1 files changed, 61 insertions, 0 deletions
diff --git a/src/MathUtil.h b/src/MathUtil.h
index 2376c2d..9e6efc7 100644
--- a/src/MathUtil.h
+++ b/src/MathUtil.h
@@ -20,12 +20,73 @@
 #ifndef ZOOM_MATHUTIL_H_
 #define ZOOM_MATHUTIL_H_
 
+#include "Triangle.h"
+
 #include <vmmlib/matrix.hpp>
 
 namespace Zoom {
 
 class MathUtil {
   public:
+    static const float EPSILON;
+
+    class Plane {
+      public:
+        Plane(const vmml::vec3f &n = vmml::vec3f::ZERO, float d0 = 0) : normal(n), d(d0) {}
+        Plane(const Triangle &t) : normal(t.computeNormal()), d(t.getVertex(0).dot(normal)) {}
+
+        bool contains(const vmml::vec3f &v) const {
+          return (fabsf(normal.dot(v) - d) < EPSILON);
+        }
+
+        bool isBehind(const vmml::vec3f &v) const {
+          return (normal.dot(v) - d) < 0;
+        }
+
+        bool isInFront(const vmml::vec3f &v) const {
+          return (normal.dot(v) - d) > 0;
+        }
+
+
+        bool contains(const Triangle &t) const {
+          for(int i = 0; i < 3; ++i) {
+            if(!contains(t.getVertex(i)))
+              return false;
+          }
+
+          return true;
+        }
+
+        bool isBehind(const Triangle &t) const {
+          for(int i = 0; i < 3; ++i) {
+            if(!isBehind(t.getVertex(i)) && !contains(t.getVertex(i)))
+              return false;
+          }
+
+          return true;
+        }
+
+        bool isInFront(const Triangle &t) const {
+          for(int i = 0; i < 3; ++i) {
+            if(!isInFront(t.getVertex(i)) && !contains(t.getVertex(i)))
+              return false;
+          }
+
+          return true;
+        }
+
+
+        const vmml::vec3f& getNormal() const {
+          return normal;
+        }
+
+        vmml::vec3f intersection(const vmml::vec3f &p, const vmml::vec3f &dir) const;
+
+      private:
+        vmml::vec3f normal;
+        float d;
+    };
+
     static vmml::mat4f perspective(float fovy, float aspect, float zNear);
 
   private: