为什么我的小鸟游戏按空格键时我的小鸟不跳？

Question

我是lua和love的新手。我正在尝试制作一个飞扬的小鸟游戏。游戏运行时，小鸟不会跳跃。这只鸟只是漂浮，直到它坠毁并且游戏结束。此外，只显示了我的原始管道，没有生成新管道。当我按下空格键并保持产卵管道时，如何让鸟跳起来？ 下面是我的代码：

--sets up game window
function love.load()
    love.window.setMode(400, 600)
    love.window.setTitle("Flappy Bird")


    --load assets
    bg= love.graphics.newImage("flappy background.png")
    bird = love.graphics.newImage("bird image.png")

    pipeImage = love.graphics.newImage("pipe-up.png")
    jumpSound = love.audio.newSource("jump sound.wav", "static")
    scoreSound = love.audio.newSource("scoring.wav", "static")
    gameOverSound = love.audio.newSource("game over.wav", "static")


    --initialize game variables
    x = 502
    jumpHeight = 500
    velocity = -300
    gapHeight = 150
    pipeX = 400
    pipeY = love.math.random(100, 400)
    scored = false
    score = 0
    gameover = false
end

--draw game objects
function love.draw()
     
    --Get the dimensions of the window
    local windowWidth, windowHeight = love.graphics.getDimensions()

    --Calculate the scaling factor for the background image
    local sx = windowWidth / bg:getWidth()
    local sy = windowHeight / bg:getHeight()

    --Draw the scaled background image
    love.graphics.draw(bg, 0, 0, 0, sx, sy)

    love.graphics.draw(bird, x, y)
    love.graphics.draw(pipeImage, pipeX, pipeY - pipeImage:getHeight() - gapHeight)
    love.graphics.draw(pipeImage, pipeX, pipeY + gapHeight)
    love.graphics.print("Score: " .. score, 10, 10)
end

--adds movement to bird
function love.keypressed(key)
    if key == "space" and not gameover then
        velocity = -jumpHeight 
        jumpSound:play() -- play the jump sound effect
    elseif key == "r" and gameover then
            --reinitialize game variables
        x = 50
        y = 300
        velocity = -120
        pipeX = 400
        pipeY = love.math.random(100, 400)
        scored = false
        score = 0
        gameover = false
    end
end

--checks collison with pipes
function checkCollision(x1, y1, w1, h1, x2, y2, w2, h2)
    return x1 < x2 + w2 and
    x2 < x1 + w1 and
    y1 < y2 + h2 and
    y2 < y1 + h1
end

function love.update(dt)
    if not gameover then
        --update the bird's position and velocity
        velocity = velocity + gravity * dt
        y = y + velocity * dt

        --update the pipe's position
        pipeX = pipeX - 200 * dt

        --reset the pipe's position if it goes offscreen
        if pipeX < -pipeImage:getWidth() then
            pipeX = -120
            pipeY = love.math.random(100, 400)
            scored = false
        end

        --check for collision with pipes
        if checkCollision(x, y, bird:getWidth(), bird:getHeight(), pipeX, pipeY - pipeImage:getHeight() - gapHeight, pipeImage:getWidth(), pipeImage:getHeight()) or
        checkCollision(x, y, bird:getWidth(), bird:getHeight(), pipeX, pipeY + gapHeight, pipeImage:getWidth(), pipeImage:getHeight()) or
        y < 0 or
        y > love.graphics.getHeight() then
            gameover = true
            gameOverSound:play()
        end

        --check for scoring
        if x > pipeX + pipeImage:getWidth() and not scored then
            score = score + 1
            scored = true
            scoreSound:play()
        end
    end
end

--adds game over screen
function drawGameOver()
    love.graphics.print("Game Over", 100, 100)
    love.graphics.print("Score: " .. score, 100, 150)
end

function love.draw()
    if not gameover then
        --Get the dimensions of the window
        local windowWidth, windowHeight = love.graphics.getDimensions()

        --Calculate the scaling factor for the background image
        local sx = windowWidth / bg:getWidth()
        local sy = windowHeight / bg:getHeight()

        --Draw the scaled background image
        love.graphics.draw(bg, 0, 0, 0, sx, sy)

    end
end
        y = 300
        love.graphics.draw(bird, x, y)
        love.graphics.draw(pipeImage, pipeX, pipeY - pipeImage:getHeight() - gapHeight)
        love.graphics.draw(pipeImage, pipeX, pipeY + gapHeight)
        love.graphics.print("Score: " .. score, 10, 10)
    else
        drawGameOver()
    end
end

--restarts the game
function love.keypressed(key)
    if key == "r" and gameover then
        --reinitialize game variables
        x = 50
        y = 300
        velocity = 0
        pipeX = 400
        pipeY = love.math.random(100, 400)
        scored = false
        score = 0
        gameover = false
        gravity = 0

我尝试调整跳跃高度、速度和重力变量来解决问题，但无济于事。我还将按键功能合并为一个，认为重启功能在跳转功能之前出现，但这也不起作用。我做错了什么？

Answer 1

看来在你让鸟跳的代码中你做错了什么。

function love.keypressed(key)
    if key == "space" and not gameover then
        velocity = -jumpHeight

您正在使鸟的速度等于

-jumpHeight

。 你应该尝试用

velocity = -jumpHeight

替换

y = y + jumpHeight

。

关于你的第二个问题，关于如何保持产卵管道。您可以通过检查

pipeX

值来检测管道是否在屏幕外（在这种情况下很可能是

pipeX < 0

）。如果是这样，您可以像重置游戏时一样重置

pipeX

和

pipeY

。