Two ECS-native, deterministic namespaces for 2D motion, driven off the fixed
frame clock so replays and lockstep netcode reproduce every frame and every
eased value exactly. Both are pure computed-inline Q16.16 / integer math (no new
runtime, no heap) — the game stores a timer on a component and calls these each
frame, exactly the way Collision.* / Grid.* are used.
Anim.* — spritesheet frame animation:
- Anim.frame(timer,fps,count) -> int looping frame index
- Anim.once(timer,fps,count) -> int one-shot, clamps on the last frame
- Anim.pingpong(timer,fps,count) -> int bounce 0..count-1..0
- Anim.finished(timer,fps,count) -> bool has a one-shot run past its end?
- Anim.duration(fps,count) -> fixed seconds for one cycle
- Anim.cell_x/cell_y(frame,cols,cell) -> int source rect on a grid sheet
Tween.* — value interpolation over a timeline:
- Tween.progress/loop/yoyo(timer,duration) -> fixed normalized amount
- Tween.done(timer,duration) -> bool
- Tween.ease(t, mode) -> fixed shape by a literal curve 0..6,
the same curves as Ease.* (now
factored into a shared ease_eval)
- Tween.number/round/point/tint(from,to,t) blend a fixed / int / Vector / color
The typed blends reuse the existing fixed / Vector / color helpers, and
Tween.ease shares Ease.*'s exact formulas via the new ease_eval(mode,t) — one
source of truth for every easing curve in the engine.
examples/library/anim.ludic asserts 34 cases (frame math, clamping, ping-pong,
cell geometry, timeline clamp/loop/yoyo, rounding, color/vector blends, and
Ease.in == Tween.ease(.,1)); wired into x test (now 62 passed). Docs: Anim +
Tween sections with 16 per-symbol pages, inventory/coverage green. Seed
reseeded; the C-free bootstrap fixpoint holds.
The stateful sugar the proposal sketches (named clips, Anim.play, fluent
Tween.chain/parallel handles, and an auto-injected advance system) is deliberately
left as a follow-up — this lands the deterministic math core both halves stand on.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
1.1 KiB
1.1 KiB
| id | name | category | kind | tokens | sig | tip | order | ns | member |
|---|---|---|---|---|---|---|---|---|---|
| tween-ease | Tween.ease | tween | namespace-method | Tween.ease | Tween.ease(t, mode) -> fixed | Shape a 0..1 amount through an easing curve chosen by a literal mode. | 5 | Tween | ease |
Shapes a normalized amount t (0.0..1.0) through one of the engine's easing curves and returns the eased fixed. mode must be a literal integer selecting the curve — the same curves as the Ease namespace:
0— linear1— ease-in (quadratic)2— ease-out (quadratic)3— smooth ease-in-out4— ease-in-back (overshoots below 0)5— ease-out-elastic (springy settle)6— ease-out-bounce
Parameters:
t— the amount to shape (afixedin 0..1, e.g. fromTween.progress)mode— a literalint0..6 selecting the curve
program Demo {
handler Run phase Update {
let t = Tween.progress(fixed(1), fixed(2))
let e = Tween.ease(t, 4) # ease-in-back
let x = Tween.round(0, 200, e)
print(x)
}
}