//
// Urho3D Engine
// Copyright (c) 2008-2011 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"

class BoundingBox;
class Frustum;
class Plane;
class Sphere;

/// Infinite straight line in three-dimensional space.
class Ray
{
public:
    /// Construct undefined.
    Ray()
    {
    }
    
    /// Construct from origin and direction. The direction must be normalized.
    Ray(const Vector3& origin, const Vector3& direction) :
        origin_(origin),
        direction_(direction)
    {
    }
    
    /// Copy-construct from another ray.
    Ray(const Ray& ray) :
        origin_(ray.origin_),
        direction_(ray.direction_)
    {
    }
    
    /// Assign from another ray.
    Ray& operator = (const Ray& rhs)
    {
        origin_ = rhs.origin_;
        direction_ = rhs.direction_;
        return *this;
    }
    
    /// Check for equality with another ray.
    bool operator == (const Ray& rhs) const { return origin_ == rhs.origin_ && direction_ == rhs.direction_; }
    /// Check for inequality with another ray.
    bool operator != (const Ray& rhs) const { return origin_ != rhs.origin_ || direction_ != rhs.direction_; }
    
    /// Define from origin and direction. The direction will be normalized.
    void Define(const Vector3& origin, const Vector3& direction)
    {
        origin_ = origin;
        direction_ = direction.Normalized();
    }
    
    /// Project a point on the ray.
    Vector3 Project(const Vector3& point) const;
    /// Return distance of a point from the ray
    float Distance(const Vector3& point) const;
    /// Return closest point to another ray.
    Vector3 ClosestPoint(const Ray& ray) const;
    /// Return hit distance to a plane, or infinity if no hit.
    float HitDistance(const Plane& plane) const;
    /// Return hit distance to a bounding box, or infinity if no hit.
    float HitDistance(const BoundingBox& box) const;
    /// Return hit distance to a frustum, or infinity if no hit.
    float HitDistance(const Frustum& frustum) const;
    /// Return hit distance to a sphere, or infinity if no hit.
    float HitDistance(const Sphere& sphere) const;
    /// Return hit distance to a triangle, or infinity if no hit.
    float HitDistance(const Vector3& v0, const Vector3& v1, const Vector3& v2) const;
    /// Return hit distance to a triangle mesh defined by vertex and index data, or infinity if no hit.
    float HitDistance(const void* vertexData, unsigned vertexSize, const void* indexData, unsigned indexSize, unsigned indexStart, unsigned indexCount) const;
    
    /// Ray origin.
    Vector3 origin_;
    /// Ray direction.
    Vector3 direction_;
};