audio_device.h

#pragma once
 
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <memory>
 
#include <glm/glm.hpp>
 
namespace Vkm::Engine {
 
struct AudioClipAsset;

using VoiceId = uint32_t;

inline constexpr size_t MAX_ACTIVE_VOICES = 128;

struct VoiceParams {
    float     volume      = 1.0f;
    float     pitch       = 1.0f;
    bool      loop        = false;
    bool      spatial     = true;
    glm::vec3 position    = {0.0f, 0.0f, 0.0f};
    float     minDistance = 1.0f;
    float     maxDistance = 50.0f;

    float heardMinDistance() const { return std::isfinite(minDistance) ? std::max(0.0f, minDistance) : 0.0f; }

    float heardMaxDistance() const { return std::isfinite(maxDistance) ? std::max(0.0f, maxDistance) : 0.0f; }

    bool hasFar() const { return heardMaxDistance() > heardMinDistance(); }
};

class AudioDevice {
    public:
        AudioDevice();
        ~AudioDevice();
 
        AudioDevice(const AudioDevice& other) = delete;
        AudioDevice& operator=(const AudioDevice& other) = delete;
 
        AudioDevice(AudioDevice && other) = delete;
        AudioDevice& operator=(AudioDevice && other) = delete;
 
    public:
        bool open();

        bool openOffline(uint32_t sampleRate, uint32_t channels);

        void close();

        uint64_t render(float* frames, uint64_t frameCount);

        VoiceId play(const AudioClipAsset& clip, const VoiceParams& params);

        void updateVoice(VoiceId voice, const VoiceParams& params);

        bool isVoiceActive(VoiceId voice) const;

        void pauseVoice(VoiceId voice);

        void resumeVoice(VoiceId voice);

        bool isVoicePaused(VoiceId voice) const;

        float voiceCursor(VoiceId voice) const;

        void seekVoice(VoiceId voice, float seconds);

        void stopVoice(VoiceId voice);

        void reapFinishedVoices();

        void stopAllVoices();

        void pauseAllVoices();

        void resumeAllVoices();

        size_t voiceCount() const;

        void setListener(const glm::vec3& position, const glm::vec3& forward, const glm::vec3& up);

        void setListenerActive(bool active);

        void setMasterVolume(float volume);
 
    public:
        bool isOpen() const noexcept { return m_backend != nullptr; }

        float masterVolume() const noexcept { return m_masterVolume; }
 
    private:
        // ma_engine, the voice table and each voice's sound; held by pointer so
        // miniaudio's header stays out of this one.
        struct Backend;
 
    private:
        void reopenLostDevice();
 
    private:
        std::unique_ptr<Backend> m_backend;
        float                    m_masterVolume = 1.0f;

        bool                     m_voiceBudgetSpent = false;
};
 
} // namespace Vkm::Engine