urho3d/Engine/Math/Plane.h

//
// Urho3D Engine
// Copyright (c) 2008-2012 Lasse Öörni
//
// 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.
//

#pragma once

#include "Vector3.h"

/// Surface in three-dimensional space.
class Plane
{
public:
    /// Construct undefined.
    Plane()
    {
    }
    
    /// Copy-construct from another plane.
    Plane(const Plane& plane) :
        normal_(plane.normal_),
        intercept_(plane.intercept_)
    {
    }
    
    /// Construct from 3 vertices.
    Plane(const Vector3& v0, const Vector3& v1, const Vector3& v2)
    {
        Define(v0, v1, v2);
    }
    
    /// Construct from a normal vector and a point on the plane.
    Plane(const Vector3& normal, const Vector3& point)
    {
        Define(normal, point);
    }
    
    /// Define from 3 vertices.
    void Define(const Vector3& v0, const Vector3& v1, const Vector3& v2)
    {
        Vector3 dist1 = v1 - v0;
        Vector3 dist2 = v2 - v0;
        
        normal_ = (dist1.CrossProduct(dist2)).Normalized();
        absNormal_ = Vector3(fabsf(normal_.x_), fabsf(normal_.y_), fabsf(normal_.z_));
        intercept_ = normal_.DotProduct(v0);
    }

    /// Define from a normal and a point.
    void Define(const Vector3& normal, const Vector3& point)
    {
        normal_ = normal;
        absNormal_ = Vector3(fabsf(normal_.x_), fabsf(normal_.y_), fabsf(normal_.z_));
        intercept_ = normal_.DotProduct(point);
    }
    
    /// Return signed distance to a point.
    float Distance(const Vector3& point) const { return normal_.DotProduct(point) - intercept_; }
    
    /// Plane normal.
    Vector3 normal_;
    /// Plane absolute normal.
    Vector3 absNormal_;
    /// Plane intercept parameter.
    float intercept_;
};