Especially to further optimize memory for large levels, Levels and
Doodads can now read and write to a ZIP file format on disk with
chunks in external files within the zip.
Existing doodads and levels can still load as normal, and will be
converted into ZIP files on the next save:
* The Chunker.ChunkMap which used to hold ALL chunks in the main json/gz
file, now becomes the cache of "hot chunks" loaded from ZIP. If there is
a ZIP file, chunks not accessed recently are flushed from the ChunkMap
to save on memory.
* During save, the ChunkMap is flushed to ZIP along with any non-loaded
chunks from a previous zipfile. So legacy levels "just work" when
saving, and levels loaded FROM Zip will manage their ChunkMap hot
memory more carefully.
Memory savings observed on "Azulian Tag - Forest.level":
* Before: 1716 MB was loaded from the old level format into RAM along
with a slow load screen.
* After: only 243 MB memory was used by the game and it loaded with
a VERY FAST load screen.
Updates to the F3 Debug Overlay:
* "Chunks: 20 in 45 out 20 cached" shows the count of chunks inside the
viewport (having bitmaps and textures loaded) vs. chunks outside which
have their textures freed (but data kept), and the number of chunks
currently hot cached in the ChunkMap.
The `doodad` tool has new commands to "touch" your existing levels
and doodads, to upgrade them to the new format (or you can simply
open and re-save them in-game):
doodad edit-level --touch ./example.level
doodad edit-doodad --touch ./example.doodad
The output from that and `doodad show` should say "File format: zipfile"
in the headers section.
To do:
* File attachments should also go in as ZIP files, e.g. wallpapers
Instead of the loadscreen eager-loading ALL level chunks to Go Images, only
load the chunks within the "LoadingViewport" - which is the on-screen
Viewport plus a margin of chunks off the screen edges.
During gameplay, every few ticks, reevaluate which chunks are inside or
outside the LoadingViewport; for chunks outside, free their SDL2 textures
and free their cached bitmaps to keep overall memory usage down. The
AzulianTag-Forest level now stays under 200 Textures at any given time
and the loadscreen goes faster as it doesn't have to load every chunk's
images up front.
The LoadUnloadChunk feature can be turned on/off with feature flags. If
disabled the old behavior is restored: loadscreen loads all images and
the LoadUnloadChunks function is not run.
Other changes:
* loadscreen: do not free textures in the Hide() function as this runs on
a different goroutine and may break. The 4 wallpaper textures are OK
to keep in memory anyway, the loadscreen is reused often!
* Free more leaked textures: on the Inventory frame and when an actor
calls Self.Destroy()
* Stop leaking goroutines in the PubSub feature of the doodad script
engine; scripting.Supervisor.Teardown() sends a stop signal to all
scripts to clean up neatly. Canvas.Destroy() tears down its scripting
supervisor automatically.
