Avoid collision - Corona

Question

I have initialized the object named jet to collide when it interacts with other objects, But when i move the jet and touch the ceiling or floor they are also exploding. How to avoid getting collision function with ceiling & Floor? Here is the code.

Ceiling Object

ceiling = display.newImage("invisibleTile.png")
ceiling:setReferencePoint(display.BottomLeftReferencePoint)
ceiling.x = 0
ceiling.y = 0
physics.addBody(ceiling, "static", {density=.1, bounce=0.1, friction=.2})
screenGroup:insert(ceiling)
local groundShape = { -280,-20, 280,-20, 280,20, -280,20 }

Floor Object

theFloor = display.newImage("invisibleTile.png")
theFloor:setReferencePoint(display.BottomLeftReferencePoint)
theFloor.x = 0
theFloor.y = 300
physics.addBody(theFloor, "static", {density=.1, bounce=0.1, friction=.2, shape=groundShape })
screenGroup:insert(theFloor)

Jet Object

jetSpriteSheet = sprite.newSpriteSheet("greenman.png", 128, 128)
jetSprites = sprite.newSpriteSet(jetSpriteSheet, 1, 4)
sprite.add(jetSprites, "jets", 1, 15, 500, 0)
jet = sprite.newSprite(jetSprites)
jet.x = 180
jet.y = 280
jet:prepare("jets")
jet:play()
**jet.collided = false**
physics.addBody(jet, {density=0.1, bounce=0.5, friction=1, radius=12})

explosive method

function explode()
explosion.x = jet.x
explosion.y = jet.y
explosion.isVisible = true
explosion:play()
jet.isVisible = false
timer.performWithDelay(3000, gameOver, 1)
end

Collision method

function onCollision(event)
if event.phase == "began" then
  if jet.collided == false then 
    jet.collided = true
    jet.bodyType = "static"
    explode()
    storyboard.gotoScene("restart", "fade", 400)
  end
end
end 

Where exactly need to specify the condition to avoid colloids objects ?please help me to resolve this issue

Answer 1

Note, if you want to not detect collisions all by themselves, you should filter collisions. This link. contains a helpful table and tutorial to help you determine the maskbits and categorybits. Another alternative is group indexing, which you can read more on the first link. at the end of the document.

But, from what i see on your code, your ceiling and floor might be exploding as well. is happening is that your collision function onCollision is treating all objects the same. You would need to assign a name to your jet object jet.name = "jet", then, on your collision function check if the object really is the jet:

function onCollision(event)
    if event.phase == "began" and "jet" == event.object1.name then
        if jet.collided == false then 
            jet.collided = true
            jet.bodyType = "static"
            explode()
            storyboard.gotoScene("restart", "fade", 400)
        end
    end
end 

Note that you should also assign a name to all other physics objects, in case you would like to do something special with each body, and don't forget to reset jet.collided once you restart your game, if it implements it.

Read more about collision detection on the Corona Docs.