osgEarth::Picker, IntersectionPicker, objectIDPicker

[user-1199]

Hello!
We're currently in the process of upgrading our application from 2.x to the latest release. We previously used a Pickers.cpp class where we gave it an x, y, and hits to determine if we've clicked on placeNode, and if there were multiple placeNodes underneath. I attempted to use intersectionPicker but it would seem that placeNodes are invisible to it (#2484 (?) + from my testing).

So, I've since migrated to ObjectIDPicker and have tagged any node that can/should be picked in the earth scene -- which has been great so far. Now, my current problem is I'm no longer able to iterate through any objects underneath the x, y coordinates using this approach. From what I understand, ObjectIDPicker only returns the ID of the highest level object (if present and tagged), and any underlying placeNodes will be ignored, fundamentally.

Is this generally the correct understanding? And is there possibly another approach/class I may be able to integrate instead to get the get the same functionality as I had before? Picking on screen, in space objects, including any overlapped ones?

Any thoughts or help is much appreciated!

Thank you!

[gwaldron]

You are correct. ObjectIDPicker uses an RTT technique to find the object at the location under the mouse. The object IDs of each on-screen object get rendered to a temporary texture, which it then queries for an object ID.

If you want to query a larger area and get nearby object IDs you can modify/write code based on the picker to do this. But this technique will not support more than one object ID at a given pixel.

PlaceNode's render in screen space which is why a normal intersector doesn't work. It sounds like you may need to roll your own code to do it.

[user-1199]

Understood, thank you!