bowed_string.hpp

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// sbl/dsp/pm/bowed_string.hpp — A bowed string (AP-032 Phase 3; AP-041 Phase 4) (Physical modeling — widget)
//
// A StringBase played by a bow. The bow — a Bow<Law>, a BowSet, a
// SwitchedExciter over two of them — is the app's and is handed in by
// reference, with its own speed, weight and law; the load at the bridge is
// the app's too. What this adds to the base is the name and the instrument's
// words: a bowed string has a nut, a bridge and a body, and says so in its
// own code. The wiring as compiled is a describe() away —
// `sbl-diagram bowed-string [--body]` (AP-037).
//
// There is no envelope: a bow drawn at a steady speed makes a steady tone,
// so the string is a drone by construction, and articulation is the bow
// moving — or its pressure going to zero, which lifts it, and the string
// rings free.
//
// Usage:
//   sbl::dsp::pm::BowSet bow;
//   bow.set_tables(sbl::dsp::pm::BOWS, 2);                // pm/bow_tables.hpp
//   sbl::dsp::pm::ModalResonator<8> body;
//   body.set_modes(CELLO, 7);
//   sbl::dsp::pm::BowedString<sbl::dsp::pm::BowSet, sbl::dsp::pm::ModalResonator<8>> string(bow, body);
//   string.set_pitch_su(pitch);
//   bow.set_velocity_su(speed);
//   string.process(buf, n);
 
#ifndef SBL_DSP_PM_BOWED_STRING_HPP_
#define SBL_DSP_PM_BOWED_STRING_HPP_
 
#include <cstdint>
 
#include <sbl/dsp/pm/string_base.hpp>
 
namespace sbl::dsp::pm {
 
template<typename Bow, typename Body, uint16_t MaxPeriod = 1536>
class BowedString : public StringBase<Bow, Body, MaxPeriod> {
    using Base = StringBase<Bow, Body, MaxPeriod>;
 
public:
    BowedString(Bow& bow, Body& body) : Base(bow, body, "BowedString") {}
 
    /// The body at the bridge, or the bare string with a rigid bridge.
    void use_body(bool on) { Base::use_load(on); }
    bool has_body() const { return Base::loaded(); }
 
    /// Where the bow sits along the string (StringBase::set_position_su).
    void set_bow_position_su(float su) { Base::set_position_su(su); }
 
    /// What is heard: 0 the body, 1 the bare string (StringBase::set_pickup_su).
    void set_body_mix_su(float su) { Base::set_pickup_su(su); }
 
    Bow& bow() { return Base::exciter(); }
    Body& body() { return Base::load(); }
};
 
} // namespace sbl::dsp::pm
 
#endif // SBL_DSP_PM_BOWED_STRING_HPP_