How do I determine sprite overlapping with zIndex? (SOLVED)

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paradine

  • I'm working on a solitaire level editor. ChatGPT has been a TREMENDOUS help on this project but we're stuck on something that I thought would be fairly simple. I'm hoping one of you experts can help!

    What I'm Trying to Do:

    When I SAVE my layout I want to iterate through all the cards and, using zIndex, figure out which cards are Covering and which cards are CoveredBy the current card. These will then get saved in instance variables, like this:

    card_spr.Covering = "3, 5, 7" (this card is covering cards 3, 5, and 7)

    card_spr.CoveredBy = "" (this card isn't covered by any cards)

    ChatGPT suggested that I create 2 families with spr_card as the only member. fam_cards has all the instance variables. fam_cards2 is for the inner loop.

    This was working, but I stupidly used Construct 3's UID in my events. This doesn't work for SAVING and LOADING, so I created a new instance variable: fam_cards.CardID and I increment this every time I create a new sprite. (It gets saved with the level.)

    But if I put CardID in the sprite my families can't access it. And if I put it in fam_cards.CardID then I can't reach it with fam_cards2.CardID.

    Any suggestions? Is there an easier way to do this?

    Code Before I made my own "CardID"

    + System: For each fam_cards

    -> fam_cards: Set Covering to ""

    -> fam_cards: Set CoveredBy to ""

    ----+ System: For each fam_cards2

    --------+ fam_cards2: Is overlapping fam_cards

    ------------+ System: fam_cards2.ZIndex < fam_cards.ZIndex

    -------------> fam_cards: Set Covering to fam_cards.Covering & fam_cards2.UID & ","

    ------------+ System: Else

    -------------> fam_cards: Set CoveredBy to fam_cards.CoveredBy & fam_cards2.UID & ","

  • (removed)

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  • Wouldn’t it be simpler to just save the type and position of each card? 

    Global text data=“”

On function save
— set data to “”
— for each card ordered by card.zindex ascending
— — add card.x&”,”&card.y&”,”&card.animationframe&”;” to data

Global text tok=“”

On function load
Repeat tokencount(data,”;”)-1 times
— set tok to tokenat(data,loopindex,”;”)
— create card at float(tokenat(tok,0,”,”)), float(tokenat(tok,1,”,”))
— card: set animation frame to int(tokenat(tok,2,”,”))

  • I made a mistake in my previous comment. This code should work:

  • Thank you dop2000 and ROJOhound!!

    These are SO MUCH easier than the suggestions I was getting from ChatGPT. I spent two days iterating on this problem and it seems like the solution was pretty simple.

    Strangely, I asked ChatGPT to help me create a pretty complex interactive bezier feature for my editor, and this only took an hour or so!

    (I can add or remove cards on the fly, and they will space themselves, with the appropriate angles, along the curve. The three dark circles are handles and the cards adjust as I drag them around! Without the AI I wouldn't even have ATTEMPTED this feature.)

  • Without the AI I wouldn't even have ATTEMPTED this feature.

    Yeah, ChatGPT is getting frighteningly good at programming tasks. Almost ROJOhound-level good :)

  • Wouldn’t it be simpler to just save the type and position of each card?

    I'm already saving the positions, angles, and instance variables for each card. I need to know covering relationships between all the cards as I plan to write a simulator that randomly "plays" each level a thousand times, just using the data. This will give me stats like "average cards remaining" that I can use to help me test my 200+ levels.

  • Just a quick follow-up.

    We had company for a few days so I was only able to try dop2000's suggestion yesterday. It works perfectly! I noticed that this only adds "CoveredBY" and not "Covering" but after a little thought, and AI confirmation, it became clear that I don't need to keep track of which cards the current card is covering.

    I had worked on this problem for two days and got help from ChatGPT, Claude Sonnet, Deepseek and several other AIs. Many couldn't give me working code at all, but after a lot of iteration I had something that *almost* worked. It was about 24 events and I still hadn't added extra code to get rid of the trailing "," in every string.

    The solution from dop2000 was only FOUR events, and there's no trailing comma.

    NOTE: I noticed that the solution included some strange question marks, so I uploaded a screenshot to ChatGPT and asked for an explanation. It provided me with a thorough and very understandable description of ternary operators and how they work!

    Thanks again, dop2000!!

  • dop2000

    I just noticed an issue with the code you provided and I'm not sure how to fix it.

    It works perfectly when I have one card being covered by another card, or if one card is covering two cards. Unfortunately, it doesn't work when I have two cards covering one card. Like this:

    In this example, the highlighted card shows that it is being covered by the middle King, but not the one to the right.

  • It depends. Will something like this be possible? Can a card overlap more than 2 cards above it?

    You'll probably need to introduce levels or layers, instead of relying on z-index.

    Say, the king here is on level 0, ten is on level 1, and seven of spades is on level 3:

    Then you could process cards in a For Each ordered loop, from the bottom level, picking up cards that overlap it and are on (Self.level+1), and add them to the CoveredBy list.

  • dop2000

    I'm testing edge cases, but this code has worked on everything I've tried so far -- including your two examples!

    Whew! I REAAAAALLY didn't want to have to mess with tons of different layers.

  • I didn't mean layout layers. I meant an instance variable - like CardLayer or CardLevel. It would make a more robust system.

  • Also, I don't like these two conditions. In case of several overlapping fam_cards, they will only compare the first instance.

    You need to use "System Pick fam_cards By Evaluate" instead.

    And the second "For each spr_card" loop is not required.

  • I've been using the code in my original post for several days and it seems to work perfectly with any overlapping cards I've tried.

    Out of curiosity I just tried your suggestion. Is this the correct implementation?

    This seems to do exactly the same thing. It's a few events shorter so I'll stick with it unless I run into an issue.

    Thanks, dop2000!

  • No, that's essentially the same what you had before.

    The condition should pick family instances - "System Pick fam_cards by evaluating ..."

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