Falling Bug

[kosinix]

Hi,

First, this is a great javascript engine. I ported an old platform game I made in flash. However, there is one critical bug when falling from high places. For example, when jumping from high platform the hero goes through a solid tile. My theory is this has something to do with the acceleration of the fall greater than the height of the solid tile, as I encountered this kind of bug with my flash engine from long time ago. Just hoping you could check this bug, that would be really cool.

thanks! Really nice game engine.

[melonjs]

oooh, thanks for reporting this ! But yes for sure you certainly right, I'll look into it.
Would you share with me your example ([email protected]), so that I have an example to debug ?

How did you fix this in your flash engine ?

And thank you, melonJS is for sure not yet perfect, but I'm happy you like it !

[melonjs]

Following email discussion with nicnacks on this, For those having the same issue, and while waiting for this to be managed correctly, you can use the setMaxVelocity function to cap the y velocity.

[amauch]

My question has similar contexts, but how can you kill your character when he/she has falling through a hole/pit. Say you are jumping from platform to platform over a big whole, and you miss the next platform and fall "to your death." What do you need to add in JavaScript to handle this issue? What I want to do is just restart the level.

[melonjs]

Actually you have two options :

1/ check the y position of the player, if y > than the level height, you can assume that you felt into a pit/hole.
this is exactly what I'm doing in Alex4, when the position is updated I have the following code :

// check if we fall somewhere
if (this.pos.y > this.ylimit) // <- ylimit being the vertical limit of the level
{
this.die();
}

2/ you can use a invisibleEntity, and make it die or go to the next level when the player touch it
This is also what I'm doing in Alex4 (in case you played it) : when you reach the end of the 1st level, you have to jump into the pit to access the next level.

I can send you alex4 source code if you want, just send me an email to [email protected]
Actually I think I should post the source of it as well, maybe add a link to it in the gallery page.

[parasyte]

I created a new ticket for doing collisions in multiple phases, mostly as a performance improvement. But it will also solve this bug by taking the guesswork out of the collision resolutions: #103

[obiot]

should be covered through #538, closing this one

[parasyte]

Reopened, since this is still an issue, as demonstrated here (using melonJS build 518 from Travis-CI): http://jsfiddle.net/4s1rauye/

[parasyte]

To make the ball properly hit the wall. Lower the velocity on line 59 like this:

this.body.vel.set(12, 0);

Then note that the ball still falls through the floor (which is only 1px thick)

[obiot]

ok, I'm closing this one for the following reasons :

• the problem was only visible in earlier version of melonJS, and the cap to maxVel is "hiding" the issue
• the ticket is redundant with other tickets were we discussed about having a better physic implementation : Physic Engine support #235 Line of Sight (Ray Tracer) #285 Physics improvements: mass and friction #588 , in the sense that the later 3 will not have such issue.