Distorted Android

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

// Copyright 2016 Leszek Koltunski                                                               //

//                                                                                               //

// This file is part of Distorted.                                                               //

//                                                                                               //

// Distorted 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.                                                           //

//                                                                                               //

// Distorted 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 Distorted.  If not, see <http://www.gnu.org/licenses/>.                            //

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

package org.distorted.library;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.util.ArrayList;

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

/**

 * Create a 3D grid composed of Cubes.

 * <p>

 * Any subset of a MxNx1 cuboid is possible.

 */

public class MeshCubes extends MeshObject

   {

   private static final float R = 0.0f;//0.2f;

   private static final float FRONTZ = 0.5f;

   private static final float BACKZ  =-0.5f;

   private static final int NORTH = 0;

   private static final int WEST  = 1;

   private static final int EAST  = 2;

   private static final int SOUTH = 3;

   private static final boolean BACK  = true;

   private static final boolean FRONT = false;

   private static final boolean UPPER = false;

   private static final boolean LOWER = true;

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

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

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

   private class Edge

     {

     final int side; 

     final int row;

     final int col;

     Edge(int s, int r, int c)

       {

       side= s; 

       row = r;

       col = c;

       }

     }

   private int mCols, mRows;

   private int[][] mCubes;

   private ArrayList<Edge> mEdges = new ArrayList<>();

   private int remainingVert;

   private int mSideBends;

   private int mEdgeNum;

   private int mSideWalls;

   private float[] mBoundingVert;

   private static float[] mBoundingVert1 = new float[] { -0.5f,+0.5f, FRONTZ,

                                                         -0.5f,-0.5f, FRONTZ,

                                                         +0.5f,+0.5f, FRONTZ,

                                                         +0.5f,-0.5f, FRONTZ };

   private static float[] mBoundingVert2 = new float[] { -0.5f,+0.5f, FRONTZ,

                                                         -0.5f,-0.5f, FRONTZ,

                                                         +0.5f,+0.5f, FRONTZ,

                                                         +0.5f,-0.5f, FRONTZ,

                                                         -0.5f,+0.5f, BACKZ ,

                                                         -0.5f,-0.5f, BACKZ ,

                                                         +0.5f,+0.5f, BACKZ ,

                                                         +0.5f,-0.5f, BACKZ  };

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

// a Block is split into two triangles along the NE-SW line iff it is in the top-right

// or bottom-left quadrant of the grid.

   private boolean isNE(int row,int col)

     {

     return ( (2*row<mRows)^(2*col<mCols) );

     }

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

// return the number of vertices our grid will contain

   private int computeDataLength(boolean frontOnly)

      {

      int frontWalls=0, frontSegments=0, triangleShifts=0, windingShifts=0;

      int shiftCol = (mCols-1)/2;

      boolean lastBlockIsNE=false;

      boolean thisBlockIsNE;        // the block we are currently looking at is split into

                                    // two triangles along the NE-SW line (rather than NW-SE)

      for(int row=0; row<mRows; row++)

        {

        if( mCols>=2 && (mCubes[row][shiftCol]%2 == 1) && (mCubes[row][shiftCol+1]%2 == 1) ) triangleShifts++;

        for(int col=0; col<mCols; col++)

          {

          if( mCubes[row][col]%2 == 1 )  // land

            {

            thisBlockIsNE = isNE(row,col);

            if( thisBlockIsNE^lastBlockIsNE ) windingShifts++;

            lastBlockIsNE = thisBlockIsNE;

            frontWalls++;

            if( col==mCols-1 || mCubes[row][col+1]%2 == 0 ) frontSegments++;

            }

          }

        }

      int frontVert = 2*( frontWalls + 2*frontSegments - 1) +2*triangleShifts + windingShifts;

      int sideVert  = 2*( mSideWalls + mSideBends + mEdgeNum -1);

      int firstWinding= (!frontOnly && (frontVert+1)%2==1 ) ? 1:0;

      int dataL = frontOnly ? frontVert : (frontVert+1) +firstWinding+ (1+sideVert+1) + (1+frontVert);

/*

      android.util.Log.e("CUBES","triangleShifts="+triangleShifts+" windingShifts="+windingShifts+" winding1="+firstWinding+" frontVert="+frontVert+" sideVert="+sideVert);

      android.util.Log.e("CUBES", "frontW="+frontWalls+" fSegments="+frontSegments+" sWalls="+mSideWalls+" sSegments="+mEdgeNum+" sideBends="+mSideBends+" dataLen="+dataL );

*/

      return dataL<0 ? 0:dataL;

      }

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

/*

   private static String debug(short[] val)

     {

     String ret="";j

     for(int i=0; i<val.length; i++) ret+=(" "+val[i]); 

     return ret;

     }

*/

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

/*

   private static String debug(float[] val, int stop)

     {

     String ret="";

     for(int i=0; i<val.length; i++) 

        {

        if( i%stop==0 ) ret+="\n";

        ret+=(" "+val[i]);

        }

     return ret;

     }

*/

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

/*

   private static String debug(Edge e)

     {

     String d = "";

     switch(e.side)

       {

       case NORTH: d+="NORTH "; break;

       case SOUTH: d+="SOUTH "; break;

       case WEST : d+="WEST  "; break;

       case EAST : d+="EAST  "; break;

       }

     d+=("("+e.row+","+e.col+")");

     return d;

     }   

*/

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

   private void prepareDataStructures(int cols, String desc, boolean frontOnly)

     {

     mRows      =0;

     mCols      =0;

     numVertices=0;

     if( cols>0 && desc.contains("1") )

       {

       mCols = cols;

       mRows = desc.length()/cols;

       mCubes = new int[mRows][mCols];

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

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

           mCubes[i][j] = (desc.charAt(i*mCols+j) == '1' ? 1:0);

       buildBoundingVert(frontOnly);

//android.util.Log.d("cubes", "VERT STRING:"+debug(mBoundingVert,3));

       markRegions();

       numVertices = computeDataLength(frontOnly);

       remainingVert = numVertices;

       }

     }

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

// full grid

   private void prepareDataStructures(int cols, int rows, boolean frontOnly)

     {

     mRows       =rows;

     mCols       =cols;

     numVertices =   0;

     if( cols>0 && rows>0 )

       {

       mCubes = new int[mRows][mCols];

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

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

           mCubes[i][j] = 1;

       mBoundingVert = frontOnly ? mBoundingVert1 : mBoundingVert2;

//android.util.Log.d("cubes", "VERT FULL:"+debug(mBoundingVert,3));

       markRegions();

       numVertices = computeDataLength(frontOnly);

       remainingVert = numVertices;

       }

     }

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

  private float retRightmost(int row)

    {

    if( row==0 )

      {

      for(int i=mCols-1; i>=0; i--)

        if( mCubes[0][i]==1 )

          return (float)(i+1);

      }

    else if(row==mRows)

      {

      for(int i=mCols-1; i>=0; i--)

        if( mCubes[mRows-1][i]==1 )

          return (float)(i+1);

      }

    else

      {

      for(int i=mCols-1; i>=0; i--)

        if( mCubes[row][i]==1 || mCubes[row-1][i]==1 )

          return (float)(i+1);

      }

    return 0.0f;

    }

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

  private float retLeftmost(int row)

    {

    if( row==0 )

      {

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

        if( mCubes[0][i]==1 )

          return (float)i;

      }

    else if(row==mRows)

      {

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

        if( mCubes[mRows-1][i]==1 )

          return (float)i;

      }

    else

      {

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

        if( mCubes[row][i]==1 || mCubes[row-1][i]==1 )

          return (float)i;

      }

    return (float)mCols;

    }

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

  private int addLeftmost(float[] temp, int row, int index)

    {

    float x2 = retLeftmost(row)/mCols - 0.5f;

    float y2 = 0.5f - (float)row/mRows;

    if( index>1 )

      {

      float x0 = temp[2*index-4];

      float y0 = temp[2*index-3];

      float x1 = temp[2*index-2];

      float y1 = temp[2*index-1];

      while( (x0-x2)*(y0-y1) >= (x0-x1)*(y0-y2) )

        {

        if( --index>1 )

          {

          x1 = x0;

          y1 = y0;

          x0 = temp[2*index-4];

          y0 = temp[2*index-3];

          }

        else break;

        }

      }

    temp[2*index  ] = x2;

    temp[2*index+1] = y2;

    return index+1;

    }

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

  private int addRightmost(float[] temp, int row, int index)

    {

    float x2 = retRightmost(row)/mCols - 0.5f;

    float y2 = 0.5f - (float)row/mRows;

    if( index>1 )

      {

      float x0 = temp[2*index-4];

      float y0 = temp[2*index-3];

      float x1 = temp[2*index-2];

      float y1 = temp[2*index-1];

      while( (x0-x2)*(y0-y1) <= (x0-x1)*(y0-y2) )

        {

        if( --index>1 )

          {

          x1 = x0;

          y1 = y0;

          x0 = temp[2*index-4];

          y0 = temp[2*index-3];

          }

        else break;

        }

      }

    temp[2*index  ] = x2;

    temp[2*index+1] = y2;

    return index+1;

    }

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

// fill up the mBoundingVert array with the smallest set of vertices which form the same convex hull

// like the whole thing.

  private void buildBoundingVert(boolean frontOnly)

    {

    int lVert=0, rVert=0;

    int firstRow=0, lastRow=mRows-1;

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

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

        if(mCubes[i][j] !=0 )

          {

          firstRow = i;

          i=mRows;

          j=mCols;

          }

    for(int i=mRows-1; i>=0; i--)

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

        if(mCubes[i][j] !=0 )

          {

          lastRow = i;

          i=-1;

          j=mCols;

          }

//android.util.Log.d("cubes", "first :"+firstRow+" last: "+lastRow);

    int numLines = lastRow-firstRow+2;

    float[] tempL = new float[2*numLines];

    float[] tempR = new float[2*numLines];

    for(int i=firstRow; i<=lastRow+1; i++)

      {

      lVert = addLeftmost (tempL,i,lVert);

      rVert = addRightmost(tempR,i,rVert);

      }

//android.util.Log.d("cubes", "LEFT :"+debug(tempL,2));

//android.util.Log.d("cubes", "RIGHT:"+debug(tempR,2));

    int numVert = lVert+rVert;

    mBoundingVert = new float[ numVert*(frontOnly ? 3:6) ];

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

      {

      mBoundingVert[3*i  ] = tempL[2*i  ];

      mBoundingVert[3*i+1] = tempL[2*i+1];

      mBoundingVert[3*i+2] = FRONTZ;

      }

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

      {

      mBoundingVert[3*(i+lVert)  ] = tempR[2*i  ];

      mBoundingVert[3*(i+lVert)+1] = tempR[2*i+1];

      mBoundingVert[3*(i+lVert)+2] = FRONTZ;

      }

    if( !frontOnly )

      {

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

        {

        mBoundingVert[3*(i+numVert)  ] = mBoundingVert[3*i  ];

        mBoundingVert[3*(i+numVert)+1] = mBoundingVert[3*i+1];

        mBoundingVert[3*(i+numVert)+2] = BACKZ;

        }

      }

    }

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

// Mark all the 'regions' of our grid  - i.e. separate pieces of 'land' (connected blocks that will 

// be rendered) and 'water' (connected holes in between) with integers. Each connected block of land

// gets a unique odd integer, each connected block of water a unique even integer.

//

// Water on the edges of the grid is also considered connected to itself!   

//   

// This function also creates a list of 'Edges'. Each Edge is a data structure from which later on we

// will start building the side walls of each connected block of land (and sides of holes of water

// inside). Each Edge needs to point from Land to Water (thus the '(SOUTH,i-1,j)' below) - otherwise

// later on setting up normal vectors wouldn't work.

  private void markRegions()

     {

     int i, j, numWater=1, numLand=0;

     for(i=0; i<mRows;i++) if( mCubes[      i][      0]==0 ) markRegion((short)2,      i,       0);

     for(i=0; i<mRows;i++) if( mCubes[      i][mCols-1]==0 ) markRegion((short)2,      i, mCols-1);

     for(i=0; i<mCols;i++) if( mCubes[0      ][      i]==0 ) markRegion((short)2,      0,       i);

     for(i=0; i<mCols;i++) if( mCubes[mRows-1][      i]==0 ) markRegion((short)2,mRows-1,       i);

     for(i=0; i<mRows; i++)

        for(j=0; j<mCols; j++)

           {

           if( mCubes[i][j] == 0 ) { numWater++; markRegion( (short)(2*numWater ),i,j); mEdges.add(new Edge(SOUTH,i-1,j)); }

           if( mCubes[i][j] == 1 ) { numLand ++; markRegion( (short)(2*numLand+1),i,j); mEdges.add(new Edge(NORTH,i  ,j)); }

           }

     // now we potentially need to kick out some Edges . Otherwise the following does not work:

     //

     // 0 1 0

     // 1 0 1

     // 0 1 0

     mEdgeNum= mEdges.size();

     int initCol, initRow, initSide, lastSide;

     Edge e1,e2;

     for(i=0; i<mEdgeNum; i++)

       {

       e1 = mEdges.get(i);

       initRow= e1.row;

       initCol= e1.col;

       initSide=e1.side;

       do

         {

         //android.util.Log.d("CUBES", "checking edge "+debug(e1));

         mSideWalls++;

         if( e1.side==NORTH || e1.side==SOUTH )

           {

           for(j=i+1;j<mEdgeNum;j++)

             {

             e2 = mEdges.get(j);

             if( e2.side==e1.side && e2.row==e1.row && e2.col==e1.col )

               {

               mEdges.remove(j);

               mEdgeNum--;

               j--;

               //android.util.Log.e("CUBES", "removing edge "+debug(e2));

               }

             }

           }

         lastSide = e1.side;

         e1 = getNextEdge(e1);

         if( e1.side!=lastSide ) mSideBends++;

         }

       while( e1.col!=initCol || e1.row!=initRow || e1.side!=initSide );

       }

     }

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

// when calling, make sure that newVal != val

  private void markRegion(short newVal, int row, int col)

     {

     int val = mCubes[row][col];

     mCubes[row][col] = newVal;

     if( row>0       && mCubes[row-1][col  ]==val ) markRegion(newVal, row-1, col  );

     if( row<mRows-1 && mCubes[row+1][col  ]==val ) markRegion(newVal, row+1, col  );

     if( col>0       && mCubes[row  ][col-1]==val ) markRegion(newVal, row  , col-1);

     if( col<mCols-1 && mCubes[row  ][col+1]==val ) markRegion(newVal, row  , col+1);

     }

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

  private void createNormals(boolean front, int row, int col)

     {

     int td,lr; 

     int nw = (col>0       && row>0      ) ? (mCubes[row-1][col-1]%2) : 0;

     int w  = (col>0                     ) ? (mCubes[row  ][col-1]%2) : 0;

     int n  = (               row>0      ) ? (mCubes[row-1][col  ]%2) : 0;

     int c  =                                (mCubes[row  ][col  ]%2);

     int sw = (col>0       && row<mRows-1) ? (mCubes[row+1][col-1]%2) : 0;

     int s  = (               row<mRows-1) ? (mCubes[row+1][col  ]%2) : 0;

     int ne = (col<mCols-1 && row>0      ) ? (mCubes[row-1][col+1]%2) : 0;

     int e  = (col<mCols-1               ) ? (mCubes[row  ][col+1]%2) : 0;

     int se = (col<mCols-1 && row<mRows-1) ? (mCubes[row+1][col+1]%2) : 0;

     if(front)

       {

       mNormalZ[0] = 1.0f;

       mNormalZ[1] = 1.0f;

       mNormalZ[2] = 1.0f;

       mNormalZ[3] = 1.0f;

       }

     else

       {

       mNormalZ[0] =-1.0f;

       mNormalZ[1] =-1.0f;

       mNormalZ[2] =-1.0f;

       mNormalZ[3] =-1.0f;

       }

     td = nw+n-w-c;

     lr = c+n-w-nw;

     if( td<0 ) td=-1;

     if( td>0 ) td= 1;

     if( lr<0 ) lr=-1;

     if( lr>0 ) lr= 1;

     mNormalX[0] = lr*R;

     mNormalY[0] = td*R;

     td = w+c-sw-s;

     lr = c+s-w-sw;

     if( td<0 ) td=-1;

     if( td>0 ) td= 1;

     if( lr<0 ) lr=-1;

     if( lr>0 ) lr= 1;

     mNormalX[1] = lr*R;

     mNormalY[1] = td*R;

     td = n+ne-c-e;

     lr = e+ne-c-n;

     if( td<0 ) td=-1;

     if( td>0 ) td= 1;

     if( lr<0 ) lr=-1;

     if( lr>0 ) lr= 1;

     mNormalX[2] = lr*R;

     mNormalY[2] = td*R;

     td = c+e-s-se;

     lr = e+se-c-s;

     if( td<0 ) td=-1;

     if( td>0 ) td= 1;

     if( lr<0 ) lr=-1;

     if( lr>0 ) lr= 1;

     mNormalX[3] = lr*R;

     mNormalY[3] = td*R;

     /*

     android.util.Log.d("CUBES", "row="+row+" col="+col);

     android.util.Log.d("CUBES", mNormalX[0]+" "+mNormalY[0]);

     android.util.Log.d("CUBES", mNormalX[1]+" "+mNormalY[1]);

     android.util.Log.d("CUBES", mNormalX[2]+" "+mNormalY[2]);

     android.util.Log.d("CUBES", mNormalX[3]+" "+mNormalY[3]);

     */

     }

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

  private int buildFrontBackGrid(boolean front, int vertex, float[] attribs)

     {

     int last, current;

     boolean seenLand=false;

     boolean lastBlockIsNE = false;

     boolean currentBlockIsNE;

     float vectZ = front?FRONTZ:BACKZ;

     //android.util.Log.d("CUBES", "buildFrontBack");

     for(int row=0; row<mRows; row++)

       {

       last =0;

       for(int col=0; col<mCols; col++)

         {

         current = mCubes[row][col];

         if( current%2 == 1 )

           {

           currentBlockIsNE = isNE(row,col);

           if( !seenLand && !front && ((vertex%2==1)^currentBlockIsNE) )

             {

             //android.util.Log.d("CUBES","repeating winding2 vertex");

             vertex = repeatLast(vertex,attribs);

             }

           createNormals(front,row,col);

           if( currentBlockIsNE )

             {

             if( (last!=current) || !lastBlockIsNE )

               {

               if( seenLand  && (last != current) ) vertex = repeatLast(vertex,attribs);

               vertex= addFrontVertex( vertex, 0, vectZ, col, row, attribs);

               if( seenLand  && (last != current) ) vertex = repeatLast(vertex,attribs);

               if( !lastBlockIsNE || (!front && !seenLand) ) vertex = repeatLast(vertex,attribs);

               vertex= addFrontVertex( vertex, 1, vectZ, col, row+1, attribs);

               }

             vertex= addFrontVertex( vertex, 2, vectZ, col+1, row, attribs);

             vertex= addFrontVertex( vertex, 3, vectZ, col+1, row+1, attribs);

             }

           else

             {

             if( (last!=current) || lastBlockIsNE )

               {

               if( seenLand  && (last != current) ) vertex = repeatLast(vertex,attribs);

               vertex= addFrontVertex( vertex, 1, vectZ, col, row+1, attribs);

               if( seenLand  && (last != current) ) vertex = repeatLast(vertex,attribs);

               if( lastBlockIsNE || (!front && !seenLand) ) vertex = repeatLast(vertex,attribs);

               vertex= addFrontVertex( vertex, 0, vectZ, col, row, attribs);

               }

             vertex= addFrontVertex( vertex, 3, vectZ, col+1, row+1, attribs);

             vertex= addFrontVertex( vertex, 2, vectZ, col+1, row  , attribs);

             }

           seenLand = true;

           lastBlockIsNE = currentBlockIsNE;

           }

         last = current;

         }

       }

     return vertex;

     }

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

  private int repeatLast(int vertex, float[] attribs)

     {

     //android.util.Log.e("CUBES", "repeating last vertex!");

     if( vertex>0 )

       {

       remainingVert--;

       attribs[8*vertex  ] = attribs[8*vertex-8];

       attribs[8*vertex+1] = attribs[8*vertex-7];

       attribs[8*vertex+2] = attribs[8*vertex-6];

       attribs[8*vertex+3] = attribs[8*vertex-5];

       attribs[8*vertex+4] = attribs[8*vertex-4];

       attribs[8*vertex+5] = attribs[8*vertex-3];

       attribs[8*vertex+6] = attribs[8*vertex-2];

       attribs[8*vertex+7] = attribs[8*vertex-1];

       vertex++;     

       }

     return vertex;

     }

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

  private int buildSideGrid(int vertex, float[] attribs)

     {

     //android.util.Log.d("CUBES", "buildSide");

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

       {

       vertex = buildIthSide(mEdges.get(i), vertex, attribs);

       } 

     return vertex;

     }

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

  private int buildIthSide(Edge curr, int vertex, float[] attribs)

     {

     Edge prev; 

     if( curr.side==NORTH ) // water outside

       {

       prev = new Edge(WEST,curr.row,curr.col);

       }

     else                   // land outside; we need to move forward one link because we are going in opposite direction and we need to start from a bend.

       {

       prev = curr;

       curr = new Edge(EAST,curr.row+1,curr.col-1);

       }

     int col = curr.col;

     int row = curr.row;

     int side= curr.side;  

     Edge next = getNextEdge(curr);

     addSideVertex(curr,BACK,LOWER,prev.side,vertex,attribs);

     vertex++;

     do

       {

       if( prev.side!=curr.side )

         {

         addSideVertex(curr,BACK,LOWER,prev.side,vertex,attribs);

         vertex++;

         addSideVertex(curr,BACK,UPPER,prev.side,vertex,attribs);

         vertex++;

         }

       addSideVertex(curr,FRONT,LOWER,next.side,vertex,attribs);

       vertex++;

       addSideVertex(curr,FRONT,UPPER,next.side,vertex,attribs);

       vertex++;

       prev = curr;

       curr = next; 

       next = getNextEdge(curr);

       }

     while( curr.col!=col || curr.row!=row || curr.side!=side );

     vertex = repeatLast(vertex,attribs);