From 2bd970116452d2b1d634856d6acfb3a83aa05929 Mon Sep 17 00:00:00 2001
From: "chappuis.daniel" <chappuis.daniel@92aac97c-a6ce-11dd-a772-7fcde58d38e6>
Date: Tue, 22 Dec 2009 16:23:09 +0000
Subject: [PATCH] git-svn-id:
 https://reactphysics3d.googlecode.com/svn/trunk@231
 92aac97c-a6ce-11dd-a772-7fcde58d38e6

---
 sources/reactphysics3d/mathematics/Vector3D.h    | 6 ++++++
 sources/reactphysics3d/mathematics/constants.h   | 1 +
 sources/reactphysics3d/mathematics/mathematics.h | 4 ++--
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/sources/reactphysics3d/mathematics/Vector3D.h b/sources/reactphysics3d/mathematics/Vector3D.h
index 42b7bd73..5ea1b49e 100644
--- a/sources/reactphysics3d/mathematics/Vector3D.h
+++ b/sources/reactphysics3d/mathematics/Vector3D.h
@@ -55,6 +55,7 @@ class Vector3D {
         Vector3D getOpposite() const;                           // Return the vector in the opposite direction
         double scalarProduct(const Vector3D& vector) const;     // Scalar product of two vectors
         Vector3D crossProduct(const Vector3D& vector) const;    // Cross product of two vectors
+        bool isParallelWith(const Vector3D& vector) const;      // Return true if two vectors are parallel
 
         // --- Overloaded operators --- //
         Vector3D operator+(const Vector3D& vector) const;     // Overloaded operator for addition
@@ -126,6 +127,11 @@ inline Vector3D Vector3D::crossProduct(const Vector3D& vector) const {
     return Vector3D(y * vector.z - z * vector.y, z * vector.x - x * vector.z , x * vector.y - y * vector.x);
 }
 
+// Return true if two vectors are parallel
+inline bool Vector3D::isParallelWith(const Vector3D& vector) const {
+    return (approxEqual(this->scalarProduct(vector), length * vector.getLength()));
+}
+
 // Overloaded operator for multiplication between a number and a Vector3D (inline)
 inline Vector3D operator * (double number, const Vector3D& vector) {
     // Compute and return the result vector
diff --git a/sources/reactphysics3d/mathematics/constants.h b/sources/reactphysics3d/mathematics/constants.h
index 8c419aa4..942fe552 100644
--- a/sources/reactphysics3d/mathematics/constants.h
+++ b/sources/reactphysics3d/mathematics/constants.h
@@ -22,6 +22,7 @@
 
 // Constant used for the precision
 const double EPSILON = 0.00001;
+const double ONE_MINUS_EPSILON = 0.99999;
 
 // Pi constant
 const double PI = 3.14159265;
diff --git a/sources/reactphysics3d/mathematics/mathematics.h b/sources/reactphysics3d/mathematics/mathematics.h
index d032e08f..f8bb7caa 100644
--- a/sources/reactphysics3d/mathematics/mathematics.h
+++ b/sources/reactphysics3d/mathematics/mathematics.h
@@ -40,7 +40,7 @@
 
 // function to test if two numbers are (almost) equal
 // We test if two numbers a and b are such that (a-b) are in [-EPSILON; EPSILON]
-inline bool equal(double a, double b) {
+inline bool approxEqual(double a, double b) {
     double difference = a - b;
     return (difference < EPSILON && difference > -EPSILON);
 }
@@ -80,7 +80,7 @@ inline std::vector<reactphysics3d::Vector3D> movePoints(const std::vector<reactp
 // will be another Segment3D.
 inline reactphysics3d::Segment3D computeParallelSegmentsIntersection(const reactphysics3d::Segment3D& segment1, const reactphysics3d::Segment3D& segment2) {
     // The two segments should be colinear
-    assert(equal(std::abs(segment1.getSegmentVector().scalarProduct(segment2.getSegmentVector())), segment1.getSegmentVector().length() * segment2.getSegmentVector().length()));
+    assert(approxEqual(std::abs(segment1.getSegmentVector().scalarProduct(segment2.getSegmentVector())), segment1.getSegmentVector().length() * segment2.getSegmentVector().length()));
 
     // Result segment
     reactphysics3d::Segment3D resultSegment;