Keep camera position during a morph when duration is 0.0

[bagnell]

For #1060.

Fixes #2065. May also fix #1518 and #1845, though I couldn't reproduce #1845 in master either.
Might want to close #451 too since the morph view at the end is whatever the user set it to.

[pjcozzi]

@bagnell @mramato let me know when the kinks are worked out, and I will take a quick look at the code.

[bagnell]

@pjcozzi This is ready for another review. I decided for an incremental improvement until the other issues can be resolved.

If the duration is 0.0, the camera will maintain its position and orientation. In the Sandcastle, add viewer.sceneModePicker.viewModel.duration = 0.0;. Also, the issues mentioned above should still be fixed.

[pjcozzi]

Code is OK with me. @mramato can you test and merge?

[mramato]

I do not agree with going back to the old fly out behavior. I also think it's confusing from a usability standpoint to have the camera stay where it is when duration is 0 vs fly out if it's non-zero. I'm super excited about the other morph fixes though (no more crashes!)

@bagnell can you please list what the remaining issues were that caused us to go back to the old behavior? The only thing I notice is jitter and tile seems.

In my opinion the graphical glitches during the morph are well worth the tradeoff to be able to morph in all cases without losing position. I'm not sure if others had time to see it in action, but git checkout 472d512cdf554fd1573dc4b42285b1743e66d741 in order to see for yourself. I'd be interested to hear what others' opinions are. If no one cases that we're still flying out, then I won't object to merging this; but it's such a common complain on the forum that I feel it's worth keeping the position around.

[hpinkos]

I do not agree with going back to the old fly out behavior

👍 People hate that they lose their position

But I don't think the morph in commit 472d512cdf554fd1573dc4b42285b1743e66d741 is quite right either. The morph between CV and 2D is good because even when you're zoomed in, you have a sense of what just happened. 3D to 2D, it's just weird to see the globe do a wiggle then stop. There's no context.
It's a little silly, but I think flying out, doing the morph, then flying back in is a better solution.
And I think it should tilt when you get into CV, otherwise you don't notice that the mode is any different from 2D until you use the middle mouse button.

Either way, I think this is a huge improvement. I haven't been able to switch between scene modes without the browser crashing in forever, so that's 100% worth merging in.

[pjcozzi]

This incremental improvement is OK with me. The user this is for is just going to do a duration=0 "morph." We can revisit as time allows.

[bagnell]

@mramato Those are the only two issues. For the second, it's not just cracks between tiles. There are whole tiles missing for certain views because the quadtree isn't updated during the morph.

@mramato @pjcozzi @hpinkos What are we doing with this PR?

[hpinkos]

I'm in favor of merging this in. I think there are some additional improvement that can be made further down the line, but this is much better than what we have now.

[pjcozzi]

+1 from me for merging this.

[mramato]

I changed the title so when people stumble on this they don't get their hopes up. I just hope we eventually get back to making this work in all cases.