axmol/core/3d/CCOBB.h

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 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#ifndef __AX_OBB_H__
#define __AX_OBB_H__

#include "3d/CCAABB.h"

NS_AX_BEGIN

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

/**
 *
 * @brief Oriented Bounding Box(OBB): OBB is similar to AABB except the bounding box has the same direction as the
 * MeshRenderer. so collision detection is more precise than AABB.
 * @js NA
 */
class AX_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_AX_END

#endif