making coin patterns

KevinM2k · March 2, 2014, 10:37pm

Firstly how do you know event.object1 is the coin and not event.object2… whats the difference?

With regards to coin detection, i find it to be very strange, I created a lot of these patterns to be scattered throughout the level, and hitting any of them came up with nothing in the collision detection… about 20/30 seconds in to the level all of sudden the detection started to work however in a very strange way as in sometimes it worked and sometimes it didn’t, and if I hit coin1 of pattern 1 then coin1 of pattern 2 would also disappear.

I’m thinking how i’m apply the physics doesn’t work.

When the coins did detect correctly the alpha did work on them

KevinM2k · March 2, 2014, 10:39pm

One more thing… I actually have the collision set on Runtime:addEventListener(‘collision’,onCollision)…

Could this be causing the issue???

KevinM2k · March 2, 2014, 11:00pm

The local collision makes sense now so i’ve changed to that instead of Runtime collision, unfortunately it has had no effect on the coins, ive moved them down so my character literally walks through them - absolutely nothing until around 20/30 seconds in to the game, then a few work / few dont - very odd

its event.other.id btw instead of event.object1.id - that seems to be one of the Runtime vs Local things

Alex10 · March 3, 2014, 12:41am

At this point, you should start simple and then make it more complicated. So, just start by creating one coin and setting it near the character and have it collide. If it’s that works, then you start adding back in more complicated code. Everything you’re doing seems to be fine, so starting small and then getting larger is the best way to tackle this one.

KevinM2k · March 3, 2014, 9:12am

If you look at my earlier code where I run createCoinGroup()…

If i ignore that and just run createCoin() instead, this creates just a single coin on its own… this does work exactly how expected.

its only when I put them in the group the physics seem to play up, even though in debug they do still have a physics square around each one.

jitenahuja · December 12, 2014, 11:16am

Alex10:

Well, we’ve got a few things here.

First, you don’t appear to be setting any variables to identify your coins when they are spawned. The variable you have here:
coin.id = "coin"
Gives the id of “coin” to every object, but that isn’t very individual. Depending on your collision listener, it might not be best practice. In addition, creating objects in this way, while technically feasible, doesn’t give much control over them. Creating them as objects in a table would give you better control over their individual interactions.

Second, and I’m just hypothesizing because I don’t know what your collision listener looks like, when you’re inserting your coins into a display group, and then inserting that display group into another display group, it can be hard to remember which objects are in which group. If you have objects that are outside of the given display group and display groups are over-written, you might not see objects collide in the right way.

Third, and again, this is a hypothesis, if you’re not using physics to have objects collide with each other, you won’t see any collisions happen. Seems obvious, but if you use transition.to instead of body.applyForce (or similar), you aren’t going to get the same results.

Here’s a quick snippet of how I build a tiled background for testing purposes:
local backg = {} local moveY = 10 local moveX = 20 local cellWidth = 34 local cellHeight = 34 local gridGroup = display.newGroup() local function buildBack1() for x = 1, 20 do backg[x] = {} for y = 1, 5 do backg[x][y] = display.newRect(0, 0, cellWidth, cellHeight) backg[x][y].x = x\*cellWidth+moveY backg[x][y].y = y\*cellHeight+moveX backg[x][y].id = ("backg["..x.."]["..y.."]") backg[x][y]:setFillColor(1, 0, 0) gridGroup:insert(backg[x][y]) end end end buildBack1()
Notice how the tiles are display objects, and also part of a table. This way, I can reference them as individual tiles, or as a large group, later on.

Is there a way you could post your collision code so we can confirm how and what is supposed to be interacting with what?

I just referred your code (minor changes) :-

local backg = {} local moveY = 10 local moveX = 20 local cellWidth = 34 local cellHeight = 34 local gridGroup = display.newGroup() local function buildBack1() for x = 1, 20 do backg[x] = {} for y = 1, 5 do backg[x][y] = display.newImage(GUI,"coin.png", cellWidth, cellHeight) physics.addBody(backg[x][y],"static",{radius=20}) backg[x][y].myName="coins" backg[x][y].x = x\*cellWidth+moveY backg[x][y].y = y\*cellHeight+moveX backg[x][y].id = ("backg["..x.."]["..y.."]") gridGroup:insert(backg[x][y]) end end end buildBack1() function jet:preCollision( event ) local platform = event.other if platform.myName == "coins" then event.contact.isEnabled = false if coin.isVisible == true then coin.isVisible=false; end print("collided") end end jet:addEventListener( "preCollision" )

there is no collision happening for me to spawn the coins …

jitenahuja · December 12, 2014, 11:16am

Alex10:

Well, we’ve got a few things here.

First, you don’t appear to be setting any variables to identify your coins when they are spawned. The variable you have here:
coin.id = "coin"
Gives the id of “coin” to every object, but that isn’t very individual. Depending on your collision listener, it might not be best practice. In addition, creating objects in this way, while technically feasible, doesn’t give much control over them. Creating them as objects in a table would give you better control over their individual interactions.

Second, and I’m just hypothesizing because I don’t know what your collision listener looks like, when you’re inserting your coins into a display group, and then inserting that display group into another display group, it can be hard to remember which objects are in which group. If you have objects that are outside of the given display group and display groups are over-written, you might not see objects collide in the right way.

Third, and again, this is a hypothesis, if you’re not using physics to have objects collide with each other, you won’t see any collisions happen. Seems obvious, but if you use transition.to instead of body.applyForce (or similar), you aren’t going to get the same results.

Here’s a quick snippet of how I build a tiled background for testing purposes:
local backg = {} local moveY = 10 local moveX = 20 local cellWidth = 34 local cellHeight = 34 local gridGroup = display.newGroup() local function buildBack1() for x = 1, 20 do backg[x] = {} for y = 1, 5 do backg[x][y] = display.newRect(0, 0, cellWidth, cellHeight) backg[x][y].x = x\*cellWidth+moveY backg[x][y].y = y\*cellHeight+moveX backg[x][y].id = ("backg["..x.."]["..y.."]") backg[x][y]:setFillColor(1, 0, 0) gridGroup:insert(backg[x][y]) end end end buildBack1()
Notice how the tiles are display objects, and also part of a table. This way, I can reference them as individual tiles, or as a large group, later on.

Is there a way you could post your collision code so we can confirm how and what is supposed to be interacting with what?

I just referred your code (minor changes) :-

local backg = {} local moveY = 10 local moveX = 20 local cellWidth = 34 local cellHeight = 34 local gridGroup = display.newGroup() local function buildBack1() for x = 1, 20 do backg[x] = {} for y = 1, 5 do backg[x][y] = display.newImage(GUI,"coin.png", cellWidth, cellHeight) physics.addBody(backg[x][y],"static",{radius=20}) backg[x][y].myName="coins" backg[x][y].x = x\*cellWidth+moveY backg[x][y].y = y\*cellHeight+moveX backg[x][y].id = ("backg["..x.."]["..y.."]") gridGroup:insert(backg[x][y]) end end end buildBack1() function jet:preCollision( event ) local platform = event.other if platform.myName == "coins" then event.contact.isEnabled = false if coin.isVisible == true then coin.isVisible=false; end print("collided") end end jet:addEventListener( "preCollision" )

there is no collision happening for me to spawn the coins …