如何改變子彈在運動方向發生碰撞後的方向（角度）sdk

Question

我想在碰撞後改變子彈的角度，碰撞後它應該改變它的移動方向，並且必須停止旋轉碰撞後....請給什麼建議？謝謝下面

local physics = require("physics") 
physics.start() 

local obj 

physics.setScale(60) 
physics.setGravity(0, 0) 

display.setStatusBar(display.HiddenStatusBar) 
local obstacle = display.newCircle(250, 250, 60) 
obstacle.x = display.contentWidth/2; obstacle.y = 200 
physics.addBody(obstacle, { density=150, friction=0.2, bounce=0}) 
obstacle.isBullet=true 


obj = display.newRect(0, 0,20,40) 
obj.x = display.contentWidth/2; obj.y = 780 
obj.isBullet = true 
obj.color = "white" 
physics.addBody(obj, { density=1, friction=0.4, bounce=0.1}) 

local target = display.newCircle(250, 250, 60) 
target.x = obj.x; target.y = obj.y; target.alpha = 0 


local function Shot(event) 
    local t = event.target 

    local phase = event.phase 
    if "began" == phase then 
     display.getCurrentStage():setFocus(t) 
     t.isFocus = true 

     t:setLinearVelocity(0, 0) 
     t.angularVelocity = 0 

     target.x = t.x 
     target.y = t.y 

     startRotation = function() 
      target.rotation = target.rotation + 4 
     end 

     Runtime:addEventListener("enterFrame", startRotation) 

     local showTarget = transition.to(target, { alpha=0.4, xScale=0.4, yScale=0.4, time=200 }) 
     myLine = nil 

    elseif t.isFocus then 
     if "moved" == phase then 

    if (myLine) then 
       myLine.parent:remove(myLine) -- erase previous line, if any 
      end 
      myLine = display.newLine(t.x,t.y, event.x,event.y) 
      myLine:setColor(255, 255, 255, 50) 
      myLine.width = 8 

     elseif "ended" == phase or "cancelled" == phase then 

      display.getCurrentStage():setFocus(nil) 
      t.isFocus = false 

      local stopRotation = function() 
       Runtime:removeEventListener("enterFrame", startRotation) 
      end 

      local hideTarget = transition.to(target, { alpha=0, xScale=1.0, yScale=1.0, time=200, onComplete=stopRotation }) 

      if (myLine) then 
       myLine.parent:remove(myLine) 
      end 

      t:applyForce((t.x - event.x), (t.y - event.y), t.x, t.y) 

     end 
    end 

return true 
end 

obj:addEventListener("touch", Shot) 

Answer 1

local physics = require "physics" 
physics.start() 

local rect1 = display.newRect(480,0,10,320) 
physics.addBody(rect1, "static") 

local rect2 = display.newRect(20,100,20,20) 

local function shot() 
    physics.addBody(rect2, "dynamic") 
    rect2:applyForce(1000, 0, rect2.x, rect2.y) 
    rect2.myName = "rect2" 
end 
rect2:addEventListener("touch", shot) 

示例代碼被寫入