If object is touching another object then arguement

I have looked at http://developer.anscamobile.com/reference/index/eventphase but haven't worked out how to use it as an argument.

such as:

1
2
3

if object1 is touching object2 then
-blah blah
end

I'm not sure what you're actually asking, how to use event phases or how to detect when two objects are touching?

If you mean event phases then imagine you wanted to print "pressed" when touched and "released" when the touch was lifted, you'd do this;

function testFunction (event)
  if event.phase == "began" then
    print "pressed"
  elseif event.phase == "ended" then
    print "released"
  end
end

I was asking whether two objects were touching, not a touch event

It is to make a jump function, where you can only jump if touching the ground

Oh right, OK - your link/wording confused me.

The easiest way is to use physics bodies, or sensors - then when the hero touches the ground set something like canJump to true, when you press the jump button set canJump to false - then you'd check if canJump was true or false and only allow jumping when it was true.

Peach :)

Hey.

I saw your post last night but didn't have time to post anything.

Here is some drag and drop code which does exactly what you asked.

The bit of interest to you is around line 130.

Feel free to ask any questions if you get stuck or anything.

display.setStatusBar(display.HiddenStatusBar)
 
physics = require("physics")
physics.start()
physics.setGravity(-9.8,0) -- change gravity to control the jump curve.
 
_H = display.contentHeight;
_W = display.contentWidth;
mRand = math.random;
 
canJump = false
 
 
--set up display groups
local background = display.newGroup()
local paralax1 = display.newGroup()
local paralax2 = display.newGroup()
local paralax3 = display.newGroup()
local groundgroup = display.newGroup()
local buttons = display.newGroup()
local enemies = display.newGroup()
local player = display.newGroup()
 
 
local player1 = display.newRect (0, 0, 50, 50)
player1.x = _W / 2 - player1.contentWidth / 2
player1.y = _H / 4 - player1.contentHeight
--player1:setFillColor(0, 0, 255)
physics.addBody(player1, {density = 1.0, friction = 0, bounce = 0.2})
player1.myName = "player1"
player:insert(player1) 
 
local function jumpPlayer1 (event)
        if canJump == true then
                player1:applyLinearImpulse( 20, 0, player1.x, player1.y ) -- the first number in brakets is the jump height
        end
canJump = false
end
 
--press red to shoot an arrow
local redButton = display.newCircle (0, 0, 30, 30)
redButton.x = _W / 6
redButton.y = _H - _H / 10
redButton:setFillColor(255, 0, 0)
redButton.alpha = .75
 
--press blue to shoot an arrow
local blueButton = display.newCircle (0, 0, 30, 30)
blueButton.x = _W / 6
blueButton.y = redButton.y - blueButton.contentHeight / 2 - _H / 10
blueButton:setFillColor(0, 0, 255)
blueButton.alpha = .75
 
blueButton:addEventListener ("touch", jumpPlayer1)
 
local function shoot (event)
        local arrow = display.newRect(0, 0, 5, 20) 
        arrow.x = player1.x + player1.contentWidth / 3
        arrow.y = player1.y + player1.contentHeight / 2 + 3
        arrow:setFillColor(255, 0, 0)
        physics.addBody(arrow, "kinematic", {density = 10.0, friction = 0, bounce = 0})
        arrow:setLinearVelocity( 0, 250)
        arrow.myName = "arrow"
                player:insert(arrow)
 
        arrow.collision = onLocalCollision
        arrow:addEventListener( "collision", arrow )
end
 
redButton:addEventListener ("tap", shoot)
 
local function spawnEnemy()
        local enemy = display.newRect(0, 0, 50, 50)
        enemy.x = _W / 2 - enemy.contentWidth / 2 - 2
        enemy.y = _H --/ _H - 50
        enemy:setFillColor(255, 0, 0)
        physics.addBody(enemy, {density = 0.01, friction = 0, bounce = 0})
        enemy.myName = "enemy"
                enemy:setLinearVelocity( 0, -100)
                enemies:insert(enemy)
 
        enemy.collision = onLocalCollision
        enemy:addEventListener( "collision", enemy )
end
 
local firstground = display.newRect(0, 0, _W / 3, _H )
firstground.x = _W / 3 - firstground.contentWidth / 2
firstground.y = _H / 2
firstground:setFillColor(0, 255, 0)
physics.addBody(firstground, "kinematic", {density = 1.0, friction = 1, bounce = 0.2})
firstground.myName = "firstground"
firstground:setLinearVelocity( 0, -100)
groundgroup:insert(firstground)
 
local ground = display.newRect(0, 0, _W / 3, _H)
ground.x = _W / 3 - ground.contentWidth / 2
ground.y = _H + ground.contentHeight - _H / 4
ground:setFillColor(0, 230, 0)
physics.addBody(ground, "kinematic", {density = 1.0, friction = 0, bounce = 0.2})
ground.myName = "ground"
ground:setLinearVelocity( 0, -100)
groundgroup:insert(ground)
 
 
function onLocalCollision( self, event )
        if ( event.phase == "began" ) then
                                ----------------------------------player hits enemy---------------------------------------------------------------------------
                        if (self.myName == "player1" and event.other.myName == "enemy") then
                        print("death")
                                local function deleteSelf()
                                player1:removeSelf()
                                end
                                Timer1 = timer.performWithDelay(1,deleteSelf, 1)        
                        end
                 ---------------------------------arrow hits enemy--------------------------------------------------------------------------       
                        if (self.myName == "arrow" and event.other.myName == "enemy") then
                        print("ZAP!")
                                                                local function deleteBoth()
                                                                display.remove(self)
                                                                display.remove(event.other)
                                                                end
                                                                Timer1 = timer.performWithDelay(1,deleteBoth, 1)        
                        end
                                ---------------------------------player hits ground-------------------------------------------------------------------------------                              
                                                if (self.myName == "player1" and event.other.myName == "ground") then
                           canJump = true     
                                                end
                                                print( self.myName .. ": collision began with " .. event.other.myName )   
                ---------------------------------player hits firsdtground-------------------------------------------------------------------------------        
                                                if (self.myName == "player1" and event.other.myName == "firstground") then
                           canJump = true     
                                                end
                                                print( self.myName .. ": collision began with " .. event.other.myName )   
                                 -----------------------------------------------------------------------------------------------------------------------------------------              
        end
end
 
player1.collision = onLocalCollision
player1:addEventListener( "collision", player1 )
 
Timer1 = timer.performWithDelay(mRand(3000, 4500),spawnEnemy, 0)

without physics:

try using Millerszone code from here

http://developer.anscamobile.com/forum/2011/09/05/best-method-collision-detection

-- Ball object
local ball = display.newImageRect("ballSmall.png", 12, 12)    
ball.x = 240; ball.y = 160
ballSizeX = 12; ballSizeY = 12
 
-- Paddle object
local leftPaddle = display.newImageRect("paddleSmall.png", 12, 60) 
leftPaddle.x = 35; leftPaddle.y = 160
paddleSizeX = 12; paddleSizeY = 60
 
 
-- Collision detection
local function collision(box1x, box1y, box1w, box1h, box2x, box2y, box2w, box2h)
        if (box1x > (box2x + box2w)) then return false 
                elseif ((box1x + box1w) < box2x) then return false 
                elseif (box1y > (box2y + box2h)) then return false 
                elseif ((box1y + box1h) < box2y) then return false 
                else return true 
        end
end
 
-- Check if ball hit paddle
if collision(ball.x, ball.y, ballSizeX, ballSizeY, leftPaddle.x, leftPaddle.y, paddleSizeX, paddleSizeY) then
        -- if ball hit paddle then do something 
end

Thanks guys :) excellent

@spider n

Nice code, I learned a few things from it.

Added to my "tool box" hehe. That was very cool!

@nic

No worries, glad you found it useful. (wait until I have the random terrain generator up and running;)

views:1888 update：2011/10/4 17:12:07


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