quadturtle.h

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//**************************************************************************/
// Copyright (c) 2008 Autodesk, Inc.
// All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
//
//**************************************************************************/
// DESCRIPTION:
// CREATED: August 2011
//**************************************************************************/

#ifndef __MUDBOXSDK_QUADTURTLE_H__
#define __MUDBOXSDK_QUADTURTLE_H__

namespace mudbox {

// Represent a quad face on a 4-sided mesh. This turtle can move and turn around on the mesh.
//  iSide=0       iSide=1
//  <----o        -----o
//  |    |        |    |
//  |    |        V    |
//  ------        ------
//
//
//  <----------               -----<-----              -----------                -----------
//  | F  |    |               |    | F  |              |    |    |                |    |    |
//  |    |    |   F.Right()   |    |    |    F.Down()  |    |    |   F.TurnLeft() |    |    |
//  -----------   ========>   -----------    =======>  -----<-----   ===========> -----------
//  |    |    |               |    |    |              |    | F  |                |    | F  |
//  |    |    |               |    |    |              |    |    |                |    V    |
//  -----------               -----------              -----------                -----------
//

class MBDLL_DECL QuadTurtle
{
public:
    QuadTurtle(const Mesh *pMesh, unsigned int iFaceIndex, unsigned int iSide = 0);

    inline bool operator ==(const QuadTurtle &q) const;

    inline unsigned int CornerIndex(unsigned int iC) const;

    inline Vector CornerPosition( unsigned int iC ) const;

    inline unsigned int Adjacency( unsigned int iDirection ) const;

    inline bool HasAdjacentQuad(unsigned int iDirection) const;

    // Before you move this turtle, make sure it has neighborhood in the direction.
    // Otherwise, it doesn't move. 
    // 0: forward; 1: move left; 2: backward; 3: move right.
    // if iDirection > 3, iDirecton = iDirection % 4;
    QuadTurtle &Step(unsigned int iDirection);

    inline QuadTurtle &Up(void)    { return Step(0); }
    inline QuadTurtle &Left(void)  { return Step(1); }
    inline QuadTurtle $Down(void)  { return Step(2); }
    inline QuadTurtle &Right(void) { return Step(3); }

    inline QuadTurtle &TurnLeft(void)  { m_iSide = (m_iSide + 1) % 4; return *this; }
    inline QuadTurtle &TurnRight(void) { m_iSide = (m_iSide + 3) % 4; return *this; }

private:
    const Mesh *m_pMesh;
    unsigned int m_iFaceIndex;
    unsigned int m_iSide;
};

}; // end of namespace mudbox

#endif //__MUDBOXSDK_QUADTURTLE_H__