[Solved] Fixing a bug in my game

zipz · February 20, 2022, 2:54am

I’ve had a bug with my game for a while now, where two blocks get selected at once and the mouse joint stays permanent. I have no idea why this happens, any ideas on how I could fix this?

MrMen · February 20, 2022, 7:34am

Should the 2 blocks be selected, or just one?

Can you expand the add mouse joint, to show the parameters? You should be setting JointID in there.

zipz · February 20, 2022, 7:50am

Only one object should ever be selected and have a mouse joint. I save the mouse joint’s id to the variable JointID and it should be getting deleted when you release the mouse, but for some reason sometimes two objects end up both selected and one permanently keeps its joint.

MrMen · February 20, 2022, 8:27am

Are there more than 2 blocks on the screen? Are the 2 blocks that get selected overlapping, or separated on the screen?

And can you expand the add mouse joint, to show the parameters?

zipz · February 20, 2022, 3:57pm

Here’s the parameters. there are more than two blocks on the screen and they are not overlapping.

MrMen · February 20, 2022, 10:40pm

Does the joint appear to be added to both block simultaneously, or only as the cursor moves over each block?

Here’s how I’ve had it working it in one of my games :

Add a mouse joint on the Draggables group has parameters of :

zipz · February 21, 2022, 2:02am

Dang, everything seems to be pretty much the same. It appears simultaneously. Here’s a link to the current version: BuildUp by ZipZ
It seems to happen most with long objects. Try selecting the red block on level 3 and often the long yellow one is also selected. I have no clue how to fix this; it might be a bug with how GDevelop detects collisions on resized long and skinny objects; it does seem it has a larger hitbox than it should for clicking on.

MrMen · February 21, 2022, 2:46am

Are the objects rotated?

You can see the object hit boxes by turning on debuging (it’s a selectable action).

zipz · February 21, 2022, 2:49am

Oh yeah you’re totally right! It is because of their collision boxes changing when rotating and then overlapping! Is there anything I can do about this?

MrMen · February 21, 2022, 2:58am

I think MouseOver just checks the larger box which is the outer points of the image, and doesn’t use the collision box which does get rotated.

The simplest fix is to check if the mouse position is colliding with the object :

zipz · February 21, 2022, 3:00am

Thanks so much, that works! Sadly roughly 30sec too late to update my game in the game jam