mpe_expression.hpp

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#pragma once

 
#include <pulp/midi/message.hpp>
#include <pulp/midi/mpe_voice_tracker.hpp>
 
#include <algorithm>
#include <cmath>
#include <cstdint>
 
namespace pulp::format::mpe {

inline std::uint8_t to_7bit(double norm) noexcept {
    const double clamped = std::clamp(norm, 0.0, 1.0);
    return static_cast<std::uint8_t>(
        std::clamp<int>(static_cast<int>(clamped * 127.0 + 0.5), 0, 127));
}

inline midi::MidiEvent pitch_bend_from_semitones(std::uint8_t channel,
                                                 double semitones) {
    const double bend_norm = std::clamp(
        semitones / static_cast<double>(
            midi::MpeVoiceTracker::kDefaultMemberBendSemitones),
        -1.0, 1.0);
    const int bend14 = static_cast<int>(std::lround(8192.0 + bend_norm * 8191.0));
    return midi::MidiEvent::pitch_bend(
        channel, static_cast<std::uint16_t>(std::clamp(bend14, 0, 16383)));
}

inline midi::MidiEvent channel_pressure(std::uint8_t channel, double norm) {
    return midi::MidiEvent{
        choc::midi::ShortMessage(
            static_cast<std::uint8_t>(0xD0 | (channel & 0x0F)),
            to_7bit(norm), 0),
        0, 0.0};
}

inline constexpr std::uint8_t kTimbreController = 74;

inline midi::MidiEvent timbre_cc(std::uint8_t channel, double norm) {
    return midi::MidiEvent::cc(channel, kTimbreController, to_7bit(norm));
}
 
}  // namespace pulp::format::mpe