reactphysics3d/src/collision/shapes/BoxShape.h

/********************************************************************************
* ReactPhysics3D physics library, http://code.google.com/p/reactphysics3d/      *
* Copyright (c) 2010-2013 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.                                                         *
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* including commercial applications, and to alter it and redistribute it        *
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*                                                                               *
* 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.                                           *
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* 2. Altered source versions must be plainly marked as such, and must not be    *
*    misrepresented as being the original software.                             *
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* 3. This notice may not be removed or altered from any source distribution.    *
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********************************************************************************/

#ifndef BOX_SHAPE_H
#define BOX_SHAPE_H

// Libraries
#include <cfloat>
#include "CollisionShape.h"
#include "../../mathematics/mathematics.h"


// ReactPhysics3D namespace
namespace reactphysics3d {

/*  -------------------------------------------------------------------
    Class BoxShape :
        This class represents a 3D box shape. Those axis are unit length.
        The three extents are half-widths of the box along the three
        axis x, y, z local axis. The "transform" of the corresponding
        rigid body gives an orientation and a position to the box.
    -------------------------------------------------------------------
*/
class BoxShape : public CollisionShape {

    private :

        // -------------------- Attributes -------------------- //

        // Extent sizes of the box in the x, y and z direction
        Vector3 mExtent;

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

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

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

    public :

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

        // Constructor
        BoxShape(const Vector3& extent);

        // Destructor
        virtual ~BoxShape();

        // Return the extents of the box
        const Vector3& getExtent() const;

        // Set the extents of the box
        void setExtent(const Vector3& extent);

        // Return the local extents in x,y and z direction
        virtual Vector3 getLocalExtents(decimal margin=0.0) const;

        // Return a local support point in a given direction
        virtual Vector3 getLocalSupportPoint(const Vector3& direction, decimal margin=0.0) const;

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

#ifdef VISUAL_DEBUG
        // Draw the Box (only for testing purpose)
        virtual void draw() const;
#endif
};

// Return the extents of the box
inline const Vector3& BoxShape::getExtent() const {
    return mExtent;
}

 // Set the extents of the box
inline void BoxShape::setExtent(const Vector3& extent) {
    this->mExtent = extent;
}

// Return the local extents of the box (half-width) in x,y and z local direction
// This method is used to compute the AABB of the box
inline Vector3 BoxShape::getLocalExtents(decimal margin) const {
    return mExtent + Vector3(margin, margin, margin);
}

// Return a local support point in a given direction
inline Vector3 BoxShape::getLocalSupportPoint(const Vector3& direction, decimal margin) const {
    assert(margin >= 0.0);
    
    return Vector3(direction.x < 0.0 ? -mExtent.x - margin : mExtent.x + margin,
                   direction.y < 0.0 ? -mExtent.y - margin : mExtent.y + margin,
                   direction.z < 0.0 ? -mExtent.z - margin : mExtent.z + margin);
}

}

#endif