在電暈中使用強力擊球的問題sdk

Question

我正在開發一個類似於空氣曲棍球的比賽我想使用下面的代碼來強制擊球，但是這個代碼的問題在於有時在擊球時碰撞）有冰球的木槌木槌消失，有時冰球也從屏幕上消失，我無法找出實際問題是從屏幕上消失的物體是什麼，但如果我改變本地開始= self.points [1 ]到本地開始= self.points [2]在getVelocity函數然後同樣消失的情況發生，請嘗試從很長一段時間，我困住這個isuue，我是新的Corona.Thanks解決問題... ...

local sqrt = math.sqrt 
local physics = require("physics") 
physics.start() 
physics.setGravity(0,0) 
physics.setDrawMode("debug") 


local source 
local target 

-- Track velocity 
local velocityTracker = { 
    points = {}  
} 

function velocityTracker:reset() 
    self.points = {} 
end 

function velocityTracker:addPoint(time, x, y) 
    -- Only keep 10 points 
    local count = #self.points + 1 
    if count == 11 then 
     count = 10 
     for i=1,10 do 
      -- Move older points to top 
      self.points[i] = self.points[i+1] 
     end 
    end 
    self.points[count] = {time = time, x = x, y = y} 
end 

function velocityTracker:getVelocity(moves) 
    if #self.points < 2 then 
     return 0 
    end 

    local start = self.points[1] 
    local totalVelocity = 0 
    local now = system.getTimer() 
    for i=2,#self.points do 
     local finish = self.points[i] 
     -- Use a vector to determine velocity 
     local timePassed = finish.time - start.time 
     local age = now - finish.time 
     -- Only use recent points 
     if age < 200 then 
      local vector = {x = finish.x - start.x, y = finish.y - start.y} 
      local distance = sqrt(vector.x^2 + vector.y^2) 
      -- Calculate velocity 
      totalVelocity = totalVelocity + (distance/timePassed) 
     end 
     start = finish 
    end 
    return totalVelocity 
end 

local function onPuckCollision(event)  
    if event.phase == "began" and event.other.isBall then 
     -- Puck just hit a ball   
     local ball = event.other 
     local puck = event.target 

     -- Use a vector to determine direction of hit 
     local vector = {x = ball.x - puck.x, y = ball.y - puck.y} 
     -- normalize vector 
     local magnitude = sqrt(vector.x^2 + vector.y^2) 
     if magnitude > 0 then 
      vector.x = vector.x/magnitude 
      vector.y = vector.y/magnitude 
     end   

     -- Use velocity to determine force 
     local force = 10 * velocityTracker:getVelocity() 

     local function smack() 
      ball:applyForce(vector.x * force, vector.y * force, ball.x, ball.y) 
     end 

     -- We can't modify phyiscs in a collision handler so we 
     -- `performWithDelay` to cause it to execute after this function 
     timer.performWithDelay(0, smack) 
    end 
end 

local function movePuck(event) 
    local t = event.target 
    local phase = event.phase 
    if "began" == phase then 
     local parent = t.parent 
     display.getCurrentStage():setFocus(t) 
     t.isFocus = true 
     -- Store initial position 
     t.x0 = event.x - t.x 
     t.y0 = event.y - t.y 
     -- Save velocity tracking state 
     velocityTracker:reset() 
     velocityTracker:addPoint(event.time, event.x, event.y) 
    elseif t.isFocus then 
     if "moved" == phase then 
      t.x = event.x - t.x0 
      t.y = event.y - t.y0 

      -- Track a movement 
      velocityTracker:addPoint(event.time, event.x, event.y) 
     elseif "ended" == phase or "cancelled" == phase then 
      display.getCurrentStage():setFocus(nil) 
      t.isFocus = false 
      velocityTracker:reset() 
     end 
    end 
    return true 
end 


target = display.newCircle(250, 250, 60) 
target.x = display.contentCenterX 
target.y = display.contentCenterY 
target:setFillColor(240, 200, 0) 
target.isBall = true 
-- Don't allow sleeping because a moving static body 
-- won't always wake it if it's asleep 
target.isSleepingAllowed = false 
physics.addBody(target,"dynamic",{radius = target.width/2}) 


source = display.newCircle(250, 250, 60) 
source.x = display.contentCenterX 
source.y = display.contentHeight - 100 
source:setFillColor(240,125,0) 
source.isPuck = true 
-- Use static body if you're going to move the object instead of 
-- letting the physics engine move it 
physics.addBody(source,"static", {radius = source.width/2}) 

source:addEventListener("collision", onPuckCollision) 

source:addEventListener("touch", movePuck) 

local bounds = { 
    left = -target.width, 
    top = -target.height, 
    right = display.contentWidth + target.width, 
    bottom = display.contentHeight + target.height, 
} 

-- Reset ball position if it leaves screen 
local function resetBall() 
    if target.x < bounds.left or target.x > bounds.right or 
     target.y < bounds.top or target.y > bounds.bottom 
     then 
     target.bodyType = 'static' -- Stop current movement 
     target.x = display.contentCenterX 
     target.y = display.contentCenterY     
     target.bodyType = 'dynamic' -- Make movable again 

     source.x = display.contentCenterX 
     source.y = display.contentHeight - 100   

     display.getCurrentStage():setFocus(nil) 
    end 
end 

timer.performWithDelay(500, resetBall, 0) 

Answer 1

更改時間表爲0你會看到這一直髮生，這可能是有時發生的事情。在除以之前總是檢查一個數字是不是零。