使用 Corona 的 lua 碰撞检测

Question

我在为特定碰撞检测表中的所有对象时遇到问题。只有当桌子上的第一个物体被雪球击中时，我才能使分数增加。这是我用于对象创建和碰撞的代码。按下按钮后，我有一个 createSnowBall() 函数调用。这部分工作正常。

local physics = require("physics")
physics.start()
physics.setGravity( 0, 0 )

local snowBalls = {}
local ornaments = {}
local score = 0

local scoreText = display.newText( "Score: " .. score, 70, 25, native.systemBoldFont, 32 )

function createSnowBall()
    snowBall = display.newImageRect( "snowball.png", 20, 20)
    snowBall.x = gun.x
    snowBall.y = HEIGHT - 110
    physics.addBody( snowBall, { density = 1.0, friction = 1, bounce = 0, radius = 20 } )
    snowBall.isSnowBall = true
    snowBalls[#snowBalls+1] = snowBall
    moveSnowBall(snowBall)
    return snowBall
end

function createOrnament(num)
        if num == 1 then
            ornament = display.newImageRect( "blueO.png", 30, 40)
        elseif num == 2 then
            ornament = display.newImageRect( "redO.png", 30, 40)
        elseif num == 3 then
            ornament = display.newImageRect( "greenO.png", 30, 40)
        end
    ornament.isOrnament = true
    ornaments[#ornaments+1] = ornament
    ornament.x = math.random(50, 270)
    ornament.y = 3
    local radius = 15
    physics.addBody( ornament, { density = 1.0, friction = 1, bounce = 1, radius = radius } )
    ornament:applyForce(35, 70, ornament.x + 4, ornament.y + 4)
    return ornament
end
createOrnament(math.random(1, 3))

function snowBallCollision(event)
    if event.phase == "began" then
        local target = event.other 
            if target.isSnowBall then
                score = score + 5
                scoreText.text = "Score: " .. score
            end
    end
end

ornament:addEventListener( "collision", snowBallCollision )

Answer 1

出现此问题的原因是：

ornament:addEventListener( "collision", snowBallCollision )

在这里，您只需向对象添加一次侦听器，然后将其分配给先前生成但尚未销毁的对象。

因此，只需从代码中删除该行，并且无论何时调用该行：

createOrnament(math.random(1, 3))

替换为：

local myOrnament = createOrnament(math.random(1, 3)) -- Since 'createOrnament' returns the object
myOrnament:addEventListener( "collision", snowBallCollision ) -- assign listener to the newly created object

这会将侦听器分配给您的所有“myOrnament”对象。

继续编码...... :)