73 lines
3.5 KiB
Markdown
73 lines
3.5 KiB
Markdown
# AG Beats - Requirements Specification
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AG Beats is a web-based, collaborative drum machine and bass sequencer that allowing multiple users to compose music together in real-time.
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## 1. Functional Requirements
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### 1.1 Step Sequencer
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- **Instruments**: Support for 5 drum tracks (Kick, Snare, Hi-Hat, Open Hat, Ride).
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- **Step Configuration**:
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- Adjustable sequence length from 4 to 64 steps (increments of 4).
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- Default length: 16 steps.
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- **Grid Interaction**:
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- Toggle notes on/off for each instrument per step.
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- Support for "drag-to-toggle" to quickly fill or clear steps in a row.
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- **Bass Line**:
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- 2-octave bass sequencer (C2 to B3).
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- Selectable notes per step (supports polyphony).
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- Visual distinction between natural and sharp notes.
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### 1.2 Audio Engine
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- **Synthesis**: Real-time sound generation using the Web Audio API.
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- Integrated synthesizers for Kick, Snare, and Hi-Hats.
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- Sine-wave based bass synthesizer.
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- **Sample Support**: Capability to load and play audio samples for instruments.
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- **Playback Controls**:
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- Global Play/Stop functionality.
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- Tempo (BPM) control range: 40 to 240 BPM (Default: 76 BPM).
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- Real-time step highlighting during playback.
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- **Mixer**:
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- Individual "Mute" toggle for each drum track.
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- Master volume control for the Drum section.
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- Master volume control for the Bass section.
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- **Interactive Preview**: Trigger individual drum sounds or bass notes by clicking their respective labels (outside of playback).
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### 1.3 Real-time Collaboration
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- **Presence**:
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- Real-time visibility of other connected users' cursors with unique colors.
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- Synchronization of connected user list.
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- **State Synchronization**:
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- Instant broadcasting of all grid changes (drums and bass).
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- Synchronization of playback state (start/stop), tempo, steps, mutes, and volumes.
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- Shared "Clear" and "Import" actions across the session.
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- **Stability**: Support for "Synchronizing" state when a new user joins an existing session.
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### 1.4 Session & Data Management
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- **Named Sessions**: Support for multiple concurrent sessions identified by a `sessionId` URL parameter.
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- **Session Sharing**: One-click functionality to copy the current session URL to the clipboard.
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- **Persistence**: Session state is maintained in-memory on the server for the duration of the session.
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- **Import/Export**:
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- Export current pattern as a `.json` file.
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- Import patterns from previously exported `.json` files.
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## 2. Technical Stack
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- **Frontend**: React 19, TypeScript, Tailwind CSS (via CDN).
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- **Backend**: Node.js with Express and WebSocket (`ws`).
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- **Communication**: WebSockets for real-time state synchronization and cursor presence.
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- **Audio**: Web Audio API for low-latency synthesis and playback.
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## 3. User Interface & Experience
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- **Responsive Design**: Mobile-friendly layout with horizontal scrolling for large sequences.
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- **Modern Aesthetics**: Sleek, slate-based color palette with vibrant accents (Orange for drums, Purple for bass).
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- **Interactive Feedback**:
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- Hover effects on sequencer cells.
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- Confirmation modals for destructive actions (e.g., Clear Pattern).
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- Scroll-wheel support for tempo adjustment.
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- Sticky labels for easy navigation in large grids.
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## 4. Constraints & Limits
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- **Tempo Range**: 40 - 240 BPM.
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- **Sequence Steps**: 4 - 64 steps (must be multiple of 4).
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- **Instruments**: Fixed set of 5 drum instruments.
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- **Storage**: State is currently ephemeral (in-memory) and lost if the server restarts or the last user leaves the session.
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