zoomedit: Big transition Ciaro -> OpenGL, enormous speedup!

19 files changed, 1114 insertions, 350 deletions

diff --git a/Makefile.am b/Makefile.am
index 4ae72e8..94ded86 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,5 +1,5 @@
 bin_PROGRAMS  	     = zoomedit
-zoomedit_SOURCES     = zoomedit.cpp window.cpp ui.cpp draw.cpp edit.cpp geometry.cpp \
-                       Vertex.cpp Line.cpp Polygon.cpp Rectangle.cpp Room.cpp
-zoomedit_CPPFLAGS    = @GTK_CFLAGS@
-zoomedit_LDADD       = @GTK_LIBS@
\ No newline at end of file
+zoomedit_SOURCES     = zoomedit.cpp window.cpp ui.cpp draw.cpp edit.cpp Vertex.cpp \
+                       Line.cpp Polygon.cpp Rectangle.cpp Room.cpp Triangle.cpp
+zoomedit_CPPFLAGS    = @GTK_CFLAGS@ @GTKGLEXT_CFLAGS@
+zoomedit_LDADD       = @GTK_LIBS@ @GTKGLEXT_LIBS@
\ No newline at end of file
diff --git a/Makefile.in b/Makefile.in
index ef8432a..9762995 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -51,9 +51,9 @@ PROGRAMS = $(bin_PROGRAMS)
 am_zoomedit_OBJECTS = zoomedit-zoomedit.$(OBJEXT) \
 	zoomedit-window.$(OBJEXT) zoomedit-ui.$(OBJEXT) \
 	zoomedit-draw.$(OBJEXT) zoomedit-edit.$(OBJEXT) \
-	zoomedit-geometry.$(OBJEXT) zoomedit-Vertex.$(OBJEXT) \
-	zoomedit-Line.$(OBJEXT) zoomedit-Polygon.$(OBJEXT) \
-	zoomedit-Rectangle.$(OBJEXT) zoomedit-Room.$(OBJEXT)
+	zoomedit-Vertex.$(OBJEXT) zoomedit-Line.$(OBJEXT) \
+	zoomedit-Polygon.$(OBJEXT) zoomedit-Rectangle.$(OBJEXT) \
+	zoomedit-Room.$(OBJEXT) zoomedit-Triangle.$(OBJEXT)
 zoomedit_OBJECTS = $(am_zoomedit_OBJECTS)
 zoomedit_DEPENDENCIES =
 DEFAULT_INCLUDES = -I.@am__isrc@
@@ -102,6 +102,8 @@ ECHO_T = @ECHO_T@
 EGREP = @EGREP@
 EXEEXT = @EXEEXT@
 GREP = @GREP@
+GTKGLEXT_CFLAGS = @GTKGLEXT_CFLAGS@
+GTKGLEXT_LIBS = @GTKGLEXT_LIBS@
 GTK_CFLAGS = @GTK_CFLAGS@
 GTK_LIBS = @GTK_LIBS@
 INSTALL = @INSTALL@
@@ -171,11 +173,11 @@ sysconfdir = @sysconfdir@
 target_alias = @target_alias@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
-zoomedit_SOURCES = zoomedit.cpp window.cpp ui.cpp draw.cpp edit.cpp geometry.cpp \
-                       Vertex.cpp Line.cpp Polygon.cpp Rectangle.cpp Room.cpp
+zoomedit_SOURCES = zoomedit.cpp window.cpp ui.cpp draw.cpp edit.cpp Vertex.cpp \
+                       Line.cpp Polygon.cpp Rectangle.cpp Room.cpp Triangle.cpp
 
-zoomedit_CPPFLAGS = @GTK_CFLAGS@
-zoomedit_LDADD = @GTK_LIBS@
+zoomedit_CPPFLAGS = @GTK_CFLAGS@ @GTKGLEXT_CFLAGS@
+zoomedit_LDADD = @GTK_LIBS@ @GTKGLEXT_LIBS@
 all: config.h
 	$(MAKE) $(AM_MAKEFLAGS) all-am
 
@@ -268,10 +270,10 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-Polygon.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-Rectangle.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-Room.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-Triangle.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-Vertex.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-draw.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-edit.Po@am__quote@
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-geometry.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-ui.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-window.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/zoomedit-zoomedit.Po@am__quote@
@@ -360,20 +362,6 @@ zoomedit-edit.obj: edit.cpp
 @AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCXX_FALSE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o zoomedit-edit.obj `if test -f 'edit.cpp'; then $(CYGPATH_W) 'edit.cpp'; else $(CYGPATH_W) '$(srcdir)/edit.cpp'; fi`
 
-zoomedit-geometry.o: geometry.cpp
-@am__fastdepCXX_TRUE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT zoomedit-geometry.o -MD -MP -MF $(DEPDIR)/zoomedit-geometry.Tpo -c -o zoomedit-geometry.o `test -f 'geometry.cpp' || echo '$(srcdir)/'`geometry.cpp
-@am__fastdepCXX_TRUE@	mv -f $(DEPDIR)/zoomedit-geometry.Tpo $(DEPDIR)/zoomedit-geometry.Po
-@AMDEP_TRUE@@am__fastdepCXX_FALSE@	source='geometry.cpp' object='zoomedit-geometry.o' libtool=no @AMDEPBACKSLASH@
-@AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
-@am__fastdepCXX_FALSE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o zoomedit-geometry.o `test -f 'geometry.cpp' || echo '$(srcdir)/'`geometry.cpp
-
-zoomedit-geometry.obj: geometry.cpp
-@am__fastdepCXX_TRUE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT zoomedit-geometry.obj -MD -MP -MF $(DEPDIR)/zoomedit-geometry.Tpo -c -o zoomedit-geometry.obj `if test -f 'geometry.cpp'; then $(CYGPATH_W) 'geometry.cpp'; else $(CYGPATH_W) '$(srcdir)/geometry.cpp'; fi`
-@am__fastdepCXX_TRUE@	mv -f $(DEPDIR)/zoomedit-geometry.Tpo $(DEPDIR)/zoomedit-geometry.Po
-@AMDEP_TRUE@@am__fastdepCXX_FALSE@	source='geometry.cpp' object='zoomedit-geometry.obj' libtool=no @AMDEPBACKSLASH@
-@AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
-@am__fastdepCXX_FALSE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o zoomedit-geometry.obj `if test -f 'geometry.cpp'; then $(CYGPATH_W) 'geometry.cpp'; else $(CYGPATH_W) '$(srcdir)/geometry.cpp'; fi`
-
 zoomedit-Vertex.o: Vertex.cpp
 @am__fastdepCXX_TRUE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT zoomedit-Vertex.o -MD -MP -MF $(DEPDIR)/zoomedit-Vertex.Tpo -c -o zoomedit-Vertex.o `test -f 'Vertex.cpp' || echo '$(srcdir)/'`Vertex.cpp
 @am__fastdepCXX_TRUE@	mv -f $(DEPDIR)/zoomedit-Vertex.Tpo $(DEPDIR)/zoomedit-Vertex.Po
@@ -444,6 +432,20 @@ zoomedit-Room.obj: Room.cpp
 @AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCXX_FALSE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o zoomedit-Room.obj `if test -f 'Room.cpp'; then $(CYGPATH_W) 'Room.cpp'; else $(CYGPATH_W) '$(srcdir)/Room.cpp'; fi`
 
+zoomedit-Triangle.o: Triangle.cpp
+@am__fastdepCXX_TRUE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT zoomedit-Triangle.o -MD -MP -MF $(DEPDIR)/zoomedit-Triangle.Tpo -c -o zoomedit-Triangle.o `test -f 'Triangle.cpp' || echo '$(srcdir)/'`Triangle.cpp
+@am__fastdepCXX_TRUE@	mv -f $(DEPDIR)/zoomedit-Triangle.Tpo $(DEPDIR)/zoomedit-Triangle.Po
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	source='Triangle.cpp' object='zoomedit-Triangle.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCXX_FALSE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o zoomedit-Triangle.o `test -f 'Triangle.cpp' || echo '$(srcdir)/'`Triangle.cpp
+
+zoomedit-Triangle.obj: Triangle.cpp
+@am__fastdepCXX_TRUE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -MT zoomedit-Triangle.obj -MD -MP -MF $(DEPDIR)/zoomedit-Triangle.Tpo -c -o zoomedit-Triangle.obj `if test -f 'Triangle.cpp'; then $(CYGPATH_W) 'Triangle.cpp'; else $(CYGPATH_W) '$(srcdir)/Triangle.cpp'; fi`
+@am__fastdepCXX_TRUE@	mv -f $(DEPDIR)/zoomedit-Triangle.Tpo $(DEPDIR)/zoomedit-Triangle.Po
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	source='Triangle.cpp' object='zoomedit-Triangle.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCXX_FALSE@	DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCXX_FALSE@	$(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(zoomedit_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) -c -o zoomedit-Triangle.obj `if test -f 'Triangle.cpp'; then $(CYGPATH_W) 'Triangle.cpp'; else $(CYGPATH_W) '$(srcdir)/Triangle.cpp'; fi`
+
 ID: $(HEADERS) $(SOURCES) $(LISP) $(TAGS_FILES)
 	list='$(SOURCES) $(HEADERS) $(LISP) $(TAGS_FILES)'; \
 	unique=`for i in $$list; do \
diff --git a/Polygon.cpp b/Polygon.cpp
index 9340135..3425727 100644
--- a/Polygon.cpp
+++ b/Polygon.cpp
@@ -1,8 +1,9 @@
 #include "Polygon.h"
+#include <list>
 #include <math.h>
 
 
-double Polygon::area() const {
+double Polygon::signedArea() const {
   double d = 0.0;
   
   for(const_iterator it = begin(); it != end(); it++) {
@@ -12,7 +13,17 @@ double Polygon::area() const {
     d += (it2->getX()+it->getX())*(it2->getY()-it->getY());
   }
   
-  return fabs(d/2);
+  return d/2;
+}
+
+Polygon::Direction Polygon::getDirection() const {
+  double area = signedArea();
+  
+  return (area > 0) ? Triangle::CW : (area < 0) ? Triangle::CCW : Triangle::Unknown;
+}
+
+double Polygon::area() const {
+  return fabs(signedArea());
 }
 
 double Polygon::perimeter() const {
@@ -103,8 +114,8 @@ bool Polygon::contains(const Vertex &v) const {
 bool Polygon::intersects(const Line &l) const {
   Line line;
   
-  for(Polygon::const_iterator it = begin(); it != end(); it++) {
-    Polygon::const_iterator it2 = it+1;
+  for(const_iterator it = begin(); it != end(); it++) {
+    const_iterator it2 = it+1;
     if(it2 == end()) it2 = begin();
     
     line.setVertex1(*it);
@@ -116,3 +127,189 @@ bool Polygon::intersects(const Line &l) const {
   
   return false;
 }
+
+bool Polygon::isConcave(const Direction &dir, const Vertex &v1, const Vertex &v2, const Vertex &v3) const {
+  switch(dir) {
+    case Triangle::CW:
+      return (v1.getX()-v2.getX())*(v3.getY()-v2.getY()) > (v3.getX()-v2.getX())*(v1.getY()-v2.getY());
+    case Triangle::CCW:
+      return (v1.getX()-v2.getX())*(v3.getY()-v2.getY()) < (v3.getX()-v2.getX())*(v1.getY()-v2.getY());
+  }
+  
+  return false;
+}
+
+bool Polygon::intersections(std::vector<Intersection> *intersections) const {
+  bool ret = false;
+  size_t s = size();
+  
+  for(size_t i = 0; i+2 < s; i++) {
+    Line l(at(i), at(i+1));
+    
+    for(size_t j = i+2; j < s; j++) {
+      if(i == (j+1)%s) continue;
+      
+      Line l2(at(j), at((j+1)%s));
+      
+      Vertex v;
+      if(l.intersects(l2, &v) == INTERSECTION_SEGMENT_SEGMENT) {
+        if(intersections) {
+          Intersection in = {i, i+1, j, ((j+1)%s), v};
+          
+          intersections->push_back(in);
+          ret = true;
+        }
+        else {
+          return true;
+        }
+      }
+    }
+  }
+  
+  return ret;
+}
+
+bool Polygon::isSimple() const {
+  return !intersections();
+}
+
+bool Polygon::simplify(Polygon &polygon) const {
+  std::vector<Intersection> ins;
+  
+  if(!intersections(&ins)) return false;
+  
+  int s = size();
+  int start = 0;
+  
+  for(int i = 1; i < s; i++) {
+    if(at(i).getX() < at(start).getX())
+      start = i;
+    else if(at(i).getX() == at(start).getX() && at(i).getY() < at(start).getY())
+      start = i;
+  }
+  
+  int dir = Triangle(at((s+start-1)%s), at(start), at((start+1)%s)).getDirection();
+  
+  int i2 = start;
+  const Vertex *v2 = &at(i2);
+  bool intersected;
+  
+  do {
+    intersected = false;
+    
+    int i = i2;
+    
+    if(dir == Triangle::CW)
+      i2 = (i2+1)%s;
+    else
+      i2 = (s+i2-1)%s;
+    
+	const Vertex *v1 = v2;
+	v2 = &at(i2);
+	
+	Vertex *v = NULL;
+	int v3, v4;
+	
+	for(std::vector<Intersection>::iterator in = ins.begin(); in != ins.end(); ++in) {
+	  if(v2->distanceSq(in->v) >= v2->distanceSq(*v1) || v1 == &in->v)
+	    continue;
+	  
+	  if(v) {
+	    if(v1->distanceSq(in->v) >= v1->distanceSq(*v))
+	      continue;
+	  }
+	  
+	  if((i == in->va1 && i2 == in->va2) || (i == in->va2 && i2 == in->va1)) {
+	    v = &in->v;
+	    v3 = in->vb1;
+	    v4 = in->vb2;
+	  }
+	  else if((i == in->vb1 && i2 == in->vb2) || (i == in->vb2 && i2 == in->vb1)) {
+	    v = &in->v;
+	    v3 = in->va1;
+	    v4 = in->va2;
+	  }
+    }
+	
+	if(v) {
+	  v2 = v;
+	  intersected = true;
+	  
+	  if(isConcave(Triangle::CW, *v1, *v2, at(v4))) {
+	    i2 = v3;
+	    dir = Triangle::CW;
+	  }
+	  else {
+	    i2 = v4;
+	    dir = Triangle::CCW;
+	  }
+	}
+	
+	polygon.push_back(*v2);
+  } while(i2 != start || intersected);
+  
+  return true;
+}
+
+// FIXME: has still some problems...
+void Polygon::doTriangulate(std::vector<Triangle> &triangles) const {
+  size_t s = size();
+  
+  if(s < 3) return;
+  
+  std::vector<size_t> p;
+  std::list<size_t> concave;
+  Direction dir = getDirection();
+  
+  for(size_t i = 0; i < s; i++) {
+    p.push_back((i+1)%s);
+    
+    if(isConcave(dir, at(i), at((i+1)%s), at((i+2)%s)))
+      concave.push_back((i+1)%s);
+  }
+  
+  for(size_t i = 0; i < p.size() && p.size() > 3; i++) {
+    size_t s2 = p.size();
+    
+    const Vertex *v0 = &at(p[i]);
+    const Vertex *v1 = &at(p[(i+1)%s2]);
+    const Vertex *v2 = &at(p[(i+2)%s2]);
+    const Vertex *v3 = &at(p[(i+3)%s2]);
+    const Vertex *v4 = &at(p[(i+4)%s2]);
+    
+    if(isConcave(dir, *v1, *v2, *v3))
+      continue;
+    
+    Triangle t(*v1, *v2, *v3);
+    
+    std::list<size_t>::iterator it = concave.begin();
+    for(; it != concave.end(); it++) {
+      if(*it != p[(i+1)%s2] && *it != p[(i+3)%s2] && t.contains(at(*it)))
+        break;
+    }
+    
+    if(it != concave.end())
+      continue;
+    
+    triangles.push_back(t);
+    
+    if(isConcave(dir, *v2, *v3, *v4) && !isConcave(dir, *v1, *v3, *v4))
+      concave.remove(p[(i+3)%s2]);
+    
+    if(isConcave(dir, *v0, *v1, *v2) && !isConcave(dir, *v0, *v1, *v3)) {
+      concave.remove(p[(i+1)%s2]);
+    }
+    
+    p.erase(p.begin()+(i+2)%s2);
+    i = 0;
+  }
+  
+  triangles.push_back(Triangle(at(p[0]), at(p[1]), at(p[2])));
+}
+
+void Polygon::triangulate(std::vector<Triangle> &triangles) const {
+  Polygon p;
+  
+  if(simplify(p)) p.doTriangulate(triangles);
+  else doTriangulate(triangles);
+}
diff --git a/Polygon.h b/Polygon.h
index 093a160..6e36bee 100644
--- a/Polygon.h
+++ b/Polygon.h
@@ -3,17 +3,39 @@
 
 #include "Vertex.h"
 #include "Line.h"
+#include "Triangle.h"
 #include <vector>
 
 class Polygon : public std::vector<Vertex> {
   private:
+    struct Intersection {
+      size_t va1, va2, vb1, vb2;
+      Vertex v;
+    };
+    
+    typedef Triangle::Direction Direction;
+    
     int quadrant(const Vertex &v) const;
+    
+    double signedArea() const;
+    
+    Triangle::Direction getDirection() const;
+    bool isConcave(const Triangle::Direction &dir, const Vertex &v1, const Vertex &v2, const Vertex &v3) const;
+    
+    bool intersections(std::vector<Intersection> *intersections = NULL) const;
+    
+    void doTriangulate(std::vector<Triangle> &triangles) const;
   public:
     double area() const;
     double perimeter() const;
     
     bool contains(const Vertex &v) const;
     bool intersects(const Line &l) const;
+    
+    bool isSimple() const;
+    bool simplify(Polygon &polygon) const;
+    
+    void triangulate(std::vector<Triangle> &triangles) const;
 };
 
 #endif /*POLYGON_H_*/
diff --git a/Rectangle.h b/Rectangle.h
index 8a61321..5e7bb94 100644
--- a/Rectangle.h
+++ b/Rectangle.h
@@ -18,13 +18,9 @@ class Rectangle {
     Vertex v1, v2;
   public:
     Rectangle() {}
-    Rectangle(const Vertex& v1, const Vertex& v2) {
-      this->v1 = v1; this->v2 = v2;
-    }
-    Rectangle(double x, double y, double width, double height) {
-      v1.setLocation(x, y);
-      v2.setLocation(x+width, y+height);
-    }
+    Rectangle(const Vertex& vertex1, const Vertex& vertex2) : v1(vertex1), v2(vertex2) {}
+    Rectangle(double x, double y, double width, double height)
+      : v1(x, y), v2(x+width, y+height) {}
     
     Vertex &getVertex1() {return v1;}
     const Vertex &getVertex1() const {return v1;}
diff --git a/Triangle.cpp b/Triangle.cpp
new file mode 100644
index 0000000..e367629
--- /dev/null
+++ b/Triangle.cpp
@@ -0,0 +1,36 @@
+#include "Triangle.h"
+#include <math.h>
+
+
+Triangle::Direction Triangle::getDirection() const {
+  double c = (va.getX()-vb.getX())*(vc.getY()-vb.getY()) - (vc.getX()-vb.getX())*(va.getY()-vb.getY());
+  
+  return (c < 0) ? CW : (c > 0) ? CCW : Unknown;
+}
+
+double Triangle::area() const {
+  double a = vb.distanceSq(vc);
+  double b = vc.distanceSq(va);
+  double c = va.distanceSq(vb);
+  
+  return sqrt((a+b+c)*a+b+c - 2*(a*a+b*b+c*c))/4;
+}
+
+double Triangle::perimeter() const {
+  return va.distance(vb) + vb.distance(vc) + vc.distance(va);
+}
+
+bool Triangle::contains(const Vertex &v) const {
+  double a = (v.getX()-vb.getX())*(vc.getY()-vb.getY()) - (vc.getX()-vb.getX())*(v.getY()-vb.getY());
+  double b = (v.getX()-vc.getX())*(va.getY()-vc.getY()) - (va.getX()-vc.getX())*(v.getY()-vc.getY());
+  double c = (v.getX()-va.getX())*(vb.getY()-va.getY()) - (vb.getX()-va.getX())*(v.getY()-va.getY());
+  
+  switch(getDirection()) {
+    case CW:
+      return ((a < 0) && (b < 0) && (c < 0));
+    case CCW:
+      return ((a > 0) && (b > 0) && (c > 0));
+  }
+  
+  return false;
+}
diff --git a/Triangle.h b/Triangle.h
new file mode 100644
index 0000000..b0a7a2e
--- /dev/null
+++ b/Triangle.h
@@ -0,0 +1,39 @@
+#ifndef TRIANGLE_H_
+#define TRIANGLE_H_
+
+
+#include "Vertex.h"
+
+class Triangle {
+  private:
+    Vertex va, vb, vc;
+  public:
+    enum Direction {
+      CW, CCW, Unknown
+    };
+        
+    Triangle() {}
+    Triangle(const Vertex& vertexa, const Vertex& vertexb, const Vertex& vertexc)
+      : va(vertexa), vb(vertexb), vc(vertexc) {}
+    
+    Vertex &getVertexA() {return va;}
+    const Vertex &getVertexA() const {return va;}
+    void setVertexA(const Vertex &v) {va = v;}
+    
+    Vertex &getVertexB() {return vb;}
+    const Vertex &getVertexB() const {return vb;}
+    void setVertexB(const Vertex &v) {vb = v;}
+    
+    Vertex &getVertexC() {return vc;}
+    const Vertex &getVertexC() const {return vc;}
+    void setVertexC(const Vertex &v) {vc = v;}
+    
+    Direction getDirection() const;
+    
+    double area() const;
+    double perimeter() const;
+    
+    bool contains(const Vertex &v) const;
+};
+
+#endif /*TRIANGLE_H_*/
diff --git a/aclocal.m4 b/aclocal.m4
index 4353dd4..680d62e 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -213,6 +213,237 @@ main ()
   rm -f conf.gtktest
 ])
 
+# Configure paths for GtkGLExt
+# Naofumi Yasufuku
+#
+# Shamelessly stolen from gtk-2.0.m4
+# Configure paths for GTK+
+# Owen Taylor     1997-2001
+
+dnl AM_PATH_GTKGLEXT_1_0([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]])
+dnl Test for GtkGLExt, and define GTKGLEXT_CFLAGS and GTKGLEXT_LIBS.
+dnl
+AC_DEFUN([AM_PATH_GTKGLEXT_1_0],
+[ no_gtkglext=""
+  GTKGLEXT_CFLAGS=""
+  GTKGLEXT_LIBS=""
+
+  # GtkGLExt pkg-config module
+  gtkglext_module=gtkglext-1.0
+
+  # minimum GtkGLExt version
+  gtkglext_min_version=ifelse([$1], ,1.0.0,$1)
+
+  # minimum pkg-config version
+  pkgconfig_min_version=0.7
+
+AC_ARG_ENABLE(gtkglext-test,
+[  --disable-gtkglext-test do not try to compile and run a test GtkGLExt program],
+, enable_gtkglext_test=yes)
+
+dnl 
+dnl Get the cflags and libraries from pkg-config
+dnl
+  pkg_config_modules=$gtkglext_module
+
+  AC_PATH_PROG(PKG_CONFIG, pkg-config, no)
+
+  if test x$PKG_CONFIG != xno ; then
+    if pkg-config --atleast-pkgconfig-version $pkgconfig_min_version ; then
+      :
+    else
+      echo ""
+      echo "*** pkg-config too old; version $pkgconfig_min_version or better required."
+      no_gtkglext=yes
+      PKG_CONFIG=no
+    fi
+  else
+    no_gtkglext=yes
+  fi
+
+  AC_MSG_CHECKING(for GtkGLExt - version >= $gtkglext_min_version)
+
+  if test x$PKG_CONFIG != xno ; then
+    ## don't try to run the test against uninstalled libtool libs
+    if $PKG_CONFIG --uninstalled $pkg_config_modules; then
+      echo ""
+      echo "Will use uninstalled version of GtkGLExt found in PKG_CONFIG_PATH"
+      enable_gtkglext_test=no
+    fi
+
+    if $PKG_CONFIG --atleast-version $gtkglext_min_version $pkg_config_modules; then
+      :
+    else
+      echo ""
+      echo "*** pkg-config cannot find $gtkglext_module >= $gtkglext_min_version"
+      echo "*** Set the environment variable PKG_CONFIG_PATH to point to the correct"
+      echo "*** configuration files."
+      no_gtkglext=yes
+      enable_gtkglext_test=no
+    fi
+  fi
+
+  if test x"$no_gtkglext" = x ; then
+    GTKGLEXT_CFLAGS=`$PKG_CONFIG --cflags $pkg_config_modules`
+    GTKGLEXT_LIBS=`$PKG_CONFIG --libs $pkg_config_modules`
+    gtkglext_config_major_version=`$PKG_CONFIG --modversion $gtkglext_module | \
+           sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\1/'`
+    gtkglext_config_minor_version=`$PKG_CONFIG --modversion $gtkglext_module | \
+           sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\2/'`
+    gtkglext_config_micro_version=`$PKG_CONFIG --modversion $gtkglext_module | \
+           sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\3/'`
+    if test "x$enable_gtkglext_test" = "xyes" ; then
+      ac_save_CFLAGS="$CFLAGS"
+      ac_save_LIBS="$LIBS"
+      CFLAGS="$CFLAGS $GTKGLEXT_CFLAGS"
+      LIBS="$GTKGLEXT_LIBS $LIBS"
+dnl
+dnl Now check if the installed GtkGLExt is sufficiently new. (Also sanity
+dnl checks the results of pkg-config to some extent)
+dnl
+      rm -f conf.gtkgltest
+      AC_TRY_RUN([
+#include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int 
+main ()
+{
+  int major, minor, micro;
+  char *tmp_version;
+
+  system ("touch conf.gtkgltest");
+
+  /* HP/UX 9 (%@#!) writes to sscanf strings */
+  tmp_version = g_strdup ("$gtkglext_min_version");
+  if (sscanf (tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3)
+    {
+      printf ("%s, bad version string\n", "$gtkglext_min_version");
+      exit (1);
+    }
+
+  if ((gtkglext_major_version != $gtkglext_config_major_version) ||
+      (gtkglext_minor_version != $gtkglext_config_minor_version) ||
+      (gtkglext_micro_version != $gtkglext_config_micro_version))
+    {
+      printf ("\n*** 'pkg-config --modversion $gtkglext_module' returned %d.%d.%d, but GtkGLExt\n",
+              $gtkglext_config_major_version, $gtkglext_config_minor_version, $gtkglext_config_micro_version);
+      printf ("*** library %d.%d.%d was found!\n",
+              gtkglext_major_version, gtkglext_minor_version, gtkglext_micro_version);
+      printf ("***\n");
+      printf ("*** If pkg-config was correct, then it is best to remove the old version\n");
+      printf ("*** of GtkGLExt. You may also be able to fix the error by modifying your\n");
+      printf ("*** LD_LIBRARY_PATH enviroment variable, or by editing /etc/ld.so.conf.\n");
+      printf ("*** Make sure you have run ldconfig if that is required on your system.\n");
+      printf ("***\n");
+      printf ("*** If pkg-config was wrong, set the environment variable PKG_CONFIG_PATH\n");
+      printf ("*** to point to the correct configuration files.\n");
+    } 
+  else if ((gtkglext_major_version != GTKGLEXT_MAJOR_VERSION) ||
+	   (gtkglext_minor_version != GTKGLEXT_MINOR_VERSION) ||
+           (gtkglext_micro_version != GTKGLEXT_MICRO_VERSION))
+    {
+      printf ("\n*** GtkGLExt header files (version %d.%d.%d) do not match library (version %d.%d.%d).\n",
+              GTKGLEXT_MAJOR_VERSION, GTKGLEXT_MINOR_VERSION, GTKGLEXT_MICRO_VERSION,
+              gtkglext_major_version, gtkglext_minor_version, gtkglext_micro_version);
+    }
+  else
+    {
+      if ((gtkglext_major_version > major) ||
+          ((gtkglext_major_version == major) && (gtkglext_minor_version > minor)) ||
+          ((gtkglext_major_version == major) && (gtkglext_minor_version == minor) && (gtkglext_micro_version >= micro)))
+        {
+          return 0;
+        }
+      else
+        {
+          printf ("\n*** An old version of GtkGLExt library (%d.%d.%d) was found.\n",
+                  gtkglext_major_version, gtkglext_minor_version, gtkglext_micro_version);
+          printf ("*** You need a version of GtkGLExt newer than %d.%d.%d. The latest version of\n",
+                  major, minor, micro);
+          printf ("*** GtkGLExt is always available from http://gtkglext.sourceforge.net/.\n");
+          printf ("***\n");
+          printf ("*** If you have already installed a sufficiently new version, this error\n");
+          printf ("*** probably means that the wrong copy of the pkg-config shell script is\n");
+          printf ("*** being found. The easiest way to fix this is to remove the old version\n");
+          printf ("*** of GtkGLExt, but you can also set the PKG_CONFIG environment to point\n");
+          printf ("*** to the correct copy of pkg-config. (In this case, you will have to\n");
+          printf ("*** modify your LD_LIBRARY_PATH enviroment variable, or edit /etc/ld.so.conf\n");
+          printf ("*** so that the correct libraries are found at run-time)\n");
+        }
+    }
+  return 1;
+}
+],, no_gtkglext=yes,[echo $ac_n "cross compiling; assumed OK... $ac_c"])
+       CFLAGS="$ac_save_CFLAGS"
+       LIBS="$ac_save_LIBS"
+     fi
+  fi
+  if test "x$no_gtkglext" = x ; then
+     AC_MSG_RESULT(yes (version $gtkglext_config_major_version.$gtkglext_config_minor_version.$gtkglext_config_micro_version))
+     ifelse([$2], , :, [$2])
+  else
+     AC_MSG_RESULT(no)
+     if test "$PKG_CONFIG" = "no" ; then
+       echo "*** A new enough version of pkg-config was not found."
+       echo "*** See http://www.freedesktop.org/software/pkgconfig/."
+     elif test "x$enable_gtkglext_test" = "xyes" ; then
+       if test -f conf.gtkgltest ; then
+        :
+       else
+          echo "*** Could not run GtkGLExt test program, checking why..."
+	  ac_save_CFLAGS="$CFLAGS"
+	  ac_save_LIBS="$LIBS"
+          CFLAGS="$CFLAGS $GTKGLEXT_CFLAGS"
+          LIBS="$LIBS $GTKGLEXT_LIBS"
+          AC_TRY_LINK([
+#include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
+#include <stdio.h>
+],      [ return ((gtkglext_major_version) || (gtkglext_minor_version) || (gtkglext_micro_version)); ],
+        [ echo "*** The test program compiled, but did not run. This usually means"
+          echo "*** that the run-time linker is not finding GtkGLExt or finding the wrong"
+          echo "*** version of GtkGLExt. If it is not finding GtkGLExt, you'll need to set your"
+          echo "*** LD_LIBRARY_PATH environment variable, or edit /etc/ld.so.conf to point"
+          echo "*** to the installed location  Also, make sure you have run ldconfig if that"
+          echo "*** is required on your system"
+	  echo "***"
+          echo "*** If you have an old version installed, it is best to remove it, although"
+          echo "*** you may also be able to get things to work by modifying LD_LIBRARY_PATH" ],
+        [ echo "*** The test program failed to compile or link. See the file config.log for the"
+          echo "*** exact error that occured. This usually means GtkGLExt is incorrectly installed."])
+          CFLAGS="$ac_save_CFLAGS"
+          LIBS="$ac_save_LIBS"
+       fi
+     fi
+     GTKGLEXT_CFLAGS=""
+     GTKGLEXT_LIBS=""
+     ifelse([$3], , :, [$3])
+  fi
+  AC_SUBST(GTKGLEXT_CFLAGS)
+  AC_SUBST(GTKGLEXT_LIBS)
+  rm -f conf.gtkgltest
+])
+
+dnl AC_GTKGLEXT_SUPPORTS_MULTIHEAD([ACTION-IF-SUPPORTED [, ACTION-IF-NOT-SUPPORTED]])
+dnl Checks whether GtkGLExt supports multihead.
+dnl
+AC_DEFUN([AC_GTKGLEXT_SUPPORTS_MULTIHEAD],
+[ AC_CACHE_CHECK([whether GtkGLExt supports multihead],
+                 [ac_cv_gtkglext_supports_multihead],
+                 [AC_TRY_LINK([#include <gdk/gdkglquery.h>], 
+                              [gdk_gl_query_extension_for_display(gdk_display_get_default());],
+                              [ac_cv_gtkglext_supports_multihead=yes],
+                              [ac_cv_gtkglext_supports_multihead=no])])
+  if test "x$ac_cv_gtkglext_supports_multihead" = "xyes" ; then
+    ifelse([$1], , :, [$1])
+  else
+    ifelse([$2], , :, [$2])
+  fi
+])
+
 # Copyright (C) 2002, 2003, 2005, 2006  Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
diff --git a/configure b/configure
index 53ed2f0..535b686 100755
--- a/configure
+++ b/configure
@@ -702,6 +702,8 @@ am__fastdepCC_FALSE
 PKG_CONFIG
 GTK_CFLAGS
 GTK_LIBS
+GTKGLEXT_CFLAGS
+GTKGLEXT_LIBS
 CPP
 GREP
 EGREP
@@ -1300,6 +1302,7 @@ Optional Features:
   --disable-dependency-tracking  speeds up one-time build
   --enable-dependency-tracking   do not reject slow dependency extractors
   --disable-gtktest       do not try to compile and run a test GTK+ program
+  --disable-gtkglext-test do not try to compile and run a test GtkGLExt program
 
 Some influential environment variables:
   CXX         C++ compiler command
@@ -4260,6 +4263,333 @@ echo "$as_me: error: zoomedit needs GTK+ 2.8.0" >&2;}
 
   rm -f conf.gtktest
 
+ no_gtkglext=""
+  GTKGLEXT_CFLAGS=""
+  GTKGLEXT_LIBS=""
+
+  # GtkGLExt pkg-config module
+  gtkglext_module=gtkglext-1.0
+
+  # minimum GtkGLExt version
+  gtkglext_min_version=1.0.0
+
+  # minimum pkg-config version
+  pkgconfig_min_version=0.7
+
+# Check whether --enable-gtkglext-test was given.
+if test "${enable_gtkglext_test+set}" = set; then
+  enableval=$enable_gtkglext_test;
+else
+  enable_gtkglext_test=yes
+fi
+
+
+  pkg_config_modules=$gtkglext_module
+
+  # Extract the first word of "pkg-config", so it can be a program name with args.
+set dummy pkg-config; ac_word=$2
+{ echo "$as_me:$LINENO: checking for $ac_word" >&5
+echo $ECHO_N "checking for $ac_word... $ECHO_C" >&6; }
+if test "${ac_cv_path_PKG_CONFIG+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  case $PKG_CONFIG in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_PKG_CONFIG="$PKG_CONFIG" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+  for ac_exec_ext in '' $ac_executable_extensions; do
+  if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then
+    ac_cv_path_PKG_CONFIG="$as_dir/$ac_word$ac_exec_ext"
+    echo "$as_me:$LINENO: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+done
+IFS=$as_save_IFS
+
+  test -z "$ac_cv_path_PKG_CONFIG" && ac_cv_path_PKG_CONFIG="no"
+  ;;
+esac
+fi
+PKG_CONFIG=$ac_cv_path_PKG_CONFIG
+if test -n "$PKG_CONFIG"; then
+  { echo "$as_me:$LINENO: result: $PKG_CONFIG" >&5
+echo "${ECHO_T}$PKG_CONFIG" >&6; }
+else
+  { echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+fi
+
+
+
+  if test x$PKG_CONFIG != xno ; then
+    if pkg-config --atleast-pkgconfig-version $pkgconfig_min_version ; then
+      :
+    else
+      echo ""
+      echo "*** pkg-config too old; version $pkgconfig_min_version or better required."
+      no_gtkglext=yes
+      PKG_CONFIG=no
+    fi
+  else
+    no_gtkglext=yes
+  fi
+
+  { echo "$as_me:$LINENO: checking for GtkGLExt - version >= $gtkglext_min_version" >&5
+echo $ECHO_N "checking for GtkGLExt - version >= $gtkglext_min_version... $ECHO_C" >&6; }
+
+  if test x$PKG_CONFIG != xno ; then
+    ## don't try to run the test against uninstalled libtool libs
+    if $PKG_CONFIG --uninstalled $pkg_config_modules; then
+      echo ""
+      echo "Will use uninstalled version of GtkGLExt found in PKG_CONFIG_PATH"
+      enable_gtkglext_test=no
+    fi
+
+    if $PKG_CONFIG --atleast-version $gtkglext_min_version $pkg_config_modules; then
+      :
+    else
+      echo ""
+      echo "*** pkg-config cannot find $gtkglext_module >= $gtkglext_min_version"
+      echo "*** Set the environment variable PKG_CONFIG_PATH to point to the correct"
+      echo "*** configuration files."
+      no_gtkglext=yes
+      enable_gtkglext_test=no
+    fi
+  fi
+
+  if test x"$no_gtkglext" = x ; then
+    GTKGLEXT_CFLAGS=`$PKG_CONFIG --cflags $pkg_config_modules`
+    GTKGLEXT_LIBS=`$PKG_CONFIG --libs $pkg_config_modules`
+    gtkglext_config_major_version=`$PKG_CONFIG --modversion $gtkglext_module | \
+           sed 's/\([0-9]*\).\([0-9]*\).\([0-9]*\)/\1/'`
+    gtkglext_config_minor_version=`$PKG_CONFIG --modversion $gtkglext_module | \
+           sed 's/\([0-9]*\).\([0-9]*\).\([0-9]*\)/\2/'`
+    gtkglext_config_micro_version=`$PKG_CONFIG --modversion $gtkglext_module | \
+           sed 's/\([0-9]*\).\([0-9]*\).\([0-9]*\)/\3/'`
+    if test "x$enable_gtkglext_test" = "xyes" ; then
+      ac_save_CFLAGS="$CFLAGS"
+      ac_save_LIBS="$LIBS"
+      CFLAGS="$CFLAGS $GTKGLEXT_CFLAGS"
+      LIBS="$GTKGLEXT_LIBS $LIBS"
+      rm -f conf.gtkgltest
+      if test "$cross_compiling" = yes; then
+  echo $ac_n "cross compiling; assumed OK... $ac_c"
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main ()
+{
+  int major, minor, micro;
+  char *tmp_version;
+
+  system ("touch conf.gtkgltest");
+
+  /* HP/UX 9 (%@#!) writes to sscanf strings */
+  tmp_version = g_strdup ("$gtkglext_min_version");
+  if (sscanf (tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3)
+    {
+      printf ("%s, bad version string\n", "$gtkglext_min_version");
+      exit (1);
+    }
+
+  if ((gtkglext_major_version != $gtkglext_config_major_version) ||
+      (gtkglext_minor_version != $gtkglext_config_minor_version) ||
+      (gtkglext_micro_version != $gtkglext_config_micro_version))
+    {
+      printf ("\n*** 'pkg-config --modversion $gtkglext_module' returned %d.%d.%d, but GtkGLExt\n",
+              $gtkglext_config_major_version, $gtkglext_config_minor_version, $gtkglext_config_micro_version);
+      printf ("*** library %d.%d.%d was found!\n",
+              gtkglext_major_version, gtkglext_minor_version, gtkglext_micro_version);
+      printf ("***\n");
+      printf ("*** If pkg-config was correct, then it is best to remove the old version\n");
+      printf ("*** of GtkGLExt. You may also be able to fix the error by modifying your\n");
+      printf ("*** LD_LIBRARY_PATH enviroment variable, or by editing /etc/ld.so.conf.\n");
+      printf ("*** Make sure you have run ldconfig if that is required on your system.\n");
+      printf ("***\n");
+      printf ("*** If pkg-config was wrong, set the environment variable PKG_CONFIG_PATH\n");
+      printf ("*** to point to the correct configuration files.\n");
+    }
+  else if ((gtkglext_major_version != GTKGLEXT_MAJOR_VERSION) ||
+	   (gtkglext_minor_version != GTKGLEXT_MINOR_VERSION) ||
+           (gtkglext_micro_version != GTKGLEXT_MICRO_VERSION))
+    {
+      printf ("\n*** GtkGLExt header files (version %d.%d.%d) do not match library (version %d.%d.%d).\n",
+              GTKGLEXT_MAJOR_VERSION, GTKGLEXT_MINOR_VERSION, GTKGLEXT_MICRO_VERSION,
+              gtkglext_major_version, gtkglext_minor_version, gtkglext_micro_version);
+    }
+  else
+    {
+      if ((gtkglext_major_version > major) ||
+          ((gtkglext_major_version == major) && (gtkglext_minor_version > minor)) ||
+          ((gtkglext_major_version == major) && (gtkglext_minor_version == minor) && (gtkglext_micro_version >= micro)))
+        {
+          return 0;
+        }
+      else
+        {
+          printf ("\n*** An old version of GtkGLExt library (%d.%d.%d) was found.\n",
+                  gtkglext_major_version, gtkglext_minor_version, gtkglext_micro_version);
+          printf ("*** You need a version of GtkGLExt newer than %d.%d.%d. The latest version of\n",
+                  major, minor, micro);
+          printf ("*** GtkGLExt is always available from http://gtkglext.sourceforge.net/.\n");
+          printf ("***\n");
+          printf ("*** If you have already installed a sufficiently new version, this error\n");
+          printf ("*** probably means that the wrong copy of the pkg-config shell script is\n");
+          printf ("*** being found. The easiest way to fix this is to remove the old version\n");
+          printf ("*** of GtkGLExt, but you can also set the PKG_CONFIG environment to point\n");
+          printf ("*** to the correct copy of pkg-config. (In this case, you will have to\n");
+          printf ("*** modify your LD_LIBRARY_PATH enviroment variable, or edit /etc/ld.so.conf\n");
+          printf ("*** so that the correct libraries are found at run-time)\n");
+        }
+    }
+  return 1;
+}
+
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  :
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+no_gtkglext=yes
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+       CFLAGS="$ac_save_CFLAGS"
+       LIBS="$ac_save_LIBS"
+     fi
+  fi
+  if test "x$no_gtkglext" = x ; then
+     { echo "$as_me:$LINENO: result: yes (version $gtkglext_config_major_version.$gtkglext_config_minor_version.$gtkglext_config_micro_version)" >&5
+echo "${ECHO_T}yes (version $gtkglext_config_major_version.$gtkglext_config_minor_version.$gtkglext_config_micro_version)" >&6; }
+     :
+  else
+     { echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+     if test "$PKG_CONFIG" = "no" ; then
+       echo "*** A new enough version of pkg-config was not found."
+       echo "*** See http://www.freedesktop.org/software/pkgconfig/."
+     elif test "x$enable_gtkglext_test" = "xyes" ; then
+       if test -f conf.gtkgltest ; then
+        :
+       else
+          echo "*** Could not run GtkGLExt test program, checking why..."
+	  ac_save_CFLAGS="$CFLAGS"
+	  ac_save_LIBS="$LIBS"
+          CFLAGS="$CFLAGS $GTKGLEXT_CFLAGS"
+          LIBS="$LIBS $GTKGLEXT_LIBS"
+          cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
+#include <stdio.h>
+
+int
+main ()
+{
+ return ((gtkglext_major_version) || (gtkglext_minor_version) || (gtkglext_micro_version));
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext &&
+       $as_test_x conftest$ac_exeext; then
+   echo "*** The test program compiled, but did not run. This usually means"
+          echo "*** that the run-time linker is not finding GtkGLExt or finding the wrong"
+          echo "*** version of GtkGLExt. If it is not finding GtkGLExt, you'll need to set your"
+          echo "*** LD_LIBRARY_PATH environment variable, or edit /etc/ld.so.conf to point"
+          echo "*** to the installed location  Also, make sure you have run ldconfig if that"
+          echo "*** is required on your system"
+	  echo "***"
+          echo "*** If you have an old version installed, it is best to remove it, although"
+          echo "*** you may also be able to get things to work by modifying LD_LIBRARY_PATH"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	 echo "*** The test program failed to compile or link. See the file config.log for the"
+          echo "*** exact error that occured. This usually means GtkGLExt is incorrectly installed."
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+          CFLAGS="$ac_save_CFLAGS"
+          LIBS="$ac_save_LIBS"
+       fi
+     fi
+     GTKGLEXT_CFLAGS=""
+     GTKGLEXT_LIBS=""
+     { { echo "$as_me:$LINENO: error: zoomedit needs GtkGLExt" >&5
+echo "$as_me: error: zoomedit needs GtkGLExt" >&2;}
+   { (exit 1); exit 1; }; }
+  fi
+
+
+  rm -f conf.gtkgltest
+
 
 # Checks for header files.
 #AC_HEADER_STDC
@@ -6123,6 +6453,8 @@ am__fastdepCC_FALSE!$am__fastdepCC_FALSE$ac_delim
 PKG_CONFIG!$PKG_CONFIG$ac_delim
 GTK_CFLAGS!$GTK_CFLAGS$ac_delim
 GTK_LIBS!$GTK_LIBS$ac_delim
+GTKGLEXT_CFLAGS!$GTKGLEXT_CFLAGS$ac_delim
+GTKGLEXT_LIBS!$GTKGLEXT_LIBS$ac_delim
 CPP!$CPP$ac_delim
 GREP!$GREP$ac_delim
 EGREP!$EGREP$ac_delim
@@ -6130,7 +6462,7 @@ LIBOBJS!$LIBOBJS$ac_delim
 LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
-  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 92; then
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 94; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5
diff --git a/configure.in b/configure.in
index 1fd6e99..9b98a75 100644
--- a/configure.in
+++ b/configure.in
@@ -16,6 +16,7 @@ AM_PROG_CC_C_O
 # Checks for libraries.
 #AC_CHECK_LIB(m, [sqrt])
 AM_PATH_GTK_2_0(2.8.0,,AC_MSG_ERROR(zoomedit needs GTK+ 2.8.0))
+AM_PATH_GTKGLEXT_1_0(1.0.0,,AC_MSG_ERROR(zoomedit needs GtkGLExt))
 
 # Checks for header files.
 #AC_HEADER_STDC
diff --git a/draw.cpp b/draw.cpp
index ab21bd3..be67364 100644
--- a/draw.cpp
+++ b/draw.cpp
@@ -1,39 +1,39 @@
 #include "draw.h"
 #include "edit.h"
-#include "geometry.h"
+#include "Rectangle.h"
 #include <math.h>
 #include <gtk/gtk.h>
-#include <cairo/cairo.h>
-#include <stdlib.h>
+#include <gtk/gtkgl.h>
+#include <GL/gl.h>
 
 
 static double scale = 100.0;
 static double xTranslate = 0.0, yTranslate = 0.0;
-static gboolean repaint = FALSE;
 
 
-static void drawGrid(cairo_t *cr, const Rectangle *rect) {
+static void drawGrid(const Rectangle &rect) {
   double depth = log10(scale)-0.75;
   double depth2 = floor(depth);
   double step = pow(0.1, depth2);
   double d;
   int i;
-  gchar *string;
-  double x1 = rect->getVertex1().getX(), y1 = rect->getVertex1().getY();
-  double x2 = rect->getVertex2().getX(), y2 = rect->getVertex2().getY();
+  //gchar *string;
+  double x1 = rect.getVertex1().getX(), y1 = rect.getVertex1().getY();
+  double x2 = rect.getVertex2().getX(), y2 = rect.getVertex2().getY();
   
   
-  cairo_set_font_size(cr, 10.0/scale);
+  glBegin(GL_LINES);
+  //cairo_set_font_size(cr, 10.0/scale);
   
   for(i = 0; 0.4*(depth-depth2+i-1) < 0.5; i++) {
     d = MIN(0.4*(depth-depth2+i), 0.5);
-    cairo_set_source_rgb(cr, d, d, d);
+    glColor3d(d, d, d);
     
     for(d = x1 - fmod(x1, step) - step; d <= x2; d+=step) {
-      cairo_move_to(cr, d, y1);
-      cairo_line_to(cr, d, y2);
+      glVertex2d(d, y1);
+      glVertex2d(d, y2);
       
-      if(step > 0.005) {
+      /*if(step > 0.005) {
         if(step > 0.5)
           string = g_strdup_printf("%i", (int)rint(d));
         else
@@ -43,14 +43,14 @@ static void drawGrid(cairo_t *cr, const Rectangle *rect) {
         cairo_show_text(cr, string);
         
         g_free(string);
-      }
+      }*/
     }
     
     for(d = y1 - fmod(y1, step) - step; d <= y2; d+=step) {
-      cairo_move_to(cr, x1, d);
-      cairo_line_to(cr, x2, d);
+      glVertex2d(x1, d);
+      glVertex2d(x2, d);
       
-      if(step > 0.005) {
+      /*if(step > 0.005) {
         if(step > 0.5)
           string = g_strdup_printf("%i", (int)rint(d));
         else
@@ -60,48 +60,48 @@ static void drawGrid(cairo_t *cr, const Rectangle *rect) {
         cairo_show_text(cr, string);
         
         g_free(string);
-      }
+      }*/
     }
     
-    cairo_stroke(cr);
-    
     step *= 10;
   }
+  
+  glEnd();
 }
 
-static void polygon2path(cairo_t *cr, const Polygon *polygon, const Rectangle *rect, gboolean close) {
-  Polygon polygon2;
+static void fillPolygon(const Polygon &polygon) {
+  std::vector<Triangle> triangles;
   
-  // no vertices
-  if(polygon->empty()) return;
+  polygon.triangulate(triangles);
   
-  if(rect)
-    simplifyPolygon(polygon, rect, &polygon2);
-  else
-    polygon2 = *polygon;
+  glBegin(GL_TRIANGLES);
   
-  if(polygon2.empty()) return;
+  for(std::vector<Triangle>::iterator t = triangles.begin(); t != triangles.end(); t++) {
+    glVertex2d(t->getVertexA().getX(), t->getVertexA().getY());
+    glVertex2d(t->getVertexB().getX(), t->getVertexB().getY());
+    glVertex2d(t->getVertexC().getX(), t->getVertexC().getY());
+  }
   
-  cairo_new_sub_path(cr);
+  glEnd();
+}
+
+static void drawPolygon(const Polygon &polygon, bool close) {
+  glBegin(GL_LINE_STRIP);
   
-  for(Polygon::iterator it = polygon2.begin(); it != polygon2.end(); it++) {
-    cairo_line_to(cr, it->getX(), it->getY());
-  }
+  for(Polygon::const_iterator vertex = polygon.begin(); vertex != polygon.end(); vertex++)
+    glVertex2d(vertex->getX(), vertex->getY());
   
   if(close)
-    cairo_close_path(cr);
+    glVertex2d(polygon.front().getX(), polygon.front().getY());
+  
+  glEnd();
 }
 
 gboolean drawTopView(GtkWidget *widget, GdkEventExpose *event, gpointer data) {
-  cairo_t *cr;
-  Vertex v1(-1, -1), v2(widget->allocation.width+1, widget->allocation.height+1);
+  GdkGLContext *context = gtk_widget_get_gl_context(widget);
+  GdkGLDrawable *drawable = gtk_widget_get_gl_drawable(widget);
+  Vertex v1(0, 0), v2(widget->allocation.width, widget->allocation.height);
   Rectangle rect;
-  gboolean vertexOk;
-  static GdkPixmap *pixmap = NULL;
-  static double lastImageWidth = 0.0, lastImageHeight = 0.0;
-  static gint lastWidth = 0, lastHeight = 0;
-  static int lastEditMode = 0;
-  int i;
   
   
   if(getLevel() == NULL) return FALSE;
@@ -112,116 +112,79 @@ gboolean drawTopView(GtkWidget *widget, GdkEventExpose *event, gpointer data) {
   rect.setVertex1(v1);
   rect.setVertex2(v2);
   
-  if(pixmap == NULL || fabs(lastImageWidth - getImageWidth()) >= 0.000001 || fabs(lastImageHeight - getImageHeight()) >= 0.000001 ||
-     lastWidth != widget->allocation.width || lastHeight != widget->allocation.height || lastEditMode != getEditMode() || repaint) 
-  {
-    if(pixmap != NULL)
-      g_object_unref(G_OBJECT(pixmap));
-    
-    pixmap = gdk_pixmap_new(widget->window, widget->allocation.width, widget->allocation.height, -1);
-    
-    lastImageWidth = getImageWidth();
-    lastImageHeight = getImageHeight();
-    lastWidth = widget->allocation.width;
-    lastHeight = widget->allocation.height;
-    lastEditMode = getEditMode();
-    repaint = FALSE;
-    
-    
-    cr = gdk_cairo_create(GDK_DRAWABLE(pixmap));
-    
-    cairo_translate(cr, getImageWidth()/2-xTranslate, getImageHeight()/2-yTranslate);
-    cairo_scale(cr, scale, scale);
-    
-    cairo_set_line_width(cr, 1.0/scale);
-    cairo_set_line_join(cr, CAIRO_LINE_JOIN_ROUND);
+  if(!gdk_gl_drawable_gl_begin(drawable, context))
+    return FALSE;
+  
+  glClear(GL_COLOR_BUFFER_BIT);
+  
+  glMatrixMode(GL_MODELVIEW);
+  glPushMatrix();
+  
+  glLineWidth(1.0);
+  
+  glTranslated(getImageWidth()/2-xTranslate, getImageHeight()/2-yTranslate, 0);
+  glScaled(scale, scale, 1);
+  
+  drawGrid(rect);
+  
+  for(Level::const_iterator room = getLevel()->begin(); room != getLevel()->end(); room++) {
+    if(&*room == getActiveRoom() && getEditMode() == EDIT_MODE_ADD) continue;
     
-    cairo_set_source_rgb(cr, 0, 0, 0);
-    cairo_paint(cr);
+    if(&*room == getActiveRoom())
+      glColor4d(0.0, 0.7, 1.0, 0.2);
+    else
+      glColor4d(0.0, 0.7, 1.0, 0.3);
     
-    drawGrid(cr, &rect);
+    fillPolygon(*room);
     
-    for(Level::iterator room = getLevel()->begin(); room != getLevel()->end(); room++) {
-      if(&*room != getActiveRoom()) {
-        polygon2path(cr, &*room, &rect, TRUE);
-      }
+    if(&*room == getActiveRoom()) {
+      glColor4d(1.0, 1.0, 1.0, 0.9);
+      glLineWidth(2.0);
     }
-    
-    cairo_set_source_rgba(cr, 0.0, 0.7, 1.0, 0.3);
-    cairo_fill_preserve(cr);
-    
-    cairo_set_source_rgba(cr, 0.0, 0.7, 1.0, 0.7);
-    cairo_stroke(cr);
-    
-    if(getEditMode() == EDIT_MODE_SELECTED) {
-      polygon2path(cr, getActiveRoom(), &rect, TRUE);
-      
-      cairo_set_source_rgba(cr, 0.0, 0.7, 1.0, 0.2);
-      cairo_fill_preserve(cr);
-    
-      cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 0.9);
-      cairo_set_line_width(cr, 2.0/scale);
-      cairo_set_line_join(cr, CAIRO_LINE_JOIN_ROUND);
-      cairo_stroke(cr);
+    else if(&*room == getHoveredRoom() && getEditMode() != EDIT_MODE_ADD) {
+      glColor4d(0.0, 0.7, 1.0, 0.7);
+      glLineWidth(2.0);
+    }
+    else {
+      glColor4d(0.0, 0.7, 1.0, 0.7);
+      glLineWidth(1.0);
     }
     
-    cairo_destroy (cr);
+    drawPolygon(*room, true);
   }
   
-  gdk_draw_drawable(GDK_DRAWABLE(widget->window), widget->style->fg_gc[GTK_WIDGET_STATE(widget)], GDK_DRAWABLE(pixmap), 0, 0, 0, 0, -1, -1);
-  
-  cr = gdk_cairo_create(GDK_DRAWABLE(widget->window));
-  
-  cairo_translate(cr, getImageWidth()/2-xTranslate, getImageHeight()/2-yTranslate);
-  cairo_scale(cr, scale, scale);
-  
-  cairo_set_line_width(cr, 2.0/scale);
-  cairo_set_line_join(cr, CAIRO_LINE_JOIN_MITER);
-  
-  if(getHoveredRoom() != NULL && getHoveredRoom() != getActiveRoom() &&
-    (getEditMode() == EDIT_MODE_VIEW || getEditMode() == EDIT_MODE_SELECTED))
-  {
-    polygon2path(cr, getHoveredRoom(), &rect, TRUE);
-    
-    cairo_set_source_rgba(cr, 0.0, 0.7, 1.0, 0.7);
-    cairo_stroke(cr);
-  }
-  else if(getEditMode() == EDIT_MODE_ADD) {
-    polygon2path(cr, getActiveRoom(), NULL, FALSE);
-    
+  if(getEditMode() == EDIT_MODE_ADD) {
     if(isPolygonOk(getActiveRoom()))
-      cairo_set_source_rgba(cr, 0.0, 0.7, 1.0, 0.2);
+      glColor4d(0.0, 0.7, 1.0, 0.2);
     else
-      cairo_set_source_rgba(cr, 1.0, 0.3, 0.3, 0.2);
-    cairo_fill_preserve(cr);
+      glColor4d(1.0, 0.3, 0.3, 0.2);
     
+    fillPolygon(*getActiveRoom());
+    
+    glLineWidth(2.0);
+    glColor4d(0.0, 0.7, 1.0, 0.7);
+    drawPolygon(*getActiveRoom(), false);
     
     if(!getActiveRoom()->empty() && getHoveredVertex()) {
-      vertexOk = isVertexOk(getHoveredVertex());
+      if(!isVertexOk(getHoveredVertex()))
+        glColor4d(1.0, 0.3, 0.3, 0.7);
       
-      if(vertexOk)
-        cairo_line_to(cr, getHoveredVertex()->getX(), getHoveredVertex()->getY());
-    }
-    
-    cairo_set_line_width(cr, 2.0/scale);
-    cairo_set_line_join(cr, CAIRO_LINE_JOIN_ROUND);
-    cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
-    cairo_set_source_rgba(cr, 0.0, 0.7, 1.0, 0.7);
-    cairo_stroke(cr);
-    
-    if(!getActiveRoom()->empty() && getHoveredVertex() && !vertexOk) {
-      cairo_set_source_rgba(cr, 1.0, 0.3, 0.3, 0.7);
+      glBegin(GL_LINES);
       
-      cairo_move_to(cr, getActiveRoom()->back().getX(), getActiveRoom()->back().getY());
-      cairo_line_to(cr, getHoveredVertex()->getX(), getHoveredVertex()->getY());
+      glVertex2d(getActiveRoom()->back().getX(), getActiveRoom()->back().getY());
+      glVertex2d(getHoveredVertex()->getX(), getHoveredVertex()->getY());
       
-      cairo_stroke(cr);
+      glEnd();
     }
   }
   
-  cairo_destroy (cr);
+  glPopMatrix();
+  
+  gdk_gl_drawable_swap_buffers(drawable);
+  
+  gdk_gl_drawable_gl_end(drawable);
   
-  return FALSE;
+  return TRUE;
 }
 
 
@@ -231,7 +194,6 @@ double getScale() {
 
 void setScale(double s) {
   scale = MAX(0.005, MIN(s, 10000));
-  repaint = TRUE;
 }
 
 void imageToView(Vertex *v) {
@@ -282,7 +244,6 @@ double getXTranslate() {
 
 void setXTranslate(double x) {
   xTranslate = x;
-  repaint = TRUE;
 }
 
 double getYTranslate() {
@@ -291,9 +252,4 @@ double getYTranslate() {
 
 void setYTranslate(double y) {
   yTranslate = y;
-  repaint = TRUE;
-}
-
-void redraw() {
-  repaint = TRUE;
 }
diff --git a/draw.h b/draw.h
index 0fcac61..3b6b974 100644
--- a/draw.h
+++ b/draw.h
@@ -2,7 +2,7 @@
 #define DRAW_H_
 
 #include <gtk/gtk.h>
-#include "geometry.h"
+#include "Vertex.h"
 
 
 gboolean drawTopView(GtkWidget *widget, GdkEventExpose *event, gpointer data);
@@ -21,6 +21,4 @@ void setXTranslate(double x);
 double getYTranslate();
 void setYTranslate(double y);
 
-void redraw();
-
 #endif /*DRAW_H_*/
diff --git a/edit.cpp b/edit.cpp
index ab19969..3023dc5 100644
--- a/edit.cpp
+++ b/edit.cpp
@@ -1,6 +1,5 @@
 #include "Level.h"
 #include "edit.h"
-#include "geometry.h"
 
 
 static int editMode = EDIT_MODE_VIEW;
@@ -145,6 +144,9 @@ bool isPolygonOk(Polygon *polygon) {
   if(polygon->size() == 1)
     return true;
   
+  if(!polygon->isSimple())
+    return false;
+  
   for(Polygon::const_iterator it = polygon->begin(); it != polygon->end(); it++) {
     Polygon::const_iterator it2 = it+1;
     if(it2 == polygon->end()) it2 = polygon->begin();
@@ -156,21 +158,6 @@ bool isPolygonOk(Polygon *polygon) {
       if(room->intersects(l))
         return false;
     }
-    
-    if(it2 != polygon->begin()) {
-      for(Polygon::const_iterator it3 = it2+1; it3 != polygon->end(); it3++) {
-        Polygon::const_iterator it4 = it3+1;
-        if(it4 == polygon->end()) it4 = polygon->begin();
-        
-        if(it == polygon->begin() && it4 == polygon->begin()) continue;
-        
-        l2.setVertex1(*it3);
-        l2.setVertex2(*it4);
-        
-        if(l.intersects(l2, NULL) == INTERSECTION_SEGMENT_SEGMENT)
-          return false;
-      }
-    }
   }
   
   return true;
diff --git a/edit.h b/edit.h
index 460fb89..1216624 100644
--- a/edit.h
+++ b/edit.h
@@ -2,7 +2,6 @@
 #define EDIT_H_
 
 #include "Level.h"
-#include "geometry.h"
 
 #define EDIT_MODE_VIEW     0
 #define EDIT_MODE_SELECTED 1
diff --git a/geometry.cpp b/geometry.cpp
deleted file mode 100644
index 0967119..0000000
--- a/geometry.cpp
+++ /dev/null
@@ -1,80 +0,0 @@
-#include "geometry.h"
-
-
-static void edgeVertex(Vertex *v, int edge, const Rectangle *rect) {
-  if(edge == EDGE_NONE)
-    edge = rect->edges(*v);
-  
-  if(edge & EDGE_LEFT) v->setX(rect->getVertex1().getX());
-  else if(edge & EDGE_RIGHT) v->setX(rect->getVertex2().getX());
-  
-  if(edge & EDGE_TOP) v->setY(rect->getVertex1().getY());
-  else if(edge & EDGE_BOTTOM) v->setY(rect->getVertex2().getY());
-}
-
-static int simplifyVertex(Vertex *v, const Vertex *to, const Rectangle *rect) {
-  Line l(*v, *to);
-  int edge, edge2;
-  
-  
-  edge = rect->edges(*v);
-  if(edge == EDGE_NONE) return EDGE_NONE;
-  
-  edge2 = rect->intersects(l, v, edge);
-  if(edge2 != EDGE_NONE) return edge2;
-  
-  edgeVertex(v, edge, rect);
-  return edge;
-}
-
-static void addSimplifiedLine(const Vertex *v1, const Vertex *v2, const Rectangle *rect, int last, Polygon *out) {
-  const Line d1(rect->getVertex1(), rect->getVertex2());
-  const Line d2(rect->getVertex1().getX(), rect->getVertex2().getY(), rect->getVertex2().getX(), rect->getVertex1().getY());
-  
-  Line l(*v1, *v2);
-  Vertex v, vi;
-  int edge1, edge2;
-  
-  
-  v = *v1;
-  if((edge1 = simplifyVertex(&v, v2, rect)) != EDGE_NONE)
-    out->push_back(v);
-  
-  v = *v2;
-  edge2 = simplifyVertex(&v, v1, rect);
-  
-  if(edge1 != EDGE_NONE && edge2 != EDGE_NONE && !(edge1 & edge2)) {
-    if(l.intersects(d1, &vi) == INTERSECTION_SEGMENT_LINE) {
-      edgeVertex(&vi, 0, rect);
-      out->push_back(vi);
-    }
-    else if(l.intersects(d1, &vi) == INTERSECTION_SEGMENT_LINE) {
-      edgeVertex(&vi, 0, rect);
-      out->push_back(vi);
-    }
-  }
-  
-  if(!last)
-    out->push_back(v);
-}
-
-void simplifyPolygon(const Polygon *in, const Rectangle *rect, Polygon *out) {
-  Vertex v;
-  
-  if(in->empty()) return;
-  else if(in->size() == 1) {
-    out->push_back(in->front());
-    return;
-  }
-  
-  v = in->front();
-  simplifyVertex(&v, &in->back(), rect);
-  out->push_back(v);
-  
-  for(Polygon::const_iterator v2 = in->begin(); v2 != in->end(); v2++) {
-    Polygon::const_iterator v3 = v2+1;
-    if(v3 == in->end()) v3 = in->begin();
-    
-    addSimplifiedLine(&*v2, &*v3, rect, (v3 == in->begin()), out);
-  }
-}
diff --git a/geometry.h b/geometry.h
deleted file mode 100644
index 633a5b4..0000000
--- a/geometry.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#ifndef GEOMETRY_H_
-#define GEOMETRY_H_
-
-
-#include "Polygon.h"
-#include "Rectangle.h"
-
-
-void simplifyPolygon(const Polygon *in, const Rectangle *rect, Polygon *out);
-
-#endif /*GEOMETRY_H_*/
diff --git a/window.cpp b/window.cpp
index d347964..ff570ce 100644
--- a/window.cpp
+++ b/window.cpp
@@ -2,10 +2,9 @@
 #include "ui.h"
 #include "edit.h"
 #include "draw.h"
-#include "geometry.h"
 #include <gtk/gtk.h>
-#include <stdlib.h>
-#include <string.h>
+#include <gtk/gtkgl.h>
+#include <GL/gl.h>
 
 
 static GtkWidget *drawingArea = NULL, *sidebarView = NULL, *sidebarAdd = NULL;
@@ -14,10 +13,111 @@ static GtkAdjustment *hAdjustment = NULL, *vAdjustment = NULL;
 static GtkWidget *entryName, *labelArea = NULL, *labelPerimeter = NULL, *buttonAdd = NULL, *buttonAddDo = NULL;
 
 
+static void refreshScrolling() {
+  if(getImageWidth() < drawingArea->allocation.width)
+    setXTranslate((getImageWidth()-drawingArea->allocation.width)/2);
+  else
+    setXTranslate(gtk_adjustment_get_value(hAdjustment));
+  
+  if(getImageHeight() < drawingArea->allocation.height)
+    setYTranslate((getImageHeight()-drawingArea->allocation.height)/2);
+  else 
+    setYTranslate(gtk_adjustment_get_value(vAdjustment));
+  
+  gtk_widget_queue_draw(drawingArea);
+}
+
+static void updateScrollbars(double x, double y) {
+  const gdouble imageWidth = getImageWidth(), imageHeight = getImageHeight();
+  const gdouble width = drawingArea->allocation.width, height = drawingArea->allocation.height;
+  gdouble upper, pageSize, value;
+  
+  gdk_window_freeze_updates(drawingArea->window);
+  
+  g_object_get(G_OBJECT(hAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
+  g_object_set(G_OBJECT(hAdjustment), "upper", imageWidth, "page_size", width, NULL);
+  gtk_adjustment_changed(hAdjustment);
+  
+  if((pageSize > upper && width < imageWidth) || upper == 0)
+    value = (imageWidth-width)/2;
+  else
+    value = (gtk_adjustment_get_value(hAdjustment)+pageSize*x)/upper*imageWidth-width*x;
+  gtk_adjustment_set_value(hAdjustment, MAX(MIN(value, imageWidth-width), 0));
+  
+  g_object_get(G_OBJECT(vAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
+  g_object_set(G_OBJECT(vAdjustment), "upper", imageHeight, "page_size", height, NULL);
+  gtk_adjustment_changed(vAdjustment);
+  
+  if((pageSize > upper && height < imageHeight) || upper == 0)
+    value = (imageHeight-height)/2;
+  else
+    value = (gtk_adjustment_get_value(vAdjustment)+pageSize*y)/upper*imageHeight-height*y;
+  gtk_adjustment_set_value(vAdjustment, MAX(MIN(value, imageHeight-height), 0));
+  
+  gdk_window_thaw_updates(drawingArea->window);
+  
+  refreshScrolling();
+}
+
 static gboolean deleteEvent(GtkWidget *widget, GdkEvent  *event, gpointer data) {
   return FALSE;
 }
 
+static void realize(GtkWidget *widget, gpointer data) {
+  GdkGLContext *context = gtk_widget_get_gl_context(widget);
+  GdkGLDrawable *drawable = gtk_widget_get_gl_drawable(widget);
+  
+  if(!gdk_gl_drawable_gl_begin(drawable, context))
+    return;
+  
+  glClearColor(0.0, 0.0, 0.0, 1.0);
+  
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glEnable(GL_BLEND);
+  
+  glEnable(GL_LINE_SMOOTH);
+  
+  glViewport(0, 0, widget->allocation.width, widget->allocation.height);
+  
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  
+  if(widget->allocation.width != 0 && widget->allocation.height != 0) {
+    glTranslated(-1, 1, 0);
+    glScaled(2.0/widget->allocation.width, -2.0/widget->allocation.height, 1);
+  }
+  
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+  
+  gdk_gl_drawable_gl_end(drawable);
+}
+
+static gboolean configureEvent(GtkWidget *widget, GdkEventConfigure *event, gpointer data) {
+  GdkGLContext *context = gtk_widget_get_gl_context(widget);
+  GdkGLDrawable *drawable = gtk_widget_get_gl_drawable(widget);
+
+  if(!gdk_gl_drawable_gl_begin(drawable, context))
+    return FALSE;
+
+  glViewport(0, 0, widget->allocation.width, widget->allocation.height);
+  
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  
+  if(widget->allocation.width != 0 && widget->allocation.height != 0) {
+    glTranslated(-1, 1, 0);
+    glScaled(2.0/widget->allocation.width, -2.0/widget->allocation.height, 1);
+  }
+  
+  gdk_gl_drawable_gl_end(drawable);
+  
+  updateScrollbars(0.5, 0.5);
+  
+  return TRUE;
+}
+
+
 static gboolean scrollEvent(GtkWidget *widget, GdkEventScroll *event, gpointer user_data) {
   const gdouble x = event->x/widget->allocation.width, y = event->y/widget->allocation.height;
   
@@ -44,8 +144,6 @@ static gboolean buttonEvent(GtkWidget *widget, GdkEventButton *event, gpointer u
               
               updateSidebar();
               
-              redraw();
-              
               break;
             case EDIT_MODE_ADD:
               viewToImage(&v);
@@ -66,8 +164,6 @@ static gboolean buttonEvent(GtkWidget *widget, GdkEventButton *event, gpointer u
 gboolean crossingNotifyEvent(GtkWidget *widget, GdkEventCrossing *event, gpointer user_data) {
   Vertex v(event->x, event->y);
   
-  
-  
   switch(event->type) {
     case GDK_ENTER_NOTIFY:
       viewToImage(&v);
@@ -99,56 +195,6 @@ static void destroy(GtkWidget *widget, gpointer data) {
   gtk_main_quit();
 }
 
-static void refreshScrolling() {
-  if(getImageWidth() < drawingArea->allocation.width)
-    setXTranslate((getImageWidth()-drawingArea->allocation.width)/2);
-  else
-    setXTranslate(gtk_adjustment_get_value(hAdjustment));
-  
-  if(getImageHeight() < drawingArea->allocation.height)
-    setYTranslate((getImageHeight()-drawingArea->allocation.height)/2);
-  else 
-    setYTranslate(gtk_adjustment_get_value(vAdjustment));
-  
-  gtk_widget_queue_draw(drawingArea);
-}
-
-static void updateScrollbars(double x, double y) {
-  const gdouble imageWidth = getImageWidth(), imageHeight = getImageHeight();
-  const gdouble width = drawingArea->allocation.width, height = drawingArea->allocation.height;
-  gdouble upper, pageSize, value;
-  
-  gdk_window_freeze_updates(drawingArea->window);
-  
-  g_object_get(G_OBJECT(hAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
-  g_object_set(G_OBJECT(hAdjustment), "upper", imageWidth, "page_size", width, NULL);
-  gtk_adjustment_changed(hAdjustment);
-  
-  if((pageSize > upper && width < imageWidth) || upper == 0)
-    value = (imageWidth-width)/2;
-  else
-    value = (gtk_adjustment_get_value(hAdjustment)+pageSize*x)/upper*imageWidth-width*x;
-  gtk_adjustment_set_value(hAdjustment, MAX(MIN(value, imageWidth-width), 0));
-  
-  g_object_get(G_OBJECT(vAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
-  g_object_set(G_OBJECT(vAdjustment), "upper", imageHeight, "page_size", height, NULL);
-  gtk_adjustment_changed(vAdjustment);
-  
-  if((pageSize > upper && height < imageHeight) || upper == 0)
-    value = (imageHeight-height)/2;
-  else
-    value = (gtk_adjustment_get_value(vAdjustment)+pageSize*y)/upper*imageHeight-height*y;
-  gtk_adjustment_set_value(vAdjustment, MAX(MIN(value, imageHeight-height), 0));
-  
-  gdk_window_thaw_updates(drawingArea->window);
-  
-  refreshScrolling();
-}
-
-static void updateScrollbarsCentered() {
-  updateScrollbars(0.5, 0.5);
-}
-
 static void sidebarNameChanged(GtkEditable *editable, gpointer user_data) {
   if(getActiveRoom() == NULL) return;
   
@@ -242,7 +288,7 @@ static GtkWidget* createSidebar() {
   return sidebar;
 }
 
-GtkWidget* createMainWindow() {
+GtkWidget* createMainWindow(GdkGLConfig *glconfig) {
   GtkWidget *window, *hPaned, *vbox, *table, *vScroll, *hScroll, *sidebar;
   GdkColor color = {0, 0, 0, 0};
   
@@ -267,8 +313,10 @@ GtkWidget* createMainWindow() {
   gtk_paned_pack1(GTK_PANED(hPaned), table, TRUE, TRUE);
   
   drawingArea = gtk_drawing_area_new();
-  gtk_widget_modify_bg(drawingArea, (GtkStateType)GTK_WIDGET_STATE(drawingArea), &color);
-  g_signal_connect(G_OBJECT(drawingArea), "configure-event", G_CALLBACK(updateScrollbarsCentered), NULL);
+  gtk_widget_set_gl_capability(drawingArea, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
+  gtk_widget_set_double_buffered(drawingArea, FALSE);
+  g_signal_connect(G_OBJECT(drawingArea), "realize", G_CALLBACK(realize), NULL);
+  g_signal_connect(G_OBJECT(drawingArea), "configure-event", G_CALLBACK(configureEvent), NULL);
   g_signal_connect(G_OBJECT(drawingArea), "expose-event", G_CALLBACK(drawTopView), NULL);
   g_signal_connect(G_OBJECT(drawingArea), "button-press-event", G_CALLBACK(buttonEvent), NULL);
   g_signal_connect(G_OBJECT(drawingArea), "button-release-event", G_CALLBACK(buttonEvent), NULL);
diff --git a/window.h b/window.h
index 396c014..8e9265a 100644
--- a/window.h
+++ b/window.h
@@ -2,9 +2,10 @@
 #define WINDOW_H_
 
 #include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
 
 
-GtkWidget* createMainWindow();
+GtkWidget* createMainWindow(GdkGLConfig *glconfig);
 
 void updateSidebar();
 
diff --git a/zoomedit.cpp b/zoomedit.cpp
index 37b6159..580e224 100644
--- a/zoomedit.cpp
+++ b/zoomedit.cpp
@@ -1,4 +1,5 @@
 #include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
 #include <stdlib.h>
 #include "Level.h"
 #include "window.h"
@@ -6,13 +7,22 @@
 
 
 int main(int argc, char *argv[]) {
+  GdkGLConfig *glconfig;
   GtkWidget *window;
   
   setLevel(new Level());
   
   gtk_init(&argc, &argv);
+  gtk_gl_init(&argc, &argv);
   
-  window = createMainWindow();
+  glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(GDK_GL_MODE_RGB | GDK_GL_MODE_DOUBLE));
+  if(!glconfig) glconfig = gdk_gl_config_new_by_mode(GDK_GL_MODE_RGB);
+  if(!glconfig) {
+    g_print ("*** No appropriate OpenGL-capable visual found.\n");
+    exit (1);
+  }
+  
+  window = createMainWindow(glconfig);
   
   gtk_widget_show(window);