Possible bug in PMO collision detection

[K1kk0z90]

Hi all!
I think I've found a bug in Platform Movement Object collision detection. Sometimes the object set to PMO simply falls down through a platform.
Here is the .mfa. Probably you won't have to play it for more than a minute before the bug happens.
Maybe it isn't a bug and I'm doing something wrong. If that's the case, how can I solve it?
Thank you in advanced for the support!

[LB]

I played it for 10 minutes and there is nothing wrong with it, nor is there anything wrong with the code. Maybe a video of this would help? Honestly with 10 minutes of solid play there were no problems at all.

[Atherton]

I think I know the problem your talking about
It's a bit difficult to spot if you don't know exactly what it is.

The only solution I've found is to make the object used for collisons shorter maybe only a couple of pixels tall.

[K1kk0z90]

I've made a video. The bug happens after about a minute: video .

@Atherton: You mean I should use an invisible object that stays at the coordinates of the visible object and make it shorter?

Thank you again for your help!

[LB]

I was finally able to reproduce it. The problem is that it is touching two jump-through platforms at the same time, one below it and one above it, which the PMO does not like because of how it does collision tests. You can use the Select Object Extension to select the one with the higher Y value (the one below the player) in the condition that checks for platform overlaps, this way the PMO does not get confused.

[K1kk0z90]

@LB
First of all thank you very much for spending your time to help me to find out the problem.
I've tried to place 2 or 3 platforms overlapped one above the other, but this bug didn't happen. I've also tried to put only one platform object for every "row", to be sure that when they wrap around the play area they couldn't overlap, and this bug happened.
I'm afraid that platform overlapping isn't the cause of the bug.

[LB]

It is, look carefully at the video. The top part of the player is touching a platform at the same time as the lower part of the player is touching a different platform. I can reproduce it every time without fail.

[K1kk0z90]

Wow! You're right!
It's great to know what causes the problem. Do you thing there is a way to solve it without the Select Object Extension? Because it's not supported in iOS.
Thank you again!

[LB]

You can make your character one pixel high for the PMO and display them however high you want

[K1kk0z90]

Perfect! Thanks for the advice!