added Polygon::add(), Polygon::containsPoint(); initial attempt at rendering Extrude objects

git-svn-id: svn://anubis/fart/trunk@272 7f9b0f55-74a9-4bce-be96-3c2cd072584d

util/Polygon.cc

@@ -1,2 +1,20 @@
 
+#include <math.h>                   /* acos(), M_PI */
+
 #include "Polygon.h"
+
+#define FP_EQUAL(x,y) (fabs((x)-(y)) < 1E-6)
+
+bool Polygon::containsPoint(const Vector & v)
+{
+    double angle_sum = 0.0;
+    for (int i = 0, sz = size(); i < sz; i++)
+    {
+        Vector v1 = *(*this)[i] - v;
+        Vector v2 = *(*this)[(i+1) % sz] - v;
+        double cosine = (v1 % v2) / (v1.mag() * v2.mag());
+        double angle = acos(cosine);
+        angle_sum += angle;
+    }
+    return FP_EQUAL(angle_sum, 2.0 * M_PI);
+}

util/Polygon.h

@@ -9,6 +9,18 @@
 
 class Polygon : public std::vector< refptr<Vector> >
 {
+    public:
+        Polygon & add(const Vector & v)
+        {
+            push_back(new Vector(v));
+            return *this;
+        }
+        Polygon & add(refptr<Vector> v)
+        {
+            push_back(v);
+            return *this;
+        }
+        bool containsPoint(const Vector & v);
 };
 
 #endif