Determine when 3D point is out of view

[Flomotion]

Hi all,

I'd like to know if anyone knows how to determine if a 3D point is out of range from the camera view.

I'm making 2D labels on top of a 3D model. And it all works nice but when camera is 180 to the object, the 2D labels appear back on the canvas.

I based what I'm doing on this example by Wingnut.

http://playground.babylonjs.com/#1HLSBC%234

You'll see the menu's floating by if you zoom a bit closer to the red sphere and make a box float behind you. So to prevent that from happening.. my question again:

I'd like to know if anyone knows how to determine if a 3D point is out of range from the camera view?

:-)

Floris

[RaananW]

Hi Floris,

 

I believe Frustum  inspection can help in your case. It will inspect if an object is in the camera's view.

The only catch is - it will return true also when an object is hidden behind another object. 

To use it, get the frustum planes of your camera:

var frustumPlanes = BABYLON.Frustum.GetPlanes(scene.getTransformMatrix());

and then use it to determine if part of the object is in the camera's view:

if(!mesh.isInFrustum(frustumPlanes)) {   doSomethingWithTheMesh(mesh);} 

You could also get the array of active meshes from the scene and use it - Simply put, active meshes can be seen as meshes in the camera's view. To Get it:

var smartActiveMeshesArray = scene.getActiveMeshes(); 

Or check if a mesh is active:

var active = scene.isActiveMesh(mesh); 

I hope it helps!

[Flomotion]

Thanks for your reply. It certainly helps!

I'd only have to add some small geometry in my scene at the desired places to solve the issue.

Floris