Boundingbox of ILightSceneNode worries

[randomMesh]

I wanted to debug my ILightSceneNode, so i set DebugDataVisible to scene::EDS_BBOX.
The radius of the light is 10.0f.

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irr::scene::ILightSceneNode* light = smgr->addLightSceneNode(
	0, irr::core::vector3df(5, 5, -5), irr::video::SColorf(1.0f, 1.0f, 1.0f), 10.0f);
light->setDebugDataVisible(irr::scene::EDS_BBOX);

In my understanding, the bounding box should be 20.f in width and height, according to the radius of 10.0f.

But in CLightSceneNode::doLightRecalc(), the box is computed like this

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const f32 r = LightData.Radius * LightData.Radius * 0.5f;
BBox.MaxEdge.set( r, r, r );
BBox.MinEdge.set( -r, -r, -r );

Means that r = 10*10*0.5 = 50.0f which results in a box that is 100 units wide.

What am i missing?

[vitek]

I've noticed this before, but been to lazy to mention it. To get a minimum bounding box for a sphere with a radius r, it should be

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BBox.MaxEdge.set( r, r, r ); 
BBox.MinEdge.set( -r, -r, -r );

So at least part of the code is right... The whole (r*r)/2.f thing is garbage. It should be LightData.Radius.

Travis

[randomMesh]

Good that it's a bug. I almost went mad.

Here's a patch against latest trunk:

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Index: source/Irrlicht/CLightSceneNode.cpp
===================================================================
--- source/Irrlicht/CLightSceneNode.cpp	(Revision 3273)
+++ source/Irrlicht/CLightSceneNode.cpp	(Arbeitskopie)
@@ -185,9 +185,8 @@
 	}
 	if ((LightData.Type == video::ELT_SPOT) || (LightData.Type == video::ELT_POINT))
 	{
-		const f32 r = LightData.Radius * LightData.Radius * 0.5f;
-		BBox.MaxEdge.set( r, r, r );
-		BBox.MinEdge.set( -r, -r, -r );
+		BBox.MaxEdge.set( LightData.Radius, LightData.Radius, LightData.Radius );
+		BBox.MinEdge.set( -LightData.Radius, -LightData.Radius, -LightData.Radius );
 		setAutomaticCulling( scene::EAC_BOX );
 		LightData.Position = getAbsolutePosition();
 	}

[vitek]

Does the bounding box look correct? i.e., if you have a light with radius R, and a surface (with lighting enabled and a valid normal), does the light show up on the surface only when the surface intersects the bounding box?

[randomMesh]

Does the bounding box look correct?

Yes.

does the light show up on the surface only when the surface intersects the bounding box?

No.

Here's a screenshot. The light has a radius of 10.0f, the bounding box is correct.
But the floor tile outside the boundingbox (at the bottom of the image) is also lit.


This one is from a different view and has some debug drawing enabled.


This one is interesting:
I merged 2 floors and now it's not lit at all. Even though the wall at the left has some lighting.



The floor is made with the geometry creator and are 'cube' meshes. I am using the OpenGL driver, latest trunk.

Seems like lighting is completely broken.