64 lines
1.7 KiB
Markdown
64 lines
1.7 KiB
Markdown
---
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id: LSN-0010
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ticket: legacy-runtime-learn-import
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title: Audio Mental Model
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created: 2026-03-27
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tags: [migration, tech-debt]
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---
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# Audio Mental Model
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Status: pedagogical
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Companion spec: [`../specs/05-audio-peripheral.md`](../../specs/05-audio-peripheral.md)
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The right mental model for audio in PROMETEU is an active peripheral with a budget, not "automatic sound".
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## Philosophy
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Sound:
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- consumes time;
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- consumes memory;
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- uses finite channels;
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- depends on explicit commands.
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That brings PROMETEU closer to classic consoles and arcades where the game "talks" to an audio block with its own rules.
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## Audio CPU Metaphor
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A useful metaphor is:
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```text
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[Game CPU] -> sends commands at 60 Hz -> [AUDIO Peripheral]
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v
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Voices + Mixer
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v
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PCM Output
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```
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This metaphor does not require a dedicated thread. It only separates responsibilities:
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- the machine defines the logical model;
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- the host decides how to deliver continuous buffers;
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- the game speaks in commands, not direct backend manipulation.
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## Good Habits
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- reuse samples;
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- limit simultaneous voices;
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- treat sound as an intentional event;
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- separate music and effects;
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- avoid triggering the same sound every frame.
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## Historical Direction
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The main influences here are:
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- NES, for the clarity of limited channels;
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- SNES, for sample playback and mixing;
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- CPS-2 and Neo Geo, for the feeling of headroom and sample presence.
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PROMETEU abstracts those references. It does not try to reproduce any of those systems literally.
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