Dumb question about coordinates Topic is solved

[slapin]

Hi, all!
Maybe it is too late for questions like that but that is kind of omission I have.
I have scene node like

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Ogre::SceneNode *pNode;

set to some node in scene. For that node I need to get/set

1. local (parent) space position/orientation
2. global space position/orientation.
   How can I get these properly? For global space coordinates I can getDerivedPosition()/getDerivedOrientation(). But what about local space?
   what is difference between _getDerivedPosition() and getPosition()?
   Till now I used global space and magic tricks to avoid digging deeper but now it is time to know for sure.

[rpgplayerrobin]

It depends on what you need it for, but first check the actual functions in the source code:

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        /** Gets the position of the node relative to it's parent.
        */
        const Vector3 & getPosition(void) const { return mPosition; }
        

    /** Gets the position of the node as derived from all parents.
    */
const Vector3 & Node::_getDerivedPosition(void) const
    {
        if (mNeedParentUpdate)
        {
            _updateFromParent();
        }
        return mDerivedPosition;
    }

But that is not always needed either.
For example, when I get the world position of a bone, I use this code:

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// Gets the world position of a bone
Vector3 CGeneric::GetPosition(Bone* bone, SceneNode* node)
{
	Vector3 p = node->_getFullTransform() * bone->_getDerivedPosition();
	return p;
}

You can also just visualize it yourself by creating an object and placing it at the position of another objects getPosition/_getDerivedPosition to understand the difference.
Many times those might be the exact same position, unless you have hierarchies of nodes.

[slapin]

Thanks, I was concerned I had some wrong understanding of things but now I got my confidence back.