class btMotionState : void getWorldTransform() ?

[durium]

Hi all !

I am going through some tutorials to use bullet with my ogre3d application.
I have read that i needed to use the btMotionState class.

When i found it, i discovered a weird function called getWorldTransform, with a return type void which asked for an argument...
In most of the tutorials I've read so far, i believe that this function was used as a setter :

Code: Select all

virtual void getWorldTransform(btTransform worldTrans) const{
    worldTrans = mTransformation;
}

However it is named as a getter...
Is it normal ?

[anthrax11]

Hi!

If getWorldTransform returned a btTransform, then it would have to allocate memory for holding the return value. Instead, the value is written directly to an existing btTransform to save time and space. So it's just a useful optimization.

Note that btTransform is a class, so the parameter is really a pointer. That's why the parameter you pass can be modified by the function.

This allows you to allocate a single btTransform and use it every time you need to do the getWorldTransform.

[durium]

ok thanks!

I should had read it more carefully...
First time i see that...