RedCore/cocos2d/cocos/3d/CCPlane.cpp

/****************************************************************************
 Copyright (c) 2014-2017 Chukong Technologies Inc.
 
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#include "3d/CCPlane.h"

NS_CC_BEGIN

Plane::Plane()
:
_normal(0.f, 0.f, 1.f),
_dist(0.f)
{
    
}

// create plane from tree point
Plane::Plane(const Vec3& p1, const Vec3& p2, const Vec3& p3)
{
    initPlane(p1, p2, p3);
}

// create plane from normal and dist
Plane::Plane(const Vec3& normal, float dist)
{
    initPlane(normal, dist);
}

// create plane from normal and a point on plane
Plane::Plane(const Vec3& normal, const Vec3& point)
{
    initPlane(normal, point);
}

void Plane::initPlane(const Vec3& p1, const Vec3& p2, const Vec3& p3)
{
    Vec3 p21 = p2 - p1;
    Vec3 p32 = p3 - p2;
    Vec3::cross(p21, p32, &_normal);
    _normal.normalize();
    _dist = _normal.dot(p1);
}

void Plane::initPlane(const Vec3& normal, float dist)
{
    float oneOverLength = 1 / normal.length();
    _normal = normal * oneOverLength;
    _dist = dist * oneOverLength;
}

void Plane::initPlane(const Vec3& normal, const Vec3& point)
{
    _normal = normal;
    _normal.normalize();
    _dist = _normal.dot(point);
}

float Plane::dist2Plane(const Vec3& p) const
{
    return _normal.dot(p) - _dist;
}


PointSide Plane::getSide(const Vec3& point) const
{
    float dist = dist2Plane(point);
    if (dist > 0)
        return PointSide::FRONT_PLANE;
    else if (dist < 0)
        return PointSide::BEHIND_PLANE;
    else
        return PointSide::IN_PLANE;
}

NS_CC_END