Adding up the frame's dt in On update makes anything that counts in
steps depend on the frame rate. A pitch sweep sounds a little
different on every run. On fixed update runs 60 times per second of
game time with dt exactly 1/60, so the same graph gives the same
result every time.
- fixedSteps in src/core/time.ts is the one rule for the fixed step:
spend the frame in steps of 1/60, keep the rest, catch up 8 steps
at most after a hitch.
- The physics now counts its steps with fixedSteps too. It behaves
as before, and On fixed update runs exactly as often as the engine
steps.
- The steps run after On mouse wheel and before On update, each as a
kind of its own with the usual Order setting.
- Each step gets its own context, so a node inside that reads dt
(Time, Move, Apply force) gets 1/60 rather than the frame.
- A paused game has no steps, also for a behavior that runs while
paused.
- The engine still takes all of a frame's steps before the behaviors
run. A force set in On fixed update acts from the next frame on.
Tests:
- fixed-update.test.ts (new): 5 tests. Step counting, uneven frames
adding up to 60 steps a second, the hitch cap, two steps at 30 Hz
before On update with dt 1/60 for the event and for Time, one step
every other frame at 120 Hz, none while paused.
- event-order, node-catalog, physics-system, game-pause: 430 tests
together with the new file, all green.
- Counter-check: with the frame's dt inside a step and without the
pause guard both world tests fail.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Until now only the editor toolbar could pause a running game. A pause
menu inside the game had no way to stop the world while its own graph
kept running, and there was no slow motion.
- Five new nodes: Pause game, Resume game, Is game paused, Set time
scale and Time scale. Pause and resume take effect on the next frame.
- A game pause stops world time, physics, animations, particles and
shader time. Only behaviors with the new "Run while paused" switch
keep running.
- Set time scale 0 freezes the world but graphs keep running, as
agreed in the issue.
- Play and Stop reset the time scale to 1, Load scene keeps it. The
pause belongs to the scene, so Load scene and Restart unpause.
- The toolbar pause stays separate and also freezes the menu. When the
game pauses itself the status line reads "The game paused itself".
- While paused, collision events are not reported, sounds keep
playing, and the editor run ignores both nodes with a log line.
Findings:
- The first status line was longer than any before and got cut with
an ellipsis. It is shorter now.
- The e2e harness did not know the key "p". It does now.
Tests:
- ./check.sh: 133 files, 1968 tests, exit 0 (before 132 / 1952)
- npm run build: exit 0
- GM_STEPS=18 fresh: ALL PASSED, 33 checks (before 26)
- 16 new unit tests: 8 catalog cases, game-pause.test.ts, editor run
- 7 new e2e checks in block 18i, driven by real keys in the game
- Six counter-checks all bite: behavior filter, collision lock, world
time, editor run, clock reset and the game clock in the browser
- Check total 1217 in README is computed (1210 + 7), CI measures it
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Particle age and shader time each read performance.now() off their own
library, and the world got the frame's delta straight from the ticker. Three
clocks, so a global time scale would have been three multiplications and a
pause three separate freezes.
core/time.ts holds one clock instead: it accumulates dt x scale per frame
rather than reading the wall clock, and Editor.tick hands the very step it
took to the play session, the editor run and the animation preview. Delta
time, particle age, shader time and that preview are the same quantity now,
so the scale is a single multiplication and a pause is that scale at 0 —
nothing underneath needs rebasing, because the clock itself stands still.
The Math.min(dt, 0.1) caps in PlaySession and EditorRun are gone: the cap
(MAX_FRAME) now sits on the raw frame before scaling, and capping twice would
make the world run slower than the particles at scale 2.
A pause gates the scale rather than overwriting it — effectiveScale() answers
0 while paused, and for anything that is not a positive finite number, while
gameClock.scale keeps its value. A slider later survives a pause that way;
the issue asks for none yet.
The clock goes back to zero at both ends of a run, so a run is reproducible
from second 0 and the scene view looks freshly loaded after Stop. Resetting
only on Stop would not do it: the editor clock runs on afterwards, and the
next Play would start at "seconds since the last Stop".
The trap in that: ParticleField keeps its origin as an absolute second of
this clock, so after a reset it lies in the future and every particle would
age backwards. One line in sync() starts such a field over, which covers the
scene, the game and the tab preview at once — and fixes an older bug of the
same shape, where releasing a particleTime() freeze left the preview empty
for good.
Found while measuring that: ParticlePreview stood at second 0.5 by computing
the clock reading that would mean 0.5 since the field started. Over 200000
random origins the round trip misses the last bit in 18.8% of them and shows
one particle too few in 9.4%, because floor(0.5 * 20) comes out 9. The check
had been flaky since it was written. The panel hands the field the age itself
now (ParticleField.hold), and the faked clock is gone.
833 checks (824 + 9), 931 unit tests (921 + 10).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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