Initialization Puzzles
These puzzles are located under the init tab and are interpreted before a Verge3D application is initialized.

"configure application"
Allows to set up application initialization parameters, including some WebGL context creation parameters.
- "compressed assets" - makes the app load a compressed scene in .xz format instead of a regular .gltf file (see Asset compression for more info);
- "default fullscreen button" - enables the default fullscreen button located in the top right corner;
- "transparent background" - makes the background transparent so that the underlying parts of a web page become visible through the WebGL canvas;
- "enable screenshots" - makes it possible to properly capture screenshots from the WebGL canvas (sets the preserveDrawingBuffer property of the WebGL context to *true*);
- "fade annotations" - makes annotations fade when they are blocked by scene objects.

"setup preloader" + "percentage"
Removes the default preloader and exposes event callbacks to allow for handling preloader progress events.

In the following example, a custom preloader is represented with a container HTML element (e.g., a <div>) with the id "preloader". Inside it, there is another element with the id "loading progress" (e.g., a <span>), in which % of loading is printed using the *persentage* puzzle. In addition to that, the width of the third element (e.g., a <div>) is dynamically changed to graphically represent the loading progress.

"load font"
Loads font from a specified URL and makes it accessible via *font-family* CSS rule.
