scene.pickPosition returns incorrect position

Reported on the forum: https://groups.google.com/forum/?hl=en#!topic/cesium-dev/0E-aKBTLESk

The user created this sandcastle example to demonstrate the problem: http://hosting.virtualcitysystems.de/demos/temp/pickProblem/Apps/Sandcastle/?src=3D Tiles.html&label=undefined

The demo is using the latest 3d-tiles branch

pickPosition works fine if you run the example inside sandcastle, but if you click ‘Open in New Window’ sometimes the returned position sits in front of the building you clicked instead of where the click intersects with it. Maybe it’s related to the canvas ratio? See the forum post for more details.

I couldn’t reproduce this with any of our sample models, but I asked the user if he could share a tile for us to test with.

[duvifn]

@emackey

1. I’m not sure that the ‘jittering’ in your animation is due to the pickPosition results . On my machine, If I set eyeOffset.z to a fixed value this doesn’t happen.

2. I think it’s worth adding scene.globe.depthTestAgainstTerrain = true; to the code in your comment, because this is not the default in the sandcastle. pickPosition returns different values on terrain if depthTestAgainstTerrain == false , usually below the ellipsoid surface (maybe of the DepthPlane).

3. The Alt string in this example code is truncated so it shows an wrong height. for example: -143976.41485355987 becomes 3976.41.

[kring]

In looking at this while debugging #4855, I saw a case where I had only a single frustum, and yet the position returned by pickPosition was wildly wrong. For example, values in pickGlobe in ScreenSpaceCameraController.js:

That’s without anything in the scene except for the globe (and sun and moon and such I suppose, but not explicitly-added primitives).

So I don’t think it’s necessarily multi-frustum related.