9 files changed, 1335 insertions, 0 deletions

diff --git a/Source/external/Box2D/Collision/Shapes/b2ChainShape.cpp b/Source/external/Box2D/Collision/Shapes/b2ChainShape.cpp
new file mode 100644
index 0000000..a709585
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2ChainShape.cpp
@@ -0,0 +1,198 @@
+/*
+* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "Box2D/Collision/Shapes/b2ChainShape.h"
+#include "Box2D/Collision/Shapes/b2EdgeShape.h"
+#include <new>
+#include <string.h>
+
+b2ChainShape::~b2ChainShape()
+{
+	Clear();
+}
+
+void b2ChainShape::Clear()
+{
+	b2Free(m_vertices);
+	m_vertices = nullptr;
+	m_count = 0;
+}
+
+void b2ChainShape::CreateLoop(const b2Vec2* vertices, int32 count)
+{
+	b2Assert(m_vertices == nullptr && m_count == 0);
+	b2Assert(count >= 3);
+	if (count < 3)
+	{
+		return;
+	}
+
+	for (int32 i = 1; i < count; ++i)
+	{
+		b2Vec2 v1 = vertices[i-1];
+		b2Vec2 v2 = vertices[i];
+		// If the code crashes here, it means your vertices are too close together.
+		b2Assert(b2DistanceSquared(v1, v2) > b2_linearSlop * b2_linearSlop);
+	}
+
+	m_count = count + 1;
+	m_vertices = (b2Vec2*)b2Alloc(m_count * sizeof(b2Vec2));
+	memcpy(m_vertices, vertices, count * sizeof(b2Vec2));
+	m_vertices[count] = m_vertices[0];
+	m_prevVertex = m_vertices[m_count - 2];
+	m_nextVertex = m_vertices[1];
+	m_hasPrevVertex = true;
+	m_hasNextVertex = true;
+}
+
+void b2ChainShape::CreateChain(const b2Vec2* vertices, int32 count)
+{
+	b2Assert(m_vertices == nullptr && m_count == 0);
+	b2Assert(count >= 2);
+	for (int32 i = 1; i < count; ++i)
+	{
+		// If the code crashes here, it means your vertices are too close together.
+		b2Assert(b2DistanceSquared(vertices[i-1], vertices[i]) > b2_linearSlop * b2_linearSlop);
+	}
+
+	m_count = count;
+	m_vertices = (b2Vec2*)b2Alloc(count * sizeof(b2Vec2));
+	memcpy(m_vertices, vertices, m_count * sizeof(b2Vec2));
+
+	m_hasPrevVertex = false;
+	m_hasNextVertex = false;
+
+	m_prevVertex.SetZero();
+	m_nextVertex.SetZero();
+}
+
+void b2ChainShape::SetPrevVertex(const b2Vec2& prevVertex)
+{
+	m_prevVertex = prevVertex;
+	m_hasPrevVertex = true;
+}
+
+void b2ChainShape::SetNextVertex(const b2Vec2& nextVertex)
+{
+	m_nextVertex = nextVertex;
+	m_hasNextVertex = true;
+}
+
+b2Shape* b2ChainShape::Clone(b2BlockAllocator* allocator) const
+{
+	void* mem = allocator->Allocate(sizeof(b2ChainShape));
+	b2ChainShape* clone = new (mem) b2ChainShape;
+	clone->CreateChain(m_vertices, m_count);
+	clone->m_prevVertex = m_prevVertex;
+	clone->m_nextVertex = m_nextVertex;
+	clone->m_hasPrevVertex = m_hasPrevVertex;
+	clone->m_hasNextVertex = m_hasNextVertex;
+	return clone;
+}
+
+int32 b2ChainShape::GetChildCount() const
+{
+	// edge count = vertex count - 1
+	return m_count - 1;
+}
+
+void b2ChainShape::GetChildEdge(b2EdgeShape* edge, int32 index) const
+{
+	b2Assert(0 <= index && index < m_count - 1);
+	edge->m_type = b2Shape::e_edge;
+	edge->m_radius = m_radius;
+
+	edge->m_vertex1 = m_vertices[index + 0];
+	edge->m_vertex2 = m_vertices[index + 1];
+
+	if (index > 0)
+	{
+		edge->m_vertex0 = m_vertices[index - 1];
+		edge->m_hasVertex0 = true;
+	}
+	else
+	{
+		edge->m_vertex0 = m_prevVertex;
+		edge->m_hasVertex0 = m_hasPrevVertex;
+	}
+
+	if (index < m_count - 2)
+	{
+		edge->m_vertex3 = m_vertices[index + 2];
+		edge->m_hasVertex3 = true;
+	}
+	else
+	{
+		edge->m_vertex3 = m_nextVertex;
+		edge->m_hasVertex3 = m_hasNextVertex;
+	}
+}
+
+bool b2ChainShape::TestPoint(const b2Transform& xf, const b2Vec2& p) const
+{
+	B2_NOT_USED(xf);
+	B2_NOT_USED(p);
+	return false;
+}
+
+bool b2ChainShape::RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+							const b2Transform& xf, int32 childIndex) const
+{
+	b2Assert(childIndex < m_count);
+
+	b2EdgeShape edgeShape;
+
+	int32 i1 = childIndex;
+	int32 i2 = childIndex + 1;
+	if (i2 == m_count)
+	{
+		i2 = 0;
+	}
+
+	edgeShape.m_vertex1 = m_vertices[i1];
+	edgeShape.m_vertex2 = m_vertices[i2];
+
+	return edgeShape.RayCast(output, input, xf, 0);
+}
+
+void b2ChainShape::ComputeAABB(b2AABB* aabb, const b2Transform& xf, int32 childIndex) const
+{
+	b2Assert(childIndex < m_count);
+
+	int32 i1 = childIndex;
+	int32 i2 = childIndex + 1;
+	if (i2 == m_count)
+	{
+		i2 = 0;
+	}
+
+	b2Vec2 v1 = b2Mul(xf, m_vertices[i1]);
+	b2Vec2 v2 = b2Mul(xf, m_vertices[i2]);
+
+	aabb->lowerBound = b2Min(v1, v2);
+	aabb->upperBound = b2Max(v1, v2);
+}
+
+void b2ChainShape::ComputeMass(b2MassData* massData, float32 density) const
+{
+	B2_NOT_USED(density);
+
+	massData->mass = 0.0f;
+	massData->center.SetZero();
+	massData->I = 0.0f;
+}
diff --git a/Source/external/Box2D/Collision/Shapes/b2ChainShape.h b/Source/external/Box2D/Collision/Shapes/b2ChainShape.h
new file mode 100644
index 0000000..7c8c1a8
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2ChainShape.h
@@ -0,0 +1,105 @@
+/*
+* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B2_CHAIN_SHAPE_H
+#define B2_CHAIN_SHAPE_H
+
+#include "Box2D/Collision/Shapes/b2Shape.h"
+
+class b2EdgeShape;
+
+/// A chain shape is a free form sequence of line segments.
+/// The chain has two-sided collision, so you can use inside and outside collision.
+/// Therefore, you may use any winding order.
+/// Since there may be many vertices, they are allocated using b2Alloc.
+/// Connectivity information is used to create smooth collisions.
+/// WARNING: The chain will not collide properly if there are self-intersections.
+class b2ChainShape : public b2Shape
+{
+public:
+	b2ChainShape();
+
+	/// The destructor frees the vertices using b2Free.
+	~b2ChainShape();
+
+	/// Clear all data.
+	void Clear();
+
+	/// Create a loop. This automatically adjusts connectivity.
+	/// @param vertices an array of vertices, these are copied
+	/// @param count the vertex count
+	void CreateLoop(const b2Vec2* vertices, int32 count);
+
+	/// Create a chain with isolated end vertices.
+	/// @param vertices an array of vertices, these are copied
+	/// @param count the vertex count
+	void CreateChain(const b2Vec2* vertices, int32 count);
+
+	/// Establish connectivity to a vertex that precedes the first vertex.
+	/// Don't call this for loops.
+	void SetPrevVertex(const b2Vec2& prevVertex);
+
+	/// Establish connectivity to a vertex that follows the last vertex.
+	/// Don't call this for loops.
+	void SetNextVertex(const b2Vec2& nextVertex);
+
+	/// Implement b2Shape. Vertices are cloned using b2Alloc.
+	b2Shape* Clone(b2BlockAllocator* allocator) const override;
+
+	/// @see b2Shape::GetChildCount
+	int32 GetChildCount() const override;
+
+	/// Get a child edge.
+	void GetChildEdge(b2EdgeShape* edge, int32 index) const;
+
+	/// This always return false.
+	/// @see b2Shape::TestPoint
+	bool TestPoint(const b2Transform& transform, const b2Vec2& p) const override;
+
+	/// Implement b2Shape.
+	bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+					const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeAABB
+	void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const override;
+
+	/// Chains have zero mass.
+	/// @see b2Shape::ComputeMass
+	void ComputeMass(b2MassData* massData, float32 density) const override;
+
+	/// The vertices. Owned by this class.
+	b2Vec2* m_vertices;
+
+	/// The vertex count.
+	int32 m_count;
+
+	b2Vec2 m_prevVertex, m_nextVertex;
+	bool m_hasPrevVertex, m_hasNextVertex;
+};
+
+inline b2ChainShape::b2ChainShape()
+{
+	m_type = e_chain;
+	m_radius = b2_polygonRadius;
+	m_vertices = nullptr;
+	m_count = 0;
+	m_hasPrevVertex = false;
+	m_hasNextVertex = false;
+}
+
+#endif
diff --git a/Source/external/Box2D/Collision/Shapes/b2CircleShape.cpp b/Source/external/Box2D/Collision/Shapes/b2CircleShape.cpp
new file mode 100644
index 0000000..fa24dc8
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2CircleShape.cpp
@@ -0,0 +1,99 @@
+/*
+* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "Box2D/Collision/Shapes/b2CircleShape.h"
+#include <new>
+
+b2Shape* b2CircleShape::Clone(b2BlockAllocator* allocator) const
+{
+	void* mem = allocator->Allocate(sizeof(b2CircleShape));
+	b2CircleShape* clone = new (mem) b2CircleShape;
+	*clone = *this;
+	return clone;
+}
+
+int32 b2CircleShape::GetChildCount() const
+{
+	return 1;
+}
+
+bool b2CircleShape::TestPoint(const b2Transform& transform, const b2Vec2& p) const
+{
+	b2Vec2 center = transform.p + b2Mul(transform.q, m_p);
+	b2Vec2 d = p - center;
+	return b2Dot(d, d) <= m_radius * m_radius;
+}
+
+// Collision Detection in Interactive 3D Environments by Gino van den Bergen
+// From Section 3.1.2
+// x = s + a * r
+// norm(x) = radius
+bool b2CircleShape::RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+							const b2Transform& transform, int32 childIndex) const
+{
+	B2_NOT_USED(childIndex);
+
+	b2Vec2 position = transform.p + b2Mul(transform.q, m_p);
+	b2Vec2 s = input.p1 - position;
+	float32 b = b2Dot(s, s) - m_radius * m_radius;
+
+	// Solve quadratic equation.
+	b2Vec2 r = input.p2 - input.p1;
+	float32 c =  b2Dot(s, r);
+	float32 rr = b2Dot(r, r);
+	float32 sigma = c * c - rr * b;
+
+	// Check for negative discriminant and short segment.
+	if (sigma < 0.0f || rr < b2_epsilon)
+	{
+		return false;
+	}
+
+	// Find the point of intersection of the line with the circle.
+	float32 a = -(c + b2Sqrt(sigma));
+
+	// Is the intersection point on the segment?
+	if (0.0f <= a && a <= input.maxFraction * rr)
+	{
+		a /= rr;
+		output->fraction = a;
+		output->normal = s + a * r;
+		output->normal.Normalize();
+		return true;
+	}
+
+	return false;
+}
+
+void b2CircleShape::ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const
+{
+	B2_NOT_USED(childIndex);
+
+	b2Vec2 p = transform.p + b2Mul(transform.q, m_p);
+	aabb->lowerBound.Set(p.x - m_radius, p.y - m_radius);
+	aabb->upperBound.Set(p.x + m_radius, p.y + m_radius);
+}
+
+void b2CircleShape::ComputeMass(b2MassData* massData, float32 density) const
+{
+	massData->mass = density * b2_pi * m_radius * m_radius;
+	massData->center = m_p;
+
+	// inertia about the local origin
+	massData->I = massData->mass * (0.5f * m_radius * m_radius + b2Dot(m_p, m_p));
+}
diff --git a/Source/external/Box2D/Collision/Shapes/b2CircleShape.h b/Source/external/Box2D/Collision/Shapes/b2CircleShape.h
new file mode 100644
index 0000000..d2c646e
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2CircleShape.h
@@ -0,0 +1,60 @@
+/*
+* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B2_CIRCLE_SHAPE_H
+#define B2_CIRCLE_SHAPE_H
+
+#include "Box2D/Collision/Shapes/b2Shape.h"
+
+/// A circle shape.
+class b2CircleShape : public b2Shape
+{
+public:
+	b2CircleShape();
+
+	/// Implement b2Shape.
+	b2Shape* Clone(b2BlockAllocator* allocator) const override;
+
+	/// @see b2Shape::GetChildCount
+	int32 GetChildCount() const override;
+
+	/// Implement b2Shape.
+	bool TestPoint(const b2Transform& transform, const b2Vec2& p) const override;
+
+	/// Implement b2Shape.
+	bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+				const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeAABB
+	void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeMass
+	void ComputeMass(b2MassData* massData, float32 density) const override;
+
+	/// Position
+	b2Vec2 m_p;
+};
+
+inline b2CircleShape::b2CircleShape()
+{
+	m_type = e_circle;
+	m_radius = 0.0f;
+	m_p.SetZero();
+}
+
+#endif
diff --git a/Source/external/Box2D/Collision/Shapes/b2EdgeShape.cpp b/Source/external/Box2D/Collision/Shapes/b2EdgeShape.cpp
new file mode 100644
index 0000000..7b8dd57
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2EdgeShape.cpp
@@ -0,0 +1,138 @@
+/*
+* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "Box2D/Collision/Shapes/b2EdgeShape.h"
+#include <new>
+
+void b2EdgeShape::Set(const b2Vec2& v1, const b2Vec2& v2)
+{
+	m_vertex1 = v1;
+	m_vertex2 = v2;
+	m_hasVertex0 = false;
+	m_hasVertex3 = false;
+}
+
+b2Shape* b2EdgeShape::Clone(b2BlockAllocator* allocator) const
+{
+	void* mem = allocator->Allocate(sizeof(b2EdgeShape));
+	b2EdgeShape* clone = new (mem) b2EdgeShape;
+	*clone = *this;
+	return clone;
+}
+
+int32 b2EdgeShape::GetChildCount() const
+{
+	return 1;
+}
+
+bool b2EdgeShape::TestPoint(const b2Transform& xf, const b2Vec2& p) const
+{
+	B2_NOT_USED(xf);
+	B2_NOT_USED(p);
+	return false;
+}
+
+// p = p1 + t * d
+// v = v1 + s * e
+// p1 + t * d = v1 + s * e
+// s * e - t * d = p1 - v1
+bool b2EdgeShape::RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+							const b2Transform& xf, int32 childIndex) const
+{
+	B2_NOT_USED(childIndex);
+
+	// Put the ray into the edge's frame of reference.
+	b2Vec2 p1 = b2MulT(xf.q, input.p1 - xf.p);
+	b2Vec2 p2 = b2MulT(xf.q, input.p2 - xf.p);
+	b2Vec2 d = p2 - p1;
+
+	b2Vec2 v1 = m_vertex1;
+	b2Vec2 v2 = m_vertex2;
+	b2Vec2 e = v2 - v1;
+	b2Vec2 normal(e.y, -e.x);
+	normal.Normalize();
+
+	// q = p1 + t * d
+	// dot(normal, q - v1) = 0
+	// dot(normal, p1 - v1) + t * dot(normal, d) = 0
+	float32 numerator = b2Dot(normal, v1 - p1);
+	float32 denominator = b2Dot(normal, d);
+
+	if (denominator == 0.0f)
+	{
+		return false;
+	}
+
+	float32 t = numerator / denominator;
+	if (t < 0.0f || input.maxFraction < t)
+	{
+		return false;
+	}
+
+	b2Vec2 q = p1 + t * d;
+
+	// q = v1 + s * r
+	// s = dot(q - v1, r) / dot(r, r)
+	b2Vec2 r = v2 - v1;
+	float32 rr = b2Dot(r, r);
+	if (rr == 0.0f)
+	{
+		return false;
+	}
+
+	float32 s = b2Dot(q - v1, r) / rr;
+	if (s < 0.0f || 1.0f < s)
+	{
+		return false;
+	}
+
+	output->fraction = t;
+	if (numerator > 0.0f)
+	{
+		output->normal = -b2Mul(xf.q, normal);
+	}
+	else
+	{
+		output->normal = b2Mul(xf.q, normal);
+	}
+	return true;
+}
+
+void b2EdgeShape::ComputeAABB(b2AABB* aabb, const b2Transform& xf, int32 childIndex) const
+{
+	B2_NOT_USED(childIndex);
+
+	b2Vec2 v1 = b2Mul(xf, m_vertex1);
+	b2Vec2 v2 = b2Mul(xf, m_vertex2);
+
+	b2Vec2 lower = b2Min(v1, v2);
+	b2Vec2 upper = b2Max(v1, v2);
+
+	b2Vec2 r(m_radius, m_radius);
+	aabb->lowerBound = lower - r;
+	aabb->upperBound = upper + r;
+}
+
+void b2EdgeShape::ComputeMass(b2MassData* massData, float32 density) const
+{
+	B2_NOT_USED(density);
+
+	massData->mass = 0.0f;
+	massData->center = 0.5f * (m_vertex1 + m_vertex2);
+	massData->I = 0.0f;
+}
diff --git a/Source/external/Box2D/Collision/Shapes/b2EdgeShape.h b/Source/external/Box2D/Collision/Shapes/b2EdgeShape.h
new file mode 100644
index 0000000..63b1a56
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2EdgeShape.h
@@ -0,0 +1,74 @@
+/*
+* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B2_EDGE_SHAPE_H
+#define B2_EDGE_SHAPE_H
+
+#include "Box2D/Collision/Shapes/b2Shape.h"
+
+/// A line segment (edge) shape. These can be connected in chains or loops
+/// to other edge shapes. The connectivity information is used to ensure
+/// correct contact normals.
+class b2EdgeShape : public b2Shape
+{
+public:
+	b2EdgeShape();
+
+	/// Set this as an isolated edge.
+	void Set(const b2Vec2& v1, const b2Vec2& v2);
+
+	/// Implement b2Shape.
+	b2Shape* Clone(b2BlockAllocator* allocator) const override;
+
+	/// @see b2Shape::GetChildCount
+	int32 GetChildCount() const override;
+
+	/// @see b2Shape::TestPoint
+	bool TestPoint(const b2Transform& transform, const b2Vec2& p) const override;
+
+	/// Implement b2Shape.
+	bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+				const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeAABB
+	void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeMass
+	void ComputeMass(b2MassData* massData, float32 density) const override;
+	
+	/// These are the edge vertices
+	b2Vec2 m_vertex1, m_vertex2;
+
+	/// Optional adjacent vertices. These are used for smooth collision.
+	b2Vec2 m_vertex0, m_vertex3;
+	bool m_hasVertex0, m_hasVertex3;
+};
+
+inline b2EdgeShape::b2EdgeShape()
+{
+	m_type = e_edge;
+	m_radius = b2_polygonRadius;
+	m_vertex0.x = 0.0f;
+	m_vertex0.y = 0.0f;
+	m_vertex3.x = 0.0f;
+	m_vertex3.y = 0.0f;
+	m_hasVertex0 = false;
+	m_hasVertex3 = false;
+}
+
+#endif
diff --git a/Source/external/Box2D/Collision/Shapes/b2PolygonShape.cpp b/Source/external/Box2D/Collision/Shapes/b2PolygonShape.cpp
new file mode 100644
index 0000000..3c8c47d
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2PolygonShape.cpp
@@ -0,0 +1,468 @@
+/*
+* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "Box2D/Collision/Shapes/b2PolygonShape.h"
+#include <new>
+
+b2Shape* b2PolygonShape::Clone(b2BlockAllocator* allocator) const
+{
+	void* mem = allocator->Allocate(sizeof(b2PolygonShape));
+	b2PolygonShape* clone = new (mem) b2PolygonShape;
+	*clone = *this;
+	return clone;
+}
+
+void b2PolygonShape::SetAsBox(float32 hx, float32 hy)
+{
+	m_count = 4;
+	m_vertices[0].Set(-hx, -hy);
+	m_vertices[1].Set( hx, -hy);
+	m_vertices[2].Set( hx,  hy);
+	m_vertices[3].Set(-hx,  hy);
+	m_normals[0].Set(0.0f, -1.0f);
+	m_normals[1].Set(1.0f, 0.0f);
+	m_normals[2].Set(0.0f, 1.0f);
+	m_normals[3].Set(-1.0f, 0.0f);
+	m_centroid.SetZero();
+}
+
+void b2PolygonShape::SetAsBox(float32 hx, float32 hy, const b2Vec2& center, float32 angle)
+{
+	m_count = 4;
+	m_vertices[0].Set(-hx, -hy);
+	m_vertices[1].Set( hx, -hy);
+	m_vertices[2].Set( hx,  hy);
+	m_vertices[3].Set(-hx,  hy);
+	m_normals[0].Set(0.0f, -1.0f);
+	m_normals[1].Set(1.0f, 0.0f);
+	m_normals[2].Set(0.0f, 1.0f);
+	m_normals[3].Set(-1.0f, 0.0f);
+	m_centroid = center;
+
+	b2Transform xf;
+	xf.p = center;
+	xf.q.Set(angle);
+
+	// Transform vertices and normals.
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		m_vertices[i] = b2Mul(xf, m_vertices[i]);
+		m_normals[i] = b2Mul(xf.q, m_normals[i]);
+	}
+}
+
+int32 b2PolygonShape::GetChildCount() const
+{
+	return 1;
+}
+
+static b2Vec2 ComputeCentroid(const b2Vec2* vs, int32 count)
+{
+	b2Assert(count >= 3);
+
+	b2Vec2 c; c.Set(0.0f, 0.0f);
+	float32 area = 0.0f;
+
+	// pRef is the reference point for forming triangles.
+	// It's location doesn't change the result (except for rounding error).
+	b2Vec2 pRef(0.0f, 0.0f);
+#if 0
+	// This code would put the reference point inside the polygon.
+	for (int32 i = 0; i < count; ++i)
+	{
+		pRef += vs[i];
+	}
+	pRef *= 1.0f / count;
+#endif
+
+	const float32 inv3 = 1.0f / 3.0f;
+
+	for (int32 i = 0; i < count; ++i)
+	{
+		// Triangle vertices.
+		b2Vec2 p1 = pRef;
+		b2Vec2 p2 = vs[i];
+		b2Vec2 p3 = i + 1 < count ? vs[i+1] : vs[0];
+
+		b2Vec2 e1 = p2 - p1;
+		b2Vec2 e2 = p3 - p1;
+
+		float32 D = b2Cross(e1, e2);
+
+		float32 triangleArea = 0.5f * D;
+		area += triangleArea;
+
+		// Area weighted centroid
+		c += triangleArea * inv3 * (p1 + p2 + p3);
+	}
+
+	// Centroid
+	b2Assert(area > b2_epsilon);
+	c *= 1.0f / area;
+	return c;
+}
+
+void b2PolygonShape::Set(const b2Vec2* vertices, int32 count)
+{
+	b2Assert(3 <= count && count <= b2_maxPolygonVertices);
+	if (count < 3)
+	{
+		SetAsBox(1.0f, 1.0f);
+		return;
+	}
+	
+	int32 n = b2Min(count, b2_maxPolygonVertices);
+
+	// Perform welding and copy vertices into local buffer.
+	b2Vec2 ps[b2_maxPolygonVertices];
+	int32 tempCount = 0;
+	for (int32 i = 0; i < n; ++i)
+	{
+		b2Vec2 v = vertices[i];
+
+		bool unique = true;
+		for (int32 j = 0; j < tempCount; ++j)
+		{
+			if (b2DistanceSquared(v, ps[j]) < ((0.5f * b2_linearSlop) * (0.5f * b2_linearSlop)))
+			{
+				unique = false;
+				break;
+			}
+		}
+
+		if (unique)
+		{
+			ps[tempCount++] = v;
+		}
+	}
+
+	n = tempCount;
+	if (n < 3)
+	{
+		// Polygon is degenerate.
+		b2Assert(false);
+		SetAsBox(1.0f, 1.0f);
+		return;
+	}
+
+	// Create the convex hull using the Gift wrapping algorithm
+	// http://en.wikipedia.org/wiki/Gift_wrapping_algorithm
+
+	// Find the right most point on the hull
+	int32 i0 = 0;
+	float32 x0 = ps[0].x;
+	for (int32 i = 1; i < n; ++i)
+	{
+		float32 x = ps[i].x;
+		if (x > x0 || (x == x0 && ps[i].y < ps[i0].y))
+		{
+			i0 = i;
+			x0 = x;
+		}
+	}
+
+	int32 hull[b2_maxPolygonVertices];
+	int32 m = 0;
+	int32 ih = i0;
+
+	for (;;)
+	{
+		b2Assert(m < b2_maxPolygonVertices);
+		hull[m] = ih;
+
+		int32 ie = 0;
+		for (int32 j = 1; j < n; ++j)
+		{
+			if (ie == ih)
+			{
+				ie = j;
+				continue;
+			}
+
+			b2Vec2 r = ps[ie] - ps[hull[m]];
+			b2Vec2 v = ps[j] - ps[hull[m]];
+			float32 c = b2Cross(r, v);
+			if (c < 0.0f)
+			{
+				ie = j;
+			}
+
+			// Collinearity check
+			if (c == 0.0f && v.LengthSquared() > r.LengthSquared())
+			{
+				ie = j;
+			}
+		}
+
+		++m;
+		ih = ie;
+
+		if (ie == i0)
+		{
+			break;
+		}
+	}
+	
+	if (m < 3)
+	{
+		// Polygon is degenerate.
+		b2Assert(false);
+		SetAsBox(1.0f, 1.0f);
+		return;
+	}
+
+	m_count = m;
+
+	// Copy vertices.
+	for (int32 i = 0; i < m; ++i)
+	{
+		m_vertices[i] = ps[hull[i]];
+	}
+
+	// Compute normals. Ensure the edges have non-zero length.
+	for (int32 i = 0; i < m; ++i)
+	{
+		int32 i1 = i;
+		int32 i2 = i + 1 < m ? i + 1 : 0;
+		b2Vec2 edge = m_vertices[i2] - m_vertices[i1];
+		b2Assert(edge.LengthSquared() > b2_epsilon * b2_epsilon);
+		m_normals[i] = b2Cross(edge, 1.0f);
+		m_normals[i].Normalize();
+	}
+
+	// Compute the polygon centroid.
+	m_centroid = ComputeCentroid(m_vertices, m);
+}
+
+bool b2PolygonShape::TestPoint(const b2Transform& xf, const b2Vec2& p) const
+{
+	b2Vec2 pLocal = b2MulT(xf.q, p - xf.p);
+
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		float32 dot = b2Dot(m_normals[i], pLocal - m_vertices[i]);
+		if (dot > 0.0f)
+		{
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool b2PolygonShape::RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+								const b2Transform& xf, int32 childIndex) const
+{
+	B2_NOT_USED(childIndex);
+
+	// Put the ray into the polygon's frame of reference.
+	b2Vec2 p1 = b2MulT(xf.q, input.p1 - xf.p);
+	b2Vec2 p2 = b2MulT(xf.q, input.p2 - xf.p);
+	b2Vec2 d = p2 - p1;
+
+	float32 lower = 0.0f, upper = input.maxFraction;
+
+	int32 index = -1;
+
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		// p = p1 + a * d
+		// dot(normal, p - v) = 0
+		// dot(normal, p1 - v) + a * dot(normal, d) = 0
+		float32 numerator = b2Dot(m_normals[i], m_vertices[i] - p1);
+		float32 denominator = b2Dot(m_normals[i], d);
+
+		if (denominator == 0.0f)
+		{	
+			if (numerator < 0.0f)
+			{
+				return false;
+			}
+		}
+		else
+		{
+			// Note: we want this predicate without division:
+			// lower < numerator / denominator, where denominator < 0
+			// Since denominator < 0, we have to flip the inequality:
+			// lower < numerator / denominator <==> denominator * lower > numerator.
+			if (denominator < 0.0f && numerator < lower * denominator)
+			{
+				// Increase lower.
+				// The segment enters this half-space.
+				lower = numerator / denominator;
+				index = i;
+			}
+			else if (denominator > 0.0f && numerator < upper * denominator)
+			{
+				// Decrease upper.
+				// The segment exits this half-space.
+				upper = numerator / denominator;
+			}
+		}
+
+		// The use of epsilon here causes the assert on lower to trip
+		// in some cases. Apparently the use of epsilon was to make edge
+		// shapes work, but now those are handled separately.
+		//if (upper < lower - b2_epsilon)
+		if (upper < lower)
+		{
+			return false;
+		}
+	}
+
+	b2Assert(0.0f <= lower && lower <= input.maxFraction);
+
+	if (index >= 0)
+	{
+		output->fraction = lower;
+		output->normal = b2Mul(xf.q, m_normals[index]);
+		return true;
+	}
+
+	return false;
+}
+
+void b2PolygonShape::ComputeAABB(b2AABB* aabb, const b2Transform& xf, int32 childIndex) const
+{
+	B2_NOT_USED(childIndex);
+
+	b2Vec2 lower = b2Mul(xf, m_vertices[0]);
+	b2Vec2 upper = lower;
+
+	for (int32 i = 1; i < m_count; ++i)
+	{
+		b2Vec2 v = b2Mul(xf, m_vertices[i]);
+		lower = b2Min(lower, v);
+		upper = b2Max(upper, v);
+	}
+
+	b2Vec2 r(m_radius, m_radius);
+	aabb->lowerBound = lower - r;
+	aabb->upperBound = upper + r;
+}
+
+void b2PolygonShape::ComputeMass(b2MassData* massData, float32 density) const
+{
+	// Polygon mass, centroid, and inertia.
+	// Let rho be the polygon density in mass per unit area.
+	// Then:
+	// mass = rho * int(dA)
+	// centroid.x = (1/mass) * rho * int(x * dA)
+	// centroid.y = (1/mass) * rho * int(y * dA)
+	// I = rho * int((x*x + y*y) * dA)
+	//
+	// We can compute these integrals by summing all the integrals
+	// for each triangle of the polygon. To evaluate the integral
+	// for a single triangle, we make a change of variables to
+	// the (u,v) coordinates of the triangle:
+	// x = x0 + e1x * u + e2x * v
+	// y = y0 + e1y * u + e2y * v
+	// where 0 <= u && 0 <= v && u + v <= 1.
+	//
+	// We integrate u from [0,1-v] and then v from [0,1].
+	// We also need to use the Jacobian of the transformation:
+	// D = cross(e1, e2)
+	//
+	// Simplification: triangle centroid = (1/3) * (p1 + p2 + p3)
+	//
+	// The rest of the derivation is handled by computer algebra.
+
+	b2Assert(m_count >= 3);
+
+	b2Vec2 center; center.Set(0.0f, 0.0f);
+	float32 area = 0.0f;
+	float32 I = 0.0f;
+
+	// s is the reference point for forming triangles.
+	// It's location doesn't change the result (except for rounding error).
+	b2Vec2 s(0.0f, 0.0f);
+
+	// This code would put the reference point inside the polygon.
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		s += m_vertices[i];
+	}
+	s *= 1.0f / m_count;
+
+	const float32 k_inv3 = 1.0f / 3.0f;
+
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		// Triangle vertices.
+		b2Vec2 e1 = m_vertices[i] - s;
+		b2Vec2 e2 = i + 1 < m_count ? m_vertices[i+1] - s : m_vertices[0] - s;
+
+		float32 D = b2Cross(e1, e2);
+
+		float32 triangleArea = 0.5f * D;
+		area += triangleArea;
+
+		// Area weighted centroid
+		center += triangleArea * k_inv3 * (e1 + e2);
+
+		float32 ex1 = e1.x, ey1 = e1.y;
+		float32 ex2 = e2.x, ey2 = e2.y;
+
+		float32 intx2 = ex1*ex1 + ex2*ex1 + ex2*ex2;
+		float32 inty2 = ey1*ey1 + ey2*ey1 + ey2*ey2;
+
+		I += (0.25f * k_inv3 * D) * (intx2 + inty2);
+	}
+
+	// Total mass
+	massData->mass = density * area;
+
+	// Center of mass
+	b2Assert(area > b2_epsilon);
+	center *= 1.0f / area;
+	massData->center = center + s;
+
+	// Inertia tensor relative to the local origin (point s).
+	massData->I = density * I;
+	
+	// Shift to center of mass then to original body origin.
+	massData->I += massData->mass * (b2Dot(massData->center, massData->center) - b2Dot(center, center));
+}
+
+bool b2PolygonShape::Validate() const
+{
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		int32 i1 = i;
+		int32 i2 = i < m_count - 1 ? i1 + 1 : 0;
+		b2Vec2 p = m_vertices[i1];
+		b2Vec2 e = m_vertices[i2] - p;
+
+		for (int32 j = 0; j < m_count; ++j)
+		{
+			if (j == i1 || j == i2)
+			{
+				continue;
+			}
+
+			b2Vec2 v = m_vertices[j] - p;
+			float32 c = b2Cross(e, v);
+			if (c < 0.0f)
+			{
+				return false;
+			}
+		}
+	}
+
+	return true;
+}
diff --git a/Source/external/Box2D/Collision/Shapes/b2PolygonShape.h b/Source/external/Box2D/Collision/Shapes/b2PolygonShape.h
new file mode 100644
index 0000000..26c5e61
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2PolygonShape.h
@@ -0,0 +1,89 @@
+/*
+* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B2_POLYGON_SHAPE_H
+#define B2_POLYGON_SHAPE_H
+
+#include "Box2D/Collision/Shapes/b2Shape.h"
+
+/// A convex polygon. It is assumed that the interior of the polygon is to
+/// the left of each edge.
+/// Polygons have a maximum number of vertices equal to b2_maxPolygonVertices.
+/// In most cases you should not need many vertices for a convex polygon.
+class b2PolygonShape : public b2Shape
+{
+public:
+	b2PolygonShape();
+
+	/// Implement b2Shape.
+	b2Shape* Clone(b2BlockAllocator* allocator) const override;
+
+	/// @see b2Shape::GetChildCount
+	int32 GetChildCount() const override;
+
+	/// Create a convex hull from the given array of local points.
+	/// The count must be in the range [3, b2_maxPolygonVertices].
+	/// @warning the points may be re-ordered, even if they form a convex polygon
+	/// @warning collinear points are handled but not removed. Collinear points
+	/// may lead to poor stacking behavior.
+	void Set(const b2Vec2* points, int32 count);
+
+	/// Build vertices to represent an axis-aligned box centered on the local origin.
+	/// @param hx the half-width.
+	/// @param hy the half-height.
+	void SetAsBox(float32 hx, float32 hy);
+
+	/// Build vertices to represent an oriented box.
+	/// @param hx the half-width.
+	/// @param hy the half-height.
+	/// @param center the center of the box in local coordinates.
+	/// @param angle the rotation of the box in local coordinates.
+	void SetAsBox(float32 hx, float32 hy, const b2Vec2& center, float32 angle);
+
+	/// @see b2Shape::TestPoint
+	bool TestPoint(const b2Transform& transform, const b2Vec2& p) const override;
+
+	/// Implement b2Shape.
+	bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+					const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeAABB
+	void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const override;
+
+	/// @see b2Shape::ComputeMass
+	void ComputeMass(b2MassData* massData, float32 density) const override;
+
+	/// Validate convexity. This is a very time consuming operation.
+	/// @returns true if valid
+	bool Validate() const;
+
+	b2Vec2 m_centroid;
+	b2Vec2 m_vertices[b2_maxPolygonVertices];
+	b2Vec2 m_normals[b2_maxPolygonVertices];
+	int32 m_count;
+};
+
+inline b2PolygonShape::b2PolygonShape()
+{
+	m_type = e_polygon;
+	m_radius = b2_polygonRadius;
+	m_count = 0;
+	m_centroid.SetZero();
+}
+
+#endif
diff --git a/Source/external/Box2D/Collision/Shapes/b2Shape.h b/Source/external/Box2D/Collision/Shapes/b2Shape.h
new file mode 100644
index 0000000..653e362
--- /dev/null
+++ b/Source/external/Box2D/Collision/Shapes/b2Shape.h
@@ -0,0 +1,104 @@
+/*
+* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B2_SHAPE_H
+#define B2_SHAPE_H
+
+#include "Box2D/Common/b2BlockAllocator.h"
+#include "Box2D/Common/b2Math.h"
+#include "Box2D/Collision/b2Collision.h"
+
+/// This holds the mass data computed for a shape.
+struct b2MassData
+{
+	/// The mass of the shape, usually in kilograms.
+	float32 mass;
+
+	/// The position of the shape's centroid relative to the shape's origin.
+	b2Vec2 center;
+
+	/// The rotational inertia of the shape about the local origin.
+	float32 I;
+};
+
+/// A shape is used for collision detection. You can create a shape however you like.
+/// Shapes used for simulation in b2World are created automatically when a b2Fixture
+/// is created. Shapes may encapsulate a one or more child shapes.
+class b2Shape
+{
+public:
+	
+	enum Type
+	{
+		e_circle = 0,
+		e_edge = 1,
+		e_polygon = 2,
+		e_chain = 3,
+		e_typeCount = 4
+	};
+
+	virtual ~b2Shape() {}
+
+	/// Clone the concrete shape using the provided allocator.
+	virtual b2Shape* Clone(b2BlockAllocator* allocator) const = 0;
+
+	/// Get the type of this shape. You can use this to down cast to the concrete shape.
+	/// @return the shape type.
+	Type GetType() const;
+
+	/// Get the number of child primitives.
+	virtual int32 GetChildCount() const = 0;
+
+	/// Test a point for containment in this shape. This only works for convex shapes.
+	/// @param xf the shape world transform.
+	/// @param p a point in world coordinates.
+	virtual bool TestPoint(const b2Transform& xf, const b2Vec2& p) const = 0;
+
+	/// Cast a ray against a child shape.
+	/// @param output the ray-cast results.
+	/// @param input the ray-cast input parameters.
+	/// @param transform the transform to be applied to the shape.
+	/// @param childIndex the child shape index
+	virtual bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
+						const b2Transform& transform, int32 childIndex) const = 0;
+
+	/// Given a transform, compute the associated axis aligned bounding box for a child shape.
+	/// @param aabb returns the axis aligned box.
+	/// @param xf the world transform of the shape.
+	/// @param childIndex the child shape
+	virtual void ComputeAABB(b2AABB* aabb, const b2Transform& xf, int32 childIndex) const = 0;
+
+	/// Compute the mass properties of this shape using its dimensions and density.
+	/// The inertia tensor is computed about the local origin.
+	/// @param massData returns the mass data for this shape.
+	/// @param density the density in kilograms per meter squared.
+	virtual void ComputeMass(b2MassData* massData, float32 density) const = 0;
+
+	Type m_type;
+
+	/// Radius of a shape. For polygonal shapes this must be b2_polygonRadius. There is no support for
+	/// making rounded polygons.
+	float32 m_radius;
+};
+
+inline b2Shape::Type b2Shape::GetType() const
+{
+	return m_type;
+}
+
+#endif