* Refactor texture caching in render.Engine:
* New interface method: NewTexture(filename string, image.Image)
* WASM immediately encodes the image to PNG and generates a JavaScript
`Image()` object to load it with a data URI and keep it in memory.
* SDL2 saves the bitmap to disk as it did before.
* WASM: deprecate the sessionStorage for holding image data. Session
storage methods panic if called. The image data is directly kept in
Go memory as a js.Value holding an Image().
* Shared Memory workaround: the level.Chunk.ToBitmap() function is where
chunk textures get cached, but it had no access to the render.Engine
used in the game. The `pkg/shmem` package holds global pointers to
common structures like the CurrentRenderEngine as a work-around.
* Also shmem.Flash() so Doodle can make its d.Flash() function
globally available, any sub-package can now flash text to the screen
regardless of source code location.
* JavaScript API for Doodads now has a global Flash() function
available.
* WASM: Handle window resize so Doodle can recompute its dimensions
instead of scaling/shrinking the view.
* Implement the pub/sub message passing system that lets the JavaScript
VM of one actor (say, a Button) send messages to other linked actors
in the level (say, an Electric Door)
* Buttons now emit a "power(true)" message while pressed and
"power(false)" when released. Sticky Buttons do not release and so do
not send the power(false) message.
* Electric Doors listen for the "power" event and open or close
themselves based on the boolean value received.
* If a Sticky Button receives power and is currently pressed down, it
will pop back up (reset to "off" position) and notify its linked
actors that they have lost power too. So if a Sticky Button held an
Electric Door open, and another Button powers the Sticky Button, it
would pop back up and also close the Electric Door.
* Events.OnCollide now receives a CollideEvent object, which makes
available the .Actor who collided and the .Overlap rect which is
zero-relative to the target actor. Doodad scripts can use the .Overlap
to see WHERE in their own box the other actor has intruded.
* Update the LockedDoor and ElectricDoor doodads to detect when the
player has entered their inner rect (since their doors are narrower
than their doodad size)
* Update the Button doodads to only press in when the player actually
touches them (because their sizes are shorter than their doodad
height)
* Update the Trapdoor to only trigger its animation when the board
along its top has been touched, not when the empty space below was
touched from the bottom.
* Events.OnLeave now implemented and fires when an actor who was
previously intersecting your doodad has left.
* The engine detects when an event JS callback returns false.
Eventually, the OnCollide can return false to signify the collision is
not accepted and the actor should be bumped away as if they hit solid
geometry.
* Add a Red Azulian as a test for mobile enemies.
* Its A.I. has it walk back and forth, changing directions when it
comes up against an obstacle for a few moments.
* It plays walking animations and can trigger collision events with
other Doodads, such as the Electric Door and Trapdoor.
* Move Gravity responsibility to the doodad scripts themselves.
* Call `Self.SetGravity(true)` to opt the Doodad in to gravity.
* The canvas.Loop() adds gravity to any doodad that has it enabled.
* 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)
* Add the JavaScript system for Doodads to run their scripts in levels,
and wire initial OnCollide() handler support.
* CLI: Add a `doodad install-script` command to the doodad tool.
* Usage: `doodad install-script <index.js> <filename.doodad>`
* Add dev-assets folder for storing source files for the official
default doodads, sprites, levels, etc. and for now add a JavaScript
for the first test doodad.
