Convert the Chunker size to a uint8 so chunk sizes are limited to 255px. This
means that inside of a chunk, uint8's can track the relative pixel coordinates
and result in a great memory savings since all of these uint8's are currently
64-bits wide apiece.
WIP on rectangular shaped doodads:
* You can create such a doodad in the editor and draw it normally.
* It doesn't draw the right size when dragged into your level however:
- In uix.Actor.Size() it gets a rect of the doodad's square Chunker size,
instead of getting the proper doodad.Size rect.
- If you give it the doodad.Size rect, it draws the Canvas size correctly
instead of a square - the full drawing appears and in gameplay its hitbox
(assuming the same large rectangle size) works correctly in-game.
- But, the doodad has scrolling issues when it gets to the top or left edge
of the screen! This old gnarly bug has come back. For some reason square
canvas doodads draw correctly but rectangular ones have the drawing scroll
just a bit - how far it scrolls is proportional to how big the doodad is,
with the Start Flag only scrolling a few pixels before it stops.
Previously: the Chunker tracks with chunks were gotten during the
current game tick and the N-1 and N-2 ticks, and chunks not accessed in
two ticks were freed immediately.
Now: they go into a "garbage collection" pool with a minimum number of
game ticks to free. So if they're needed again, they're saved from the
gc pool. F3 overlay data shows the count of the gc pool.
Water pixels finally do something other than turn your character blue!
* When the player character is "wet" (touching water pixels, and so appearing in
a blue mask), water physics apply: gravity is slower, your jump height is
halved, but you get infinite jumps to swim higher in the water.
* Holding the jump key under water will incur a short delay between jumps, so
that you don't just fly straight up to the surface. Tap the jump button to
move up quicker, you can spam it all you want.
Azulians are also able to handle being under water:
* They'll sink to the bottom and keep walking back and forth normally.
* If you are above them and noticed, they'll jump (swim) up towards you,
aware of the water and it jumps like you do.
* The Blue Azulian has the poorest vertical aggro range so it isn't a
very good swimmer. The White Azulian is very good at navigating water
as it can pursue the player from the furthest distance of them all.
Changes to the editor:
* New brush pattern added: bubbles.png
* It's the default pattern now for the "water" color of all
of the built-in palettes instead of ink.png
* A repeating pattern of bubbles carved out showing the
level wallpaper.
* The old "Bubbles (circles.png)" is renamed "Circles"
* The last scroll position is saved with the Level file, so when you reload
the level later it's scrolled at where you left it.
The gamepad mouse cursor has become THE mouse cursor. It is always visible and your
real cursor is hidden, and this way the game can swap out other cursors for certain
scenarios:
* The Pencil Tool in the editor will use a pencil cursor over the level canvas.
* The Flood Tool has a custom Flood cursor so you don't forget it's selected!
Other improvements:
* The Palette buttons in the editor now render using their swatch's pattern
instead of only using its color.
* If you have an ultra HD monitor and open a Bounded level in the editor which
is too small to fill your screen, the editor canvas limits its size to fit
the level (preferable over showing parts of the level you can't actually play
as it's out of bounds).
* The "brush size" box is only drawn around the cursor when a relevant tool is
selected (Pencil, Line, Rect, Ellipse, Eraser)
* Editor: Auto-save on a background goroutine so you don't randomly freeze
the editor up during.
* Fix actor linking issues when you drag and re-place a linked doodad: the
level was too eagerly calling PruneLinks() whenever a doodad was 'destroyed'
(such as the one just picked up) breaking half of the link connection.
* Chunk unloader: do not unload a chunk that has been modified (Set or Delete
called on), keep them in memory until the next ZIP file save to flush them
out to disk.
* Link Tool: if you clicked an actor and don't want to connect a link, click
the first actor again to de-select it.
Updates to the `doodad` tool:
* `doodad edit-level --resize <int>` can re-chunk a level to use a different
chunk size than the default 128. Large chunk sizes 512+ lead to performance
problems.
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.
* Added to the F3 Debug Overlay is a "Texture:" label that counts the number
of textures currently loaded by the (SDL2) render engine.
* Added Teardown() functions to Level, Doodad and the Chunker they both use
to free up SDL2 textures for all their cached graphics.
* The Canvas.Destroy() function now cleans up all textures that the Canvas
is responsible for: calling the Teardown() of the Level or Doodad, calling
Destroy() on all level actors, and cleaning up Wallpaper textures.
* The Destroy() method of the game's various Scenes will properly Destroy()
their canvases to clean up when transitioning to another scene. The
MainScene, MenuScene, EditorScene and PlayScene.
* Fix the sprites package to actually cache the ui.Image widgets. The game
has very few sprites so no need to free them just yet.
Some tricky places that were leaking textures have been cleaned up:
* Canvas.InstallActors() destroys the canvases of existing actors before it
reinitializes the list and installs the replacements.
* The DraggableActor when the user is dragging an actor around their level
cleans up the blueprint masked drag/drop actor before nulling it out.
Misc changes:
* The player character cheats during Play Mode will immediately swap out the
player character on the current level.
* Properly call the Close() function instead of Hide() to dismiss popup
windows. The Close() function itself calls Hide() but also triggers
WindowClose event handlers. The Doodad Dropper subscribes to its close
event to free textures for all its doodad canvases.
* Loadscreen: put the progress bar between the Title and Subtitle so it
looks good even on mobile landscape orientation (narrow height)
* Bugfixes around window OnResize events: the loadscreen handles
resizing correctly now and the Level Editor (or w/e) will also be the
right size if you resized the window during loading.
* Fix the Doodad Dropper and Registration windows not stealing the focus
when they are opened via menu bars.
* Bugfixes in gamepad support: stop at the first controller found,
Draw() to handle controllers going away and hide the mouse cursor
* magicform is a helper package that may eventually be part of the go/ui
library, for easily creating structured form layouts.
* The Level Publisher UI is the first to utilize magicform.
Refactor how level publishing works:
* Level data now stores SaveDoodads and SaveBuiltins (bools) and when
the level editor saves the file, it will attach custom and/or builtin
doodads just before save.
* Move the menu item from the File menu to Level->Publish
* The Publisher UI just shows the checkboxes to toggle the level
settings and a convenient Save button along with descriptive text.
* Free versions get the "Register" window popping up if they click the
Save Now button from within the publisher window.
Note: free versions can still toggle the booleans on/off but their game
will not attach any new doodads on save.
* Free games which open a level w/ embedded doodads will get a pop-up
warning that the doodads aren't available.
* If they DON'T turn off the SaveDoodads option, they can still edit and
save the level and keep the existing doodads attached.
* If they UNCHECK the option and save, all attached doodads are removed
from the level.
* New doodad: Invisible Warp Door
* All warp doors require the player to be grounded (if affected by
gravity) to open them. No jumping or falling thru and opening
a warp door mid-air!
* Title Screen now randomly selects from a couple of levels.
* Title Screen: if it fails to load a level it sets up a basic
blank level with a wallpaper instead.
* New developer shell command: titlescreen <level>
Opens the MainScene with a custom user level as the background.
* Add Auto-save to the Editor to save your drawing every 5 minutes
* Add a MenuBar to the Play Scene for easier navigation to other
features of the game.
* Doodad JS API: time.Since() now available.
* The "Giant Screenshot" feature takes a very long time, so it is made
asynchronous. If you try and run a second one while the first is busy,
you get an error flash. You can continue editing the level, even
playtest it, or load a different level, and it will continue crunching
on the Giant Screenshot and flash when it's finished.
* Updated the player physics to use proper Velocity to jump off the
ground rather than the hacky timer-based fixed speed approach.
* FlashError() function to flash "error level" messages to the screen.
They appear in orange text instead of the usual blue, and most error
messages in the game use this now. The dev console "error <msg>"
command can simulate an error message.
* Flashed message fonts are updated. The blue font now uses softer
stroke and shadow colors and the same algorithm applies to the orange
error flashes.
Some other changes to player physics:
* Max velocity, acceleration speed, and gravity have been tweaked.
* Fast turn-around if you are moving right and then need to go left.
Your velocity resets to zero at the transition so you quickly get
going the way you want to go.
Some levels that need a bit of love for the new platforming physics:
* Tutorial 3.level
* New keybind: 'v' to open a new Viewport in the Level Editor.
* New keybind: Backspace to close the topmost UI window,
and Shift+Backspace to close them all.
* Zoom has graduated out of experimental feature status. Still a bit
buggy but workable.
* Viewport windows now copy the Tool and BrushSize of the toplevel
editor, so drawing in and out of viewports works well.
* Viewport window UI improved: buttons to grow or shrink the window
size, refresh the actors, etc.
In the level editor, the "Play (P)" button has a new feature: Play
From Here. On mouse down you begin dragging a silhouette of Boy or
whoever the default player character is, as if you were dragging a
doodad onto your level.
Drop the silhouette on your level and enter Play Mode from that
location instead of the Start Flag.
Release your cursor over the Play button or press the "P" key to
spawn at the Start Flag as usual.
In the editor, clicking and dragging with the middle mouse button
will scroll the view of the editor in place of the arrow keys.
When entering Play Mode, the original scroll position in the level
editor is remembered for when you come back - no more having to
scroll from 0,0 each time to get back to where you were working!
Improvements to the Zoom feature:
* Actor position and size within your level scales up and down
appropriately. The canvas size of the actor is scaled and its canvas
is told the Zoom number of the parent so it will render its own
graphic scaled correctly too.
Other features:
* "Experimental" tab added to the Settings window as a UI version of the
--experimental CLI option. The option saves persistently to disk.
* The "Replace Palette" experimental feature now works better. Debating
whether it's a useful feature to even have.
* 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.
* pkg/loadscreen implements a global Loading Screen for loading heavy
levels for playing or editing.
* All chunks in a level are pre-rendered to bitmap before gameplay
begins, which reduces stutter as chunks were being lazily rendered on
first appearance before.
* The loading screen can be played with in the developer console:
$ loadscreen.Show()
$ loadscreen.Hide()
Along with ShowWithProgress(), SetProgress(float64) and IsActive()
* Chunker: separate the concerns between Bitmaps an (SDL2) Textures.
* Chunker.Prerender() converts a chunk to a bitmap (a Go image.Image)
and caches it, only re-rendering if marked as dirty.
* Chunker.Texture() will use the pre-cached bitmap if available to
immediately produce the SDL2 texture.
Other miscellaneous changes:
* Added to the Colored Pencil palette: Sandstone
* Added "perlin noise" brush pattern
Note: this commit introduces instability and crashes:
* New `asyncSetup()` functions run on a goroutine, but SDL2 texture
calls must run on the main thread.
* Chunker avoids this by caching bitmaps, not textures.
* Wallpaper though is unstable, sometimes works, sometimes has graphical
glitches, sometimes crashes the game.
* Wallpaper.Load() and the *Texture() functions are where it crashes.
* Levels and Doodad files will be written in gzip-compressed JSON format
* `boolProp compress-drawings false` to disable compression and save as
classic JSON format directly
* The game can still read uncompressed JSON files
The file size savings on some built-in assets:
* Tutorial 2.level: 2.2M -> 414K (82% smaller)
* warp-door-orange.doodad: 105K -> 17K (84% smaller)
* The pattern textures for level palettes have been brightened and work
better with bright colors.
* The three default palettes for new levels now have patterns applied to
each of their colors.
* Bugfix around resetting keybind states for Zoom In/Out, Scroll to
Origin and Reset Zoom Level bindings.
* Added a Settings window for game options, such as enabling the
horizontal toolbars in Edit Mode. The Settings window also has a
Controls tab showing the gameplay buttons and keyboard shortcuts.
* The Settings window is available as a button on the home screen OR
from the Edit->Settings menu in the EditScene.
* Bugfix: using WASD to move the player character now works better and
is considered by the game to be identical to the arrow key inputs. Boy
now updates his animation based on these keys, and they register as
boolean on/off keys instead of affected by key-repeat.
* Refactor the boolProps: they are all part of usercfg now, and if you
run e.g. "boolProp show-all-doodads true" and then cause the user
settings to save to disk, that boolProp will be permanently enabled
until turned off again.
* Free (shareware) versions of the game will not be able to Publish
Levels (attach custom doodads to the level file) and they will not be
able to load a level which relies on embedded doodads.
* The UI for the Publish Level window is still available, but clicking
on the confirm button will just open the Register (License) window.
* When loading a level containing embedded doodads: if some can't load
because they're embedded and you're using the free version of the
game, the error message is customized to reflect that.
* The Publisher is all hooked up. No native Save File dialogs yet, so
uses the dev shell Prompt() to ask for output filename.
* Custom-only or builtin doodads too can be stored in the level's file
data, at "assets/doodads/*.doodad"
* When loading the embedded level in the Editor: it gets its custom
doodads out of its file, and you can drag and drop them elsehwere,
link them, Play Mode can use them, etc. but they won't appear in the
Doodad Dropper if they are not installed in your local doodads
directory.
* Fleshed out serialization API for the Doodad files:
- LoadFromEmbeddable() looks to load a doodad from embeddable file
data in addition to the usual places.
- Serialize() returns the doodad in bytes, for easy access to embed
into level data.
- Deserialize() to parse and return from bytes.
* When loading a level that references doodads not found in its embedded
data or the filesystem: an Alert modal appears listing the missing
doodads. The rest of the level loads fine, but the actors referenced
by these doodads don't load.
* Added Feature Flag support, run doodle with --experimental to enable
all flags. Eraser Tool is behind a feature flag now.
* + and - on the top row of keyboard keys will zoom the drawing in and
out in Edit Mode. The wallpaper zooms nicely enough, but level
chunkers need work.
* A View menu is added with Zoom in/out, reset zoom, and scroll to
origin options. The whole menu is behind the Zoom feature flag.
* Update README with lots of details for fun debug mode options to play
around with.
* pkg/keybinds holds central functions to check global keybinds, like
DebugOverlay (F3), Undo (Ctrl-Z), GotoPlay/GotoEdit (p/e), etc.
* The Tools menu in the editor mode lists out more options to select
various drawing tools (line, pencil, etc.) - and showing the hotkey
for each tool.
* When editing a doodad in the Editor Mode, the toolbar has a "Lyr."
button that opens the Layers window.
* The Layers window allows switching the active doodad layer that you
are drawing on, as well as create and rename layers.
* With this feature, Doodads may be fully drawn in-game, including
adding alternate named layers for animations and multiple-state
doodads.
* Update the Pager component to have a configurable MaxPageButtons.
Controls that have more pages than this limit will stop having buttons
drawn after the limit. The "Forward" and "Next" buttons can still
navigate into the extra pages.
* Refactored and centralized the various popup windows in Editor Mode
into editor_ui_popups.go; the SetupPopups() and various methods such
as ShowPaletteWindow() and ShowDoodadDropper() make management of
popups simple for the editor_ui!
* The Menu Bar in Editor Mode now has context-specific tools in the
Tools menu: the Doodad Dropper for levels and Layers for doodads.
* Bugfix the Palette Editor window to work equally between Levels and
Doodads, by only having it care about the Palette and not the Level
that owns it.
* Adds global modal support in the pkg/modal/ package. It has easy
Alert() and Confirm() methods to prompt the user before calling a
callback function on affirmative response.
* Modals have global app state: they're processed in the main loop in
pkg/doodle.go similar to the global command shell.
* When a modal is active, a semitransparent black frame covers the
screen (gameplay loop paused, last game frame rendered below) and the
modal window appears on top.
* The developer console retains higher priority than the modal system
and always renders on top.
* Editor Mode: track when the level pixels have been modified, and
confirm the user about unsaved changes when they attempt to close the
level (New, Open, Close, etc.)
* Global: the Escape key no longer immediately shuts down the game, but
will confirm the user's intent via a modal.
* File->Quit in the Editor Mode also invokes the confirm shutdown modal.
* Implement Brush Sizes for drawtool.Stroke and add a UI to the tools panel
to control the brush size.
* Brush sizes: 1, 2, 4, 8, 16, 24, 32, 48, 64
* Add the Eraser Tool to editor mode. It uses a default brush size of 16
and a max size of 32 due to some performance issues.
* The Undo/Redo system now remembers the original color of pixels when
you change them, so that Undo will set them back how they were instead
of deleting the pixel entirely. Due to performance issues, this only
happens when your Brush Size is 0 (drawing single-pixel shapes).
* UI: Add an IntVariable option to ui.Label to bind showing the value of
an int reference.
Aforementioned performance issues:
* When we try to remember whole rects of pixels for drawing thick
shapes, it requires a ton of scanning for each step of the shape. Even
de-duplicating pixel checks, tons of extra reads are constantly
checked.
* The Eraser is the only tool that absolutely needs to be able to
remember wiped pixels AND have large brush sizes. The performance
sucks and lags a bit if you erase a lot all at once, but it's a
trade-off for now.
* So pixels aren't remembered when drawing lines in your level with
thick brushes, so the Undo action will simply delete your pixels and not
reset them. Only the Eraser can bring back pixels.
* The `doodad` CLI tool got a lot of new commands:
* `doodad show` to verbosely print details about Levels and Doodads.
* `edit-level` and `edit-doodad` to update details about Levels and
Doodads, such as their Title, Author, page type and size, etc.
* Doodads gain a `Hidden bool` that hides them from the palette in
Editor Mode. The player character (Blue Azulian) is Hidden.
* Add some boolProps to the balance/ package and made a dynamic system
to easily configure these with the in-game dev console.
* Command: `boolProp list` returns available balance.boolProps
* `boolProp <name>` returns the current value.
* `boolProp <name> <true or false>` sets the value.
* The new boolProps are:
* showAllDoodads: enable Hidden doodads on the palette UI (NOTE:
reload the editor to take effect)
* writeLockOverride: edit files that are write locked anyway
* prettyJSON: pretty-format the JSON files saved by the game.
* Rudimentary scrolling shows a Left and Right button at the top of the
Doodad Palette if your window is deemed not tall enough to contain all
of the doodads.
* A "progress bar" is shown between the buttons indicating the
percentage of your scroll down the doodad list. When you're able to
see the final row of doodads, the progress bar is at 100%.
* Add support for the LineTool and RectTool while in the EditorMode to
easily draw straight lines and rectangle outlines.
* Key bindings were added to toggle tools in lieu of a proper UI to
select the tool from a toolbar.
* "F" for Pencil (Freehand) Tool (since "P" is for "Playtest")
* "L" for Line Tool
* "R" for Rectangle Tool
* Add new pkg/drawtool with utilities to abstract away drawing actions
into Strokes and track undo/redo History for them.
* The freehand Pencil tool in EditorMode has been refactored to create a
Stroke of Shape=Freehand and queue up its world pixels there instead
of directly modifying the level chunker in real time. When the mouse
button is released, the freehand Stroke is committed to the level
chunker and added to the UndoHistory.
* UndoHistory is (temporarily) stored with the level.Level so it can
survive trips to PlayScene and back, but is not stored as JSON on
disk.
* Ctrl-Z and Ctrl-Y in EditorMode for undo and redo, respectively.
* Add a Level Exit doodad, which for now is a little blue flag on a pole
that reads "END"
* JavaScript API: global function EndLevel() will end the level. The
exit doodad calls this when touched by the player.
* Add a "Level Completed" alert box UI to PlayScene with dynamic button
layouts.
* The alert box pops up when a doodad calls EndLevel() and contains
action buttons what to do next.
* "Play Again" restarts the current level again.
* "Edit Level" if you came from the EditorScene; otherwise this button
is not visible.
* "Next Level" is a to-be-implemented button to advance in the single
player story mode. Only shows up when PlayScene.HasNext=true.
* "Exit to Menu" is always visible and closes out to the MainScene.
* Instead of needing to press the "P" and "E" keys to toggle from edit
mode to play mode (and back again), respectively, the UI now draws a
"Play (P)" or "Edit (E)" button on the bottom right corner of the
level canvas. Clicking it will toggle the mode.
* Fix the EditorUI not showing the correct palette baked into the level
and only showing the default. This was tricky because the palette UI
can only be configured at setup time but not updated later.
* Add a new default palette for the Blueprint theme. Blueprint has a
dark background, so the palette colors should be bright. This palette
is chosen when you start a map with the blueprint wallpaper.
* Add a background Canvas to the MenuScene. In the "New Level" screen,
the background canvas will update to show the wallpaper settings
you've chosen as a preview of the level theme you're about to create.
* Add some encoding/decoding functions for binary msgpack format for
levels and doodads. Currently it writes msgpack files that can be
decoded and printed by Python (mp2json.py) but it can't re-read from
the binary format. For now, levels will continue to write in JSON
format.
* Add filesystem abstraction functions to the balance/ package to search
multiple paths to find Levels and Doodads, to make way for
system-level doodads.
* CLI: fix the `doodad convert` command to share the same Palette when
converting each frame (layer) of a doodad so subsequent layers find
the correct color swatches for serialization.
* Scripting: add timers and intervals to Doodad scripts to allow them to
animate themselves or add delayed callbacks. The timers have the same
API as a web browser: setTimeout(), setInterval(), clearTimeout(),
clearInterval().
* Add support for uix.Actor to change its currently rendered layer in
the level. For example a Button Doodad can set its image to Layer 1
(pressed) when touched by the player, and Trapdoors can cycle through
their layers to animate opening and closing.
* Usage from a Doodad script: Self.ShowLayer(1)
* Default Doodads: added scripts for all Buttons, Doors, Keys and the
Trapdoor to run their various animations when touched (in the case of
Keys, destroy themselves when touched, because there is no player
inventory yet)
Fixes:
* Move the call to CollidesWithGrid() inside the Canvas instead of
outside in the PlayScene.movePlayer() so it can apply to all Actors
in motion.
* PlayScene.movePlayer() in turn just sets the player's Velocity so the
Canvas.Loop() can move the actor itself.
* When keeping the player inside the level boundaries: previously it was
assuming the player Position was relative to the window, and was
checking the WorldIndexAt and getting wrong results.
* Canvas scrolling (loopFollowActor): check that the actor is getting
close to the screen edge using the Viewport into the world, NOT the
screen-relative coordinates of the Canvas bounding boxes.
* Scenes can insert custom key/value labels to the debug overlay and
track string variables in real time
* Added ability to unthrottle FPS in main loop
