best way to fix collision problem

[method72]

I have a simple active as a player with 4 direction movement.
several backdrops in place as obstacles, and a group of actives as enemies.

the enemies look in the direction of the player and move that way, but when they hit an obstacle, they are stopped,.. but
they slowly tend to work thier way thru the object... i am trying to figure out how to make them either bounce or reverse or do something
other then try and slowly push themselves over the obstacle.

i know this has been discussed before, but the threads i found that had links to examples, the examples files were no longer hosted...

thanks

[King_Cool]

Enemy is NOT overlapping Obstacle
- set Enemy MemoryX_ to Enemy X position
- set Enemy MemoryY_ to Enemy Y position

Enemy is overlapping Obstacle
- set Enemy X to Enemy MemoryX_
- set Enemy Y to Enemy MemoryY_

...
Another metod:
- If all your 'collision masks' are sqare, you can achieve pixel perfect colision results without loops of any kind. Say the word and ill explain it to you

[method72]

hmm, not sure wha the "memory" parameter is your refering to..
i am not using any fast loops in my detection, not sure how to modify the collision mask,

this is a problem i have had in several games i made, even something like a break-out/bat-and-ball
clone.. where if the ball gets into a spot where it sort of gets stuck between obstacles, or will eventually penetrate thru.. i never really figured out the proper way to fix it.

how do i verify if my collision masks are boxes? are you refering to backdrops only?
or can you set a specific mask on any active?

[King_Cool]

MemoryX_ and MemoryY_ are just AlterableValues in the Object which collides.
rergardless of using Backdrops or Actives as Obstacles, simple drae the graphics as square boxes with 4 90 degree corners.

I might make an example later

[Gustavo]

try using the condition "collides with backdrop" instead of "overlapping the backdrop". I dont know why, but they stop going through solid objects that way

[method72]

ok thanks, i will give it a go.

[brett]

Thanks for this fix! It helps a lot, but I noticed that my character would get stuck because the memory value would position the character so he was still overlapping so I added the following:
If moving right, then set Memory X value to X position -2
If moving left, then set Memory X value to Y position +2

This seemed to resolve the issue. I think it should work for up and down motion too. By the way, my character is using the platform movement. Thanks,
Brett