Intersection with glTF model

sherousee · October 8, 2018, 7:43pm

Omar,

Thanks for the reply, I am checking out v1.50. I am particularly interested in the scene.pickFromRay() api. Curious if there is a sandcastle example for this? Seems straightforward, but I'm actually generating some exceptions, at least on the 3D Tiles that I have tried to use.

-Eric

omar · October 9, 2018, 3:15pm

There isn’t a Sandcastle example for it yet I think because it’s still a private function, so its API may change. I believe Sean is still developing this, this is the latest PR:

With that said, of course Cesium is an open source library and you can hack away at it to your heart’s content. I think you can get some insight on how the pickFromRay is used internally by looking at the scene clampToHeight function:

github.com

CesiumGS/cesium/blob/master/Source/Scene/Scene.js#L3837-L3848


 * var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
 * handler.setInputAction(function(movement) {
 *     console.log(scene.cartesianToCanvasCoordinates(position));
 * }, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
 */
Scene.prototype.cartesianToCanvasCoordinates = function(position, result) {
    return SceneTransforms.wgs84ToWindowCoordinates(this, position, result);
};


/**
 * Instantly completes an active transition.
 */

sherousee · October 9, 2018, 3:43pm

Ah, I see. Thanks Omar!

sherousee · October 12, 2018, 4:42pm

Omar,

I submitted a PR for the issue I described above: https://github.com/AnalyticalGraphicsInc/cesium/pull/7129

Ended up running into another issue after that. 'scene.pickFromRay()' will occasionally return undefined in cases where I know it should actually return a result. From what I can tell, I think the issue is in 'PickFramebuffer.prototype.end' either 'context.readPixels()' is not invoked correctly or the colors are not being indexed correctly from the 'pixels' object. Of course, I could be completely wrong.

Should I report this on github?

Thanks,
Eric

omar · October 12, 2018, 5:54pm

Awesome, thank you so much for the contribution Eric! This’ll definitely help as Sean is actively developing this.

This might be worth mentioning in the same PR, and @mention-ing Sean. He might have more insight here, and if it is a bug perhaps it could get fixed in the same PR?