Box2d - 2D physics

[mentalthink]

Hi friends, I´ve got a question about the polygon creator command.

Well I try to make shapes whit more of 7 index on the first dimension of the array, but the code crashes.

It´s limited this command to 7 index (1st Index), or perhaps I made some wrong.

Kinds Regards,
Iván J.

[neseir]

Hi

There are a limitation in the Box2D code that limits the number of polygonvertices to 8. It is located in the b2settings.h file (line 75 : const int32 b2_maxPolygonVertices = 8;)

Regards
Eirik

[mentalthink]

HI neseir, lot of thanks I go to see this.
Thanks 

Iván J.

[quangdx]

Is there a command to destroy/remove objects after they've been created?
Also there doesn't seem to be any commands to manually set the x and y position of an object that has already been created.
Any help here would be great.

[backslider]

Hi there,

you should download the library from page 6 in this thread.

The direct link is: http://www.glbasic.com/forum/index.php?action=dlattach;topic=3561.0;attach=2262

Then you can use some "new" functions:

edited functions:
 - b_CreateCircle (extended parameters)
 - b_CreateBox    (extended parameters)
 - b_CreatePoly   (extended parameters)

new functions:
 - b_DestroyJoint% (function has now code to destroy joints)
 - b_destroyBody    (delete bodys that you don´t need)

cheers

[Kitty Hello]

wouldn't it be better to put the extended parameters into a seperate function and update "any" shape after creation?

[quangdx]

Hi there,

you should download the library from page 6 in this thread.

The direct link is: http://www.glbasic.com/forum/index.php?action=dlattach;topic=3561.0;attach=2262

Then you can use some "new" functions:

edited functions:
 - b_CreateCircle (extended parameters)
 - b_CreateBox    (extended parameters)
 - b_CreatePoly   (extended parameters)

new functions:
 - b_DestroyJoint% (function has now code to destroy joints)
 - b_destroyBody    (delete bodys that you don´t need)

cheers

Many thanks dude,
So for me to manually change the location of an Object at a later point,
I have to destroy the body then recreate it in the new location?
Would be a lot easy to just update the X pos and Y pos.

[backslider]

Ah, sorry.

To move an object, you have to add the following function to your box2d library

Code: GLBasic [Select]

FUNCTION b_BodySetXForm: body%, x, y, angle // add this function to the wrapper
        INLINE
                b2Vec2 pos = bBody(body)->GetPosition();
                pos.x=x;
                pos.y=y;
                bBody(body)->SetXForm(b2Vec2(x,y), angle);
        ENDINLINE
ENDFUNCTION
 

Somebody should update the library with all functions in this thread and put it into the first post.

[bigsofty]

I started to add some features a while back but later programers would alter a copy of the original source and erase my changes in the process. It was like running up a sandy hill... this lib desperately needs an SVN IMHO. 

[backslider]

*sign*

[Kitty Hello]

I implemented all changes (except the parameter on creation extension - I''d like to see that in a seperate function) and updated post #1.

[Crivens]

Out of interest I've read box2d is compatible with iOS with a small change to compiler parameters, but what about Android and WebOS?

Cheers

[backslider]

With webOS the box2d-wrapper worked fine for me!
On Android I don´t know, but why not.

[Crivens]

That's interesting to know. Thanks for that!

Cheers

[Kitty Hello]

the iOS compiler is broken. The others are pretty up to date so no problems I hope.