Magic Cube

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// Copyright 2019 Leszek Koltunski                                                               //

//                                                                                               //

// This file is part of Magic Cube.                                                              //

//                                                                                               //

// Magic Cube is free software: you can redistribute it and/or modify                            //

// it under the terms of the GNU General Public License as published by                          //

// the Free Software Foundation, either version 2 of the License, or                             //

// (at your option) any later version.                                                           //

//                                                                                               //

// Magic Cube is distributed in the hope that it will be useful,                                 //

// but WITHOUT ANY WARRANTY; without even the implied warranty of                                //

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                 //

// GNU General Public License for more details.                                                  //

//                                                                                               //

// You should have received a copy of the GNU General Public License                             //

// along with Magic Cube.  If not, see <http://www.gnu.org/licenses/>.                           //

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import android.content.SharedPreferences;

import org.distorted.library.type.Static3D;

import org.distorted.library.type.Static4D;

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class Cubit

  {

  private final Static3D mOrigPosition;

  private RubikObject mParent;

  Cubit(RubikObject parent, Static3D position)

    {

    float x = position.get0();

    float y = position.get1();

    float z = position.get2();

    mParent          = parent;

    mOrigPosition    = new Static3D(x,y,z);

    mQuatIndex       = 0;

    mNumAxis     = mParent.ROTATION_AXIS.length;

    mRotationRow = new float[mNumAxis];

    computeRotationRow();

    }

// Because of quatMultiplication, errors can accumulate - so to avoid this, we

// correct the value of the 'scramble' quat to what it should be - one of the legal quats from the

// We also have to remember that the group of unit quaternions is a double-cover of rotations

// in 3D ( q represents the same rotation as -q ) - so invert if needed.

    {

    float y = quat.get1();

    float z = quat.get2();

    float w = quat.get3();

    float diff, mindiff = Float.MAX_VALUE;

    int ret=0;

    int num_quats = mParent.QUATS.length;

    Static4D qt;

      yd = y - qt.get1();

      zd = z - qt.get2();

      wd = w - qt.get3();

      diff = xd*xd + yd*yd + zd*zd + wd*wd;

      if( diff < mindiff )

        mindiff = diff;

      xd = x + qt.get0();

      yd = y + qt.get1();

      zd = z + qt.get2();

      wd = w + qt.get3();

      diff = xd*xd + yd*yd + zd*zd + wd*wd;

      if( diff < mindiff )

        mindiff = diff;

      }

    float cubitCenterY = mCurrentPosition.get1();

    float cubitCenterZ = mCurrentPosition.get2();

    Static4D cubitCenter =  new Static4D(cubitCenterX, cubitCenterY, cubitCenterZ, 0);

    Static4D rotatedCenter = RubikSurfaceView.rotateVectorByQuat( cubitCenter, quat);

    float rotatedY = rotatedCenter.get1();

    float rotatedZ = rotatedCenter.get2();

    mParent.clampPos(mCurrentPosition);

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void computeRotationRow()

    {

    Static3D axis;

    float x = mCurrentPosition.get0();

    float y = mCurrentPosition.get1();

    float z = mCurrentPosition.get2();

    for(int i=0; i<mNumAxis; i++)

      {

      axis = mParent.ROTATION_AXIS[i];

      tmp = x*axis.get0() + y*axis.get1() + z*axis.get2();

  int computeAssociation()

    {

    int row, result = 0, accumulativeShift = 0;

    for(int axis=0; axis<mNumAxis; axis++)

      {

      row = (int)(mRotationRow[axis]+0.5f);

      result += (1<<(row+accumulativeShift));

    return result;

    }

  void savePreferences(SharedPreferences.Editor editor)

    {

    String number = mOrigPosition.get0()+"_"+mOrigPosition.get1()+"_"+mOrigPosition.get2();

///////////////////////////////////////////////////////////////////////////////////////////////////

    String number = mOrigPosition.get0()+"_"+mOrigPosition.get1()+"_"+mOrigPosition.get2();

    modifyCurrentPosition(mParent.QUATS[mQuatIndex]);

///////////////////////////////////////////////////////////////////////////////////////////////////

// return if the Cubit, when rotated with its own mQuatScramble, would have looked any different

// then if it were rotated by quaternion 'quat'.

// No it is not so simple as the quats need to be the same - imagine a 4x4x4 cube where the two

// middle squares get interchanged. No visible difference!

//

// So: this is true iff the cubit

// a) is a corner or edge and the quaternions are the same

// b) is inside one of the faces and after rotations by both quats it ends up on the same face.

    int belongsToHowManyFaces = 0;

    int size = mParent.getSize()-1;

    final float MAX_ERROR = 0.01f;

    for(int i=0; i<mNumAxis; i++)

      {

      if( (row     <MAX_ERROR && row     >-MAX_ERROR) ||

          (row-size<MAX_ERROR && row-size>-MAX_ERROR)  ) belongsToHowManyFaces++;

    switch(belongsToHowManyFaces)

      {

      case 0 : return true ;  // 'inside' cubit that does not lie on any face

      case 1 :                // cubit that lies inside one of the faces

               float cubitCenterY = mOrigPosition.get1();

               float cubitCenterZ = mOrigPosition.get2();

               Static4D quat2 = mParent.QUATS[mQuatIndex];

               Static4D rotated2 = RubikSurfaceView.rotateVectorByQuat( cubitCenter, quat2 );

               Static3D axis;

               float x1 = rotated1.get0();

               float y1 = rotated1.get1();

               float z1 = rotated1.get2();

               float x2 = rotated2.get0();

               float y2 = rotated2.get1();

               float z2 = rotated2.get2();

               for(int i=0; i<mNumAxis; i++)

                 {

                 axis = mParent.ROTATION_AXIS[i];

                 ax = axis.get0();

                 ay = axis.get1();

                 az = axis.get2();

                 row2 = ((x2*ax + y2*ay + z2*az) - mParent.mStart) / mParent.mStep;

                 row3 = row1 - size;

                 row4 = row2 - size;

                     (row3<MAX_ERROR && row3>-MAX_ERROR && row4<MAX_ERROR && row4>-MAX_ERROR)  )

                   return true;

                   }

                 }

               return false;

      }

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    mQuatIndex = normalizeScrambleQuat(q);

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  void solve()

    {

  float getDistSquared(float[] point)

    {

    float dx = mCurrentPosition.get0() - point[0];

    float dy = mCurrentPosition.get1() - point[1];

    float dz = mCurrentPosition.get2() - point[2];

    return dx*dx + dy*dy + dz*dz;

    }