TwistyPuzzleLib

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

// Copyright 2022 Leszek Koltunski                                                               //

//                                                                                               //

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

//                                                                                               //

// Magic Cube is proprietary software licensed under an EULA which you should have received      //

// along with the code. If not, check https://distorted.org/magic/License-Magic-Cube.html        //

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

package org.distorted.objectlib.touchcontrol;

import org.distorted.library.helpers.QuatHelper;

import org.distorted.library.type.Static3D;

import org.distorted.library.type.Static4D;

import org.distorted.objectlib.main.TwistyObject;

import static org.distorted.objectlib.main.TwistyObject.SQ2;

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

// Ball-shaped objects: map the 2D swipes of user's fingers to 3D rotations

public class TouchControlBall extends TouchControl

{

  private static final float MIN_LEN = 0.35f;

  private static final float[] mTmp = new float[4];

  private final Static3D[] mRotAxis;

  private final float[] mPoint, mCamera, mTouch;

  private final int[] mEnabledRotAxis;

  private final int[][][] mEnabled;

  private final float[] mMove2D;

  private final float[][] mCastedRotAxis;

  private float[][] mTouchBorders;

  private float mLongitude, mLatitude;

  private float mX, mY, mZ;

  private static final float X = (float)Math.sqrt( (2-SQ2)/(6+SQ2) );

  private static final float Y = (float)Math.sqrt( (2+SQ2)/(6+SQ2) );

  public static final Static3D[] FACE_AXIS = new Static3D[]

        {

          new Static3D( X, Y, Y),

          new Static3D( X,-Y, Y),

          new Static3D( Y, Y, X),

          new Static3D( Y,-Y, X),

          new Static3D( Y, Y,-X),

          new Static3D( Y,-Y,-X),

          new Static3D( X, Y,-Y),

          new Static3D( X,-Y,-Y),

          new Static3D(-X, Y,-Y),

          new Static3D(-X,-Y,-Y),

          new Static3D(-Y, Y,-X),

          new Static3D(-Y,-Y,-X),

          new Static3D(-Y, Y, X),

          new Static3D(-Y,-Y, X),

          new Static3D(-X, Y, Y),

          new Static3D(-X,-Y, Y),

        };

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

  public TouchControlBall(TwistyObject object)

    {

    super(object.getObjectRatio());

    int[] numLayers       = object.getNumLayers();

    float[][] cuts        = object.getCuts(numLayers);

    boolean[][] rotatable = object.getLayerRotatable(numLayers);

    float size            = object.getSize();

    mRotAxis = object.getRotationAxis();

    mEnabled = object.getEnabled();

    mMove2D  = new float[2];

    mPoint = new float[3];

    mCamera= new float[3];

    mTouch = new float[3];

    int numRotAxis = mRotAxis.length;

    mEnabledRotAxis = new int[numRotAxis+1];

    mCastedRotAxis = new float[numRotAxis][2];

    computeBorders(cuts,rotatable,size);

    }

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

  private float[] computeBorder(float[] cuts, boolean[] rotatable, float size)

    {

    if( cuts==null ) return null;

    int len = cuts.length;

    float[] border = new float[len];

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

      {

      if( !rotatable[i] )

        {

        border[i] = i>0 ? border[i-1] : -Float.MAX_VALUE;

        }

      else

        {

        if( rotatable[i+1] ) border[i] = cuts[i]/size;

        else

          {

          int found = -1;

          for(int j=i+2; j<=len; j++)

            {

            if( rotatable[j] )

              {

              found=j;

              break;

              }

            }

          border[i] = found>0 ? (cuts[i]+cuts[found-1])/(2*size) : Float.MAX_VALUE;

          }

        }

      }

    return border;

    }

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

// size, not numLayers (see Master Skewb where size!=numLayers) - also cuboids.

  void computeBorders(float[][] cuts, boolean[][] rotatable, float size)

    {

    int numCuts = cuts.length;

    mTouchBorders = new float[numCuts][];

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

      {

      mTouchBorders[axis] = computeBorder(cuts[axis],rotatable[axis],size);

      }

    }

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

  private int computeRowFromOffset(int axisIndex, float offset)

    {

    float[] borders = mTouchBorders[axisIndex];

    if( borders==null ) return 0;

    int len = borders.length;

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

      {

      if( offset<borders[i] ) return i;

      }

    return len;

    }

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

// Longitude spans from 0 (at Guinea Bay) increasing to the east all the way to 2PI

// Latitude - from -PI/2 (South Pole) to +PI/2 (North Pole)

  private void computeLongitudeAndLatitude(float A, float B, float C)

    {

    float sqrt = (float)Math.sqrt(B*B - 4*A*C);

    float alpha= (-B+sqrt)/(2*A); // this is the closer point

    float cx = mCamera[0];

    float cy = mCamera[1];

    float cz = mCamera[2];

    float vx = mCamera[0]-mPoint[0];

    float vy = mCamera[1]-mPoint[1];

    float vz = mCamera[2]-mPoint[2];

    mX = cx + alpha*vx;

    mY = cy + alpha*vy;

    mZ = cz + alpha*vz;

    mLongitude = mZ==0 ? 0 : (float)Math.atan(mX/mZ);

    mLatitude  = (float)Math.asin(2*mY);

    if( mZ<0 ) mLongitude += Math.PI;

    else if( mX<0 ) mLongitude += 2*Math.PI;

    }

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

// this is Masterball-specific. See TwistyMasterball.getEnabled()

  private int returnTouchedFace()

    {

    float t = (float)(mLongitude + Math.PI/8);

    if( t>2*Math.PI ) t-=(2*Math.PI);

    int ret = (int)(t/(Math.PI/4));

    return ret<8 ? ret : 7;

    }

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

// this is Masterball-specific. No parts in any faces.

  private int returnTouchedPart()

    {

    return 0;

    }

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

  private float computeOffset(int rotIndex)

    {

    Static3D axis = mRotAxis[rotIndex];

    return mX*axis.get0() + mY*axis.get1() + mZ*axis.get2();

    }

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

  private void computeEnabledAxis()

    {

    int face = returnTouchedFace();

    int part = returnTouchedPart();

    int num = mEnabled[face][0].length;

    mEnabledRotAxis[0] = num;

    System.arraycopy(mEnabled[face][part], 0, mEnabledRotAxis, 1, num);

    }

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

  public float returnRotationFactor(int[] numLayers, int row)

    {

    return 1.0f;

    }

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

  public int getTouchedCubitFace()

    {

    return 0;

    }

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

  public float[] getTouchedPuzzleCenter()

    {

    return null;

    }

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

  public int getTouchedCubit()

    {

    return 0;

    }

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

  public boolean objectTouched(Static4D rotatedTouchPoint, Static4D rotatedCamera)

    {

    mPoint[0]  = rotatedTouchPoint.get0()/mObjectRatio;

    mPoint[1]  = rotatedTouchPoint.get1()/mObjectRatio;

    mPoint[2]  = rotatedTouchPoint.get2()/mObjectRatio;

    mCamera[0] = rotatedCamera.get0()/mObjectRatio;

    mCamera[1] = rotatedCamera.get1()/mObjectRatio;

    mCamera[2] = rotatedCamera.get2()/mObjectRatio;

    float vx = mCamera[0]-mPoint[0];

    float vy = mCamera[1]-mPoint[1];

    float vz = mCamera[2]-mPoint[2];

    float R = 0.5f;

    float A = vx*vx + vy*vy + vz*vz;

    float B = 2*(vx*mCamera[0] + vy*mCamera[1] + vz*mCamera[2]);

    float C = (mCamera[0]*mCamera[0] + mCamera[1]*mCamera[1] + mCamera[2]*mCamera[2]) - R*R;

    if( B*B >= 4*A*C )

      {

      computeLongitudeAndLatitude(A,B,C);

      return true;

      }

    return false;

    }

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

  public void newRotation(int[] output, Static4D rotatedTouchPoint, Static4D quat)

    {

    computeEnabledAxis();

    mTouch[0]  = rotatedTouchPoint.get0()/mObjectRatio;

    mTouch[1]  = rotatedTouchPoint.get1()/mObjectRatio;

    mTouch[2]  = rotatedTouchPoint.get2()/mObjectRatio;

    float x = mTouch[0]-mPoint[0];

    float y = mTouch[1]-mPoint[1];

    float z = mTouch[2]-mPoint[2];

    QuatHelper.rotateVectorByQuat(mTmp,x,y,z,0,quat);

    mMove2D[0] = mTmp[0];

    mMove2D[1] = mTmp[1];

    for(int i=1; i<=mEnabledRotAxis[0]; i++)

      {

      int enabled = mEnabledRotAxis[i];

      Static3D axis = mRotAxis[enabled];

      float[] vector = mCastedRotAxis[enabled];

      float bx = axis.get0();

      float by = axis.get1();

      float bz = axis.get2();

      QuatHelper.rotateVectorByQuat(mTmp,bx,by,bz,0,quat);

      float len = (float)Math.sqrt(mTmp[0]*mTmp[0] + mTmp[1]*mTmp[1]);

      if( len<MIN_LEN )

        {

        vector[0] = 1000f;  // switch off the axis because when casted

        vector[1] = 1000f;  // onto the screen it is too short

        }

      else

        {

        vector[0] = mTmp[0]/len;

        vector[1] = mTmp[1]/len;

        }

      }

    int rotIndex = computeRotationIndex( mCastedRotAxis, mMove2D, mEnabledRotAxis);

    float offset = computeOffset(rotIndex);

    int row      = computeRowFromOffset(rotIndex,offset);

    output[0] = rotIndex;

    output[1] = row;

    }

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

// simply cast the appropriate rotational axis of the object to the screen surface.

  public void getCastedRotAxis(float[] output, Static4D quat, int axisIndex)

    {

    Static3D a = mRotAxis[axisIndex];

    Static4D result = QuatHelper.rotateVectorByQuat(a.get0(),a.get1(),a.get2(),0,quat);

    float cx = result.get0();

    float cy = result.get1();

    float len= (float)Math.sqrt(cx*cx+cy*cy);

    if( len!=0 )

      {

      output[0] = cx/len;

      output[1] = cy/len;

      }

    else

      {

      output[0] = 1;

      output[1] = 0;

      }

    }

}