IInstrumentHost

#include "crosspad/instrument/IInstrumentHost.hpp"

Generated from crosspad/instrument/IInstrumentHost.hpp in crosspad-core. Edit the header’s doxygen comments to change this page.

Types

crosspad::IInstrumentHost

Lends the pitched sample engine to an app that plays an instrument of its own (Pitch Play), and keeps that app’s instrument library.

The pitched engine and the kit engine take turns using the same memory, so one of them is active at a time. An app borrows it: a load stops the kits’ engine and builds the app’s bank; release() frees the bank and puts the current kit back as it was. Everything that touches the card reading WAVs, reading and writing instrument files, copying samples runs on the host’s worker, never on the caller’s (UI) thread: a request returns at once and the caller polls state().

An instrument is a kit.json with “engine”:“pitched” (KitInfo::instrument), kept in libraryRoot() rather than among the kits, so the Kits list never shows it. Zone samples resolve the way a kit’s do: relative to the folder of KitInfo::path, or as absolute logical paths (“/crosspad/…”).

Field	Type	Description
kFileName	constexpr const char *
kMaxZoneSeconds	constexpr float	A zone longer than this is cut to it on load: an instrument is notes, and the limit keeps loading fast and the bank small.

Members

Member	Description
requestLoad	Take the engine, if it is not held already, and build spec's bank.
requestOpen	Read the instrument file at path (logical, like KitInfo::path) and load it.
requestSave	Write spec to its KitInfo::path, making the folder.
release	Give the engine back: the bank goes and the current kit is reloaded.
state
instrument	The instrument of the last load, open or save that succeeded, its zones’ roots filled in where the load detected them.
message	Why the last request failed, or what a load that succeeded had to cut short.
libraryRoot	The folder instruments live in, logical (“/crosspad/pitchplay”): one sub-folder per instrument, its file named kFileName.
zoneAudio

Methods

requestLoad

virtual bool requestLoad(const KitInfo &spec) = 0

Take the engine, if it is not held already, and build spec's bank.

A request made while another runs waits for it; one already waiting is replaced (newest wins). State stays Busy until the last is through. False only where the host cannot take requests at all.

requestOpen

virtual bool requestOpen(const std::string &path) = 0

Read the instrument file at path (logical, like KitInfo::path) and load it.

instrument() is what was read once it is Ready.

requestSave

virtual bool requestSave(const KitInfo &spec) = 0

Write spec to its KitInfo::path, making the folder.

A zone whose sample lives outside that folder is copied into it first, so an instrument outlives the takes it was made from. On success instrument() is the spec as written (its zones relative).

release

virtual void release() = 0

Give the engine back: the bank goes and the current kit is reloaded.

Safe when nothing is held. Call from the UI thread.

state

virtual State state() const =0

instrument

virtual KitInfo instrument() const =0

The instrument of the last load, open or save that succeeded, its zones’ roots filled in where the load detected them.

message

virtual std::string message() const =0

Why the last request failed, or what a load that succeeded had to cut short.

Empty when there is nothing to say.

libraryRoot

virtual std::string libraryRoot() const =0

The folder instruments live in, logical (“/crosspad/pitchplay”): one sub-folder per instrument, its file named kFileName.

zoneAudio

virtual ZoneAudio zoneAudio(uint8_t zoneIdx) const

Declared in crosspad/instrument/IInstrumentHost.hpp:27.

crosspad::IInstrumentHost::ZoneAudio

What the loaded bank made of a zone: the length of its PCM and the rate it ended up at.

A caller setting loop points needs this the spec stores them as frames, and frames mean nothing without a length to put them against, so a UI without it can only guess.

Not pure, and zero where nothing is loaded: a host that does not keep its bank around (the PC simulator) is still a host, and a caller must treat frames == 0 as “cannot say” rather than “empty”.

Field	Type	Description
frames	uint32_t
sampleRate	uint32_t

Declared in crosspad/instrument/IInstrumentHost.hpp:80.