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How can I destroy my bullets when they touch the enemies? — Gideros Forum
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    How can I destroy my bullets when they touch the enemies?

    AxlFlameAxlFlame Member
    edited September 2014 in Game & application design
    Hi everyone! I was wondering if anyone can give me some light on this problem...

    So, I have a minigame where the player controls a ship and is able to shoot some bullets and those bullets destroy the enemies he faces.
    The idea is simple, I just want to be able to destroy the bullets when they touch the enemy, but for some reason only some bullets get destroyed with my current code... not only that, but the enemies are sometimes taking multiple hits from the same bullet, which I thought wasn't supposed to happen, since they only take damage if the bullet is added to the game...

    Here's my code so far:

    I'm using the TNT Virtual Pad, so this code right here is activated when the user presses the button:
    			fireT = CEO_Shot.new(player.xPos + 16, player.yPos + 14)
			bulletArray[iBullet] = fireT
			self:addChild(bulletArray[iBullet])
			bulletArray[iBullet].isDead = false
			iBullet = iBullet + 1
    And this is my onEnterFrame, where I check the collisions:
    function CEO_M1:onEnterFrame()
	for key,value in pairs(bulletArray)do
		print ("key: ", key)
		if enemies[0]:hitTestPoint(bulletArray[key]:getX(), bulletArray[key]:getY()) then
			if this:contains(bulletArray[key]) then
				enemies[0]:takeDamage(5)
				bulletArray[key].isDead = true
			end
		elseif enemies[1]:hitTestPoint(bulletArray[key]:getX(), bulletArray[key]:getY()) then
			if this:contains(bulletArray[key]) then
				enemies[1]:takeDamage(5)
				bulletArray[key].isDead = true
			end
		elseif enemies[2]:hitTestPoint(bulletArray[key]:getX(), bulletArray[key]:getY()) then
			if this:contains(bulletArray[key]) then
				enemies[2]:takeDamage(5)
				bulletArray[key].isDead = true
			end
		end
 
		if bulletArray[key]:getX() > self.w then
			bulletArray[key].isDead = true
		end
	end
	CEO_M1:killBullets()
end
    This is the code for the killBullets method:
    function CEO_M1:killBullets()
	for i=0, iBullet-1, 1 do
		if this:contains(bulletArray[i]) then
			if bulletArray[i].isDead == true then
				this:removeChild(bulletArray[i])
				iBullet = iBullet - 1
			end
		end
	end
end
    And finally, this is the class from where the bullets are created (C.E.O_Shot):
    CEO_Shot = Core.class(Sprite)
 
function CEO_Shot:init(x, y)
	--parametros do minigame
	self.h= application:getContentHeight()
	self.w= application:getContentWidth()
	self.fire =	Bitmap.new(Texture.new("images/Minigames/CEO/M1/Pewpew.png"))
	self.fire:setAnchorPoint(.5, .5)
	self.xPos = x
	self.yPos = y
	self.fire:setScale(0.8,0.8)
	self:setPosition(self.xPos, self.yPos)
	self:addChild(self.fire)
	--self:setVisible
	self:addEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
end
 
function CEO_Shot:onEnterFrame(Event)
	self.xPos = self.xPos + 180 *Event.deltaTime
	self:setPosition(self.xPos, self.yPos)
	if self.xPos > self.w then
		self:removeEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
		self:removeChild(self.fire)
	end
end
    Any help will be deeply appreciated!
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    Comments

    • EricCarrEricCarr Member
      Why don't you check if the bullet IsDead directly? Also, check it once instead of once for every enemy.
      e.g.

      if not value.isDead then
      for i=1,enemyCount,1 do
      if enemies[i]:hitTest...
      end
      end

      Likes: AxlFlame

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    • DiscipleDisciple Member
      Accepted Answer
      Can't quite tell without messing around with the code but an easier way to remove sprites is through removeFromParent(). So the way I'd do it is to get rid of the "isDead" variable and remove them right away by writing "bulletArray[key]:removeFromParent()". It also gets rid of the events in the bullets.

      Also, but it's only about style and ease (not to solve the problem), I'd write something like "local currentBullet = bulletArray[key]" and then deal with the currentBullet variable instead of with bulletArray[key] each time.
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    • AxlFlameAxlFlame Member
      Thanks a lot, @Disciple, I tried using removeFromParent() and it worked perfectly!

      Now, I'm not sure I understand what you meant, about using a currentBullet instead of dealing with the bulletArray[key]... what would be the difference? I mean, in both cases you deal with one bullet per for cycle, right?

      Likes: Disciple

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    • DiscipleDisciple Member
      edited September 2014
      I'm glad it worked :)

      Yeah it's the same and it's off topic to your question. I just meant for tidiness sake. Personally I prefer something like this but it's the same (sorry for not putting it as code, I don't know how to :/) :
      function CEO_M1:onEnterFrame()
	for key,value in pairs(bulletArray)do
		print ("key: ", key)
                bullet = bulletArray[key]
		if enemies[0]:hitTestPoint(bullet:getX(), bullet:getY()) then
			if this:contains(bullet) then
				enemies[0]:takeDamage(5)
				bullet.isDead = true
			end
		elseif enemies[1]:hitTestPoint(bullet:getX(), bullet:getY()) then
			if this:contains(bullet) then
				enemies[1]:takeDamage(5)
				bullet.isDead = true
			end
		elseif enemies[2]:hitTestPoint(bullet:getX(), bullet:getY()) then
			if this:contains(bullet) then
				enemies[2]:takeDamage(5)
				bullet.isDead = true
			end
		end
 
		if bullet:getX() > self.w then
			bullet.isDead = true
		end
	end
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