From 22519b5a0c7418c33b5e09a450b599a0f47566fa Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Tue, 17 Feb 2009 05:20:38 +0000
Subject: [PATCH] fixed bug in shapes/Plane, added shapes/Box

git-svn-id: svn://anubis/fart/trunk@119 7f9b0f55-74a9-4bce-be96-3c2cd072584d
---
 shapes/Box.cc   | 76 +++++++++++++++++++++++++++++++++++++++++++++++++
 shapes/Box.h    | 19 +++++++++++++
 shapes/Plane.cc | 12 ++++----
 3 files changed, 101 insertions(+), 6 deletions(-)
 create mode 100644 shapes/Box.cc
 create mode 100644 shapes/Box.h

diff --git a/shapes/Box.cc b/shapes/Box.cc
new file mode 100644
index 0000000..cdc7112
--- /dev/null
+++ b/shapes/Box.cc
@@ -0,0 +1,76 @@
+
+#include "Box.h"
+#include "util/Solver.h"
+#include <math.h>
+#include <iostream>
+using namespace std;
+
+#define FP_EQUAL(x,y) (fabs((x)-(y)) < 0.000001)
+
+Box::Box(refptr<Vector> size)
+{
+    m_size = *size;
+    m_size[0] = fabs(m_size[0]);
+    m_size[1] = fabs(m_size[1]);
+    m_size[2] = fabs(m_size[2]);
+}
+
+Shape::IntersectList Box::intersect(const Ray & ray)
+{
+    Ray ray_inv = m_inverse.transform_ray(ray);
+
+    IntersectList res;
+    /*
+     * Ray equation:   R = R0 + tRd
+     *                 x = R0x + tRdx
+     *                 y = R0y + tRdy
+     *                 z = R0z + tRdz
+     * Side equation:  x - size_x = 0
+     * Combined:       R0x + (t)Rdx - size_x = 0
+     */
+    for (int dim = 0; dim < 3; dim++)
+    {
+        for (int side = -1; side <= 1; side += 2)
+        {
+            LinearSolver solver(ray_inv.getDirection()[dim],
+                                ray_inv.getOrigin()[dim]
+                                    + side * m_size[dim]);
+            Solver::Result solutions = solver.solve();
+            for (int i = 0; i < solutions.numResults; i++)
+            {
+                if (solutions.results[i] >= 0.0)
+                {
+                    Vector isect_point = ray_inv[solutions.results[i]];
+                    if ( (dim == 0 || fabs(isect_point[0]) <= m_size[0])
+                      && (dim == 1 || fabs(isect_point[1]) <= m_size[1])
+                      && (dim == 2 || fabs(isect_point[2]) <= m_size[2]) )
+                    {
+                        res.push_back(m_transform.transform_point(isect_point));
+                    }
+                }
+            }
+        }
+    }
+
+    return res;
+}
+
+Vector Box::getNormalAt(const Vector & pt)
+{
+    Vector local_pt = m_inverse.transform_point(pt);
+
+    Vector normal(0, 0, -1);
+
+    if      ( FP_EQUAL(local_pt[0],  m_size[0]) )
+        normal = Vector(1, 0, 0);
+    else if ( FP_EQUAL(local_pt[0], -m_size[0]) )
+        normal = Vector(-1, 0, 0);
+    else if ( FP_EQUAL(local_pt[1],  m_size[1]) )
+        normal = Vector(0, 1, 0);
+    else if ( FP_EQUAL(local_pt[1], -m_size[1]) )
+        normal = Vector(0, -1, 0);
+    else if ( FP_EQUAL(local_pt[2],  m_size[2]) )
+        normal = Vector(0, 0, 1);
+
+    return m_transform.transform_normal(normal);
+}
diff --git a/shapes/Box.h b/shapes/Box.h
new file mode 100644
index 0000000..caf809d
--- /dev/null
+++ b/shapes/Box.h
@@ -0,0 +1,19 @@
+
+#ifndef BOX_H
+#define BOX_H BOX_H
+
+#include "Shape.h"
+
+class Box : public Shape
+{
+    public:
+        Box(refptr<Vector> size);
+        IntersectList intersect(const Ray & ray);
+        Vector getNormalAt(const Vector & pt);
+
+    protected:
+        Vector m_size;
+};
+
+#endif
+
diff --git a/shapes/Plane.cc b/shapes/Plane.cc
index 513e7f4..b04bfce 100644
--- a/shapes/Plane.cc
+++ b/shapes/Plane.cc
@@ -28,12 +28,12 @@ Shape::IntersectList Plane::intersect(const Ray & ray)
      *           aR0x + (t)aRdx + bR0y + (t)bRdy + cR0z + (t)cRdz + d = 0
      *           (t)(aRdx + bRdy + cRdz) + aR0x + bR0y + cR0z + d = 0
      */
-    LinearSolver solver(  m_a * ray.getDirection()[0]
-                        + m_b * ray.getDirection()[1]
-                        + m_c * ray.getDirection()[2],
-                          m_a * ray.getOrigin()[0]
-                        + m_b * ray.getOrigin()[1]
-                        + m_c * ray.getOrigin()[2]
+    LinearSolver solver(  m_a * ray_inv.getDirection()[0]
+                        + m_b * ray_inv.getDirection()[1]
+                        + m_c * ray_inv.getDirection()[2],
+                          m_a * ray_inv.getOrigin()[0]
+                        + m_b * ray_inv.getOrigin()[1]
+                        + m_c * ray_inv.getOrigin()[2]
                         + m_d);
     Solver::Result solutions = solver.solve();
     if (solutions.numResults > 0)