Bounding boxes dont follow nodes?

[Mauc]

Hi to all, my first post here. :)
I´ve been playing around with Irrlicht for couple of weeks now, and there is something that seems odd. When I draw a bounding box for a node

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driver->draw3DBox(node->getBoundingBox(), SColor(255, 255, 255, 255));

the bounding box always appears to be at (0,0,0), no matter where the node is. So I always get true for all collision detection using bounding boxes, because all the bounding boxes are at same location :P What am I missing here ?

[jox]

Hi. The box you get with node->getBoundingBox() probably contains only local coordinates. Maybe a way would be to set the driver transformation before drawing the box:

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core::matrix4() m;
m.setTranslation(node->getPosition());
driver->setTransform(video::ETS_WORLD, m);

driver->draw3DBox(node->getBoundingBox(), SColor(255, 255, 255, 255)); 

a good idea also would be to set the material for the driver beforehand:

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video::SMaterial m; 
m.Lighting = false; 
driver->setMaterial(m);

core::matrix4() m;
m.setTranslation(node->getPosition());
driver->setTransform(video::ETS_WORLD, m);

driver->draw3DBox(node->getBoundingBox(), SColor(255, 255, 255, 255)); 

Maybe there is a better way.
Hope this helps...

[jox]

Oh and don't forget the rotation...

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video::SMaterial m; 
m.Lighting = false; 
driver->setMaterial(m); 

core::matrix4() m; 
m.setTranslation(node->getPosition()); 
m.setRotationDegrees(node->getRotation()); // <----
driver->setTransform(video::ETS_WORLD, m); 

driver->draw3DBox(node->getBoundingBox(), SColor(255, 255, 255, 255)); 

[jox]

Oops sorry, I accidentaly named the matrix and the material both "m". This is of course stupid. Name them differently...

[mAUC]

Thanks !

[luvcraft]

I have a related problem. I have 2 mesh nodes in my scene, and when I call draw3DBox() passing either of their bounding boxes, the bounding box appears around the most-recently-created node that's also visible. So, if node 2 is behind the camera, it will draw the box around node 1, but if they're both in the scene, it will draw the box around node 2. The dimensions of the box are determined by which node I pass it, but the position of the box goes to whichever node was created last.

Any ideas on how to fix this, or is it a bug in Irrlicht?

Oh, I should also mention that I've tried this both with node->getBoundingBox() and mesh->getBoundingBox() with the same result.

[jox]

luvcraft, I don't know if I understand correctly, but it seems you just have to set the world transformation before drawing the/each box. Like I explained before... Same thing...

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core::matrix4() m; 
m.setTranslation(node->getPosition()); 
m.setRotationDegrees(node->getRotation());
m.setScale(node->getScale());
driver->setTransform(video::ETS_WORLD, m); 
driver->draw3DBox(node->getBoundingBox(), SColor(255, 255, 255, 255));

[Domarius]

You use getTransformedBoundingBox, instead of getBoundingBox, simple. (read the help )

[jox]

Great, even better

Well, sometimes there are handy functions available where you need them (just have to find them).
Sometimes not, like getParent() for example (just have to implement them).

[luvcraft]

well I feel stupid... and I also feel the need to write good documentation. :)X

Thanks for the help!

[luvcraft]

so I did the transformedboundingbox thing, and I still have the exact same problem -- the box will be attached to the most-recently-created node that's visible -- except NOW, the box floats way off behind and below whichever node it's attached to, which makes it even less useful.

Also, for some reason, the box is brown, regardless of what color I tell it to be.

[jox]

@luvcraft.

1. If you use the TranformedBoundingBox, then you might have to reset the absolute tranformation of the driver to zero beforehand.

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driver->setTransform(video::ETS_WORLD, core::matrix4()); // identity matrix

2. To get the color right you might have to set the material of the driver first. A while ago I posted an example on how to do that:
http://irrlicht.sourceforge.net/phpBB2/ ... php?t=2266

Hope this helps,
greets,
jox

[luvcraft]

unfortunately, the box is still floating in the same place behind the character. I'm thinking some of the box's attributes are getting mixed up, since when I turn the character the box's dimensions change.

[jox]

Have you tried ISceneNode::setDebugDataVisible()? It also shows the bounding boxes.

[Domarius]

so I did the transformedboundingbox thing, and I still have the exact same problem -- the box will be attached to the most-recently-created node that's visible -- except NOW, the box floats way off behind and below whichever node it's attached to, which makes it even less useful.

Also, for some reason, the box is brown, regardless of what color I tell it to be.

Well for me, transformedBoundingBox was the answer, and fixed the exact same problem you initially described.
This must be related to some other error then, which I don't know of.

However, are you viewing the real bounding box? A testing thing I use, is to use getTransformedBoundingBox, and use "drawCube" or whatever it is, to draw it, so I can see exactly where it is.

Maybe that setDebugDataVisible does the same thing, but easier, but I haven't used it (never knew about it )

BTW, I think the help is fine; the "transformedboundingbox" feature is a function of SceneNode (or whatever), so when I was having trouble with the bounding box of a scene node, I knew exactly where to look in the help, and I saw that function next to "getBoundingBox".