Magic Cube

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

// 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/>.                           //

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

package org.distorted.main;

import android.app.ActivityManager;

import android.content.Context;

import android.content.pm.ConfigurationInfo;

import android.opengl.GLES30;

import android.opengl.GLSurfaceView;

import android.util.AttributeSet;

import android.util.DisplayMetrics;

import android.view.MotionEvent;

import com.google.firebase.crashlytics.FirebaseCrashlytics;

import org.distorted.library.type.Static2D;

import org.distorted.library.type.Static4D;

import org.distorted.objects.TwistyObject;

import org.distorted.objects.Movement;

import org.distorted.screens.RubikScreenReady;

import org.distorted.solvers.SolverMain;

import org.distorted.screens.ScreenList;

import org.distorted.screens.RubikScreenPlay;

import org.distorted.screens.RubikScreenSolver;

import org.distorted.screens.RubikScreenSolving;

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

public class RubikSurfaceView extends GLSurfaceView

{

    private static final int NUM_SPEED_PROBES = 10;

    private static final int INVALID_POINTER_ID = -1;

    public static final int MODE_ROTATE  = 0;

    public static final int MODE_DRAG    = 1;

    public static final int MODE_REPLACE = 2;

    // Moving the finger from the middle of the vertical screen to the right edge will rotate a

    // given face by SWIPING_SENSITIVITY/2 degrees.

    private final static int SWIPING_SENSITIVITY  = 240;

    // Moving the finger by 0.3 of an inch will start a Rotation.

    private final static float ROTATION_SENSITIVITY = 0.3f;

    private final Static4D CAMERA_POINT = new Static4D(0, 0, 0, 0);

    private RubikRenderer mRenderer;

    private RubikPreRender mPreRender;

    private Movement mMovement;

    private boolean mDragging, mBeginningRotation, mContinuingRotation;

    private int mScreenWidth, mScreenHeight, mScreenMin;

    private float mRotAngle, mInitDistance;

    private float mStartRotX, mStartRotY;

    private float mAxisX, mAxisY;

    private float mRotationFactor;

    private int mLastCubitColor, mLastCubitFace, mLastCubit;

    private int mCurrentAxis, mCurrentRow;

    private float mCurrentAngle, mCurrRotSpeed;

    private float[] mLastX;

    private float[] mLastY;

    private long[] mLastT;

    private int mFirstIndex, mLastIndex;

    private int mDensity;

    private int mPointer1, mPointer2;

    private float mX1, mY1, mX2, mY2, mX, mY;

    private boolean mIsAutomatic;

    private static final Static4D mQuat= new Static4D(-0.25189602f,0.3546389f,0.009657208f,0.90038127f);

    private static final Static4D mTemp= new Static4D(0,0,0,1);

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

    void setScreenSize(int width, int height)

      {

      mScreenWidth = width;

      mScreenHeight= height;

      mScreenMin = Math.min(width, height);

      }

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

    boolean isVertical()

      {

      return mScreenHeight>mScreenWidth;

      }

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

    RubikRenderer getRenderer()

      {

      return mRenderer;

      }

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

    RubikPreRender getPreRender()

      {

      return mPreRender;

      }

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

    void setQuat()

      {

      mQuat.set(mTemp);

      }

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

    Static4D getQuat()

      {

      return mQuat;

      }

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

    void setMovement(Movement movement)

      {

      mMovement = movement;

      }

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

    private Static4D quatFromDrag(float dragX, float dragY)

      {

      float axisX = dragY;  // inverted X and Y - rotation axis is perpendicular to (dragX,dragY)

      float axisY = dragX;  // Why not (-dragY, dragX) ? because Y axis is also inverted!

      float axisZ = 0;

      float axisL = (float)Math.sqrt(axisX*axisX + axisY*axisY + axisZ*axisZ);

      if( axisL>0 )

        {

        axisX /= axisL;

        axisY /= axisL;

        axisZ /= axisL;

        float ratio = axisL;

        ratio = ratio - (int)ratio;     // the cos() is only valid in (0,Pi)

        float cosA = (float)Math.cos(Math.PI*ratio);

        float sinA = (float)Math.sqrt(1-cosA*cosA);

        return new Static4D(axisX*sinA, axisY*sinA, axisZ*sinA, cosA);

        }

      return new Static4D(0f, 0f, 0f, 1f);

      }

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

// cast the 3D axis we are currently rotating along (which is already casted to the surface of the

// currently touched face AND converted into a 4D vector - fourth 0) to a 2D in-screen-surface axis

    private void computeCurrentAxis(Static4D axis)

      {

      Static4D result = rotateVectorByQuat(axis, mQuat);

      mAxisX =result.get0();

      mAxisY =result.get1();

      float len = (float)Math.sqrt(mAxisX*mAxisX + mAxisY*mAxisY);

      mAxisX /= len;

      mAxisY /= len;

      }

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

// return quat1*quat2

    public static Static4D quatMultiply( Static4D quat1, Static4D quat2 )

      {

      float qx = quat1.get0();

      float qy = quat1.get1();

      float qz = quat1.get2();

      float qw = quat1.get3();

      float rx = quat2.get0();

      float ry = quat2.get1();

      float rz = quat2.get2();

      float rw = quat2.get3();

      float tx = rw*qx - rz*qy + ry*qz + rx*qw;

      float ty = rw*qy + rz*qx + ry*qw - rx*qz;

      float tz = rw*qz + rz*qw - ry*qx + rx*qy;

      float tw = rw*qw - rz*qz - ry*qy - rx*qx;

      return new Static4D(tx,ty,tz,tw);

      }

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

// rotate 'vector' by quat  ( i.e. return quat*vector*(quat^-1) )

    public static Static4D rotateVectorByQuat(Static4D vector, Static4D quat)

      {

      float qx = quat.get0();

      float qy = quat.get1();

      float qz = quat.get2();

      float qw = quat.get3();

      Static4D quatInverted= new Static4D(-qx,-qy,-qz,qw);

      Static4D tmp = quatMultiply(quat,vector);

      return quatMultiply(tmp,quatInverted);

      }

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

// rotate 'vector' by quat^(-1)  ( i.e. return (quat^-1)*vector*quat )

    public static Static4D rotateVectorByInvertedQuat(Static4D vector, Static4D quat)

      {

      float qx = quat.get0();

      float qy = quat.get1();

      float qz = quat.get2();

      float qw = quat.get3();

      Static4D quatInverted= new Static4D(-qx,-qy,-qz,qw);

      Static4D tmp = quatMultiply(quatInverted,vector);

      return quatMultiply(tmp,quat);

      }

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

    private void addSpeedProbe(float x, float y)

      {

      long currTime = System.currentTimeMillis();

      boolean theSame = mLastIndex==mFirstIndex;

      mLastIndex++;

      if( mLastIndex>=NUM_SPEED_PROBES ) mLastIndex=0;

      mLastT[mLastIndex] = currTime;

      mLastX[mLastIndex] = x;

      mLastY[mLastIndex] = y;

      if( mLastIndex==mFirstIndex)

        {

        mFirstIndex++;

        if( mFirstIndex>=NUM_SPEED_PROBES ) mFirstIndex=0;

        }

      if( theSame )

        {

        mLastT[mFirstIndex] = currTime;

        mLastX[mFirstIndex] = x;

        mLastY[mFirstIndex] = y;

        }

      }

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

    private void computeCurrentSpeedInInchesPerSecond()

      {

      long firstTime = mLastT[mFirstIndex];

      long lastTime  = mLastT[mLastIndex];

      float fX = mLastX[mFirstIndex];

      float fY = mLastY[mFirstIndex];

      float lX = mLastX[mLastIndex];

      float lY = mLastY[mLastIndex];

      long timeDiff = lastTime-firstTime;

      mLastIndex = 0;

      mFirstIndex= 0;

      mCurrRotSpeed = timeDiff>0 ? 1000*retFingerDragDistanceInInches(fX,fY,lX,lY)/timeDiff : 0;

      }

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

    private float retFingerDragDistanceInInches(float xFrom, float yFrom, float xTo, float yTo)

      {

      float xDist = mScreenWidth*(xFrom-xTo);

      float yDist = mScreenHeight*(yFrom-yTo);

      float distInPixels = (float)Math.sqrt(xDist*xDist + yDist*yDist);

      return distInPixels/mDensity;

      }

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

    private void setUpDragOrRotate(boolean down, float x, float y)

      {

      int mode = ScreenList.getMode();

      if( mode==MODE_DRAG )

        {

        mDragging           = true;

        mBeginningRotation  = false;

        mContinuingRotation = false;

        }

      else

        {

        TwistyObject object = mPreRender.getObject();

        CAMERA_POINT.set2( object==null ? 1.21f : object.getCameraDist() );

        Static4D touchPoint = new Static4D(x, y, 0, 0);

        Static4D rotatedTouchPoint= rotateVectorByInvertedQuat(touchPoint, mQuat);

        Static4D rotatedCamera= rotateVectorByInvertedQuat(CAMERA_POINT, mQuat);

        if( mMovement!=null && mMovement.faceTouched(rotatedTouchPoint,rotatedCamera) )

          {

          mDragging           = false;

          mContinuingRotation = false;

          if( mode==MODE_ROTATE )

            {

            mBeginningRotation= !mPreRender.isTouchBlocked();

            }

          else if( mode==MODE_REPLACE )

            {

            mBeginningRotation= false;

            if( down )

              {

              RubikScreenSolver solver = (RubikScreenSolver) ScreenList.SVER.getScreenClass();

              mLastCubitFace = mMovement.getTouchedFace();

              float[] point = mMovement.getTouchedPoint3D();

              int color = solver.getCurrentColor();

              mLastCubit = object.getCubit(point);

              mPreRender.setTextureMap( mLastCubit, mLastCubitFace, color );

              mLastCubitColor = SolverMain.cubitIsLocked(object.getObjectList(), object.getNumLayers(), mLastCubit);

              }

            }

          }

        else

          {

          final RubikActivity act = (RubikActivity)getContext();

          final boolean locked= act.isLocked();

          mDragging           = (!locked || mIsAutomatic);

          mBeginningRotation  = false;

          mContinuingRotation = false;

          if( !mDragging ) reddenLockIcon(act);

          }

        }

      }

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

    private void reddenLockIcon(RubikActivity act)

      {

      ScreenList curr = ScreenList.getCurrentScreen();

      if( curr==ScreenList.PLAY )

        {

        RubikScreenPlay play = (RubikScreenPlay) ScreenList.PLAY.getScreenClass();

        play.reddenLock(act);

        }

      else if( curr==ScreenList.READ )

        {

        RubikScreenReady read = (RubikScreenReady) ScreenList.READ.getScreenClass();

        read.reddenLock(act);

        }

      else if( curr==ScreenList.SOLV )

        {

        RubikScreenSolving solv = (RubikScreenSolving) ScreenList.SOLV.getScreenClass();

        solv.reddenLock(act);

        }

      }

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

    private void drag(float x, float y)

      {

      if( mPointer1!=INVALID_POINTER_ID && mPointer2!=INVALID_POINTER_ID)

        {

        float x2 = (mX2 - mScreenWidth*0.5f)/mScreenMin;

        float y2 = (mScreenHeight*0.5f - mY2)/mScreenMin;

        float angleNow = getAngle(x,y,x2,y2);

        float angleDiff = angleNow-mRotAngle;

        float sinA =-(float)Math.sin(angleDiff);

        float cosA = (float)Math.cos(angleDiff);

        Static4D dragQuat = quatMultiply(new Static4D(0,0,sinA,cosA), mQuat);

        mTemp.set(dragQuat);

        mRotAngle = angleNow;

        float distNow  = (float)Math.sqrt( (x-x2)*(x-x2) + (y-y2)*(y-y2) );

        float distQuot = mInitDistance<0 ? 1.0f : distNow/ mInitDistance;

        mInitDistance = distNow;

        TwistyObject object = mPreRender.getObject();

        if( object!=null ) object.setObjectRatio(distQuot);

        }

      else

        {

        Static4D dragQuat = quatMultiply(quatFromDrag(mX-x,y-mY), mQuat);

        mTemp.set(dragQuat);

        }

      mPreRender.setQuatOnNextRender();

      mX = x;

      mY = y;

      }

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

    private void finishRotation()

      {

      computeCurrentSpeedInInchesPerSecond();

      int angle = mPreRender.getObject().computeNearestAngle(mCurrentAxis,mCurrentAngle, mCurrRotSpeed);

      mPreRender.finishRotation(angle);

      mPreRender.rememberMove(mCurrentAxis,mCurrentRow,angle);

      if( angle!=0 )

        {

        if( ScreenList.getCurrentScreen()== ScreenList.SOLV )

          {

          RubikActivity act = (RubikActivity)getContext();

          RubikScreenSolving solving = (RubikScreenSolving) ScreenList.SOLV.getScreenClass();

          solving.addMove(act, mCurrentAxis, mCurrentRow, angle);

          }

        if( ScreenList.getCurrentScreen()== ScreenList.PLAY )

          {

          RubikActivity act = (RubikActivity)getContext();

          RubikScreenPlay play = (RubikScreenPlay) ScreenList.PLAY.getScreenClass();

          play.addMove(act, mCurrentAxis, mCurrentRow, angle);

          }

        }

      mContinuingRotation = false;

      mBeginningRotation  = false;

      mDragging           = true;

      }

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

    private void continueRotation(float x, float y)

      {

      float dx = x-mStartRotX;

      float dy = y-mStartRotY;

      float alpha = dx*mAxisX + dy*mAxisY;

      float x2 = dx - alpha*mAxisX;

      float y2 = dy - alpha*mAxisY;

      float len = (float)Math.sqrt(x2*x2 + y2*y2);

      // we have the length of 1D vector 'angle', now the direction:

      float tmp = mAxisY==0 ? -mAxisX*y2 : mAxisY*x2;

      float angle = (tmp>0 ? 1:-1)*len*mRotationFactor;

      mCurrentAngle = SWIPING_SENSITIVITY*angle;

      mPreRender.getObject().continueRotation(mCurrentAngle);

      addSpeedProbe(x2,y2);

      }

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

    private void beginRotation(float x, float y)

      {

      mStartRotX = x;

      mStartRotY = y;

      TwistyObject object = mPreRender.getObject();

      int numLayers = object.getNumLayers();

      Static4D touchPoint2 = new Static4D(x, y, 0, 0);

      Static4D rotatedTouchPoint2= rotateVectorByInvertedQuat(touchPoint2, mQuat);

      Static2D res = mMovement.newRotation(numLayers,rotatedTouchPoint2);

      mCurrentAxis = (int)res.get0();

      mCurrentRow  = (int)res.get1();

      computeCurrentAxis( mMovement.getCastedRotAxis(mCurrentAxis) );

      mRotationFactor = mMovement.returnRotationFactor(numLayers,mCurrentRow);

      object.beginNewRotation( mCurrentAxis, mCurrentRow );

      if( ScreenList.getCurrentScreen()== ScreenList.READ )

        {

        RubikScreenSolving solving = (RubikScreenSolving) ScreenList.SOLV.getScreenClass();

        solving.resetElapsed();

        final RubikActivity act = (RubikActivity)getContext();

        act.runOnUiThread(new Runnable()

          {

          @Override

          public void run()

            {

            ScreenList.switchScreen( act, ScreenList.SOLV);

            }

          });

        }

      addSpeedProbe(x,y);

      mBeginningRotation = false;

      mContinuingRotation= true;

      }

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

    private float getAngle(float x1, float y1, float x2, float y2)

      {

      return (float) Math.atan2(y1-y2, x1-x2);

      }

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

    void initialize()

      {

      mPointer1 = INVALID_POINTER_ID;

      mPointer2 = INVALID_POINTER_ID;

      }

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

    private void prepareDown(MotionEvent event)

      {

      mPointer1 = event.getPointerId(0);

      mX1 = event.getX();

      mY1 = event.getY();

      mPointer2 = INVALID_POINTER_ID;

      }

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

    private void prepareMove(MotionEvent event)

      {

      int index1 = event.findPointerIndex(mPointer1);

      if( index1>=0 )

        {

        mX1 = event.getX(index1);

        mY1 = event.getY(index1);

        }

      int index2 = event.findPointerIndex(mPointer2);

      if( index2>=0 )

        {

        mX2 = event.getX(index2);

        mY2 = event.getY(index2);

        }

      }

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

    private void prepareUp(MotionEvent event)

      {

      mPointer1 = INVALID_POINTER_ID;

      mPointer2 = INVALID_POINTER_ID;

      }

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

    private void prepareDown2(MotionEvent event)

      {

      int index = event.getActionIndex();

      if( mPointer1==INVALID_POINTER_ID )

        {

        mPointer1 = event.getPointerId(index);

        mX1 = event.getX(index);

        mY1 = event.getY(index);

        }

      else if( mPointer2==INVALID_POINTER_ID )

        {

        mPointer2 = event.getPointerId(index);

        mX2 = event.getX(index);

        mY2 = event.getY(index);

        }

      }

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

    private void prepareUp2(MotionEvent event)

      {

      int index = event.getActionIndex();

           if( index==event.findPointerIndex(mPointer1) ) mPointer1 = INVALID_POINTER_ID;

      else if( index==event.findPointerIndex(mPointer2) ) mPointer2 = INVALID_POINTER_ID;

      }

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

// PUBLIC API

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

    public RubikSurfaceView(Context context, AttributeSet attrs)

      {

      super(context,attrs);

      if(!isInEditMode())

        {

        mIsAutomatic = false;

        mLastCubitColor = -1;

        mCurrRotSpeed   = 0.0f;

        mLastX = new float[NUM_SPEED_PROBES];

        mLastY = new float[NUM_SPEED_PROBES];

        mLastT = new long[NUM_SPEED_PROBES];

        mFirstIndex =0;

        mLastIndex  =0;

        mRenderer  = new RubikRenderer(this);

        mPreRender = new RubikPreRender(this);

        RubikActivity act = (RubikActivity)context;

        DisplayMetrics dm = new DisplayMetrics();

        act.getWindowManager().getDefaultDisplay().getMetrics(dm);

        mDensity = dm.densityDpi;

        final ActivityManager activityManager= (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

        try

          {

          final ConfigurationInfo configurationInfo = activityManager.getDeviceConfigurationInfo();

          int esVersion = configurationInfo.reqGlEsVersion>>16;

          setEGLContextClientVersion(esVersion);

          setRenderer(mRenderer);

          }

        catch(Exception ex)

          {

          act.OpenGLError();

          String shading = GLES30.glGetString(GLES30.GL_SHADING_LANGUAGE_VERSION);

          String version = GLES30.glGetString(GLES30.GL_VERSION);

          String vendor  = GLES30.glGetString(GLES30.GL_VENDOR);

          String renderer= GLES30.glGetString(GLES30.GL_RENDERER);

          FirebaseCrashlytics crashlytics = FirebaseCrashlytics.getInstance();

          crashlytics.setCustomKey("GLSL Version"  , shading );

          crashlytics.setCustomKey("GL version"    , version );

          crashlytics.setCustomKey("GL Vendor "    , vendor  );

          crashlytics.setCustomKey("GLSL renderer" , renderer);

          crashlytics.recordException(ex);

          }

        }

      }

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

    public void prepareDown()

      {

      mIsAutomatic = true;

      mPointer1 = 0;

      mPointer2 = INVALID_POINTER_ID;

      }

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

    public void prepareDown2()

      {

      mPointer2 = 0;

      }

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

    public void prepareMove(float x1, float y1, float x2, float y2)

      {

      mX1 = x1;

      mY1 = y1;

      mX2 = x2;

      mY2 = y2;

      }

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

    public void prepareUp()

      {

      mIsAutomatic = false;

      mPointer1 = INVALID_POINTER_ID;

      mPointer2 = INVALID_POINTER_ID;

      }

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

    public void actionMove(float x1, float y1, float x2, float y2)

      {

      float pX = mPointer1 != INVALID_POINTER_ID ? x1 : x2;

      float pY = mPointer1 != INVALID_POINTER_ID ? y1 : y2;

      float x = (pX - mScreenWidth*0.5f)/mScreenMin;

      float y = (mScreenHeight*0.5f -pY)/mScreenMin;

      if( mBeginningRotation )

        {

        if( retFingerDragDistanceInInches(mX,mY,x,y) > ROTATION_SENSITIVITY )

          {

          beginRotation(x,y);

          }

        }

      else if( mContinuingRotation )

        {

        continueRotation(x,y);

        }

      else if( mDragging )

        {

        drag(x,y);

        }

      else

        {

        setUpDragOrRotate(false,x,y);

        }

      }

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

    public void actionDown(float x, float y)

      {

      mX = (x -  mScreenWidth*0.5f)/mScreenMin;

      mY = (mScreenHeight*0.5f - y)/mScreenMin;

      setUpDragOrRotate(true,mX,mY);

      }

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

    public void actionUp()

      {

      if( mContinuingRotation )

        {

        finishRotation();

        }

      if( mLastCubitColor>=0 )

        {

        mPreRender.setTextureMap( mLastCubit, mLastCubitFace, mLastCubitColor );

        mLastCubitColor = -1;

        }

      }

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

    public void actionDown2(float x1, float y1, float x2, float y2)

      {

      mRotAngle = getAngle(x1,-y1, x2,-y2);

      mInitDistance = -1;

      mX = (x1 - mScreenWidth*0.5f )/mScreenMin;

      mY = (mScreenHeight*0.5f - y1)/mScreenMin;

      if( mBeginningRotation )

        {

        mContinuingRotation = false;

        mBeginningRotation  = false;

        mDragging           = true;

        }

      else if( mContinuingRotation )

        {

        finishRotation();

        }

      }

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

    public void actionUp2(boolean p1isUp, float x1, float y1, boolean p2isUp, float x2, float y2)

      {

      if( p1isUp )

        {

        mX = (x2 -  mScreenWidth*0.5f)/mScreenMin;

        mY = (mScreenHeight*0.5f - y2)/mScreenMin;

        }

      if( p2isUp )

        {

        mX = (x1 -  mScreenWidth*0.5f)/mScreenMin;

        mY = (mScreenHeight*0.5f - y1)/mScreenMin;

        }

      }

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

    @Override

    public boolean onTouchEvent(MotionEvent event)

      {

      int action = event.getActionMasked();

      switch(action)

         {

         case MotionEvent.ACTION_DOWN        : prepareDown(event);

                                               actionDown(mX1, mY1);

                                               break;

         case MotionEvent.ACTION_MOVE        : prepareMove(event);

                                               actionMove(mX1, mY1, mX2, mY2);

                                               break;

         case MotionEvent.ACTION_UP          : prepareUp(event);

                                               actionUp();

                                               break;

         case MotionEvent.ACTION_POINTER_DOWN: prepareDown2(event);

                                               actionDown2(mX1, mY1, mX2, mY2);

                                               break;

         case MotionEvent.ACTION_POINTER_UP  : prepareUp2(event);

                                               boolean p1isUp = mPointer1==INVALID_POINTER_ID;

                                               boolean p2isUp = mPointer2==INVALID_POINTER_ID;

                                               actionUp2(p1isUp, mX1, mY1, p2isUp, mX2, mY2);

                                               break;

         }

      return true;

      }

}