This saves popping, destroying, recreating, and pushing the stack frame,
and then reassigning the warp mode attribute for every block to block
step in the execution.
Run-time Optimisation
The thread.stackFrames array is accessed all the time to retrieve the
'parent' stack frame. This is done using as index of [this.stack.length
- 1]. However, a lot of the time this evaluated to [-1]. Although this
results in null, which is fine, to get to this javascript actually
defers from a numeric array lookup to an object lookup using the string
"-1". This is roughly 100 times slower to compute and so a simple catch
for negative indexes is well worth the extra check.
When popping down the stack frame it is assumed that you keep using the
previous warp state rather than looking at the warp state of the level
you just popped out to. This causes the loss of screen updates if the
warping block was the last statement in a loop as the loop does not obey
it's 'non warp' status.
Changes include:
- Added missing JSDoc for items in `scratch3_pen.js` and `target.js`.
- Moved constants used by `Scratch3PenBlocks` into the class.
- Created a constant for minimum and maximum pen size.
- Added `util/clone.js` to host cloning functionality.
- Pen blocks now check for the renderer before trying to use it.
- The pen integration test covers all blocks, though `clear`, `stamp`,
and `pen down` will skip some of their functionality when there is no
renderer.
These blocks implement pen features as found in Scratch 2.0
Supporting changes include:
- `Target` is now an event emitter
- `RenderedTarget` now emits an event when it moves
- `Target` can now store arbitrary "extra" data, called "custom state"
in the code, using a `Target`'s `setCustomState` and `getCustomState`
methods. This is used to store per-target pen state without requiring
`Target` or `RenderedTarget` to know anything about the pen.
- `Cast` can now cast to an RGB color object.
- `Color` now has functions to convert between RGB and HSV, constants
for for black & white, and a `mixRgb` function to lerp between two
colors.
This allows costume data to reach listeners even when the sprite isn't the editing target.
Filter out non-editing target reports in the playground to match previous behavior.
These events signal when any threads are running or when all threads have stopped running. This maps to whether the green flag or the stop button should be illuminated in the GUI.
Use it before loading projects so targets don't accumulate when multiple projects are loaded on the same instance.
Move check to see if the clone is the original clone onto the block implementation so all clones can be removed.
Fixes#274
