BansheeEngine/CamelotUtility/Source/CmPlane.cpp

/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2011 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/

#include "CmPlane.h"
#include "CmMatrix3.h"
#include "CmAABox.h"
#include "CmRay.h"

namespace CamelotFramework {
	//-----------------------------------------------------------------------
	Plane::Plane ()
	{
		normal = Vector3::ZERO;
		d = 0.0;
	}
	//-----------------------------------------------------------------------
	Plane::Plane (const Plane& rhs)
	{
		normal = rhs.normal;
		d = rhs.d;
	}
	//-----------------------------------------------------------------------
	Plane::Plane (const Vector3& rkNormal, float fConstant)
	{
		normal = rkNormal;
		d = -fConstant;
	}
	//---------------------------------------------------------------------
	Plane::Plane (float a, float b, float c, float _d)
		: normal(a, b, c), d(_d)
	{
	}
	//-----------------------------------------------------------------------
	Plane::Plane (const Vector3& rkNormal, const Vector3& rkPoint)
	{
		redefine(rkNormal, rkPoint);
	}
	//-----------------------------------------------------------------------
	Plane::Plane (const Vector3& rkPoint0, const Vector3& rkPoint1,
		const Vector3& rkPoint2)
	{
		redefine(rkPoint0, rkPoint1, rkPoint2);
	}
	//-----------------------------------------------------------------------
	float Plane::getDistance (const Vector3& rkPoint) const
	{
		return normal.dot(rkPoint) + d;
	}
	//-----------------------------------------------------------------------
	Plane::Side Plane::getSide (const Vector3& rkPoint) const
	{
		float fDistance = getDistance(rkPoint);

		if ( fDistance < 0.0 )
			return Plane::NEGATIVE_SIDE;

		if ( fDistance > 0.0 )
			return Plane::POSITIVE_SIDE;

		return Plane::NO_SIDE;
	}


	//-----------------------------------------------------------------------
	Plane::Side Plane::getSide (const AABox& box) const
	{
        return getSide(box.getCenter(), box.getHalfSize());
	}
    //-----------------------------------------------------------------------
    Plane::Side Plane::getSide (const Vector3& centre, const Vector3& halfSize) const
    {
        // Calculate the distance between box centre and the plane
        float dist = getDistance(centre);

        // Calculate the maximise allows absolute distance for
        // the distance between box centre and plane
        float maxAbsDist = Math::abs(normal.x * halfSize.x) + Math::abs(normal.y * halfSize.y) + Math::abs(normal.z * halfSize.z);

        if (dist < -maxAbsDist)
            return Plane::NEGATIVE_SIDE;

        if (dist > +maxAbsDist)
            return Plane::POSITIVE_SIDE;

        return Plane::BOTH_SIDE;
    }
	//-----------------------------------------------------------------------
	void Plane::redefine(const Vector3& rkPoint0, const Vector3& rkPoint1,
		const Vector3& rkPoint2)
	{
		Vector3 kEdge1 = rkPoint1 - rkPoint0;
		Vector3 kEdge2 = rkPoint2 - rkPoint0;
		normal = kEdge1.cross(kEdge2);
		normal.normalize();
		d = -normal.dot(rkPoint0);
	}
	//-----------------------------------------------------------------------
	void Plane::redefine(const Vector3& rkNormal, const Vector3& rkPoint)
	{
		normal = rkNormal;
		d = -rkNormal.dot(rkPoint);
	}
	//-----------------------------------------------------------------------
	Vector3 Plane::projectVector(const Vector3& p) const
	{
		// We know plane normal is unit length, so use simple method
		Matrix3 xform;
		xform[0][0] = 1.0f - normal.x * normal.x;
		xform[0][1] = -normal.x * normal.y;
		xform[0][2] = -normal.x * normal.z;
		xform[1][0] = -normal.y * normal.x;
		xform[1][1] = 1.0f - normal.y * normal.y;
		xform[1][2] = -normal.y * normal.z;
		xform[2][0] = -normal.z * normal.x;
		xform[2][1] = -normal.z * normal.y;
		xform[2][2] = 1.0f - normal.z * normal.z;
		return xform.transform(p);

	}
	//-----------------------------------------------------------------------
    float Plane::normalize(void)
    {
        float fLength = normal.length();

        // Will also work for zero-sized vectors, but will change nothing
        if (fLength > 1e-08f)
        {
            float fInvLength = 1.0f / fLength;
            normal *= fInvLength;
            d *= fInvLength;
        }

        return fLength;
    }

	std::pair<bool, float> Plane::intersects(const Ray& ray) const
	{
		float denom = normal.dot(ray.getDirection());
		if (Math::abs(denom) < std::numeric_limits<float>::epsilon())
		{
			// Parallel
			return std::pair<bool, float>(false, 0.0f);
		}
		else
		{
			float nom = normal.dot(ray.getOrigin()) + d;
			float t = -(nom/denom);
			return std::pair<bool, float>(t >= 0, t);
		}
	}
}