Magic Cube

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// Copyright 2020 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/>.                           //

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package org.distorted.object;

import org.distorted.library.type.Static2D;

import org.distorted.library.type.Static3D;

import org.distorted.library.type.Static4D;

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public abstract class RubikObjectMovement

  {

  float[] mTouch;

  int mRotationVect, mLastTouchedAxis;

  private float[] mPoint, mCamera, mDiff;

  private int mLastTouchedLR;

  private int mNumAxis, mNumFacesPerAxis;

  private int[] mPossible;

  private float mDistanceCenterFace;

  private Static3D[] mAxis;

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  abstract boolean isInsideFace(float[] point);

  abstract float fillUpRotationVectAndOffset(float[] vect, int[] possible);

  abstract float returnAngle(float[] vect, int[] possible);

  abstract void fillPossibleRotations(int axis, int[] output);

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

  RubikObjectMovement(Static3D[] axis, int numFacesPerAxis, float distance)

    {

    mPoint = new float[3];

    mCamera= new float[3];

    mDiff  = new float[3];

    mTouch = new float[3];

    mAxis = axis;

    mNumAxis = mAxis.length;

    mNumFacesPerAxis = numFacesPerAxis;

    mDistanceCenterFace = distance;

    mPossible = new int[mNumAxis-1];

    }

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

  private boolean faceIsVisible(Static3D axis, int lr)

    {

    float castCameraOnAxis = mCamera[0]*axis.get0() + mCamera[1]*axis.get1() + mCamera[2]*axis.get2();

    return (2*lr-1)*castCameraOnAxis > mDistanceCenterFace;

    }

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

// 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)) [and this

//    distance is +-mDistanceCenterFace, depending if it is the face on the left or the right end of

//    the axis] (lr=0 or 1, so (2lr-1)*mDistanceCenterFace)

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

//

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

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

    {

    float d0 = mPoint[0]-mCamera[0];

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

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

    float a0 = axis.get0();

    float a1 = axis.get1();

    float a2 = axis.get2();

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

    if( denom != 0.0f )

      {

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

      float distance = (2*lr-1)*mDistanceCenterFace;

      float alpha = (distance-axisCam)/denom;

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

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

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

      }

    }

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

// PUBLIC API

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

  public boolean faceTouched(Static4D rotatedTouchPoint, Static4D rotatedCamera)

    {

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

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

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

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

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

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

    for( mLastTouchedAxis=0; mLastTouchedAxis<mNumAxis; mLastTouchedAxis++)

      {

      for( mLastTouchedLR=0; mLastTouchedLR<mNumFacesPerAxis; mLastTouchedLR++)

        {

        if( faceIsVisible(mAxis[mLastTouchedAxis], mLastTouchedLR) )

          {

          castTouchPointOntoFace(mAxis[mLastTouchedAxis], mLastTouchedLR, mTouch);

          if( isInsideFace(mTouch) )

            {

            fillPossibleRotations(mLastTouchedAxis, mPossible);

            return true;

            }

          }

        }

      }

    return false;

    }

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

  public Static2D newRotation(Static4D rotatedTouchPoint)

    {

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

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

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

    castTouchPointOntoFace(mAxis[mLastTouchedAxis], mLastTouchedLR, mDiff);

    mDiff[0] -= mTouch[0];

    mDiff[1] -= mTouch[1];

    mDiff[2] -= mTouch[2];

    float offset = fillUpRotationVectAndOffset(mDiff, mPossible);

    mTouch[0] = mPoint[0];

    mTouch[1] = mPoint[1];

    mTouch[2] = mPoint[2];

    return new Static2D(mRotationVect,offset);

    }

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

  public float continueRotation(Static4D rotatedTouchPoint)

    {

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

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

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

    return (mLastTouchedLR-0.5f)*returnAngle(mDiff, mPossible);

    }

  }