92 lines
5.6 KiB
Markdown
92 lines
5.6 KiB
Markdown
# Internal instruments and effects
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No plugin downloads, search paths or external libraries are needed. The original
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built-in sine remains available for existing projects.
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Choose **Internal: Soft Keys** or **Internal: Sub Bass** in a MIDI track's
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instrument dropdown. Soft Keys blends a sine with a third harmonic; Sub Bass
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uses a pure sine. Both have 32 voices, velocity sensitivity,
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short attack/release envelopes, sustain pedal, note-off and panic handling.
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High harmonics are omitted near Nyquist. The default sounds remain compatible with fixed presets from v13. See the
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Phase 41 controls below. A sample library is not provided by these oscillators.
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In **Modular Graph**, select a wire and choose **Edit → Insert internal delay on
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wire** or **Insert internal reverb on wire**. This preserves the route and inserts
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the effect into the signal path. **File → Add internal delay/reverb** creates an
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unconnected device for manual wiring. Select its node and use **Edit → Selected
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plugin control** to edit it, or **Selected plugin automation** to automate it.
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Changes use the existing stopped-engine preparation and undo workflow.
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- **Delay:** time (1–2000 ms), feedback (0–0.95), dry/wet mix (0–1).
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- **Reverb:** four parallel damped feedback combs, with decay (0–0.95), damping
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(0–0.95) and dry/wet mix (0–1). Decay is a feedback coefficient, not seconds.
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These are basic mono processors; stereo plans use independent instances. Reverb
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is deliberately simple and has no room model or stereo diffusion. Delay time
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changes can click; there is no crossfade or tempo sync. Transport seeks retain
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existing effect history, like LADSPA. Effect tails require continued rendering;
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playback/export does not automatically extend the song for tails.
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Project format 13 stores internal devices as format 4 with reserved module path
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`/xtc/internal`, stable numeric identity and index (0 keys, 1 bass, 2 delay,
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3 reverb). This is a virtual identifier, never an external binary. Effect controls
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and automation are saved using the existing plugin records; instruments are fixed
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presets. Readers still accept formats 1–12. Older xtc builds reject format 13.
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All buffers are allocated during preparation; processing performs no allocation,
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file access, library loading, locking or GUI calls.
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Validation: `make BUILD_DIR=build/phase38 all gui test test-gui-instruments
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test-gui-modern-plugins test-gui-plugins analyze` (join onto one line).
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`test-builtins` checks impulse tails, dry mix, feedback bounds, block partition
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consistency, note release/panic and instrument/effect project round trips.
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## Phase 40 acceptance checks
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`make BUILD_DIR=build/phase40 all gui test test-reliability test-gui builtin-preview`
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checks all four device identities and GUI paths without external plugin binaries.
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The reliability runner fails each internal preparation allocation in turn and
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forbids allocation/free, direct file I/O and blocking locks during processing.
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Core tests compare persisted rendering for both instruments and both automated
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effects, corrupt an internal module identity transactionally, and cover voice
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exhaustion, sustain, repeated notes, partitioning and transport reset/seek/panic.
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The existing portability suite verifies older project migrations.
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For repeatable manual listening, run `make builtin-preview` and audition
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`build/builtin-{0,1,2,3}.wav` at a conservative level: 0 is Soft Keys, 1 Sub Bass,
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2 Delay and 3 Reverb. Each six-second file includes held tones or two impulses
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followed by silence for tails. Check onset/release, unwanted discontinuities,
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finite decay and the documented mono character. Generation is verified;
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human listening and physical-device qualification remain pending.
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## Phase 41 instrument controls and presets
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**Edit → Selected instrument controls** edits an assigned internal instrument.
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The five ports are harmonic amount (0..1), attack (0.1..2000 ms), release
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(1..5000 ms), low-pass cutoff (20..24000 Hz; 24000 bypasses the filter) and
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pitch-bend range (0..24 semitones, default 2). The harmonic is a third harmonic;
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it is suppressed before crossing Nyquist. Attack/release are exponential time
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constants, not times to absolute silence. Defaults preserve the original sounds.
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**Selected instrument automation** accepts `port tick mode value`, with absolute
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project ticks, linear mode 0, hold mode 1, or -1 to remove a point. Automation
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uses absolute sample positions, including seeks and 256-frame instrument chunks.
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Static edits stop/reprepare playback and are undoable. Existing v13 assignments
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with no parameters upgrade to defaults when opened in the editor.
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**File → Save/Load instrument preset** uses an explicit absolute path. Presets
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are versioned single-instrument `.xtc` containers with no clips. Public C APIs
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`xtc_plugin_preset_save/load` provide atomic saving and transactional metadata
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loading; they never execute plugin code. Loading into a track is an undoable,
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prepared edit. Parameter automation is included. Preset paths are ordinary files;
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saving uses the existing project replacement semantics.
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Live MIDI pitch bend uses standard 14-bit messages (8192 center) and is applied
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at the event's sample offset per channel. Panic clears the affected channel's
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bend and sustain. The original unassigned sine ignores bend; CLAP MIDI/VST2
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receive raw bend, while native-note CLAP/VST3 do not yet map it to expressions.
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No external-plugin parameter support is implied.
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Format 14 adds instrument controls and automation. Readers still accept v1–v13;
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old fixed internal assignments use their original defaults. Older builds reject
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v14. Tests cover legacy-default sound equality, v13 migration, parameter/preset
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round trips, pitch-bend offsets, automated block partitions, undo and GUI edits.
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