From ef25fe4a5b02715015bd02b2bd955d88e1ec3978 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Fri, 27 Feb 2009 22:43:49 +0000
Subject: [PATCH] added Subtract, including Union and Subtract in Shape.h

git-svn-id: svn://anubis/fart/trunk@158 7f9b0f55-74a9-4bce-be96-3c2cd072584d
---
 shapes/Shape.h     |  2 ++
 shapes/Subtract.cc | 66 ++++++++++++++++++++++++++++++++++++++++++++++
 shapes/Subtract.h  | 20 ++++++++++++++
 shapes/Union.cc    |  1 -
 4 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 shapes/Subtract.cc
 create mode 100644 shapes/Subtract.h

diff --git a/shapes/Shape.h b/shapes/Shape.h
index c7c09cb..babb0a3 100644
--- a/shapes/Shape.h
+++ b/shapes/Shape.h
@@ -124,6 +124,8 @@ class Shape
 #include "Intersect.h"
 #include "Plane.h"
 #include "Sphere.h"
+#include "Subtract.h"
+#include "Union.h"
 
 #endif
 
diff --git a/shapes/Subtract.cc b/shapes/Subtract.cc
new file mode 100644
index 0000000..9d9d0e5
--- /dev/null
+++ b/shapes/Subtract.cc
@@ -0,0 +1,66 @@
+
+#include "Subtract.h"
+#include <iostream>
+using namespace std;
+
+Subtract::Subtract(refptr<Shape> shape1, refptr<Shape> shape2)
+{
+    m_shape1 = shape1;
+    m_shape2 = shape2;
+}
+
+Shape::IntersectionList Subtract::intersect(refptr<Shape> _this, const Ray & ray)
+{
+    IntersectionList res1 = m_shape1->intersect(m_shape1, ray);
+    IntersectionList res2 = m_shape2->intersect(m_shape2, ray);
+    BoolIntersectionList merged(res1, res2, ray.getOrigin());
+
+    IntersectionList res;
+    bool in1 = false, in2 = false;
+    bool in_bool = false;
+
+    for (int i = 0, sz = merged.size(); i < sz; i++)
+    {
+        Vector normal = merged[i].intersection.shape->getNormalAt(
+                            merged[i].intersection.vector);
+        double dot = - (ray.getDirection() % normal);
+        bool front = dot > 0.0;
+        bool left = merged[i].left;
+        if (front)
+        {
+            if (left)
+                in1 = true;
+            else
+                in2 = true;
+            if (!in_bool && in1 && !in2)
+            {
+                /* we found an intersection point with the boolean object */
+                in_bool = true;
+                res.add( merged[i].intersection );
+            }
+        }
+        else
+        {
+            if (left)
+                in1 = false;
+            else
+                in2 = false;
+            if (in_bool && !(in1 && !in2))
+            {
+                /* we found an intersection point with the boolean object */
+                res.add( merged[i].intersection );
+                in_bool = false;
+            }
+        }
+    }
+
+    return res;
+}
+
+Vector Subtract::getNormalAt(const Vector & pt)
+{
+    /* this should not be called */
+    cerr << __FILE__ << ": " << __LINE__ <<
+        ": error: Subtract::getNormalAt() was called!" << endl;
+    return Vector(0, 0, 0);
+}
diff --git a/shapes/Subtract.h b/shapes/Subtract.h
new file mode 100644
index 0000000..fb44642
--- /dev/null
+++ b/shapes/Subtract.h
@@ -0,0 +1,20 @@
+
+#ifndef SUBTRACT_H
+#define SUBTRACT_H SUBTRACT_H
+
+#include "Shape.h"
+
+class Subtract : public Shape
+{
+    public:
+        Subtract(refptr<Shape> shape1, refptr<Shape> shape2);
+        IntersectionList intersect(refptr<Shape> _this, const Ray & ray);
+        Vector getNormalAt(const Vector & pt);
+
+    protected:
+        refptr<Shape> m_shape1;
+        refptr<Shape> m_shape2;
+};
+
+#endif
+
diff --git a/shapes/Union.cc b/shapes/Union.cc
index a3257f9..902872f 100644
--- a/shapes/Union.cc
+++ b/shapes/Union.cc
@@ -19,7 +19,6 @@ Shape::IntersectionList Union::intersect(refptr<Shape> _this, const Ray & ray)
     bool in1 = false, in2 = false;
     bool in_bool = false;
 
-    /* TODO: finish */
     for (int i = 0, sz = merged.size(); i < sz; i++)
     {
         Vector normal = merged[i].intersection.shape->getNormalAt(