Shell贪吃蛇（38快乐版）(2017-03-09)

楠妹子发了一个活动，要用代码来庆祝3.8节：。
这里就把 Shell 飞机游戏(2013-03-15) 拿来改一个庆祝节日的贪吃蛇吧 :D
贴上游戏截图，一只庆祝快乐的蛇来收集爱心（v 字母像一个爱心吧，就拿它来充当了，没试出打印 ascii 爱心的办法）。

   
    

#!/bin/bash
# Snake.sh
# Created by seesea <seesea2517#126.com> @ 2017-03-08
#
# 楠妹子发了一个活动，要用代码来庆祝3.8节：http://bbs.chinaunix.net/thread-4260145-1-1.html
# 这里就把 Shell 飞机游戏(2013-03-15) 拿来改一个庆祝节日的贪吃蛇吧 :D
# 一只庆祝快乐的蛇来收集爱心（v 字母像一个爱心吧，就拿它来充当了，没试出打印 ascii 爱心的办法）
# 做为简单 Demo，而且快乐的蛇应该是不死的，所以不做 GameOver 的处理啦

source colors.sh

# ============================================================================
# 常量
# ============================================================================

# 响应的信号
declare -r SIG_UP=SIGRTMIN+1
declare -r SIG_DOWN=SIGRTMIN+2
declare -r SIG_LEFT=SIGRTMIN+3
declare -r SIG_RIGHT=SIGRTMIN+4
declare -r SIG_PAUSE=SIGRTMIN+6
declare -r SIG_EXIT=SIGRTMIN+7

# 响应的按键（注意：使用大写配置）
declare -r KEY_UP="W"
declare -r KEY_DOWN="S"
declare -r KEY_LEFT="A"
declare -r KEY_RIGHT="D"
declare -r KEY_PAUSE="P"
declare -r KEY_EXIT="Q"

# 游戏区域位置大小
declare -r GAME_AREA_TOP=30
declare -r GAME_AREA_LEFT=40
declare -r GAME_AREA_WIDTH=40
declare -r GAME_AREA_HEIGHT=20

# 游戏边界显示字符（分横向和纵向两种字符）
declare -r BORDER_H="${BHIG} ${NOR}"
declare -r BORDER_V="${BHIG} ${NOR}"

# ============================================================================
# 全局变量/常量
# ============================================================================

declare stty_save                 # 终端设置
declare game_overed=0             # 游戏中止标志
declare game_paused=0             # 游戏暂停

declare pid_loop                  # 消息循环的进程pid

declare screen_width              # 屏宽
declare screen_height             # 屏高
declare game_map_width            # 屏宽
declare game_map_height           # 屏高

declare pos_head_r                # 当前蛇头坐标：行
declare pos_head_c                # 当前蛇头坐标：列

declare move_dir                  # 移动方向

declare snake_len                 # 蛇长
declare -a snake                  # 蛇体数据数组
declare -a pos_snake_r            # 每一节蛇体的坐标行值
declare -a pos_snake_c            # 每一节蛇体的坐标列值
declare old_tail_pos_r            # 移动后的蛇尾位置r
declare old_tail_pos_c            # 移动后的蛇尾位置c

declare -ar food_style=( "${RED}v${NOR}" "${GRN}v${NOR}" "${YEL}v${NOR}" "${BLU}v${NOR}" "${MAG}v${NOR}" "${CYN}v${NOR}" "${WHT}v${NOR}" "${HIR}v${NOR}" "${HIG}v${NOR}" "${HIY}v${NOR}" "${HIB}v${NOR}" "${HIM}v${NOR}" "${HIC}v${NOR}" "${HIW}v${NOR}" )
declare -r  food_style_count=${#food_style[@]}
declare food
declare food_pos_r
declare food_pos_c
declare food_style_index

# ============================================================================
# 函数定义
# ============================================================================

# 随机函数
# 参数一：随机数的上限+1，缺省为 10
function random()
{
    echo $(( RANDOM % ${1:-10} ))
}

# 键盘输入响应函数
function Input()
{
    while true
    do
        read -s -n 1 -a key
        key="${key[@]: -1}"
        case $key in
            $KEY_UP) sign=$SIG_UP ;;
            $KEY_DOWN) sign=$SIG_DOWN ;;
            $KEY_LEFT) sign=$SIG_LEFT ;;
            $KEY_RIGHT) sign=$SIG_RIGHT ;;
            $KEY_PAUSE) sign=$SIG_PAUSE ;;
            $KEY_EXIT) sign=$SIG_EXIT ;;
            *) continue ;;
        esac

        kill -s $sign $pid_loop

        # 若是退出按键，则根据游戏循环是否存在来判断是否确认退出
        if (( sign == SIG_EXIT ))
        then
            sleep 0.1
            if ! ps -p $pid_loop > /dev/null
            then
                break
            fi
        fi
    done
}

# 输入动作响应函数
# 输入参数一：键盘消息
function Action()
{
    sign=$1

    # 若游戏暂停，则只响应暂停信号和退出信号
    if (( game_paused && sign != SIG_PAUSE && sign != SIG_EXIT ))
    then
        return
    fi

    # 输入线程的暂停处理
    if (( game_overed && sign == SIG_PAUSE ))
    then
        return
    fi

    case $sign in
        $SIG_UP) OnPressPlayerMove "U" ;;
        $SIG_DOWN) OnPressPlayerMove "D" ;;
        $SIG_LEFT) OnPressPlayerMove "L" ;;
        $SIG_RIGHT) OnPressPlayerMove "R" ;;
        $SIG_PAUSE) OnPressGamePause ;;
        $SIG_EXIT) OnPressGameExit ;;
    esac
}

# 系统初始化
function Init()
{
    screen_width=$(tput cols)
    screen_height=$(tput lines)

    game_map_width=$GAME_AREA_WIDTH
    game_map_height=$GAME_AREA_HEIGHT

    # 终端设置
    stty_save=$(stty -g) # 保存stty配置
    stty -echo              # 关闭输入回显
    tput civis              # 关闭光标
    shopt -s nocasematch    # 开启大小写case比较的开关
    clear

    # 有时候echo会提示中断的函数调用，目前没啥解决办法，就把错误提示屏蔽了先
    exec 2> /dev/null
}

# 按键响应：游戏暂停
function OnPressGamePause()
{
    game_paused=$(( ! game_paused ))
}

# 按键响应：退出游戏
function OnPressGameExit()
{
    game_overed=1
}

# 按键响应：玩家动作
# $1: U D L R = up down left right
function OnPressPlayerMove()
{
    move_dir="$1"
}

function GameInit()
{
    # 设定输入响应函数
    # trap Action $SIG_UP $SIG_DOWN $SIG_LEFT $SIG_RIGHT $SIG_PAUSE $SIG_SHOOT $SIG_EXIT
    trap "Action $SIG_UP" $SIG_UP
    trap "Action $SIG_DOWN" $SIG_DOWN
    trap "Action $SIG_LEFT" $SIG_LEFT
    trap "Action $SIG_RIGHT" $SIG_RIGHT
    trap "Action $SIG_PAUSE" $SIG_PAUSE
    trap "Action $SIG_EXIT" $SIG_EXIT

    DrawBorder

    (( pos_head_c = game_map_width / 2 + $GAME_AREA_LEFT - 1 ))
    (( pos_head_r = game_map_height / 2 + $GAME_AREA_TOP - 1 ))
    game_overed=0
    move_dir='X'

    # 测试和截图用 :D snake=(H A P P Y 3 . 8 "${HIM}v${NOR}" "${WHT}v${NOR}" "${RED}v${NOR}" "${GRN}v${NOR}" "${YEL}v${NOR}" "${YEL}v${NOR}" "${BLU}v${NOR}" "${MAG}v${NOR}" "${MAG}v${NOR}" "${CYN}v${NOR}" "${WHT}v${NOR}" "${HIR}v${NOR}" "${HIG}v${NOR}" "${HIY}v${NOR}" "${HIB}v${NOR}" "${MAG}v${NOR}" "${HIM}v${NOR}")
    snake=(H A P P Y 3 . 8)
    snake_len=${#snake[*]}
    for (( i = 0; i < snake_len; ++i ))
    do
        pos_snake_r[$i]=$pos_head_r
        pos_snake_c[$i]=$(( ((pos_head_c + i + 1 + game_map_width - $GAME_AREA_LEFT) % game_map_width) + $GAME_AREA_LEFT ))
    done

    RandomFood
}

# 游戏循环
function GameLoop()
{
    GameInit

    while true
    do
        if (( game_overed ))
        then
            break
        fi

        FrameAction
        sleep 0.04  # 每秒25帧，sleep 0.04
    done
}

function GameStart()
{
    GameLoop &
    pid_loop=$!
}

function FrameAction()
{
    # 若游戏暂停，则不进行帧动作
    if (( game_paused ))
    then
        return
    fi

    MoveSnake
    if CheckAndEatFood
    then
        RandomFood
    fi

    DrawSnake
}

# 如果有吃到食物，返回真 0，否则返回假 1
function CheckAndEatFood()
{
    if (( pos_head_r != food_pos_r || pos_head_c != food_pos_c ))
    then
        return 1
    fi

    snake[$snake_len]=$food
    pos_snake_r[$snake_len]=$old_tail_pos_r
    pos_snake_c[$snake_len]=$old_tail_pos_c
    (( ++snake_len ))

    return 0
}

function MoveSnake()
{
    case $move_dir in
        'U') (( pos_head_r = ((pos_head_r - 1 + game_map_height - $GAME_AREA_TOP) % game_map_height) + $GAME_AREA_TOP )) ;;
        'D') (( pos_head_r = ((pos_head_r + 1 + game_map_height - $GAME_AREA_TOP) % game_map_height) + $GAME_AREA_TOP )) ;;
        'L') (( pos_head_c = ((pos_head_c - 1 + game_map_width - $GAME_AREA_LEFT) % game_map_width) + $GAME_AREA_LEFT )) ;;
        'R') (( pos_head_c = ((pos_head_c + 1 + game_map_width - $GAME_AREA_LEFT) % game_map_width) + $GAME_AREA_LEFT )) ;;
        *) return ;;
    esac

    (( tail_index = snake_len - 1 ))
    old_tail_pos_r=${pos_snake_r[$tail_index]}
    old_tail_pos_c=${pos_snake_c[$tail_index]}

    for (( i = snake_len - 1; i >= 1; --i ))
    do
        pos_snake_r[$i]=${pos_snake_r[$(( i - 1 ))]}
        pos_snake_c[$i]=${pos_snake_c[$(( i - 1 ))]}
    done

    pos_snake_r[0]=$pos_head_r
    pos_snake_c[0]=$pos_head_c
}

function DrawSnake()
{
    echo -ne "${ESC}[${old_tail_pos_r};${old_tail_pos_c}H "

    for (( i = 0; i < snake_len; ++i ))
    do
        pos_r=${pos_snake_r[$i]}
        pos_c=${pos_snake_c[$i]}

        echo -ne "${ESC}[${pos_r};${pos_c}H${snake[$i]}"
    done
}

function DrawSnakeXXX()
{
    echo -ne "${ESC}[${old_tail_pos_r};${old_tail_pos_c}H "

    for (( i = 1; i < snake_len - 1; ++i ))
    do
        (( j = i - 1 ))
        pos_r=${pos_snake_r[$j]}
        pos_c=${pos_snake_c[$j]}

        echo -ne "${ESC}[${pos_r};${pos_c}H${snake[$i]}"
    done

    echo -ne "${ESC}[${pos_head_r};${pos_head_c}H${snake[0]}"
}

function RandomFood()
{
    # 暂不考虑蛇满屏的时候无法生成新食物的情况
    while true
    do
        (( food_pos_r = $(random game_map_height) + $GAME_AREA_TOP ))
        (( food_pos_c = $(random game_map_width) + $GAME_AREA_LEFT ))

        again=0
        for (( i = 0; i < snake_len; ++i ))
        do
            if (( pos_snake_r[i] == food_pos_r && pos_snake_c[i] == food_pos_c ))
            then
                again=1
                break
            fi
        done

        if (( again == 0 ))
        then
            break
        fi
    done

    food_style_index=$(random $food_style_count)
    food=${food_style[$food_style_index]}
    echo -ne "${ESC}[${food_pos_r};${food_pos_c}H$food"
}

# 退出游戏清理操作
function ExitClear()
{
    # 恢复大小写case比较的开关
    shopt -u nocasematch

    # 恢复stty配置
    stty $stty_save
    tput cnorm

    clear
}

# 绘制边界
function DrawBorder()
{
    local i
    local border_h
    local border_v
    local r
    local c
    local c2

    border_h=""
    for (( i = 0; i < GAME_AREA_WIDTH + 1; ++i ))
    do
        border_h="$border_h$BORDER_H"
    done

    # 画顶边
    r=$(( GAME_AREA_TOP - 1 ))
    c=$(( GAME_AREA_LEFT - 1 ))
    echo -ne "${ESC}[${r};${c}H${border_h}"

    # 画底边
    r=$(( GAME_AREA_TOP + GAME_AREA_HEIGHT ))
    echo -ne "${ESC}[${r};${c}H${border_h}"

    c2=$(( GAME_AREA_LEFT - 1 + GAME_AREA_WIDTH + 1 ))
    for (( r = GAME_AREA_TOP - 1; r < GAME_AREA_TOP + GAME_AREA_HEIGHT + 1; ++r ))
    do
        echo -ne "${ESC}[${r};${c}H${BORDER_V}${ESC}[${r};${c2}H${BORDER_V}"
    done
}

# 主函数
function Main()
{
    Init

    GameStart
    Input
    ExitClear
}

Main