physic engine

[dav74]

Hi and happy new year,

 

will there be an announcement (on this forum or on twitter....) when the implementation of the physics engine will be effective ?

 

thank you

 

 

[gwenael]

Happy new year.

 

Deltakosh released 1.8.0 which integrates cannon.js.

More about it here: http://blogs.msdn.com/b/eternalcoding/archive/2013/12/19/create-wonderful-interactive-games-for-the-web-using-webgl-and-a-physics-engine-babylon-js-amp-cannon-js.aspx

[dav74]

Shame on me, i'm so sorry for my stupid question 

thank you gwenael

 

But...i've another question : is it possible to apply a force (vector) on an object ?

[gwenael]

Haven't played with it so far. Sorry. First, check if it's possible with cannon.js

[dav74]

@gwenael : thank you for your answer

obviously, it's possible to apply a force with cannon.js

[GameMonetize]

And yes you can

 

and the line you need:

BABYLON.Mesh.prototype.applyImpulse = function(force, contactPoint) {

[dav74]

@Deltakosh ok, thank you, i'm going to look at

[dav74]

My results are very strange when i use (other things works very well ) :

sphere.applyImpulse(new BABYLON.Vector3(15,0,0),new BABYLON.Vector3(0,0,0));

my mesh goes to the right (all is ok), but after few seconds, it goes to the left !!

 

all my code :

var canvas = document.getElementById("renderCanvas");var engine = new BABYLON.Engine(canvas, true);var scene = new BABYLON.Scene(engine);var camera = new BABYLON.ArcRotateCamera("ArcRotateCamera",0,1.3,100, new BABYLON.Vector3(0, 0, 0), scene);camera.attachControl(canvas);var light = new BABYLON.PointLight("pointLumineux1", new BABYLON.Vector3(100, 100, 0), scene); var ground=BABYLON.Mesh.CreateBox("sol",100,scene);ground.scaling.y=0.001var sphere=BABYLON.Mesh.CreateSphere("sph",20,6,scene);sphere.position=new BABYLON.Vector3(0,4,0);scene.enablePhysics();scene.setGravity(new BABYLON.Vector3(0,-10,0)); sphere.setPhysicsState({ impostor: BABYLON.PhysicsEngine.SphereImpostor, mass: 1 });ground.setPhysicsState({ impostor: BABYLON.PhysicsEngine.BoxImpostor, mass: 0, friction: 0.5, restitution: 0 });sphere.applyImpulse(new BABYLON.Vector3(0,0,15),new BABYLON.Vector3(0,0,0));engine.runRenderLoop(function () {     scene.render(); });

thank you for your help

[GameMonetize]

could you try with a less powerful force?

[dav74]

Hello Deltakosh,

same problem with a less powerful force, same problem with a force on x (forward then back) !

[GameMonetize]

I have to see that. Could you create a small jsfiddle?

[dav74]

it's done :

 

http://jsfiddle.net/dav74130/RFmWz/4/

 

thank you for your help

[gwenael]

dav74,

 

please replace your external ressources links by the following ones:

 

https://rawgithub.com/BabylonJS/Babylon.js/v1.8.0/cannon.js

https://rawgithub.com/BabylonJS/Babylon.js/v1.8.0/babylon.1.8.0.js

 

No '.' between 'raw' and 'github' so the file are served with the right mime type (thanks to the proxy rawgithub.com)

'master' is replaced by 'v1.8.0' so your jsfiddle will work as long as the tag is not deleted on GitHub whereas if the master branch is updated with a new version of babylonJS (babylon.1.8.1.js), the link is not valid anymore.

[gwenael]

http://jsfiddle.net/gwenaelhagenmuller/jtLJG/1/

[dav74]

@gwenael : thank you for your help

 

http://jsfiddle.net/dav74130/RFmWz/4/

[GameMonetize]

Sounds logic to me as the impulse made the sphere rotating in the opposite direction

[GameMonetize]

Try with a box to see it rotating

[dav74]

i apply impulse to the sphere center (0,0,0). I should have a translation, no ? I think that i haven't understood applyImpulse's use, i'm going to wait documentation or tutorial  

 

edit : with no friction on ground, all is ok (i think that i had a "retro effect" (with friction))

 

other question : how to stop the impulse ? (or how long lasts the impulse ?)

 

thank you for your help

[GameMonetize]

The impluse trans;it a force that need to be removed by friction or collisions

[gwenael]

I made a post you could be interested by: http://www.html5gamedevs.com/topic/3083-spaces-world-parent-pivot-local/?p=19938

 

And here the result with your example: http://jsfiddle.net/gwenaelhagenmuller/4QgPm/

[Boz]

Hello !

I get the same "problem" than Dav.

 

I noticed when you apply a vertical impulse on a sphere like this : sphere.applyImpulse(new BABYLON.Vector3(0,5,0), new BABYLON.Vector3(0,0,0)), there are 2 differents results :

 

- if the sphere is located at (0,0,0) point, all is ok, the sphere jumps and stops.

- if the sphere is elsewhere, like (5,0,0), it jumps and start rolling along x axis.

- if the sphere is elsewhere, like (0,0,5), it jumps and start rolling along z axis.

The speed the sphere is rolling is according to the power of the impulse.

 

I use babylonjs 1.11

Thanks for your feedback

[Dad72]

Hi,

 

This behavior seems normal. I have not read any of the subject, but from what you explain, I see no problem.

[Boz]

The fact is when I apply an impulse like (0, 5, 0), I just want my sphere to go up, if I want it to go up AND right I have to apply an impulse like (5, 5, 0)

I thought the impulse did not depend of the position of your mesh.

[Wingnut]

Hi

 

You are correct, Pouet.  Position of the sphere should not matter.

 

It might be wise to use SOME contact point vector... to ensure a direction.  For a +y impulse... maybe do this.

 

sphere.applyImpulse(new BABYLON.Vector3(0,5,0), new BABYLON.Vector3(0,-.1,0))

 

This puts the impulse contact point UNDER the center of the sphere, and may give you more predictable behavior from the impulse.  In many ways, a contactPoint vector is a direction vector... and a direction vector of 0,0,0 is a un-set and confused vector.  It is like asking a sphere to point the way home.  Not much information available.  heh

 

Just a thought.  Good luck.  Please report your discoveries.  Thanks!

[kidandcat]

I got it!! just:

 

sphere.applyImpulse(new BABYLON.Vector3(0,5,0), sphere.position);