collision glitch - now a non pro discussion

Riffel

Hi friends,

I have made this video to show my problem



here the code:

the big white cube (wall actor) has no code

it's a shoot'm up game, the white missiles suppose do destroy when collides with the big box, notice lots of missiles crosses the big actor

how to avoid the "tunneling" problem?

there is an method for Continuous Collision Detection (CCD)?

Thank you,
Marcos Riffel

Riffel

Hi friends,

I have made this video to show my problem



it's a shoot'm up game, the white missiles suppose do destroy when collides with the big box, notice lots of missiles crosses the big actor

how to avoid the "tunneling" problem?

there is an method for Continuous Collision Detection (CCD)?

Thank you,
Marcos Riffel

JohnPapiomitis

Merged these two threads for you.

Cheers
John

tatiang

As I understand it, the problem is that when your speed/velocity is that high (e.g. 2000), the actors actually skip past the wall actor. I don't know if you've been able to verify that, but that's my guess... that some of the actors aren't ever landing on the wall.

POM

Clearly some of the actors are crossing too fast for the CPU to notice.
Why not use a different rule instead
Something like
When "self.position.X" > 600
Destroy

Or simply slow down those missiles to 1000 maybe?!

Roy.

famekrafts

First u have put collision detection in cannon, it needs to be in missile? Second timer is 0,3 it should be 0.3 right? And check run to completion.

famekrafts

You have made cannon to move while you are spawning missiles bit confusing, make sure the timer is ok and lower the speed 1000 will be good enough

Riffel

ops, I inverted the titles! the cannon spawn missile actors

Riffel

missile speed set to 1000
using the x>N don't is a solution. I have more walls in the scene, now the wall actor has a sensor, notice the missile hits the second wall sometimes the third.

TesseractEngine

I can't say this with certainty, @Riffel, but I suspect you've simply hit a ceiling with GS performance. 2000 is just too fast for the engine to catch a discrete collision every cycle.

You've already hit the nail on the head mentioning CCD. I'm certainly not clever enough to figure out how GS could do a priori collision detection, and I've not seen anyone else suggest a method.

I'm guessing the LUA-free engine _might_ help when it is released. But 2000 is fast!

Would love to know if anyone CAN figure out continuous, tho!

tatiang

One way I've gotten around the speed issue is by making the walls much wider, if that's an option for you.

The_Gamesalad_Guru

Make the density on the walls higher than the bullets.

adlaim

when actor is collide change color alpha to zero

tatiang

I opened a new project, added the rules you have and tested it. The bullet actors all stopped at the wall (actually, they appear to move slightly past it, but they are destroyed when they collide with it). Is it possible you adjusted some of the physics settings (such as @FryingBaconStudios mentioned) and that that is causing the problem?

[Edit: if I let it run long enough, the bullet actors do make it through the wall sometimes, just not as often as yours in the initial video you posted. The weird thing is if I click between the preview window and the debugged window, it causes the bullets to bypass the wall at a much quicker rate...]

The_Gamesalad_Guru

Here i got it to work. using a density of 10 and a friction of 10 on the wall. Remember density affects how actors overpower eachother. Link to file http://fryingbacon.com/temp/firebullets.zip

tatiang

Here's the file.

Riffel

thank you all for helping! :-bd

The_Gamesalad_Guru

@tatiang we need to coordinate.....LOL. *-:)

TesseractEngine

Great investigative work @FryingBaconStudios and @tatiang!

Putting 'Collide with Bullet' on the wall really does seem to do the trick!

tatiang

@FryingBaconStudios we do! And I gave you an awesome for your bullet vortex effect.