Intersect not triggering

[Sekoshiba]

Hello, I'm having issues with the intersect command triggering when I use "move without waiting" on the object that is meant to be intersecting, additionally any IF statements after the movement do not seem to proc and I'm very unsure of why this is...

My code at the moment is looking like this.

Code: Select all

on spawnstart
   set the filename of image "enemy1" to "./BetterSprites/Enemy.php.gif"
   Set the bottom of image "enemy1" to the top of this card
   send enemy1 to me in 3 seconds
end spawnstart

on enemy1
   Set the bottom of image "Enemy1" to the top of this card
   put item 1 of the loc of image "enemy1" into tX
   put item 2 of the loc of image "enemy1" into tY
   put random(400) into tX
   set the loc of image "enemy1" to tX,tY
   if the left of image "enemy1" < the left of this card then
      set the left of image "enemy1" to the left of this card
   end if
   if the right of image "enemy1" > the right of this card then
      set the right of image "enemy1" to the right of this card
   end if
   put item 1 of the loc of image "enemy1" into tX
   set the loc of image "enemy1" to tX,tY
   put "false" into intersect1
   move image "enemy1" to tX,520 without waiting ---------------------------------< Erroneous line? Perhaps move does not allow IFs to proc?
   ---------------------------------------------------------------------------------------------------Up to this point works fine, i assume it's an error with the previous line(???)
      if the top of image "enemy1" > the bottom of this card then
         loselife
        spawnstart
     end if
   If intersect(image "enemy1", image "Laser1") then
      scoregain
    spawnstart
   set the top of image "Laser1" to the bottom of this card
   set the right of image "Laser1" to the left of this card
end if
If intersect(image "enemy1", image "Laser2") then
   scoregain
 spawnstart
   set the top of image "Laser2" to the bottom of this card
   set the right of image "Laser2" to the left of this card
end if
if intersect(image "enemy1", image "player") then
   loselife
   spawnstart
end if
end enemy1

I've tried to switch out the "move without waiting" syntax in favor of "move relative" in a conditional loop, but that creates even more issues and the intersects still do not always trigger... Any help would be deeply appreciated, and I'm pretty stumped about what is going wrong

[dunbarx]

Hi.

Your script runs OK, but there is no reason for the intersect to trigger, because the handler ends way before any of your intersect tests have a chance to work. Put this just before the "end enemy1" handler:

Code: Select all

end if
answer "End of Handler"
end enemy1

You need to rework this so that your tests are made while the move is being made. Do you need help with this?

Craig Newman

[Sekoshiba]

As, so it isn't a semantic error as I thought? Just a timing one?

That explains why the repeat was working earlier, perhaps I could put the IF statements in a conditonal loop or something so they continually execute? Or would that cause problems...?

Thanks anyway, Your reply was very helpful

edit: tried a repeat, it failed

I suppose I could just end the handler with a "send to me" and contain the IF statements there...

edit2: Failing the above it is now stuck in an infinite loop...is there a command like "Command ." on mac for windows that I can use to abort the loop?

[Sekoshiba]

Manually backdated because of the loop, i'm completely stumped as to how to go about having the IF statements execute during the move...

Edit/bump: Halp D:

[jacque]

The "move" command blocks, the rest of the handler will not execute while it happens. You can add "with messages" but even so, the current handler will not continue; only other user actions will trigger.

So the move command is not appropriate here. Instead you need to move the object to the mouseloc using a "send <msg> in <time>" construct.

There are many examples of this in the forums, but if you need help then ask.

[Sekoshiba]

The "move" command blocks, the rest of the handler will not execute while it happens. You can add "with messages" but even so, the current handler will not continue; only other user actions will trigger.

So the move command is not appropriate here. Instead you need to move the object to the mouseloc using a "send <msg> in <time>" construct.

There are many examples of this in the forums, but if you need help then ask.

I'm not sure I follow, the "send" command as "send to me in x seconds"? Or another syntax? Your answer answered my queries as to why it was not working, but i'm still fairly unfamiliar with the syntax variations and I'm not entirely sure what you mean, sorry.

[Simon]

Hi Sekoshiba,
Try this, set a breakpoint like shown below

Code: Select all

--Up to this point works fine, i assume it's an error with the previous line(???)
breakpoint
      if the top of image "enemy1" > the bottom of this card then
         loselife
        spawnstart
     end if

Now how often is that breakpoint triggered?
I can see that you are thinking there is a "polling" taking place where it checks your intersect but there is none. That code does not loop... 1 time only.
Now I'm not saying you should put a loop in there as they are not good for this sort of thing. But as suggested can you figure out how to use send in time?

Simon

[Sekoshiba]

Hi Sekoshiba,
Try this, set a breakpoint like shown below

Code: Select all

--Up to this point works fine, i assume it's an error with the previous line(???)
breakpoint
      if the top of image "enemy1" > the bottom of this card then
         loselife
        spawnstart
     end if

Now how often is that breakpoint triggered?
I can see that you are thinking there is a "polling" taking place where it checks your intersect but there is none. That code does not loop... 1 time only.
Now I'm not saying you should put a loop in there as they are not good for this sort of thing. But as suggested can you figure out how to use send in time?

Simon

See, that's an issue that I couldn't get around...

The intersects happens at various times throughout the movement so i can't use send in a way that works 100% of the time, there's too much variation in intersect times, and the intersecting item is also moving so I can't allocate the intersect to that either ...

[Simon]

Lot of "can't" in there.

Here this will help put you out of your misery:
https://sites.google.com/a/pgcps.org/livecode/home
Go to Example Games lots of kids using send with intersect.

Simon

[dunbarx]

Hi.

Make three buttons. Name one of them "movingButton" and place it on the left side of the card. Make another, named "targetButton", and place it on the right side of the card, but at the same Y location as the first (on the same horizontal."line"). Now make another button and place this in its script:

Code: Select all

on mouseUp
   put "movingButton" into tButton
   moveThatThing tButton
end mouseUp

on moveThatThing var
   set the left of btn var to the left of btn var + 1
   if intersect(btn var, btn "targetButton") then
      answer "HIT!"
      exit to top
   end if
   send "moveThatThing var" to me in 1
end moveThatThing

The nice thing about using the "send" command this way is that, as Jacque pointed out, it is not blocking. You have control over everything while the button is moving. There is a lot of stuff you need to do to this sort of script to make your project work the way you want it to, but this is just an example of how to create a "loop", without using "repeat", to move an object without using "move", and to get out of it all when the intersect actually happens, not at some undetermined time.

Craig Newman

[Sekoshiba]

Hi.

Make three buttons. Name one of them "movingButton" and place it on the left side of the card. Make another, named "targetButton", and place it on the right side of the card, but at the same Y location as the first (on the same horizontal."line"). Now make another button and place this in its script:

Code: Select all

on mouseUp
   put "movingButton" into tButton
   moveThatThing tButton
end mouseUp

on moveThatThing var
   set the left of btn var to the left of btn var + 1
   if intersect(btn var, btn "targetButton") then
      answer "HIT!"
      exit to top
   end if
   send "moveThatThing var" to me in 1
end moveThatThing

The nice thing about using the "send" command this way is that, as Jacque pointed out, it is not blocking. You have control over everything while the button is moving. There is a lot of stuff you need to do to this sort of script to make your project work the way you want it to, but this is just an example of how to create a "loop", without using "repeat", to move an object without using "move", and to get out of it all when the intersect actually happens, not at some undetermined time.

Craig Newman

aaaah, I see what you mean

I shall try this!

[Sekoshiba]

Having tried the "send in x" suggestions, it worked

The intersects however...still do not :c

The module I used as a synthetic repeat is as follows...

Code: Select all

on checkforcollisions
        if the top of image "enemy1" > the bottom of this card then
         loselife
        spawnstart
     end if
   If intersect( image "enemy1" , image "Laser1" ) then
      scoregain
    spawnstart
   set the top of image "Laser1" to the bottom of this card
   set the right of image "Laser1" to the left of this card
end if
If intersect( image "enemy1" , image "Laser2" ) then
   scoregain
 spawnstart
   set the top of image "Laser2" to the bottom of this card
   set the right of image "Laser2" to the left of this card
end if
if intersect( image "enemy1" , image "player" ) then
   loselife
   spawnstart
end if
send checkforcollisions to me in 1 millisecond
end checkforcollisions

[dunbarx]

Hi.

How do the objects move? If you step through the handler, what happens when you see the objects intersect visually?

Craig

[Sekoshiba]

Hi.

How do the objects move? If you step through the handler, what happens when you see the objects intersect visually?

Craig

The intersects now work, I called the synthetic loop -before- the movement to be certain it would carry through and it is now working...However the program freezes on card transition and references there being "no such object as (object from last card)"...I tried to use a variable to make sure no modules are triggering post-transition, but it seemingly makes no difference.

The spawn/intersect script:

Code: Select all

on enemy1
   if gamecard is "true" then
   Set the bottom of image "Enemy1" to the top of this card
   put item 1 of the loc of image "enemy1" into tX
   put item 2 of the loc of image "enemy1" into tY
   put random(400) into tX
   set the loc of image "enemy1" to tX,tY
   if the left of image "enemy1" < the left of this card then
      set the left of image "enemy1" to the left of this card
   end if
   if the right of image "enemy1" > the right of this card then
      set the right of image "enemy1" to the right of this card
   end if
   put item 1 of the loc of image "enemy1" into tX
   set the loc of image "enemy1" to tX,tY
   put "false" into intersect1
     send checkforcollisions to me
     move image "enemy1" to tX,520 in 5 seconds
     end if
end enemy1

on checkforcollisions
   if gamecard is "true" then
        if the top of image "enemy1" > the bottom of this card then
         loselife
          if gamecard is "true" then
      enemy1
      end if
   end if
     If intersect(image "enemy1" , image "Laser1" , "opaque pixels") then
        put "false" into var_bool_fired
      scoregain
     if gamecard is "true" then
      enemy1
      end if
   set the top of image "Laser1" to the bottom of this card
   set the right of image "Laser1" to the left of this card
end if
If intersect( image "enemy1" , image "Laser2" , "opaque pixels") then
   put "false" into var_bool_fired
   scoregain
   if gamecard is "true" then
      enemy1
      end if
   set the top of image "Laser2" to the bottom of this card
   set the right of image "Laser2" to the left of this card
end if
if intersect(image "enemy1" , image "player" , "opaque pixels") then
   loselife
   if gamecard is "true" then
      enemy1
      end if
end if
send checkforcollisions to me in 0.01 seconds
end if
end checkforcollisions

The variable that I thought would deactivate the loop/movements:

Code: Select all

on loselife
   add "-1" to var_lives
   if var_lives is 2 then
      set the filename of image "lives" to "./Bettersprites/text/twolives.png"
   end if
     if var_lives is 1 then
      set the filename of image "lives" to "./Bettersprites/text/onelife.png"
      end if
   if var_lives is 0 then
      put "false" into gamecard
      go to card 3
   end if
end loselife

I assume that the synthetic loop is the issue as removing it seems to solve the freezes...but of course i need it for the intersects...

[dunbarx]

Hi.

When you navigate to another card, you have to be careful that references to objects on other cards are called with explicit pathnames. It may seem excessive to constantly say "image soAndSo of card someCard", and this is true if you stay on a single card, since the current card is always assumed by LC unless it is told differently.

But you should be able to find the error in your code. And then just rewrite all object references that are causing problems to explicit ones.

Craig