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john-science/snake.sh

Created August 7, 2017 22:53
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  1. john-science created this gist Aug 7, 2017.
    265 changes: 265 additions & 0 deletions snake.sh
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,265 @@
    #!/bin/bash
    #
    # Centipede game
    #
    # v2.0
    #
    # Author: [email protected]
    #
    # Functions

    drawborder() {
    # Draw top
    tput setf 6
    tput cup $FIRSTROW $FIRSTCOL
    x=$FIRSTCOL
    while [ "$x" -le "$LASTCOL" ];
    do
    printf %b "$WALLCHAR"
    x=$(( $x + 1 ));
    done

    # Draw sides
    x=$FIRSTROW
    while [ "$x" -le "$LASTROW" ];
    do
    tput cup $x $FIRSTCOL; printf %b "$WALLCHAR"
    tput cup $x $LASTCOL; printf %b "$WALLCHAR"
    x=$(( $x + 1 ));
    done

    # Draw bottom
    tput cup $LASTROW $FIRSTCOL
    x=$FIRSTCOL
    while [ "$x" -le "$LASTCOL" ];
    do
    printf %b "$WALLCHAR"
    x=$(( $x + 1 ));
    done
    tput setf 9
    }

    apple() {
    # Pick coordinates within the game area
    APPLEX=$[( $RANDOM % ( $[ $AREAMAXX - $AREAMINX ] + 1 ) ) + $AREAMINX ]
    APPLEY=$[( $RANDOM % ( $[ $AREAMAXY - $AREAMINY ] + 1 ) ) + $AREAMINY ]
    }

    drawapple() {
    # Check we haven't picked an occupied space
    LASTEL=$(( ${#LASTPOSX[@]} - 1 ))
    x=0
    apple
    while [ "$x" -le "$LASTEL" ];
    do
    if [ "$APPLEX" = "${LASTPOSX[$x]}" ] && [ "$APPLEY" = "${LASTPOSY[$x]}" ];
    then
    # Invalid coords... in use
    x=0
    apple
    else
    x=$(( $x + 1 ))
    fi
    done
    tput setf 4
    tput cup $APPLEY $APPLEX
    printf %b "$APPLECHAR"
    tput setf 9
    }

    growsnake() {
    # Pad out the arrays with oldest position 3 times to make snake bigger
    LASTPOSX=( ${LASTPOSX[0]} ${LASTPOSX[0]} ${LASTPOSX[0]} ${LASTPOSX[@]} )
    LASTPOSY=( ${LASTPOSY[0]} ${LASTPOSY[0]} ${LASTPOSY[0]} ${LASTPOSY[@]} )
    RET=1
    while [ "$RET" -eq "1" ];
    do
    apple
    RET=$?
    done
    drawapple
    }

    move() {
    case "$DIRECTION" in
    u) POSY=$(( $POSY - 1 ));;
    d) POSY=$(( $POSY + 1 ));;
    l) POSX=$(( $POSX - 1 ));;
    r) POSX=$(( $POSX + 1 ));;
    esac

    # Collision detection
    ( sleep $DELAY && kill -ALRM $$ ) &
    if [ "$POSX" -le "$FIRSTCOL" ] || [ "$POSX" -ge "$LASTCOL" ] ; then
    tput cup $(( $LASTROW + 1 )) 0
    stty echo
    echo " GAME OVER! You hit a wall!"
    gameover
    elif [ "$POSY" -le "$FIRSTROW" ] || [ "$POSY" -ge "$LASTROW" ] ; then
    tput cup $(( $LASTROW + 1 )) 0
    stty echo
    echo " GAME OVER! You hit a wall!"
    gameover
    fi

    # Get Last Element of Array ref
    LASTEL=$(( ${#LASTPOSX[@]} - 1 ))
    #tput cup $ROWS 0
    #printf "LASTEL: $LASTEL"

    x=1 # set starting element to 1 as pos 0 should be undrawn further down (end of tail)
    while [ "$x" -le "$LASTEL" ];
    do
    if [ "$POSX" = "${LASTPOSX[$x]}" ] && [ "$POSY" = "${LASTPOSY[$x]}" ];
    then
    tput cup $(( $LASTROW + 1 )) 0
    echo " GAME OVER! YOU ATE YOURSELF!"
    gameover
    fi
    x=$(( $x + 1 ))
    done

    # clear the oldest position on screen
    tput cup ${LASTPOSY[0]} ${LASTPOSX[0]}
    printf " "

    # truncate position history by 1 (get rid of oldest)
    LASTPOSX=( `echo "${LASTPOSX[@]}" | cut -d " " -f 2-` $POSX )
    LASTPOSY=( `echo "${LASTPOSY[@]}" | cut -d " " -f 2-` $POSY )
    tput cup 1 10
    #echo "LASTPOSX array ${LASTPOSX[@]} LASTPOSY array ${LASTPOSY[@]}"
    tput cup 2 10
    echo "SIZE=${#LASTPOSX[@]}"

    # update position history (add last to highest val)
    LASTPOSX[$LASTEL]=$POSX
    LASTPOSY[$LASTEL]=$POSY

    # plot new position
    tput setf 2
    tput cup $POSY $POSX
    printf %b "$SNAKECHAR"
    tput setf 9

    # Check if we hit an apple
    if [ "$POSX" -eq "$APPLEX" ] && [ "$POSY" -eq "$APPLEY" ]; then
    growsnake
    updatescore 10
    fi
    }

    updatescore() {
    SCORE=$(( $SCORE + $1 ))
    tput cup 2 30
    printf "SCORE: $SCORE"
    }
    randomchar() {
    [ $# -eq 0 ] && return 1
    n=$(( ($RANDOM % $#) + 1 ))
    eval DIRECTION=\${$n}
    }

    gameover() {
    tput cvvis
    stty echo
    sleep $DELAY
    trap exit ALRM
    tput cup $ROWS 0
    exit
    }

    ###########################END OF FUNCS##########################

    # Prettier characters but not supported
    # by all termtypes/locales
    #SNAKECHAR="\0256" # Character to use for snake
    #WALLCHAR="\0244" # Character to use for wall
    #APPLECHAR="\0362" # Character to use for apples
    #
    # Normal boring ASCII Chars
    SNAKECHAR="@" # Character to use for snake
    WALLCHAR="X" # Character to use for wall
    APPLECHAR="o" # Character to use for apples
    #
    SNAKESIZE=3 # Initial Size of array aka snake
    DELAY=0.2 # Timer delay for move function
    FIRSTROW=3 # First row of game area
    FIRSTCOL=1 # First col of game area
    LASTCOL=40 # Last col of game area
    LASTROW=20 # Last row of game area
    AREAMAXX=$(( $LASTCOL - 1 )) # Furthest right play area X
    AREAMINX=$(( $FIRSTCOL + 1 )) # Furthest left play area X
    AREAMAXY=$(( $LASTROW - 1 )) # Lowest play area Y
    AREAMINY=$(( $FIRSTROW + 1)) # Highest play area Y
    ROWS=`tput lines` # Rows in terminal
    ORIGINX=$(( $LASTCOL / 2 )) # Start point X - use bc as it will round
    ORIGINY=$(( $LASTROW / 2 )) # Start point Y - use bc as it will round
    POSX=$ORIGINX # Set POSX to start pos
    POSY=$ORIGINY # Set POSY to start pos

    # Pad out arrays
    ZEROES=`echo |awk '{printf("%0"'"$SNAKESIZE"'"d\n",$1)}' | sed 's/0/0 /g'`
    LASTPOSX=( $ZEROES ) # Pad with zeroes to start with
    LASTPOSY=( $ZEROES ) # Pad with zeroes to start with

    SCORE=0 # Starting score

    clear
    echo "
    Keys:
    W - UP
    S - DOWN
    A - LEFT
    D - RIGHT
    X - QUIT
    If characters do not display properly, consider changing
    SNAKECHAR, APPLECHAR and WALLCHAR variables in script.
    Characters supported depend upon your terminal setup.
    Press Return to continue
    "

    stty -echo
    tput civis
    read RTN
    tput setb 0
    tput bold
    clear
    drawborder
    updatescore 0

    # Draw the first apple on the screen
    # (has collision detection to ensure we don't draw
    # over snake)
    drawapple
    sleep 1
    trap move ALRM

    # Pick a random direction to start moving in
    DIRECTIONS=( u d l r )
    randomchar "${DIRECTIONS[@]}"

    sleep 1
    move
    while :
    do
    read -s -n 1 key
    case "$key" in
    w) DIRECTION="u";;
    s) DIRECTION="d";;
    a) DIRECTION="l";;
    d) DIRECTION="r";;
    x) tput cup $COLS 0
    echo "Quitting..."
    tput cvvis
    stty echo
    tput reset
    printf "Bye Bye!\n"
    trap exit ALRM
    sleep $DELAY
    exit 0
    ;;
    esac
    done