* The "Story Mode" button on the MainScene opens the levelpacks window.
* Levelpacks from all places are shown (built-in and user files), basic
level picker works.
* When playing a level out of a levelpack: the PlayScene gets the file
data from the zipfile and plays it OK.
* When a levelpack level is solved, the "Next Level" button appears on
the success modal and hitting Return will advance to the next level in
the pack. The final level doesn't show this button.
* The user can edit levelpack levels! Clicking the "Edit" button on the
Play Mode moves the loaded level over to the EditScene and the user
could save it to disk or edit/playtest it perfectly OK! The link to
the levelpack is lost upon opening in the editor, so the "Next Level"
victory button doesn't appear.
The title screen is now responsive to landscape mode. If the window is
not tall enough to show all the menu buttons (~600px) it will switch to
a horizontal layout with the title on the left and buttons on the right.
WIP "Story Mode" button that brings up a Level Packs selection window.
* The loading screen for Edit and Play modes is stable and the risk of
game crash is removed. The root cause was the setupAsync() functions
running on a background goroutine, and running SDL2 draw functions
while NOT on the main thread, which causes problems.
* The fix is all SDL2 Texture draws become lazy loaded: when the main
thread is presenting, any Wallpaper or ui.Image that has no texture
yet gets one created at that time from the cached image.Image.
* All internal game logic then uses image.Image types, to cache bitmaps
of Level Chunks, Wallpaper images, Sprite icons, etc. and the game is
free to prepare these asynchronously; only the main thread ever
Presents and the SDL2 textures initialize on first appearance.
* Several functions had arguments cleaned up: Canvas.LoadLevel() does
not need the render.Engine as (e.g. wallpaper) textures don't render
at that stage.
* Tightens up the surface area of API methods available to the
JavaScript VMs for doodads. Variables and functions are carefully
passed in one-by-one so the doodad script can only access intended
functions and not snoop on undocumented APIs.
* Wrote tons of user documentation for Doodad Scripts: documented the
full surface area of the exposed JavaScript API now that the surface
area is known and limited.
* Early WIP code for the Campaign JSON
