Lua Create multiple collisions - lua

Question

I'm trying to create a break breaker game that contains brinks that can be hit twice before the disappear.
I have tried:
--FOR STRONGER DEFENDERS
for i = 1, len do
for j = 1, level_W do
if(level[i][j] == 2) then
local strong = display.newImage('images/strongdefender.png')
strong.name = 'strong'
strong.x = def_W * j - offset
strong.y = def_H * i
physics.addBody(strong, {density = 1, friction = 0, bounce = 0})
strong.bodyType = 'static'
strongs.insert(strongs, strong)
end
end
end
for i = 1, len do
for j = 1, level_W do
if(level[i][j] == 2) then
local defender = display.newImage('images/defender.png')
defender.name = 'defender'
defender.x = def_W * j - offset
defender.y = def_H * i
physics.addBody(defender, {density = 1, friction = 0, bounce = 0})
defender.bodyType = 'static'
end
end
end
level is a table which is filled with 0 and 2. 2 is where the defender image will be in the game.
My collision event is like so:
function onCollision(e)
if(e.other.name == 'defender' or e.other.name == 'strong' and (ball.x + ball.width * 0.5) < (e.other.x + e.other.width * 0.5)) then
xSpeed = -5
elseif(e.other.name == 'defender' or e.other.name == 'strong' and (ball.x + ball.width * 0.5) >= (e.other.x + e.other.width * 0.5)) then
xSpeed = 5
end
if(e.other.name == 'defender') then
audio.play(defencePop)
ySpeed = ySpeed * -1
e.other:removeSelf()
e.other = nil
defenders.numChildren = defenders.numChildren - 1
--SORT SCORE
score = score + 1
scoreNum.text = score * points
scoreNum:setReferencePoint(display.CenterLeftReferencePoint)
scoreNum.x = 54
elseif(e.other.name == 'strong') then
audio.play(defencePop)
ySpeed = ySpeed * -1
e.other:removeSelf()
e.other = nil
defenders.numChildren = defenders.numChildren - 1
--SORT SCORE
score = score + 1
scoreNum.text = score * points
scoreNum:setReferencePoint(display.CenterLeftReferencePoint)
scoreNum.x = 54
end
--defenders.numChildren < 0
if(strongs.numChildren < 0) then
bgAlert('win')
gameStatus = 'win'
end
end -- removeDefender
When the ball collides with the element, both of them disappear. How can I make one disappear at a time?

Answer 1

I would suggest you just put the strong on the screen and add an event listener to them the weaker brick is created when the collision occurs with the stronger brick. The idea is to remove the object and add a new one when the collision occurs.
First you would display the strong object and add them to physics. You would also add a local collision event listener to the object
for i = 1, len do
for j = 1, level_W do
if(level[i][j] == 2) then
local strong = display.newImage('images/strongdefender.png')
strong.name = 'strong'
strong.x = def_W * j - offset
strong.y = def_H * i
physics.addBody(strong, {density = 1, friction = 0, bounce = 0})
strong.bodyType = 'static'
strong.collision = onBrickCollision --onStrongCollision is the name of the collision handler function
strong:addEventListener("collision" , strong) --add collision listener
strongs.insert(strongs, strong)
end
end
end
The event listener would be like
function onBrickCollision(self , event)
if event.phase == "began" and event.other.name == "ball" then
if (ball.x + ball.width * 0.5) < (self.x + self.width * 0.5) then
xSpeed = -5
else
xSpeed = 5
end
if self.name == "strong" then
audio.play(defencePop)
ySpeed = ySpeed * -1
--Create defender on the position of strong and add it to physics
local defender = display.newImage('images/defender.png')
defender.name = 'defender'
set the position same as the object which is hit by ball
defender.x = self.x
defender.y = self.y
physics.addBody(defender, {density = 1, friction = 0, bounce = 0})
defender.bodyType = 'static'
defender.collision = onBrickCollision
defender:addEventListener("collision", defender)
--remove the strong brick
self:removeSelf()
self = nil
--SORT SCORE
score = score + 1
scoreNum.text = score * points
scoreNum:setReferencePoint(display.CenterLeftReferencePoint)
scoreNum.x = 54
elseif self.name == "defender" then
audio.play(defencePop)
ySpeed = ySpeed * -1
self:removeSelf()
self = nil
defenders.numChildren = defenders.numChildren - 1
--SORT SCORE
score = score + 1
scoreNum.text = score * points
scoreNum:setReferencePoint(display.CenterLeftReferencePoint)
scoreNum.x = 54
end
end
Hope the code is self explanatory :) Feel free to ask me if you have any further questions.