Cesium usability improvements

[pjcozzi]

A few notes from past hackathons.

• Inconsistent variable names makes it hard to copy and paste code. Sandcastle has widget, HelloWorld.html has cesiumWidget.
• What is the future of Sandcastle.highlight? It gets in the way when copying and pasting into HelloWorld.html, and the mouse-over highlighting gets in the way by changing scroll position away from where we were reading. Perhaps reorganizing the Sandcastle examples will eliminate the name for this feature.
• Can billboard.imageIndex reference an image that doesn’t exist yet? In general, making the texture atlas should be easier.
• Not sure if this is still true: "working with camera flights is extremely painful. Even worse when starting/ending views are in different reference frames." @bagnell?

[pjcozzi]

For the top bullet, sometimes it is also called viewer like in the camera tutorial.

[emackey]

@pjcozzi note that viewer and widget are two different widgets.

[pjcozzi]

@pjcozzi note that viewer and widget are two different widgets.

Yes, of course. Using them 50/50 throughout the examples is confusing though, especially for new folks looking to copy and paste. I'm still looking into what is best, e.g., use viewer just about everywhere, always call it widget, etc.

[emackey]

Agreed, it's confusing. Not sure that viewer is correct for 100% of the examples though, but I would like to see viewer used more frequently than it is. This could possibly be done by "turning off" sub-widgets that don't apply to certain examples. For instance, some examples avoid viewer just to avoid a scene mode switch, when they could just turn off the scene mode widget and use the rest of viewer. In other cases though, we want folks to focus on example content, and not have viewer's UI in the way. Not sure the best answer.

[pjcozzi]

Agreed. Perhaps we just about always use it but turn things off as needed. The examples are inconsistent now and a newbie will not always know widget.scene can be used in place of viewer.scene, for example.

Open to other folk's thoughts here.

[pjcozzi]

Closing as now duplicate with #1688 (texture atlas) and #1060 (camera).