/********************************************************************************
* ReactPhysics3D physics library, http://www.reactphysics3d.com                 *
* Copyright (c) 2010-2015 Daniel Chappuis                                       *
*********************************************************************************
*                                                                               *
* 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 REACTPHYSICS3D_TRIANGLE_SHAPE_H
#define REACTPHYSICS3D_TRIANGLE_SHAPE_H

// Libraries
#include "mathematics/mathematics.h"
#include "ConvexShape.h"

/// ReactPhysics3D namespace
namespace reactphysics3d {

/// Raycast test side for the triangle
enum TriangleRaycastSide {

    /// Raycast against front triangle
    FRONT,

    /// Raycast against back triangle
    BACK,

    /// Raycast against front and back triangle
    FRONT_AND_BACK
};

// Class TriangleShape
/**
 * This class represents a triangle collision shape that is centered
 * at the origin and defined three points.
 */
class TriangleShape : public ConvexShape {

    protected:

        // -------------------- Attribute -------------------- //

        /// Three points of the triangle
        Vector3 mPoints[3];

        /// Raycast test type for the triangle (front, back, front-back)
        TriangleRaycastSide mRaycastTestType;

        // -------------------- Methods -------------------- //

        /// Private copy-constructor
        TriangleShape(const TriangleShape& shape);

        /// Private assignment operator
        TriangleShape& operator=(const TriangleShape& shape);

        /// Return a local support point in a given direction without the object margin
        virtual Vector3 getLocalSupportPointWithoutMargin(const Vector3& direction,
                                                          void** cachedCollisionData) const;

        /// Return true if a point is inside the collision shape
        virtual bool testPointInside(const Vector3& localPoint, ProxyShape* proxyShape) const;

        /// Raycast method with feedback information
        virtual bool raycast(const Ray& ray, RaycastInfo& raycastInfo, ProxyShape* proxyShape) const;

        /// Return the number of bytes used by the collision shape
        virtual size_t getSizeInBytes() const;

    public:

        // -------------------- Methods -------------------- //

        /// Constructor
        TriangleShape(const Vector3& point1, const Vector3& point2, const Vector3& point3,
                      decimal margin = OBJECT_MARGIN);

        /// Destructor
        virtual ~TriangleShape();

        /// Return the local bounds of the shape in x, y and z directions.
        virtual void getLocalBounds(Vector3& min, Vector3& max) const;

        /// Set the local scaling vector of the collision shape
        virtual void setLocalScaling(const Vector3& scaling);

        /// Return the local inertia tensor of the collision shape
        virtual void computeLocalInertiaTensor(Matrix3x3& tensor, decimal mass) const;

        /// Update the AABB of a body using its collision shape
        virtual void computeAABB(AABB& aabb, const Transform& transform) const;

        /// Return the raycast test type (front, back, front-back)
        TriangleRaycastSide getRaycastTestType() const;

        // Set the raycast test type (front, back, front-back)
        void setRaycastTestType(TriangleRaycastSide testType);

        /// Return the coordinates of a given vertex of the triangle
        Vector3 getVertex(int index) const;

        // ---------- Friendship ---------- //

        friend class ConcaveMeshRaycastCallback;
};

// Return the number of bytes used by the collision shape
inline size_t TriangleShape::getSizeInBytes() const {
    return sizeof(TriangleShape);
}

// Return a local support point in a given direction without the object margin
inline Vector3 TriangleShape::getLocalSupportPointWithoutMargin(const Vector3& direction,
                                                              void** cachedCollisionData) const {
    Vector3 dotProducts(direction.dot(mPoints[0]), direction.dot(mPoints[1]), direction.dot(mPoints[2]));
    return mPoints[dotProducts.getMaxAxis()];
}

// Return the local bounds of the shape in x, y and z directions.
// This method is used to compute the AABB of the box
/**
 * @param min The minimum bounds of the shape in local-space coordinates
 * @param max The maximum bounds of the shape in local-space coordinates
 */
inline void TriangleShape::getLocalBounds(Vector3& min, Vector3& max) const {

    const Vector3 xAxis(mPoints[0].x, mPoints[1].x, mPoints[2].x);
    const Vector3 yAxis(mPoints[0].y, mPoints[1].y, mPoints[2].y);
    const Vector3 zAxis(mPoints[0].z, mPoints[1].z, mPoints[2].z);
    min.setAllValues(xAxis.getMinValue(), yAxis.getMinValue(), zAxis.getMinValue());
    max.setAllValues(xAxis.getMaxValue(), yAxis.getMaxValue(), zAxis.getMaxValue());

    min -= Vector3(mMargin, mMargin, mMargin);
    max += Vector3(mMargin, mMargin, mMargin);
}

// Set the local scaling vector of the collision shape
inline void TriangleShape::setLocalScaling(const Vector3& scaling) {

    mPoints[0] = (mPoints[0] / mScaling) * scaling;
    mPoints[1] = (mPoints[1] / mScaling) * scaling;
    mPoints[2] = (mPoints[2] / mScaling) * scaling;

    CollisionShape::setLocalScaling(scaling);
}

// Return the local inertia tensor of the triangle shape
/**
 * @param[out] tensor The 3x3 inertia tensor matrix of the shape in local-space
 *                    coordinates
 * @param mass Mass to use to compute the inertia tensor of the collision shape
 */
inline void TriangleShape::computeLocalInertiaTensor(Matrix3x3& tensor, decimal mass) const {
    tensor.setToZero();
}

// Update the AABB of a body using its collision shape
/**
 * @param[out] aabb The axis-aligned bounding box (AABB) of the collision shape
 *                  computed in world-space coordinates
 * @param transform Transform used to compute the AABB of the collision shape
 */
inline void TriangleShape::computeAABB(AABB& aabb, const Transform& transform) const {

    const Vector3 worldPoint1 = transform * mPoints[0];
    const Vector3 worldPoint2 = transform * mPoints[1];
    const Vector3 worldPoint3 = transform * mPoints[2];

    const Vector3 xAxis(worldPoint1.x, worldPoint2.x, worldPoint3.x);
    const Vector3 yAxis(worldPoint1.y, worldPoint2.y, worldPoint3.y);
    const Vector3 zAxis(worldPoint1.z, worldPoint2.z, worldPoint3.z);
    aabb.setMin(Vector3(xAxis.getMinValue(), yAxis.getMinValue(), zAxis.getMinValue()));
    aabb.setMax(Vector3(xAxis.getMaxValue(), yAxis.getMaxValue(), zAxis.getMaxValue()));
}

// Return true if a point is inside the collision shape
inline bool TriangleShape::testPointInside(const Vector3& localPoint, ProxyShape* proxyShape) const {
    return false;
}

// Return the raycast test type (front, back, front-back)
inline TriangleRaycastSide TriangleShape::getRaycastTestType() const {
    return mRaycastTestType;
}

// Set the raycast test type (front, back, front-back)
/**
 * @param testType Raycast test type for the triangle (front, back, front-back)
 */
inline void TriangleShape::setRaycastTestType(TriangleRaycastSide testType) {
    mRaycastTestType = testType;
}

// Return the coordinates of a given vertex of the triangle
/**
 * @param index Index (0 to 2) of a vertex of the triangle
 */
inline Vector3 TriangleShape::getVertex(int index) const {
    assert(index >= 0 && index < 3);
    return mPoints[index];
}

}

#endif