Magic Cube

  private float[] mPoint, mCamera, mDiff, m2Dpoint;

    m2Dpoint = new float[2];

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

// 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)

  private void convertTo2Dcoords(float[] point3D, Static3D axis, int lr, float[] output)

    {

    float y0,y1,y2, x0,x1,x2;  // base X and Y vectors of the 2D coord system

    float a0 = axis.get0();

    float a1 = axis.get1();

    float a2 = axis.get2();

    if( lr==0 )

      {

      a0=-a0; a1=-a1; a2=-a2;

      }

    if( a0==0.0f && a2==0.0f )

      {

      y0=0; y1=0; y2=-a1;

      }

    else if( a1==0.0f )

      {

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

      }

    else

      {

      float norm = (float)(-a1/Math.sqrt(1-a1*a1));

      y0 = norm*a0; y1= norm*(a1-1/a1); y2=a2;

      }

    x0 = y1*a2 - y2*a1;  //

    x1 = y2*a0 - y0*a2;  // (2D coord baseY) x (axis) = 2D coord baseX

    x2 = y0*a1 - y1*a0;  //

    float originAlpha = point3D[0]*a0 + point3D[1]*a1 + point3D[2]*a2;

    float origin0 = originAlpha*a0; // coords of the point where axis

    float origin1 = originAlpha*a1; // intersects surface plane i.e.

    float origin2 = originAlpha*a2; // 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;

    }

          convertTo2Dcoords(mTouch, mAxis[mLastTouchedAxis], mLastTouchedLR, m2Dpoint);

          if( isInsideFace(m2Dpoint) )

 // android.util.Log.e("move", "touched "+mLastTouchedAxis+" touch point: ("+m2Dpoint[0]+","+m2Dpoint[1]+")");

    mDiff[0] = rotatedTouchPoint.get0()/RubikObject.OBJECT_SCREEN_RATIO - mPoint[0];

    mDiff[1] = rotatedTouchPoint.get1()/RubikObject.OBJECT_SCREEN_RATIO - mPoint[1];

    mDiff[2] = rotatedTouchPoint.get2()/RubikObject.OBJECT_SCREEN_RATIO - mPoint[2];