BASH TETRIS

This one is a pure bash tetris game.
Surprisingly working beyond all expectations.




#!/bin/bash
# Tetris Game 
# 10.21.2003 xhchen 
# http://read.pudn.com/downloads99/sourcecode/game/404711/tetris.sh__.htm
# Copyright (C) xhchen
#color definition 
cRed=1 
cGreen=2 
cYellow=3 
cBlue=4 
cFuchsia=5 
cCyan=6 
cWhite=7 
colorTable=($cRed $cGreen $cYellow $cBlue $cFuchsia $cCyan $cWhite) 
#size & position 
iLeft=3 
iTop=2 
((iTrayLeft = iLeft + 2)) 
((iTrayTop = iTop + 1)) 
((iTrayWidth = 10)) 
((iTrayHeight = 15)) 
#style definition 
cBorder=$cGreen 
cScore=$cFuchsia 
cScoreValue=$cCyan 
#control signal 
sigRotate=25 
sigLeft=26 
sigRight=27 
sigDown=28 
sigAllDown=29 
sigExit=30 
#boxes
box0=(0 0 0 1 1 0 1 1) 
box1=(0 2 1 2 2 2 3 2 1 0 1 1 1 2 1 3) 
box2=(0 0 0 1 1 1 1 2 0 1 1 0 1 1 2 0) 
box3=(0 1 0 2 1 0 1 1 0 0 1 0 1 1 2 1) 
box4=(0 1 0 2 1 1 2 1 1 0 1 1 1 2 2 2 0 1 1 1 2 0 2 1 0 0 1 0 1 1 1 2) 
box5=(0 1 1 1 2 1 2 2 1 0 1 1 1 2 2 0 0 0 0 1 1 1 2 1 0 2 1 0 1 1 1 2) 
box6=(0 1 1 1 1 2 2 1 1 0 1 1 1 2 2 1 0 1 1 0 1 1 2 1 0 1 1 0 1 1 1 2) 
box=(${box0[@]} ${box1[@]} ${box2[@]} ${box3[@]} ${box4[@]} ${box5[@]} ${box6[@]}) 
countBox=(1 2 2 2 4 4 4 ) 
offsetBox=(0 1 3 5 7 11 15) 
#score
iScoreEachLevel=50   #be greater than 7 
#Runtime data 
sig=0 
iScore=0 
iLevel=0 
boxNew=()         #new box 
cBoxNew=0         #new box color 
iBoxNewType=0     #new box type 
iBoxNewRotate=0   #new box rotate degree 
boxCur=()         #current box 
cBoxCur=0         #current box color 
iBoxCurType=0     #current box type 
iBoxCurRotate=0   #current box rotate degree 
boxCurX=-1        #current X position 
boxCurY=-1        #current Y position 
iMap=() 
for ((i = 0; i < iTrayHeight * iTrayWidth; i++)); do iMap[$i]=-1; done 
RunAsKeyReceiver() { 
   local pidDisplayer key aKey sig cESC sTTY 
   pidDisplayer=$1 
   aKey=(0 0 0) 
   cESC=`echo -ne "\033"` 
   cSpace=`echo -ne "\040"` 
   sTTY=`stty -g` 
    
   trap "MyExit;" INT TERM 
   trap "MyExitNoSub;" $sigExit 
    
   echo -ne "\033[?25l" 
   while : 
   do 
      read -s -n 1 key 
      aKey[0]=${aKey[1]} 
      aKey[1]=${aKey[2]} 
      aKey[2]=$key 
      sig=0 
      if [[ $key == $cESC && ${aKey[1]} == $cESC ]] 
      then 
         MyExit 
      elif [[ ${aKey[0]} == $cESC && ${aKey[1]} == "[" ]] 
      then 
         if [[ $key == "A" ]]; then sig=$sigRotate 
         elif [[ $key == "B" ]]; then sig=$sigDown 
         elif [[ $key == "D" ]]; then sig=$sigLeft 
         elif [[ $key == "C" ]]; then sig=$sigRight 
         fi 
      elif [[ $key == "W" || $key == "w" ]]; then sig=$sigRotate 
      elif [[ $key == "S" || $key == "s" ]]; then sig=$sigDown 
      elif [[ $key == "A" || $key == "a" ]]; then sig=$sigLeft 
      elif [[ $key == "D" || $key == "d" ]]; then sig=$sigRight 
      elif [[ "[$key]" == "[]" ]]; then sig=$sigAllDown 
      elif [[ $key == "Q" || $key == "q" ]] 
      then 
         MyExit 
      fi 
      if [[ $sig != 0 ]] 
      then 
         kill -$sig $pidDisplayer 
      fi 
   done 
} 
MyExitNoSub(){ 
   local y 
   stty $sTTY 
   ((y = iTop + iTrayHeight + 4)) 
   echo -e "\033[?25h\033[${y};0H" 
   exit 
} 
MyExit(){ 
   kill -$sigExit $pidDisplayer 
   MyExitNoSub 
} 
RunAsDisplayer(){ 
   local sigThis 
   InitDraw 
   trap "sig=$sigRotate;" $sigRotate 
   trap "sig=$sigLeft;" $sigLeft 
   trap "sig=$sigRight;" $sigRight 
   trap "sig=$sigDown;" $sigDown 
   trap "sig=$sigAllDown;" $sigAllDown 
   trap "ShowExit;" $sigExit 
   while :
   do 
      for ((i = 0; i < 21 - iLevel; i++)) 
      do 
         usleep 20000 
         sigThis=$sig 
         sig=0 
         if ((sigThis == sigRotate)); then BoxRotate; 
         elif ((sigThis == sigLeft)); then BoxLeft; 
         elif ((sigThis == sigRight)); then BoxRight; 
         elif ((sigThis == sigDown)); then BoxDown; 
         elif ((sigThis == sigAllDown)); then BoxAllDown; 
         fi 
      done 
      #kill -$sigDown $$ 
      BoxDown 
   done 
} 
BoxMove(){
   local j i x y xTest yTest 
   yTest=$1 
   xTest=$2 
   for ((j = 0; j < 8; j += 2)) 
   do 
      ((i = j + 1)) 
      ((y = ${boxCur[$j]} + yTest)) 
      ((x = ${boxCur[$i]} + xTest)) 
      if (( y < 0 || y >= iTrayHeight || x < 0 || x >= iTrayWidth)) 
      then 
         return 1 
      fi 
      if ((${iMap[y * iTrayWidth + x]} != -1 )) 
      then 
         return 1 
      fi 
   done 
   return 0; 
} 
Box2Map(){ 
   local j i x y xp yp line 
   for ((j = 0; j < 8; j += 2)) 
   do 
      ((i = j + 1)) 
      ((y = ${boxCur[$j]} + boxCurY)) 
      ((x = ${boxCur[$i]} + boxCurX)) 
      ((i = y * iTrayWidth + x)) 
      iMap[$i]=$cBoxCur 
   done 
   line=0 
   for ((j = 0; j < iTrayWidth * iTrayHeight; j += iTrayWidth)) 
   do 
      for ((i = j + iTrayWidth - 1; i >= j; i--)) 
      do 
         if ((${iMap[$i]} == -1)); then break; fi 
      done 
      if ((i >= j)); then continue; fi 
    
      ((line++))    
      for ((i = j - 1; i >= 0; i--)) 
      do 
         ((x = i + iTrayWidth)) 
         iMap[$x]=${iMap[$i]} 
      done 
      for ((i = 0; i < iTrayWidth; i++)) 
      do 
         iMap[$i]=-1 
      done 
   done 
   if ((line == 0)); then return; fi 
   ((x = iLeft + iTrayWidth * 2 + 7)) 
   ((y = iTop + 11)) 
   ((iScore += line * 2 - 1)) 
   echo -ne "\033[1m\033[3${cScoreValue}m\033[${y};${x}H${iScore}         " 
   if ((iScore % iScoreEachLevel < line * 2 - 1)) 
   then 
      if ((iLevel < 20)) 
      then 
         ((iLevel++)) 
         ((y = iTop + 14)) 
         echo -ne "\033[3${cScoreValue}m\033[${y};${x}H${iLevel}        " 
      fi 
   fi 
   echo -ne "\033[0m" 
   for ((y = 0; y < iTrayHeight; y++)) 
   do 
      ((yp = y + iTrayTop + 1)) 
      ((xp = iTrayLeft + 1)) 
      ((i = y * iTrayWidth)) 
      echo -ne "\033[${yp};${xp}H" 
      for ((x = 0; x < iTrayWidth; x++)) 
      do 
         ((j = i + x)) 
         if ((${iMap[$j]} == -1)) 
         then 
            echo -ne "  " 
         else 
            echo -ne "\033[1m\033[7m\033[3${iMap[$j]}m\033[4${iMap[$j]}m\040\040\033[0m" 
         fi 
      done 
   done 
} 
BoxDown(){ 
   local y s 
   ((y = boxCurY + 1)) 
   if BoxMove $y $boxCurX 
   then 
      s="`DrawCurBox 0`" 
      ((boxCurY = y)) 
      s="$s`DrawCurBox 1`" 
      echo -ne $s 
   else 
      Box2Map 
      RandomBox 
   fi 
} 
BoxLeft(){ 
   local x s 
   ((x = boxCurX - 1)) 
   if BoxMove $boxCurY $x 
   then 
      s=`DrawCurBox 0` 
      ((boxCurX = x)) 
      s=$s`DrawCurBox 1` 
      echo -ne $s 
   fi 
} 
BoxRight(){ 
   local x s 
   ((x = boxCurX + 1)) 
   if BoxMove $boxCurY $x 
   then 
      s=`DrawCurBox 0` 
      ((boxCurX = x)) 
      s=$s`DrawCurBox 1` 
      echo -ne $s 
   fi 
} 
BoxAllDown(){ 
   local k j i x y iDown s 
   iDown=$iTrayHeight 
   for ((j = 0; j < 8; j += 2)) 
   do 
      ((i = j + 1)) 
      ((y = ${boxCur[$j]} + boxCurY)) 
      ((x = ${boxCur[$i]} + boxCurX)) 
      for ((k = y + 1; k < iTrayHeight; k++)) 
      do 
         ((i = k * iTrayWidth + x)) 
         if (( ${iMap[$i]} != -1)); then break; fi 
      done 
      ((k -= y + 1)) 
      if (( $iDown > $k )); then iDown=$k; fi 
   done 
   s=`DrawCurBox 0` 
   ((boxCurY += iDown)) 
   s=$s`DrawCurBox 1` 
   echo -ne $s 
   Box2Map 
   RandomBox 
} 
BoxRotate(){ 
   local iCount iTestRotate boxTest j i s 
   iCount=${countBox[$iBoxCurType]} 
   ((iTestRotate = iBoxCurRotate + 1)) 
   if ((iTestRotate >= iCount)) 
   then 
      ((iTestRotate = 0)) 
   fi 
   for ((j = 0, i = (${offsetBox[$iBoxCurType]} + $iTestRotate) * 8; j < 8; j++, i++)) 
   do 
      boxTest[$j]=${boxCur[$j]} 
      boxCur[$j]=${box[$i]} 
   done 
   if BoxMove $boxCurY $boxCurX 
   then 
      for ((j = 0; j < 8; j++)) 
      do 
         boxCur[$j]=${boxTest[$j]} 
      done 
      s=`DrawCurBox 0` 
      for ((j = 0, i = (${offsetBox[$iBoxCurType]} + $iTestRotate) * 8; j < 8; j++, i++)) 
      do 
         boxCur[$j]=${box[$i]} 
      done 
      s=$s`DrawCurBox 1` 
      echo -ne $s 
      iBoxCurRotate=$iTestRotate 
   else 
      for ((j = 0; j < 8; j++)) 
      do 
         boxCur[$j]=${boxTest[$j]} 
      done 
   fi 
} 
DrawCurBox(){ 
   local i j t bDraw sBox s 
   bDraw=$1 
   s="" 
   if (( bDraw == 0 )) 
   then 
      sBox="\040\040" 
   else 
      sBox="\040\040" 
      s=$s"\033[1m\033[7m\033[3${cBoxCur}m\033[4${cBoxCur}m"       
   fi 
   for ((j = 0; j < 8; j += 2)) 
   do 
      ((i = iTrayTop + 1 + ${boxCur[$j]} + boxCurY)) 
      ((t = iTrayLeft + 1 + 2 * (boxCurX + ${boxCur[$j + 1]}))) 
      s=$s"\033[${i};${t}H${sBox}" 
   done 
   s=$s"\033[0m" 
   echo -n $s 
} 
RandomBox(){ 
   local i j t 
   #change current box 
   iBoxCurType=${iBoxNewType} 
   iBoxCurRotate=${iBoxNewRotate} 
   cBoxCur=${cBoxNew} 
   for ((j = 0; j < ${#boxNew[@]}; j++)) 
   do 
      boxCur[$j]=${boxNew[$j]} 
   done 
   if (( ${#boxCur[@]} == 8 )) 
   then 
      #calculate current box's starting position 
      for ((j = 0, t = 4; j < 8; j += 2)) 
      do 
         if ((${boxCur[$j]} < t)); then t=${boxCur[$j]}; fi 
      done 
      ((boxCurY = -t)) 
      for ((j = 1, i = -4, t = 20; j < 8; j += 2)) 
      do 
         if ((${boxCur[$j]} > i)); then i=${boxCur[$j]}; fi 
         if ((${boxCur[$j]} < t)); then t=${boxCur[$j]}; fi 
      done 
      ((boxCurX = (iTrayWidth - 1 - i - t) / 2)) 
      echo -ne `DrawCurBox 1` 
      if ! BoxMove $boxCurY $boxCurX 
      then 
         kill -$sigExit ${PPID} 
         ShowExit 
      fi 
   fi 
   #clear old box 
   for ((j = 0; j < 4; j++)) 
   do 
      ((i = iTop + 1 + j)) 
      ((t = iLeft + 2 * iTrayWidth + 7)) 
      echo -ne "\033[${i};${t}H        " 
   done 
   #get a random new box 
   ((iBoxNewType = RANDOM % ${#offsetBox[@]})) 
   ((iBoxNewRotate = RANDOM % ${countBox[$iBoxNewType]})) 
   for ((j = 0, i = (${offsetBox[$iBoxNewType]} + $iBoxNewRotate) * 8; j < 8; j++, i++)) 
   do 
      boxNew[$j]=${box[$i]}; 
   done 
   ((cBoxNew = ${colorTable[RANDOM % ${#colorTable[@]}]})) 
   #display new box 
   echo -ne "\033[1m\033[7m\033[3${cBoxNew}m\033[4${cBoxNew}m" 
   for ((j = 0; j < 8; j += 2)) 
   do 
      ((i = iTop + 1 + ${boxNew[$j]})) 
      ((t = iLeft + 2 * iTrayWidth + 7 + 2 * ${boxNew[$j + 1]})) 
      echo -ne "\033[${i};${t}H\040\040" 
   done 
   echo -ne "\033[0m" 
} 
InitDraw(){ 
   clear 
   RandomBox 
   RandomBox 
   local i t1 t2 t3 
   #draw border 
   echo -ne "\033[1m" 
   echo -ne "\033[3${cBorder}m\033[4${cBorder}m" 
   ((t2 = iLeft + 1)) 
   ((t3 = iLeft + iTrayWidth * 2 + 3)) 
   for ((i = 0; i < iTrayHeight; i++)) 
   do 
      ((t1 = i + iTop + 2)) 
      echo -ne "\033[${t1};${t2}H\040\040" 
      echo -ne "\033[${t1};${t3}H\040\040" 
   done 
   ((t2 = iTop + iTrayHeight + 2)) 
   for ((i = 0; i < iTrayWidth + 2; i++)) 
   do 
      ((t1 = i * 2 + iLeft + 1)) 
      echo -ne "\033[${iTrayTop};${t1}H\040\040" 
      echo -ne "\033[${t2};${t1}H\040\040" 
   done 
   echo -ne "\033[0m" 
   #draw score & level prompt 
   echo -ne "\033[1m" 
   ((t1 = iLeft + iTrayWidth * 2 + 7)) 
   ((t2 = iTop + 10)) 
   echo -ne "\033[3${cScore}m\033[${t2};${t1}HScore" 
   ((t2 = iTop + 11)) 
   echo -ne "\033[3${cScoreValue}m\033[${t2};${t1}H${iScore}" 
   ((t2 = iTop + 13)) 
   echo -ne "\033[3${cScore}m\033[${t2};${t1}HLevel" 
   ((t2 = iTop + 14)) 
   echo -ne "\033[3${cScoreValue}m\033[${t2};${t1}H${iLevel}" 
   echo -ne "\033[0m" 
} 
ShowExit(){ 
   local y 
   ((y = iTrayHeight + iTrayTop + 3)) 
   echo -e "\033[${y};0HGameOver!\033[0m" 
   exit 
} 
#Start from here. 
if [[ $1 != "--go" ]] 
then 
  $0 --go& 
  RunAsKeyReceiver $! 
  exit 
else 
   RunAsDisplayer 
   exit 
fi