reactphysics3d/src/shapes/BoxShape.h

/********************************************************************************
* ReactPhysics3D physics library, http://code.google.com/p/reactphysics3d/      *
* Copyright (c) 2010 Daniel Chappuis                                            *
*********************************************************************************
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#ifndef BOX_SHAPE_H
#define BOX_SHAPE_H

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


// ReactPhysics3D namespace
namespace reactphysics3d {

/*  -------------------------------------------------------------------
    Class BoxShape :
        This class represents a 3D box. 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 Shape {
    private :
        Vector3 extent;           // Extent sizes of the box in the x, y and z direction

    public :
        BoxShape(const Vector3& extent);        // Constructor
        virtual ~BoxShape();                     // Destructor

        const Vector3& getExtent() const;                                                           // Return the extents of the box
        void setExtent(const Vector3& extent);                                                      // Set the extents of the box
        virtual Vector3 getLocalExtents(double margin=0.0) const;                                   // Return the local extents in x,y and z direction
        virtual Vector3 getLocalSupportPoint(const Vector3& direction, double margin=0.0) const;    // Return a local support point in a given direction
        virtual void computeLocalInertiaTensor(Matrix3x3& tensor, double mass) const;               // Return the local inertia tensor of the shape

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

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

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

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

// Return a local support point in a given direction
inline Vector3 BoxShape::getLocalSupportPoint(const Vector3& direction, double margin) const {
    assert(margin >= 0.0);
    
    return Vector3(direction.getX() < 0.0 ? -extent.getX()-margin : extent.getX()+margin,
                    direction.getY() < 0.0 ? -extent.getY()-margin : extent.getY()+margin,
                    direction.getZ() < 0.0 ? -extent.getZ()-margin : extent.getZ()+margin);
}

}; // End of the ReactPhysics3D namespace

#endif