Orkuncakilkaya
e4d1e95dcb
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>
31 lines
984 B
Markdown
31 lines
984 B
Markdown
---
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id: tween-yoyo
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name: Tween.yoyo
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category: tween
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kind: namespace-method
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tokens: Tween.yoyo
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sig: Tween.yoyo(timer, duration) -> fixed
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tip: A repeating 0..1..0 triangle amount over duration.
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order: 3
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ns: Tween
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member: yoyo
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---
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Returns a triangle wave: <code>timer / duration</code> ramps <code>0.0</code>→<code>1.0</code> over the first <code>duration</code>, then <code>1.0</code>→<code>0.0</code> over the next, and repeats. The smooth back-and-forth for a hover bob, a pulsing highlight, or a breathing scale — no snap at the ends the way <a href="tween-loop"><code>Tween.loop</code></a> has.
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Parameters:
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- `timer` — elapsed seconds (a `fixed`)
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- `duration` — seconds for each leg (a `fixed`)
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```ludic
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program Demo {
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property Bob { timer: fixed = 0.0 }
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model Pickup { Bob }
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handler Run phase Update {
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Bob.timer = Bob.timer + Time.delta()
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let t = Tween.yoyo(Bob.timer, fixed(1))
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let y = Tween.round(100, 108, Tween.ease(t, 3))
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print(y)
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}
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}
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```
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