From bceef6b8ade2ab8341153e4bf18a5e01d27c90b3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Sat, 28 Apr 2012 01:28:20 +0200
Subject: [PATCH] Physics: Plane % Line collision.

---
 src/Physics/Plane.cpp          | 19 +++++++++++++++++++
 src/Physics/Plane.h            | 11 +++++++++++
 src/Physics/Test/PlaneTest.cpp | 16 ++++++++++++++++
 src/Physics/Test/PlaneTest.h   |  5 +++--
 4 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/Physics/Plane.cpp b/src/Physics/Plane.cpp
index 7301a79d3..a192fbe00 100644
--- a/src/Physics/Plane.cpp
+++ b/src/Physics/Plane.cpp
@@ -15,6 +15,13 @@
 
 #include "Plane.h"
 
+#include <limits>
+
+#include "Math/Geometry/Intersection.h"
+
+using namespace std;
+using namespace Magnum::Math::Geometry;
+
 namespace Magnum { namespace Physics {
 
 void Plane::applyTransformation(const Matrix4& transformation) {
@@ -22,4 +29,16 @@ void Plane::applyTransformation(const Matrix4& transformation) {
     _transformedNormal = transformation.rotation()*_normal;
 }
 
+bool Plane::collides(const AbstractShape* other) const {
+    if(other->type() == Type::Line)
+        return *this % *static_cast<const Line*>(other);
+
+    return AbstractShape::collides(other);
+}
+
+bool Plane::operator%(const Line& other) const {
+    float t = Intersection::planeLine(transformedPosition(), transformedNormal(), other.transformedA(), other.transformedB());
+    return t != t || (t != numeric_limits<float>::infinity() && t != -numeric_limits<float>::infinity());
+}
+
 }}
diff --git a/src/Physics/Plane.h b/src/Physics/Plane.h
index e7daa7b93..40c061be6 100644
--- a/src/Physics/Plane.h
+++ b/src/Physics/Plane.h
@@ -21,6 +21,8 @@
 
 #include "AbstractShape.h"
 
+#include "Line.h"
+
 namespace Magnum { namespace Physics {
 
 /** @brief Infinite plane, defined by position and normal */
@@ -31,6 +33,8 @@ class PHYSICS_EXPORT Plane: public AbstractShape {
 
         void applyTransformation(const Matrix4& transformation);
 
+        bool collides(const AbstractShape* other) const;
+
         /** @brief Position */
         inline Vector3 position() const { return _position; }
 
@@ -57,6 +61,9 @@ class PHYSICS_EXPORT Plane: public AbstractShape {
             return _transformedNormal;
         }
 
+        /** @brief Collision with line */
+        bool operator%(const Line& other) const;
+
     protected:
         inline Type type() const { return Type::Plane; }
 
@@ -65,6 +72,10 @@ class PHYSICS_EXPORT Plane: public AbstractShape {
             _normal, _transformedNormal;
 };
 
+#ifndef DOXYGEN_GENERATING_OUTPUT
+inline bool operator%(const Line& a, const Plane& b) { return b % a; }
+#endif
+
 }}
 
 #endif
diff --git a/src/Physics/Test/PlaneTest.cpp b/src/Physics/Test/PlaneTest.cpp
index 75907c2c1..1a65f72b2 100644
--- a/src/Physics/Test/PlaneTest.cpp
+++ b/src/Physics/Test/PlaneTest.cpp
@@ -36,4 +36,20 @@ void PlaneTest::applyTransformation() {
     QVERIFY(plane.transformedNormal() == Vector3(Math::Constants<float>::Sqrt2, -Math::Constants<float>::Sqrt2, 0));
 }
 
+void PlaneTest::collisionLine() {
+    Physics::Plane plane(Vector3(), Vector3::yAxis());
+    Physics::Line line({0.0f, 0.0f, 0.0f}, {1.0f, 0.0f, 0.0f});
+    Physics::Line line2({0.0f, -1.0f, 0.0f}, {1.0f, 1.0f, 0.0f});
+    Physics::Line line3({0.0f, 1.0f, 0.0f}, {1.0f, 1.0f, 0.0f});
+
+    randomTransformation(plane);
+    randomTransformation(line);
+    randomTransformation(line2);
+    randomTransformation(line3);
+
+    VERIFY_COLLIDES(plane, line);
+    VERIFY_COLLIDES(plane, line2);
+    VERIFY_NOT_COLLIDES(plane, line3);
+}
+
 }}}
diff --git a/src/Physics/Test/PlaneTest.h b/src/Physics/Test/PlaneTest.h
index 51d89b8d0..6deff3649 100644
--- a/src/Physics/Test/PlaneTest.h
+++ b/src/Physics/Test/PlaneTest.h
@@ -15,15 +15,16 @@
     GNU Lesser General Public License version 3 for more details.
 */
 
-#include <QtCore/QObject>
+#include "AbstractShapeTest.h"
 
 namespace Magnum { namespace Physics { namespace Test {
 
-class PlaneTest: public QObject {
+class PlaneTest: public AbstractShapeTest {
     Q_OBJECT
 
     private slots:
         void applyTransformation();
+        void collisionLine();
 };
 
 }}}