二十多年前写的一款游戏

今天整理邮件时，偶然发现了我在二十多年前，上小学时写的一个类似《小蜜蜂》的游戏，大概是小学五年级或者六年级，用的 QBasic。

因为我没有配置 QBasic 的环境，所以也不确定还能不能用。但看这个程序，真的恍如隔世。

DECLARE SUB Initialize ()
DECLARE SUB DrawPlayer ()
DECLARE SUB MovePlayer (direction AS INTEGER)
DECLARE SUB Shoot ()
DECLARE SUB CheckInput ()
DECLARE SUB InitializeEnemies ()
DECLARE SUB MoveEnemies ()
DECLARE SUB EnemyShoot ()
DECLARE SUB MoveEnemyBullets ()
DECLARE SUB DrawEnemies ()
DECLARE SUB CheckCollisions ()
DECLARE SUB GameOver ()
DECLARE SUB DrawGame ()

CONST screenWidth = 80
CONST screenHeight = 25
CONST playerChar = "A"
CONST bulletChar = "^"
CONST enemyBulletChar = "*"
CONST enemyChar = "V"
CONST maxEnemies = 5
CONST maxEnemyBullets = 10

TYPE Enemy
    x AS INTEGER
    y AS INTEGER
    dx AS INTEGER
    active AS BOOLEAN
END TYPE

TYPE Bullet
    x AS INTEGER
    y AS INTEGER
    active AS BOOLEAN
END TYPE

DIM SHARED playerX AS INTEGER, playerY AS INTEGER
DIM SHARED playerBullet AS Bullet
DIM SHARED enemies(maxEnemies) AS Enemy
DIM SHARED enemyBullets(maxEnemyBullets) AS Bullet
DIM SHARED score AS INTEGER
DIM SHARED gameRunning AS BOOLEAN

RANDOMIZE TIMER
Initialize

DO WHILE gameRunning AND NOT INKEY$ = CHR$(27) 
    CALL CheckInput
    CALL MoveEnemies
    CALL EnemyShoot
    CALL MoveEnemyBullets
    CALL CheckCollisions
    CALL DrawGame
    SLEEP 1
LOOP

IF NOT gameRunning THEN
    CALL GameOver
END IF

SUB Initialize
    playerX = screenWidth / 2
    playerY = screenHeight - 1
    playerBullet.active = FALSE
    score = 0
    gameRunning = TRUE
    CALL InitializeEnemies
END SUB

SUB InitializeEnemies
    FOR i = 1 TO maxEnemies
        enemies(i).x = INT(RND * (screenWidth - 2)) + 2
        enemies(i).y = INT(RND * 5) + 1
        enemies(i).dx = IIF(RND > 0.5, 1, -1)
        enemies(i).active = TRUE
    NEXT i
END SUB

SUB DrawGame
    CLS
    LOCATE playerY, playerX
    PRINT playerChar;
    IF playerBullet.active THEN
        LOCATE playerBullet.y, playerBullet.x
        PRINT bulletChar;
    END IF
    FOR i = 1 TO maxEnemies
        IF enemies(i).active THEN
            LOCATE enemies(i).y, enemies(i).x
            PRINT enemyChar;
        END IF
    NEXT i
    FOR i = 1 TO maxEnemyBullets
        IF enemyBullets(i).active THEN
            LOCATE enemyBullets(i).y, enemyBullets(i).x
            PRINT enemyBulletChar;
        END IF
    NEXT i
    LOCATE 1, 1
    PRINT "Score: "; score
END SUB

SUB MovePlayer (direction AS INTEGER)
    IF direction = -1 AND playerX > 1 THEN
        playerX = playerX - 1
    ELSEIF direction = 1 AND playerX < screenWidth THEN
        playerX = playerX + 1
    END IF
END SUB

SUB Shoot
    IF NOT playerBullet.active THEN
        playerBullet.x = playerX
        playerBullet.y = playerY - 1
        playerBullet.active = TRUE
    END IF
END SUB

SUB CheckInput
    DIM key AS STRING
    key = INKEY$
    SELECT CASE key
    CASE CHR$(75) ' left
        CALL MovePlayer(-1)
    CASE CHR$(77) ' right
        CALL MovePlayer(1)
    CASE " " ' space
        CALL Shoot
    END SELECT
END SUB

SUB MoveEnemies
    FOR i = 1 TO maxEnemies
        IF enemies(i).active THEN
            enemies(i).x = enemies(i).x + enemies(i).dx
            IF enemies(i).x <= 1 OR enemies(i).x >= screenWidth THEN
                enemies(i).dx = -enemies(i).dx
                enemies(i).y = enemies(i).y + 1
            END IF
            IF enemies(i).y >= screenHeight THEN
                enemies(i).y = 1
            END IF
        END IF
    NEXT i
END SUB

SUB EnemyShoot
    FOR i = 1 TO maxEnemies
        IF enemies(i).active AND INT(RND * 10) < 2 THEN
            FOR j = 1 TO maxEnemyBullets
                IF NOT enemyBullets(j).active THEN
                    enemyBullets(j).x = enemies(i).x
                    enemyBullets(j).y = enemies(i).y + 1
                    enemyBullets(j).active = TRUE
                    EXIT FOR
                END IF
            NEXT j
        END IF
    NEXT i
END SUB

SUB MoveEnemyBullets
    FOR i = 1 TO maxEnemyBullets
        IF enemyBullets(i).active THEN
            enemyBullets(i).y = enemyBullets(i).y + 1
            IF enemyBullets(i).y > screenHeight THEN
                enemyBullets(i).active = FALSE
            END IF
        END IF
    NEXT i
END SUB

SUB CheckCollisions
    IF playerBullet.active THEN
        FOR i = 1 TO maxEnemies
            IF enemies(i).active THEN
                IF playerBullet.x = enemies(i).x AND playerBullet.y = enemies(i).y THEN
                    playerBullet.active = FALSE
                    enemies(i).active = FALSE
                    score = score + 10
                    EXIT FOR
                END IF
            END IF
        NEXT i
    END IF
    
    FOR i = 1 TO maxEnemyBullets
        IF enemyBullets(i).active THEN
            IF enemyBullets(i).x = playerX AND enemyBullets(i).y = playerY THEN
                gameRunning = FALSE
            END IF
        END IF
    NEXT i
END SUB

SUB GameOver
    CLS
    LOCATE screenHeight / 2, (screenWidth / 2) - 5
    PRINT "Game Over! Score: "; score
    SLEEP 5
END SUB