axmol/cocos/3d/CCOBB.h

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 Copyright (c) 2014 Chukong Technologies Inc.
 
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#ifndef __CC_OBB_H__
#define __CC_OBB_H__

#include "3d/CCAABB.h"

NS_CC_BEGIN

/**
 * @addtogroup _3d
 * @{
 */

/**
 * Oriented Bounding Box(OBB)
 * @brief the OBB is similar to the AABB but the bounding box has the same direction as Sprite3D. so it's collision detection more precise than AABB
 * @js NA
 */
class CC_DLL OBB
{
public:
    OBB();

    /*
     * Construct obb from oriented bounding box
     *
     * @lua NA
     */
    OBB(const AABB& aabb);
    
    /*
     * Construct obb from points
     *
     * @lua NA
     */
    OBB(const Vec3* verts, int num);
    
    /*
     * Check point in
     */
    bool containPoint(const Vec3& point) const;

    /*
     * Specify obb values
     */
    void set(const Vec3& center, const Vec3& _xAxis, const Vec3& _yAxis, const Vec3& _zAxis, const Vec3& _extents);
    
    /*
     * Clear obb
     */ 
    void reset();

    /* face to the obb's -z direction
     * verts[0] : left top front
     * verts[1] : left bottom front
     * verts[2] : right bottom front
     * verts[3] : right top front
     *
     * face to the obb's z direction
     * verts[4] : right top back
     * verts[5] : right bottom back
     * verts[6] : left bottom back
     * verts[7] : left top back
     */
    void getCorners(Vec3* verts) const;
    
    /*
     * Check intersect with other
     */
    bool intersects(const OBB& box) const;
    
	/**
     * Transforms the obb by the given transformation matrix.
     */
    void transform(const Mat4& mat);
    
protected:
    /*
    * compute extX, extY, extZ
    */
    void computeExtAxis()
    {
        _extentX = _xAxis * _extents.x;
        _extentY = _yAxis * _extents.y;
        _extentZ = _zAxis * _extents.z;
    }
    
    /*
     * Project point to the target axis
     */
    float projectPoint(const Vec3& point, const Vec3& axis) const;
    
    /*
     * Calculate the min and max project value of through the box's corners
     */
    void getInterval(const OBB& box, const Vec3& axis, float &min, float &max) const;
    
    /*
     * Get the edge of x y z axis direction
     */
    Vec3 getEdgeDirection(int index) const;
    
    /*
     * Get the face of x y z axis direction
     */
    Vec3 getFaceDirection(int index) const;

public:
    Vec3 _center;   // obb center
    Vec3 _xAxis;    // x axis of obb, unit vector
    Vec3 _yAxis;    // y axis of obb, unit vector
    Vec3 _zAxis;    // z axis of obb, unit vector
    Vec3 _extentX;  // _xAxis * _extents.x
    Vec3 _extentY;  // _yAxis * _extents.y
    Vec3 _extentZ;  // _zAxis * _extents.z
    Vec3 _extents;  // obb length along each axis
};

// end of 3d group
/// @}

NS_CC_END

#endif