TwistyPuzzleLib

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// 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        //

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  {

  // it doesn't matter where we touch a face - the list of enabled rotAxis will always be the same

  public static final int TYPE_NOT_SPLIT    = 0;

  // each face is split into several parts by lines coming from its center to the midpoints of each edge

  public static final int TYPE_SPLIT_EDGE   = 1;

  // each face is split into several parts by lines coming from its center to the vertices

  public static final int TYPE_SPLIT_CORNER = 2;

  public static final int TC_TETRAHEDRON       =   4;

  public static final int TC_OCTAHEDRON        =   8;

  public static final int TC_DODECAHEDRON      =  12;

  public static final int TC_CHANGING_SQUARE   = 101;

  public static final int TC_CHANGING_SHAPEMOD = 102;

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  public void setObjectRatio(float ratio)

    {

    mObjectRatio = ratio;

    }

// Convert the 3D point3D into a 2D point on the same face surface, but in a different

// coordinate system: a in-plane 2D coord where the origin is in the point where the axis intersects

// the surface, and whose Y axis points 'north' i.e. is in the plane given by the 3D origin, the

// original 3D Y axis and our 2D in-plane origin.

// If those 3 points constitute a degenerate triangle which does not define a plane - which can only

// happen if axis is vertical (or in theory when 2D origin and 3D origin meet, but that would have to

// mean that the distance between the center of the Object and its faces is 0) - then we arbitrarily

// decide that 2D Y = (0,0,-1) in the North Pole and (0,0,1) in the South Pole)

// (ax,ay,az) - vector normal to the face surface.

  void convertTo2Dcoords(float[] point3D, float ax, float ay, float az , float[] output)

    {

    float y0,y1,y2; // base Y vector of the 2D coord system

    if( ax==0.0f && az==0.0f )

      {

      y0=0; y1=0; y2=-ay;

      }

    else if( ay==0.0f )

      {

      y0=0; y1=1; y2=0;

      }

    else

      {

      float norm = (float)(-ay/Math.sqrt(1-ay*ay));

      y0 = norm*ax; y1= norm*(ay-1/ay); y2=norm*az;

      }

    float x0 = y1*az - y2*ay;  //

    float x1 = y2*ax - y0*az;  // (2D coord baseY) x (axis) = 2D coord baseX

    float x2 = y0*ay - y1*ax;  //

    float originAlpha = point3D[0]*ax + point3D[1]*ay + point3D[2]*az;

    float origin0 = originAlpha*ax; // coords of the point where axis

    float origin1 = originAlpha*ay; // intersects surface plane i.e.

    float origin2 = originAlpha*az; // the origin of our 2D coord system

    float v0 = point3D[0] - origin0;

    float v1 = point3D[1] - origin1;

    float v2 = point3D[2] - origin2;

    output[0] = v0*x0 + v1*x1 + v2*x2;

    output[1] = v0*y0 + v1*y1 + v2*y2;

    }

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// find the casted axis with which our move2D vector forms an angle closest to 90 deg.

  int computeRotationIndex(float[][] rotAxis, float[] move2D, int[] enabled)

    {

    float cosAngle, minCosAngle = Float.MAX_VALUE;

    int minIndex=0, index;

    float m0 = move2D[0];

    float m1 = move2D[1];

    int numAxis = enabled[0];

    for(int axis=1; axis<=numAxis; axis++)

      {

      index = enabled[axis];

      cosAngle = m0*rotAxis[index][0] + m1*rotAxis[index][1];

      if( cosAngle<0 ) cosAngle = -cosAngle;

      if( cosAngle<minCosAngle )

        {

        minCosAngle=cosAngle;

        minIndex = index;

        }

      }

    return minIndex;

    }

  public abstract boolean objectTouched(Static4D rotatedTouchPoint, Static4D rotatedCamera);

  public abstract int getTouchedCubit();

  }