43 lines
1.2 KiB
Markdown
43 lines
1.2 KiB
Markdown
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# Design
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## Context
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Input, placement, HiDPI, and grid are implemented. Simulation state (`sim_paused`, `ACTION_PAUSE`, `ACTION_STEP`, speed actions) exists but is unused. See proposal.md.
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## Goals / Non-Goals
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**Goals:**
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- Conway tick loop with adjustable interval.
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- Pause/resume, stepping, speed control.
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- Paused-only cell editing via mouse, including drag painting.
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**Non-Goals:**
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- Pattern detection or statistics.
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- Undo/redo.
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- Multi-threading.
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## Decisions
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### D1: Tick timing
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- Use monotonic clock in the frame loop; accumulate elapsed time; when >= interval, compute next generation and reset accumulator.
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### D2: Next generation buffer
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- Allocate a second grid buffer; compute into it, then swap pointers (or copy). Prefer swap of `cells` pointers with size unchanged.
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### D3: Editing while paused
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- Pointer button handler sets/clears cells if `sim_paused`; drag paints using motion events while button held.
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### D4: Speed bounds
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- Interval range 0.05s..1.0s (20 tps..1 tps), step factor 2.
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### D5: Default bindings
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- Add `p`, `n`, `+`/`-` to default config (merge).
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## Risks / Trade-offs
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- [Tick cost on large grids] -> grid is small (50x50), fine.
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- [Editing during tick race] -> editing only while paused avoids races.
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## Open Questions
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None.
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