Slopes with ceilings errors

#1 This was a known issue and was put on the 'will not be fixed' list because it was seen as more of a level design issue than a physics issue. The problem can easily be solved by putting a collision box in the crack where you want the player to stop moving. The alternative would be making the player physics more complicated.

EDIT: If this sort of functionality is neccesary for your game or the collision box solution is insufficient let me know.

#2 Well, I do sort of the need capability but I suppose I COULD work around it with level design. The main reason I need it to be flexible is the player will be controlling characters with different collision polygons...like say, a mouse that can get in small holes, or a human character that can 't. See what I mean?

That being said, I thought it was an unknown error - if it can be fixed, it would be appreciated, otherwise I will add it to my list of needed modifications and do it myself.

#3 It can definitely be changed to work that way. What you'd want to do is take a look at the ResolveActorCollision method in ActorComponent.cs.

I'm looking at it right now, and it seems like I actually did put in a special check for cases like this. If you take a look at the following section starting at line 1159 you'll see what I'm talking about:

if (_onGround && !groundSurface)
{
    // don't let the clamp push us off the ground or into the ground!
    // accomplish this by clamping the collision normal against the ground normal
    float groundDot = Vector2.Dot(info.Normal, _groundSurfaceNormal);

    // remove any portion of the ground surface normal from the collision normal
    info.Normal -= groundDot * _groundSurfaceNormal;

    // cancel move speed (this isn't a ground surface that we hit)
    _moveSpeed.X = 0;
}

On second thought, is it possible that the ceiling in your case doesn't have a platform component? That would definitely explain why _moveSpeed isn't getting reset (allowing the player to keep walking).

ActorComponent.cs (line 1088)

public virtual void OnCollision(...)
{
    // call our custom collision resolve
    // (this is almost exactly the same as clamp, but takes *both* objects' velocity into account)
    if (theirObject.TestObjectType(PlatformerData.PlatformObjectType))
        resolve = ResolveActorCollision;
    else
        resolve = null;

    -...-
}

As you can see, if the ceiling isn't a platform, the actor will not resolve against it. If the ceiling is then resolving against the actor it could most definitely push the actor down through the floor.

Let me know if this isn't the case and I'll dig a little deeper.

#4 Ok Thomas

I really don't know I perceived this right or not but what I have understood is that you do not want the player to slip through the crack between the slope top and ceiling above while a smaller player should.

I tried this with the ninja one and this is the remedy I came out with (again without scripting).

No idea this will work with you or not ( as you not using cast collision) but my guess is you have already sorted this out.

I used an invisible data object in between the slope(with custom polygon points.) and there is no way the character will go through, but the points of the object can be made at such a height that a smaller character can easily go through without colliding with the invisible points and if you have many such cracks, then just copy paste the invisible object.

Does this idea helps ?

I wish I could do everything without scripting, but that is not possible lols ;)




BTW- My ninja has very small custom polygon and not square one thats why I used invisible object a bit lower.

#5 Thomas:

Both the ceiling and the ground have the platform component applied. After some more tweaking, I've managed to make the play jitter oddly. It is most prominent when going left, but also exists when going right. I would find it very hard to believe if this bug is because of improper scene setup.