private void calculeRoof(){
        boolean matrixAuxiliar[][] = new boolean[matrix_height][matrix_width];
        int auxLen;
        for(int row = 0; row < matrix_height; row++){
            for(int col = 0; col < matrix_width; col++){
                if(!matrixAuxiliar[row][col] && matrix[row][col]==1){
                    auxLen = chaseRoof(row, col);
                    for(int i=0;i<auxLen;i++){
                        matrixAuxiliar[row][col+i]=true;
                    }
                    if(auxLen>0){
                        tracert.add(new LineTrace(col,row,col+auxLen,row, RunGame.TILE_LEN));
         //tracert.add(new LineTrace(this,"drawHorizontalLine",new Object[] {(Object) g,(Object)row,(Object) col,(Object) auxLen}));
                    }
                }else if(matrix[row][col]==2){
                    ballsToEat++;
                }
            }
        }
    }