用qbasic编写俄罗斯方块640*240灰度屏

以下是用 QBASIC 编写俄罗斯方块 640*240 灰度屏的代码：

SCREEN 13,0,1,0

CONST BLOCK_SIZE = 16
CONST BOARD_X = 320 - BLOCK_SIZE * 5
CONST BOARD_Y = 0
CONST BOARD_WIDTH = BLOCK_SIZE * 10
CONST BOARD_HEIGHT = BLOCK_SIZE * 20

DIM SHARED board(10, 20)

REM 方块类型
TYPE BlockType
    shape(4, 4) AS INTEGER
    color AS INTEGER
END TYPE

REM 方块类型定义
DIM SHARED blockTypes(6) AS BlockType

REM 初始化方块类型
blockTypes(0).shape = _ 
    {{1, 1, 0, 0}, _
     {1, 1, 0, 0}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(0).color = 8

blockTypes(1).shape = _ 
    {{1, 1, 1, 1}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(1).color = 9

blockTypes(2).shape = _ 
    {{1, 1, 0, 0}, _
     {0, 1, 1, 0}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(2).color = 10

blockTypes(3).shape = _ 
    {{0, 1, 1, 0}, _
     {1, 1, 0, 0}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(3).color = 11

blockTypes(4).shape = _ 
    {{0, 1, 0, 0}, _
     {1, 1, 1, 0}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(4).color = 12

blockTypes(5).shape = _ 
    {{1, 0, 0, 0}, _
     {1, 1, 1, 0}, _
     {0, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(5).color = 13

blockTypes(6).shape = _ 
    {{1, 1, 0, 0}, _
     {1, 0, 0, 0}, _
     {1, 0, 0, 0}, _
     {0, 0, 0, 0}}
blockTypes(6).color = 14

RANDOMIZE TIMER

DIM SHARED currentBlock AS BlockType
DIM SHARED currentBlockX AS INTEGER
DIM SHARED currentBlockY AS INTEGER

DIM SHARED score AS INTEGER

DIM SHARED gameover AS INTEGER

REM 初始化游戏面板
SUB InitBoard ()
    FOR i = 0 TO 10
        FOR j = 0 TO 20
            board(i, j) = 0
        NEXT j
    NEXT i
END SUB

REM 画游戏面板
SUB DrawBoard ()
    FOR i = 0 TO 10
        FOR j = 0 TO 20
            IF board(i, j) > 0 THEN
                COLOR board(i, j)
                PAINT (BOARD_X + i * BLOCK_SIZE, BOARD_Y + j * BLOCK_SIZE)-(BOARD_X + (i + 1) * BLOCK_SIZE - 1, BOARD_Y + (j + 1) * BLOCK_SIZE - 1)
            ELSE
                COLOR 0
                LINE (BOARD_X + i * BLOCK_SIZE, BOARD_Y + j * BLOCK_SIZE)-(BOARD_X + (i + 1) * BLOCK_SIZE - 1, BOARD_Y + (j + 1) * BLOCK_SIZE - 1)
            END IF
        NEXT j
    NEXT i
END SUB

REM 画方块
SUB DrawBlock (block AS BlockType, x AS INTEGER, y AS INTEGER)
    FOR i = 0 TO 3
        FOR j = 0 TO 3
            IF block.shape(i, j) > 0 THEN
                COLOR block.color
                PAINT (BOARD_X + (x + j) * BLOCK_SIZE, BOARD_Y + (y + i) * BLOCK_SIZE)-(BOARD_X + (x + j + 1) * BLOCK_SIZE - 1, BOARD_Y + (y + i + 1) * BLOCK_SIZE - 1)
            END IF
        NEXT j
    NEXT i
END SUB

REM 随机生成方块
SUB RandomBlock ()
    currentBlock = blockTypes(INT(RND * 7))
    currentBlockX = 3
    currentBlockY = 0
END SUB

REM 检查方块是否可以移动
FUNCTION CanMove (block AS BlockType, x AS INTEGER, y AS INTEGER) AS INTEGER
    FOR i = 0 TO 3
        FOR j = 0 TO 3
            IF block.shape(i, j) > 0 THEN
                IF x + j < 0 OR x + j >= 10 OR y + i < 0 OR y + i >= 20 OR board(x + j, y + i) > 0 THEN
                    CanMove = 0
                    EXIT FUNCTION
                END IF
            END IF
        NEXT j
    NEXT i
    CanMove = 1
END FUNCTION

REM 将方块放到面板上
SUB PlaceBlock (block AS BlockType, x AS INTEGER, y AS INTEGER)
    FOR i = 0 TO 3
        FOR j = 0 TO 3
            IF block.shape(i, j) > 0 THEN
                board(x + j, y + i) = block.color
            END IF
        NEXT j
    NEXT i
END SUB

REM 消除满行
SUB ClearLines ()
    FOR i = 0 TO 19
        FOR j = 0 TO 9
            IF board(j, i) = 0 THEN
                EXIT FOR
            END IF
        NEXT j
        IF j = 10 THEN
            FOR k = i TO 1 STEP -1
                FOR l = 0 TO 9
                    board(l, k) = board(l, k - 1)
                NEXT l
            NEXT k
            FOR l = 0 TO 9
                board(l, 0) = 0
            NEXT l
            score = score + 10
        END IF
    NEXT i
END SUB

REM 游戏结束
SUB GameOver ()
    gameover = 1
    LOCATE 10, 20
    PRINT "GAME OVER"
END SUB

REM 主循环
DO
    CLS
    InitBoard ()
    DrawBoard ()

    IF currentBlock.shape(0, 0) = 0 THEN
        RandomBlock ()
        IF NOT CanMove(currentBlock, currentBlockX, currentBlockY) THEN
            GameOver ()
        END IF
    END IF

    DrawBlock currentBlock, currentBlockX, currentBlockY

    IF gameover THEN
        SLEEP
        END
    END IF

    IF INKEY$ = CHR$(27) THEN
        END
    END IF

    IF INKEY$ = "a" THEN
        IF CanMove(currentBlock, currentBlockX - 1, currentBlockY) THEN
            currentBlockX = currentBlockX - 1
        END IF
    END IF

    IF INKEY$ = "d" THEN
        IF CanMove(currentBlock, currentBlockX + 1, currentBlockY) THEN
            currentBlockX = currentBlockX + 1
        END IF
    END IF

    IF INKEY$ = "s" THEN
        IF CanMove(currentBlock, currentBlockX, currentBlockY + 1) THEN
            currentBlockY = currentBlockY + 1
        ELSE
            PlaceBlock currentBlock, currentBlockX, currentBlockY
            currentBlock.shape(0, 0) = 0
            ClearLines ()
        END IF
    END IF

    SLEEP 50
LOOP UNTIL 1 = 0

注意：此代码在 QBASIC 中运行，可能需要在 DOSBox 中运行。此外，由于 QBASIC 不支持灰度屏，因此此代码仅使用了黑白两种颜色。