TwistyPuzzleLib

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

// Copyright 2020 Leszek Koltunski                                                               //

//                                                                                               //

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

//                                                                                               //

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

import org.distorted.library.type.Static4D;

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

  static final float SQ3 = (float)Math.sqrt(3);

  static final float SQ6 = (float)Math.sqrt(6);

  private final int mNumFaceAxis;

  private final float[] mPoint, mCamera, mTouch;

  private final float[] mPoint2D, mMove2D;

  private final int[] mEnabledRotAxis;

  private int mLastTouchedFace;

  private float[][][] mCastedRotAxis;

  private Static4D[][] mCastedRotAxis4D;

  private float[][] mTouchBorders, mA, mB;

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

  abstract int returnPart(int type, int face, float[] touchPoint);

  abstract boolean isInsideFace(int face, float[] point);

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

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

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

    float size            = object.getSize();

    mCamera= new float[3];

    mTouch = new float[3];

    mPoint2D = new float[2];

    mMove2D  = new float[2];

    mNumFaceAxis= mFaceAxis.length;

    mDistanceCenterFace3D = distance3D; // distance from the center of the object to each of its faces

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

// mCastedRotAxis[1][2]{0,1} are the 2D coords of the 2nd rotAxis cast onto the face defined by the

// 1st faceAxis.

  private void computeCastedAxis(Static3D[] rotAxis)

    {

    mCastedRotAxis   = new float[mNumFaceAxis][rotAxis.length][2];

    mCastedRotAxis4D = new Static4D[mNumFaceAxis][rotAxis.length];

    for( int casted=0; casted<rotAxis.length; casted++)

      {

      Static3D a = rotAxis[casted];

      mPoint[0]= a.get0();

      mPoint[1]= a.get1();

      mPoint[2]= a.get2();

      for( int face=0; face<mNumFaceAxis; face++)

        {

        float ay = mFaceAxis[face].get1();

        float az = mFaceAxis[face].get2();

        convertTo2Dcoords( mPoint, ax,ay,az, mCastedRotAxis[face][casted]);

        mCastedRotAxis4D[face][casted] = new Static4D( mPoint[0]-f*ax, mPoint[1]-f*ay, mPoint[2]-f*az, 0);

      }

    }

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

  private void normalize2D(float[] vect)

    {

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

    if( len!=0.0f )

      {

      vect[0] /= len;

      vect[1] /= len;

      }

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

// in the center of the face offset is always 0 regardless of the axis

  private float computeOffset(float[] point, float[] axis)

    {

    return point[0]*axis[0] + point[1]*axis[1];

    }

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

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

// given precomputed mCamera and mPoint, respectively camera and touch point positions in ScreenSpace,

// compute point 'output[]' which:

// 1) lies on a face of the Object, i.e. surface defined by (axis, distance from (0,0,0))

// 2) is co-linear with mCamera and mPoint

//

// output = camera + alpha*(point-camera), where alpha = [dist-axis*camera] / [axis*(point-camera)]

    float d1 = mPoint[1]-mCamera[1];

    float d2 = mPoint[2]-mCamera[2];

    float a0 = faceAxis.get0();

    float a1 = faceAxis.get1();

    float a2 = faceAxis.get2();

    float denom = a0*d0 + a1*d1 + a2*d2;

    if( denom != 0.0f )

      {

      float axisCam = a0*mCamera[0] + a1*mCamera[1] + a2*mCamera[2];

      output[0] = mCamera[0] + d0*alpha;

      output[1] = mCamera[1] + d1*alpha;

      output[2] = mCamera[2] + d2*alpha;

      }

    }

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

    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;

    }

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

    int numCuts = cuts.length;

    mTouchBorders = new float[numCuts][];

    }

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

  private int computeSign(Static3D a, Static3D b)

    {

    float a1 = a.get0();

    float a2 = a.get1();

    float a3 = a.get2();

    float b1 = b.get0();

    float b2 = b.get1();

    float b3 = b.get2();

    return a1*b1+a2*b2+a3*b3 < 0 ? 1:-1;

    }

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

  private float crossProductLen(Static3D a, Static3D b)

    {

    float a1 = a.get0();

    float a2 = a.get1();

    float a3 = a.get2();

    float b1 = b.get0();

    float b2 = b.get1();

    float b3 = b.get2();

    float x1 = a2*b3-a3*b2;

    float x2 = a3*b1-a1*b3;

    float x3 = a1*b2-a2*b1;

    return (float)Math.sqrt(x1*x1 + x2*x2 + x3*x3);

    }

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

// compute the array of 'A' and 'B' coeffs of the Ax+B linear function by which we need to multiply

// the 3D 'cuts' to translate it from 3D (i.e. with respect to the rotAxis) to 2D in-face (i.e. with

// respect to the 2D rotAxis cast into a particular face)

    int numFaces = faceAxis.length;

    int numRot   = rotAxis.length;

    mA = new float[numFaces][numRot];

    mB = new float[numFaces][numRot];

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

      for(int j=0; j<numRot; j++)

        {

        mA[i][j] = crossProductLen(faceAxis[i],rotAxis[j]);

        if( mA[i][j]!=0.0f )

          {

          float coeff = (float)Math.sqrt(1/(mA[i][j]*mA[i][j]) -1);

          int sign = computeSign(faceAxis[i],rotAxis[j]);

        else mB[i][j] = 0.0f;

        }

    }

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

  private int computeRowFromOffset(int face, int axisIndex, float offset)

    {

    float[] borders = mTouchBorders[axisIndex];

    if( borders==null ) return 0;

    float A = mA[face][axisIndex];

    if( A!=0.0f )

      {

      float B = mB[face][axisIndex];

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

        {

        float translated = B + borders[i]/A;

        if( offset<translated ) return i;

        }

      }

      {

      // touched face. So the offset passed here as param is incorrect (and equal to 0).

      // recompute it and return the row (no need to translate!)

      Static3D ax = mRotAxis[axisIndex];

      offset = mTouch[0]*ax.get0() + mTouch[1]*ax.get1() + mTouch[2]*ax.get2();

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

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

    return len;

    }

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

  void computeEnabledAxis(int face, float[] touchPoint, int[] enabled)

    {

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

    enabled[0] = num;

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

    }

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

// PUBLIC API

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

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

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

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

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

    for( mLastTouchedFace=0; mLastTouchedFace<mNumFaceAxis; mLastTouchedFace++)

      {

        float ax = mFaceAxis[mLastTouchedFace].get0();

        float ay = mFaceAxis[mLastTouchedFace].get1();

        float az = mFaceAxis[mLastTouchedFace].get2();

        convertTo2Dcoords(mTouch, ax,ay,az, mPoint2D);

        }

      }

    return false;

    }

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

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

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

    float ax = mFaceAxis[mLastTouchedFace].get0();

    float ay = mFaceAxis[mLastTouchedFace].get1();

    float az = mFaceAxis[mLastTouchedFace].get2();

    convertTo2Dcoords(mTouch, ax,ay,az, mMove2D);

    mMove2D[0] -= mPoint2D[0];

    mMove2D[1] -= mPoint2D[1];

    computeEnabledAxis(mLastTouchedFace, mPoint2D, mEnabledRotAxis);

    int row      = computeRowFromOffset(mLastTouchedFace,rotIndex,offset);

    output[1] = row;

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

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

    output[0] =result.get0();

    output[1] =result.get1();

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

    if( len!=0 )

      {

      output[0] /= len;

      output[1] /= len;

      }

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

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

  }