rotate_extrude() is not defined for 3D child objects!");
diff --git a/src/PolySetEvaluator.cc b/src/PolySetEvaluator.cc
index b5075ba..fc68fb2 100644
--- a/src/PolySetEvaluator.cc
+++ b/src/PolySetEvaluator.cc
@@ -7,8 +7,8 @@
 /*!
 	The task of PolySetEvaluator is to create, keep track of and cache PolySet instances.
 
-	All instances of PolySet which are not strictly temporary should be requested through this
-	class.
+	All instances of PolySet which are not strictly temporary should be
+	requested through this class.
 */
 
 /*!
diff --git a/src/context.cc b/src/context.cc
index df884de..57df902 100644
--- a/src/context.cc
+++ b/src/context.cc
@@ -45,6 +45,7 @@ Context::Context(const Context *parent, const Module *library)
 	ctx_stack.push_back(this);
 	if (parent) document_path = parent->document_path;
 	if (library) {
+		// FIXME: Don't access module members directly
 		this->functions_p = &library->functions;
 		this->modules_p = &library->modules;
 		this->usedlibs_p = &library->usedlibs;
@@ -148,24 +149,24 @@ Value Context::evaluate_function(const std::string &name,
 
 AbstractNode *Context::evaluate_module(const ModuleInstantiation &inst) const
 {
-	if (this->modules_p && this->modules_p->find(inst.modname) != this->modules_p->end()) {
-		AbstractModule *m = this->modules_p->find(inst.modname)->second;
-		std::string replacement = Builtins::instance()->isDeprecated(inst.modname);
+	if (this->modules_p && this->modules_p->find(inst.name()) != this->modules_p->end()) {
+		AbstractModule *m = this->modules_p->find(inst.name())->second;
+		std::string replacement = Builtins::instance()->isDeprecated(inst.name());
 		if (!replacement.empty()) {
-			PRINTF("DEPRECATED: The %s() module will be removed in future releases. Use %s() instead.", inst.modname.c_str(), replacement.c_str());
+			PRINTF("DEPRECATED: The %s() module will be removed in future releases. Use %s() instead.", inst.name().c_str(), replacement.c_str());
 		}
 		return m->evaluate(this, &inst);
 	}
 	if (this->usedlibs_p) {
 		BOOST_FOREACH(const ModuleContainer::value_type &m, *this->usedlibs_p) {
-			if (m.second->modules.find(inst.modname) != m.second->modules.end()) {
+			if (m.second->modules.find(inst.name()) != m.second->modules.end()) {
 				Context ctx(this->parent, m.second);
-				return m.second->modules[inst.modname]->evaluate(&ctx, &inst);
+				return m.second->modules[inst.name()]->evaluate(&ctx, &inst);
 			}
 		}
 	}
 	if (this->parent) return this->parent->evaluate_module(inst);
-	PRINTF("WARNING: Ignoring unknown module '%s'.", inst.modname.c_str());
+	PRINTF("WARNING: Ignoring unknown module '%s'.", inst.name().c_str());
 	return NULL;
 }
 
diff --git a/src/dxfdata.cc b/src/dxfdata.cc
index cf9248f..2bc21e2 100644
--- a/src/dxfdata.cc
+++ b/src/dxfdata.cc
@@ -42,6 +42,20 @@
 #include <QDir>
 #include "value.h"
 
+/*! \class DxfData
+
+	The DxfData class fulfils multiple tasks, partially for historical reasons.
+	FIXME: It's a bit messy and is a prime target for refactoring.
+
+	1) Read DXF file from disk
+	2) Store contents of DXF files as points, paths and dims
+	3) Store 2D polygons, both from the polygon() module and from 2D CSG operations.
+	   Used for tesselation into triangles
+  4) Store 2D polygons before exporting to DXF
+	
+
+ */
+
 struct Line {
 	int idx[2]; // indices into DxfData::points
 	bool disabled;
diff --git a/src/export.cc b/src/export.cc
index 99bce98..5ce2d15 100644
--- a/src/export.cc
+++ b/src/export.cc
@@ -102,6 +102,9 @@ void export_stl(CGAL_Nef_polyhedron *root_N, std::ostream &output, QProgressDial
 				double ny = dn[2]*dn[3] - dn[0]*dn[5];
 				double nz = dn[0]*dn[4] - dn[1]*dn[3];
 				double nlength = sqrt(nx*nx + ny*ny + nz*nz);
+				// Avoid generating normals for polygons with zero area
+				double eps = 0.000001;
+				if (nlength < eps) nlength = 1.0;
 				output << "  facet normal "
 							 << nx / nlength << " "
 							 << ny / nlength << " "
diff --git a/src/glview.cc b/src/glview.cc
index d9f6bb5..f25cac6 100644
--- a/src/glview.cc
+++ b/src/glview.cc
@@ -105,7 +105,7 @@ void GLView::init()
 void GLView::setRenderer(Renderer *r)
 {
 	this->renderer = r;
-	updateGL();
+	if (r) updateGL(); // Let the last image stay, e.g. to avoid animation flickering
 }
 
 void GLView::initializeGL()
diff --git a/src/mainwin.cc b/src/mainwin.cc
index 3567ddd..f9ce5c1 100644
--- a/src/mainwin.cc
+++ b/src/mainwin.cc
@@ -583,7 +583,7 @@ void MainWindow::load()
 AbstractNode *MainWindow::find_root_tag(AbstractNode *n)
 {
 	BOOST_FOREACH (AbstractNode *v, n->children) {
-		if (v->modinst->tag_root) return v;
+		if (v->modinst->isRoot()) return v;
 		if (AbstractNode *vroot = find_root_tag(v)) return vroot;
 	}
 	return NULL;
@@ -1505,7 +1505,7 @@ void MainWindow::actionFlushCaches()
 #endif
 	dxf_dim_cache.clear();
 	dxf_cross_cache.clear();
-	Module::libs_cache.clear();
+	Module::clear_library_cache();
 }
 
 void MainWindow::viewModeActionsUncheck()
diff --git a/src/module.cc b/src/module.cc
index 269e128..ba0112d 100644
--- a/src/module.cc
+++ b/src/module.cc
@@ -68,7 +68,6 @@ std::string ModuleInstantiation::dump(const std::string &indent) const
 {
 	std::stringstream dump;
 	dump << indent;
-	if (!label.empty()) dump << label <<": ";
 	dump << modname + "(";
 	for (size_t i=0; i < argnames.size(); i++) {
 		if (i > 0) dump << ", ";
@@ -96,10 +95,11 @@ AbstractNode *ModuleInstantiation::evaluate(const Context *ctx) const
 	if (this->ctx) {
 		PRINTF("WARNING: Ignoring recursive module instantiation of '%s'.", modname.c_str());
 	} else {
+		// FIXME: Casting away const..
 		ModuleInstantiation *that = (ModuleInstantiation*)this;
 		that->argvalues.clear();
-		BOOST_FOREACH (Expression *v, that->argexpr) {
-			that->argvalues.push_back(v->evaluate(ctx));
+		BOOST_FOREACH (Expression *expr, that->argexpr) {
+			that->argvalues.push_back(expr->evaluate(ctx));
 		}
 		that->ctx = ctx;
 		node = ctx->evaluate_module(*this);
@@ -113,9 +113,9 @@ std::vector<AbstractNode*> ModuleInstantiation::evaluateChildren(const Context *
 {
 	if (!ctx) ctx = this->ctx;
 	std::vector<AbstractNode*> childnodes;
-	BOOST_FOREACH (ModuleInstantiation *v, this->children) {
-		AbstractNode *n = v->evaluate(ctx);
-		if (n != NULL) childnodes.push_back(n);
+	BOOST_FOREACH (ModuleInstantiation *modinst, this->children) {
+		AbstractNode *node = modinst->evaluate(ctx);
+		if (node) childnodes.push_back(node);
 	}
 	return childnodes;
 }
@@ -124,9 +124,9 @@ std::vector<AbstractNode*> IfElseModuleInstantiation::evaluateElseChildren(const
 {
 	if (!ctx) ctx = this->ctx;
 	std::vector<AbstractNode*> childnodes;
-	BOOST_FOREACH (ModuleInstantiation *v, this->else_children) {
-		AbstractNode *n = v->evaluate(this->ctx);
-		if (n != NULL) childnodes.push_back(n);
+	BOOST_FOREACH (ModuleInstantiation *modinst, this->else_children) {
+		AbstractNode *node = modinst->evaluate(ctx);
+		if (node != NULL) childnodes.push_back(node);
 	}
 	return childnodes;
 }
@@ -200,3 +200,8 @@ std::string Module::dump(const std::string &indent, const std::string &name) con
 	}
 	return dump.str();
 }
+
+void Module::clear_library_cache()
+{
+	Module::libs_cache.clear();
+}
diff --git a/src/module.h b/src/module.h
index 93eafa5..557b7c5 100644
--- a/src/module.h
+++ b/src/module.h
@@ -9,28 +9,38 @@
 class ModuleInstantiation
 {
 public:
-	std::string label;
-	std::string modname;
+	ModuleInstantiation(const std::string &name = "") 
+	: ctx(NULL), 
+		tag_root(false), tag_highlight(false), tag_background(false), modname(name) { }
+	virtual ~ModuleInstantiation();
+
+	std::string dump(const std::string &indent) const;
+	class AbstractNode *evaluate(const class Context *ctx) const;
+	std::vector<AbstractNode*> evaluateChildren(const Context *ctx = NULL) const;
+
+	const std::string &name() const { return this->modname; }
+	bool isBackground() const { return this->tag_background; }
+	bool isHighlight() const { return this->tag_highlight; }
+	bool isRoot() const { return this->tag_root; }
+
 	std::vector<std::string> argnames;
-	std::vector<class Expression*> argexpr;
 	std::vector<Value> argvalues;
+	std::vector<class Expression*> argexpr;
 	std::vector<ModuleInstantiation*> children;
+	const Context *ctx;
 
 	bool tag_root;
 	bool tag_highlight;
 	bool tag_background;
-	const class Context *ctx;
-
-	ModuleInstantiation() : tag_root(false), tag_highlight(false), tag_background(false), ctx(NULL) { }
-	virtual ~ModuleInstantiation();
+protected:
+	std::string modname;
 
-	std::string dump(const std::string &indent) const;
-	class AbstractNode *evaluate(const Context *ctx) const;
-	std::vector<AbstractNode*> evaluateChildren(const Context *ctx = NULL) const;
+	friend class Module;
 };
 
 class IfElseModuleInstantiation : public ModuleInstantiation {
 public:
+	IfElseModuleInstantiation() : ModuleInstantiation("if") { }
 	virtual ~IfElseModuleInstantiation();
 	std::vector<AbstractNode*> evaluateElseChildren(const Context *ctx = NULL) const;
 
@@ -48,18 +58,18 @@ public:
 class Module : public AbstractModule
 {
 public:
-	typedef boost::unordered_map<std::string, class Module*> ModuleContainer;
-	ModuleContainer usedlibs;
+	Module() { }
+	virtual ~Module();
+	virtual AbstractNode *evaluate(const Context *ctx, const ModuleInstantiation *inst) const;
+	virtual std::string dump(const std::string &indent, const std::string &name) const;
 
-	struct libs_cache_ent {
-		Module *mod;
-		std::string cache_id, msg;
-	};
-	static boost::unordered_map<std::string, libs_cache_ent> libs_cache;
-	static Module *compile_library(const std::string &filename);
+	void addChild(ModuleInstantiation *ch) { this->children.push_back(ch); }
 
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
+	static Module *compile_library(std::string filename);
+	static void clear_library_cache();
+
+	typedef boost::unordered_map<std::string, class Module*> ModuleContainer;
+	ModuleContainer usedlibs;
 
 	std::vector<std::string> assignments_var;
 	std::vector<Expression*> assignments_expr;
@@ -71,11 +81,17 @@ public:
 
 	std::vector<ModuleInstantiation*> children;
 
-	Module() { }
-	virtual ~Module();
+	std::vector<std::string> argnames;
+	std::vector<Expression*> argexpr;
 
-	virtual AbstractNode *evaluate(const Context *ctx, const ModuleInstantiation *inst) const;
-	virtual std::string dump(const std::string &indent, const std::string &name) const;
+protected:
+
+private:
+	struct libs_cache_ent {
+		Module *mod;
+		std::string cache_id, msg;
+	};
+	static boost::unordered_map<std::string, libs_cache_ent> libs_cache;
 };
 
 #endif
diff --git a/src/node.cc b/src/node.cc
index eccb9a6..e61174f 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -97,7 +97,7 @@ void AbstractNode::progress_report() const
 std::ostream &operator<<(std::ostream &stream, const AbstractNode &node)
 {
 	// FIXME: Don't use deep access to modinst members
-	if (node.modinst->tag_background) stream << "%";
+	if (node.modinst->isBackground()) stream << "%";
 	stream << node.toString();
 	return stream;
 }
diff --git a/src/node.h b/src/node.h
index 9b075fc..42547db 100644
--- a/src/node.h
+++ b/src/node.h
@@ -35,7 +35,9 @@ public:
 	    overloaded to provide specialization for e.g. CSG nodes, primitive nodes etc.
 	    Used for human-readable output. */
 	virtual std::string name() const;
-  /*! Should return a PolySet of the given geometry. Returns NULL if smth. goes wrong */
+  /*! Should return a PolySet of the given geometry. Returns NULL if smth. goes wrong.
+	 This is only called by PolySetEvaluator, to make sure polysets are inserted into 
+	 the cache*/
 	virtual class PolySet *evaluate_polyset(class PolySetEvaluator *) const { return NULL; }
 
 	const std::vector<AbstractNode*> &getChildren() const { 
diff --git a/src/parser.y b/src/parser.y
index b8da50d..df652f5 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -144,7 +144,7 @@ statement:
 	'{' inner_input '}' |
 	module_instantiation {
 		if ($1) {
-			module->children.push_back($1);
+			module->addChild($1);
 		} else {
 			delete $1;
 		}
@@ -191,10 +191,8 @@ statement:
 children_instantiation:
 	module_instantiation {
 		$$ = new ModuleInstantiation();
-		if ($1) {
+		if ($1) { 
 			$$->children.push_back($1);
-		} else {
-			delete $1;
 		}
 	} |
 	'{' module_instantiation_list '}' {
@@ -204,7 +202,6 @@ children_instantiation:
 if_statement:
 	TOK_IF '(' expr ')' children_instantiation {
 		$$ = new IfElseModuleInstantiation();
-		$$->modname = "if";
 		$$->argnames.push_back("");
 		$$->argexpr.push_back($3);
 
@@ -260,8 +257,7 @@ module_instantiation_list:
 	module_instantiation_list module_instantiation {
 		$$ = $1;
 		if ($$) {
-			if ($2)
-				$$->children.push_back($2);
+			if ($2) $$->children.push_back($2);
 		} else {
 			delete $2;
 		}
@@ -269,19 +265,12 @@ module_instantiation_list:
 
 single_module_instantiation:
 	TOK_ID '(' arguments_call ')' {
-		$$ = new ModuleInstantiation();
-		$$->modname = $1;
+		$$ = new ModuleInstantiation($1);
 		$$->argnames = $3->argnames;
 		$$->argexpr = $3->argexpr;
 		free($1);
 		delete $3;
 	} |
-	TOK_ID ':' single_module_instantiation {
-		$$ = $3;
-		if ($$)
-			$$->label = $1;
-		free($1);
-	} |
 	'!' single_module_instantiation {
 		$$ = $2;
 		if ($$)
diff --git a/src/polyset.cc b/src/polyset.cc
index 09d3ea8..778201b 100644
--- a/src/polyset.cc
+++ b/src/polyset.cc
@@ -25,11 +25,20 @@
  */
 
 #include "polyset.h"
-// FIXME: Reenable/rewrite - don't be dependant on GUI
-// #include "Preferences.h"
 #include "linalg.h"
 #include <Eigen/LU>
 
+/*! /class PolySet
+
+	The PolySet class fulfils multiple tasks, partially for historical reasons.
+	FIXME: It's a bit messy and is a prime target for refactoring.
+
+	1) Store 2D and 3D polygon meshes from all origins
+	2) Store 2D outlines, used for rendering edges
+	3) Rendering of polygons and edges
+
+ */
+
 PolySet::PolySet() : grid(GRID_FINE), is2d(false), convexity(1)
 {
 }
diff --git a/testdata/scad/features/color-tests.scad b/testdata/scad/features/color-tests.scad
index 3ef2540..3fc98c8 100644
--- a/testdata/scad/features/color-tests.scad
+++ b/testdata/scad/features/color-tests.scad
@@ -13,3 +13,4 @@ translate([12,0,0]) color([0,0,1],0.5) object();
 translate([24,0,0]) color(c="Green",alpha=0.2) object();
 translate([-12,12,0]) color() object();
 translate([-12,0,0]) color(alpha=0.5) object();
+translate([24,-12,0]) color([1,0,0]) color([0,0,1]) object();
diff --git a/testdata/scad/misc/normal-nan.scad b/testdata/scad/misc/normal-nan.scad
new file mode 100644
index 0000000..1c3f6ce
--- /dev/null
+++ b/testdata/scad/misc/normal-nan.scad
@@ -0,0 +1,16 @@
+/*
+  When exporting this to STL, null polygons appear, causing
+  problems normalizing normal vectors (nan output in STL files)
+*/
+
+$fs=0.2;
+
+difference() {  
+  cube(8);
+ 
+  translate([0,20,4]) rotate([90,0,0]) union() {
+    translate([0,-3,14.5]) cube([5.4,6,2.4],center=true);
+    translate([0,0,13.3]) rotate([0,0,30]) cylinder(r=3.115,h=2.4,$fn=6);
+  }
+}
+
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index dd4e6a8..1e96627 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -362,6 +362,13 @@ set_target_properties(cgaltest PROPERTIES COMPILE_FLAGS "-DENABLE_CGAL ${CGAL_CX
 target_link_libraries(cgaltest tests-cgal ${CGAL_LIBRARY} ${CGAL_3RD_PARTY_LIBRARIES} ${QT_LIBRARIES} ${OPENGL_LIBRARY} ${Boost_LIBRARIES})
 
 #
+# cgalstlsanitytest
+#
+add_executable(cgalstlsanitytest cgalstlsanitytest.cc)
+set_target_properties(cgalstlsanitytest PROPERTIES COMPILE_FLAGS "-DENABLE_CGAL ${CGAL_CXX_FLAGS_INIT}")
+target_link_libraries(cgalstlsanitytest tests-cgal ${CGAL_LIBRARY} ${CGAL_3RD_PARTY_LIBRARIES} ${QT_LIBRARIES} ${OPENGL_LIBRARY} ${Boost_LIBRARIES})
+
+#
 # cgalpngtest
 #
 add_executable(cgalpngtest cgalpngtest.cc bboxhelp.cc ../src/CGALRenderer.cc ../src/renderer.cc ../src/rendersettings.cc)
@@ -536,6 +543,8 @@ list(APPEND OPENCSGTEST_FILES ${CGALPNGTEST_FILES})
 list(APPEND OPENCSGTEST_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/bugs/bbox-transform-bug.scad)
 list(APPEND THROWNTOGETHERTEST_FILES ${OPENCSGTEST_FILES})
 
+list(APPEND CGALSTLSANITYTEST_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/normal-nan.scad)
+
 # Disable tests which are known to cause floating point comparison issues
 # Once we're capable of comparing these across platforms, we can put these back in
 disable_tests(dumptest_transform-tests
@@ -599,6 +608,9 @@ add_cmdline_test(csgtermtest txt ${MINIMAL_FILES})
 add_cmdline_test(cgalpngtest png ${CGALPNGTEST_FILES})
 add_cmdline_test(opencsgtest png ${OPENCSGTEST_FILES})
 add_cmdline_test(throwntogethertest png ${THROWNTOGETHERTEST_FILES})
+# FIXME: We don't actually need to compare the output of cgalstlsanitytest
+# with anything. It's self-contained and returns != 0 on error
+add_cmdline_test(cgalstlsanitytest txt ${CGALSTLSANITYTEST_FILES})
 
 message("Available test configurations: ${TEST_CONFIGS}")
 #foreach(CONF ${TEST_CONFIGS})
diff --git a/tests/cgalstlsanitytest.cc b/tests/cgalstlsanitytest.cc
new file mode 100644
index 0000000..a078dff
--- /dev/null
+++ b/tests/cgalstlsanitytest.cc
@@ -0,0 +1,163 @@
+/*
+ *  OpenSCAD (www.openscad.org)
+ *  Copyright (C) 2009-2011 Clifford Wolf <clifford@clifford.at> and
+ *                          Marius Kintel <marius@kintel.net>
+ *
+ *  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.
+ *
+ *  As a special exception, you have permission to link this program
+ *  with the CGAL library and distribute executables, as long as you
+ *  follow the requirements of the GNU GPL in regard to all of the
+ *  software in the executable aside from CGAL.
+ *
+ *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "tests-common.h"
+#include "openscad.h"
+#include "node.h"
+#include "module.h"
+#include "context.h"
+#include "value.h"
+#include "export.h"
+#include "builtin.h"
+#include "Tree.h"
+#include "CGAL_Nef_polyhedron.h"
+#include "CGALEvaluator.h"
+#include "PolySetCGALEvaluator.h"
+
+#include <QApplication>
+#include <QFile>
+#include <QDir>
+#include <QSet>
+#include <QTextStream>
+#ifndef _MSC_VER
+#include <getopt.h>
+#endif
+#include <iostream>
+#include <assert.h>
+#include <sstream>
+
+std::string commandline_commands;
+QString currentdir;
+QString examplesdir;
+QString librarydir;
+
+using std::string;
+
+void cgalTree(Tree &tree)
+{
+	assert(tree.root());
+
+	CGALEvaluator evaluator(tree);
+	Traverser evaluate(evaluator, *tree.root(), Traverser::PRE_AND_POSTFIX);
+	evaluate.execute();
+}
+
+AbstractNode *find_root_tag(AbstractNode *n)
+{
+	foreach(AbstractNode *v, n->children) {
+		if (v->modinst->tag_root) return v;
+		if (AbstractNode *vroot = find_root_tag(v)) return vroot;
+	}
+	return NULL;
+}
+
+int main(int argc, char **argv)
+{
+	int retval = 0;
+
+	if (argc != 3) {
+		fprintf(stderr, "Usage: %s <file.scad> <output.txt>\n", argv[0]);
+		exit(1);
+	}
+
+	const char *filename = argv[1];
+	const char *outfilename = argv[2];
+
+	Builtins::instance()->initialize();
+
+	QApplication app(argc, argv, false);
+	QDir original_path = QDir::current();
+
+	currentdir = QDir::currentPath();
+
+	QDir libdir(QApplication::instance()->applicationDirPath());
+#ifdef Q_WS_MAC
+	libdir.cd("../Resources"); // Libraries can be bundled
+	if (!libdir.exists("libraries")) libdir.cd("../../..");
+#elif defined(Q_OS_UNIX)
+	if (libdir.cd("../share/openscad/libraries")) {
+		librarydir = libdir.path();
+	} else
+	if (libdir.cd("../../share/openscad/libraries")) {
+		librarydir = libdir.path();
+	} else
+	if (libdir.cd("../../libraries")) {
+		librarydir = libdir.path();
+	} else
+#endif
+	if (libdir.cd("libraries")) {
+		librarydir = libdir.path();
+	}
+
+	Context root_ctx;
+	register_builtin(root_ctx);
+
+	AbstractModule *root_module;
+	ModuleInstantiation root_inst;
+
+	root_module = parsefile(filename);
+	if (!root_module) {
+		exit(1);
+	}
+
+	QFileInfo fileInfo(filename);
+	QDir::setCurrent(fileInfo.absolutePath());
+
+	AbstractNode::resetIndexCounter();
+	AbstractNode *absolute_root_node = root_module->evaluate(&root_ctx, &root_inst);
+	AbstractNode *root_node;
+	// Do we have an explicit root node (! modifier)?
+	if (!(root_node = find_root_tag(absolute_root_node))) root_node = absolute_root_node;
+
+	Tree tree(root_node);
+
+	CGALEvaluator cgalevaluator(tree);
+ 	PolySetCGALEvaluator psevaluator(cgalevaluator);
+
+	CGAL_Nef_polyhedron N = cgalevaluator.evaluateCGALMesh(*root_node);
+
+	QDir::setCurrent(original_path.absolutePath());
+	if (!N.empty()) {
+		std::ofstream outfile;
+		outfile.open(outfilename);
+
+		std::stringstream out;
+		export_stl(&N, out, NULL);
+		if (out.str().find("nan") != string::npos) {
+			outfile << "Error: nan found\n";
+			retval = 2;
+		}
+		if (out.str().find("inf") != string::npos) {
+			outfile << "Error: inf found\n";
+			retval = 2;
+		}
+		outfile.close();
+	}
+
+	Builtins::instance(true);
+
+	return retval;
+}
diff --git a/tests/regression/cgalpngtest/color-tests-expected.png b/tests/regression/cgalpngtest/color-tests-expected.png
index 207fc5b..c7385d2 100644
--- a/tests/regression/cgalpngtest/color-tests-expected.png
+++ b/tests/regression/cgalpngtest/color-tests-expected.png
diff --git a/tests/regression/cgalstlsanitytest/normal-nan-expected.txt b/tests/regression/cgalstlsanitytest/normal-nan-expected.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/regression/cgalstlsanitytest/normal-nan-expected.txt
diff --git a/tests/regression/dumptest/color-tests-expected.txt b/tests/regression/dumptest/color-tests-expected.txt
index 1224e2d..95fe012 100644
--- a/tests/regression/dumptest/color-tests-expected.txt
+++ b/tests/regression/dumptest/color-tests-expected.txt
@@ -52,4 +52,13 @@
 			}
 		}
 	}
+	multmatrix([[1, 0, 0, 24], [0, 1, 0, -12], [0, 0, 1, 0], [0, 0, 0, 1]]) {
+		color([1, 0, 0, 1]) {
+			color([0, 0, 1, 1]) {
+				group() {
+					cube(size = [10, 10, 10], center = false);
+				}
+			}
+		}
+	}