Add a method to retrieve a buffer's name

[alure.git] / include / AL / alure2.h

#ifndef AL_ALURE2_H
#define AL_ALURE2_H

#include <vector>
#include <string>
#include <memory>
#include <cmath>

#include "alc.h"
#include "al.h"

#ifdef _WIN32
#if defined(ALURE_BUILD_STATIC) || defined(ALURE_STATIC_LIB)
#define ALURE_API
#elif defined(ALURE_BUILD_DLL)
#define ALURE_API __declspec(dllexport)
#else
#define ALURE_API __declspec(dllimport)
#endif

#else

#define ALURE_API
#endif

#ifndef EFXEAXREVERBPROPERTIES_DEFINED
#define EFXEAXREVERBPROPERTIES_DEFINED
typedef struct {
    float flDensity;
    float flDiffusion;
    float flGain;
    float flGainHF;
    float flGainLF;
    float flDecayTime;
    float flDecayHFRatio;
    float flDecayLFRatio;
    float flReflectionsGain;
    float flReflectionsDelay;
    float flReflectionsPan[3];
    float flLateReverbGain;
    float flLateReverbDelay;
    float flLateReverbPan[3];
    float flEchoTime;
    float flEchoDepth;
    float flModulationTime;
    float flModulationDepth;
    float flAirAbsorptionGainHF;
    float flHFReference;
    float flLFReference;
    float flRoomRolloffFactor;
    int   iDecayHFLimit;
} EFXEAXREVERBPROPERTIES, *LPEFXEAXREVERBPROPERTIES;
#endif

namespace alure {

class DeviceManager;
class Device;
class Context;
class Listener;
class Buffer;
class Source;
class SourceGroup;
class AuxiliaryEffectSlot;
class Effect;
class Decoder;
class DecoderFactory;
class MessageHandler;


// A SharedPtr implementation, defaults to C++11's std::shared_ptr. If this is
// changed, you must recompile the library.
template<typename T>
using SharedPtr = std::shared_ptr<T>;
template<typename T, typename... Args>
constexpr inline SharedPtr<T> MakeShared(Args&&... args)
{
    return std::make_shared<T>(std::forward<Args>(args)...);
}

// A UniquePtr implementation, defaults to C++11's std::unique_ptr. If this is
// changed, you must recompile the library.
template<typename T>
using UniquePtr = std::unique_ptr<T>;
template<typename T, typename... Args>
constexpr inline UniquePtr<T> MakeUnique(Args&&... args)
{
#if __cplusplus >= 201402L
    return std::make_unique<T>(std::forward<Args>(args)...);
#else
    return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
#endif
}

// A Vector implementation, defaults to C++'s std::vector. If this is changed,
// you must recompile the library.
template<typename T>
using Vector = std::vector<T>;

// A String implementation, default's to C++'s std::string. If this is changed,
// you must recompile the library.
using String = std::string;


struct FilterParams {
    ALfloat mGain;
    ALfloat mGainHF; // For low-pass and band-pass filters
    ALfloat mGainLF; // For high-pass and band-pass filters
};


class ALURE_API Vector3 {
    std::array<ALfloat,3> mValue;

public:
    constexpr Vector3() noexcept
      : mValue{{0.0f, 0.0f, 0.0f}}
    { }
    constexpr Vector3(const Vector3 &rhs) noexcept
      : mValue{{rhs.mValue[0], rhs.mValue[1], rhs.mValue[2]}}
    { }
    constexpr Vector3(ALfloat val) noexcept
      : mValue{{val, val, val}}
    { }
    constexpr Vector3(ALfloat x, ALfloat y, ALfloat z) noexcept
      : mValue{{x, y, z}}
    { }
    Vector3(const ALfloat *vec) noexcept
      : mValue{{vec[0], vec[1], vec[2]}}
    { }

    const ALfloat *getPtr() const noexcept
    { return mValue.data(); }

    ALfloat& operator[](size_t i) noexcept
    { return mValue[i]; }
    constexpr const ALfloat& operator[](size_t i) const noexcept
    { return mValue[i]; }

#define ALURE_DECL_OP(op)                                            \
    constexpr Vector3 operator op(const Vector3 &rhs) const noexcept \
    {                                                                \
        return Vector3(mValue[0] op rhs.mValue[0],                   \
                       mValue[1] op rhs.mValue[1],                   \
                       mValue[2] op rhs.mValue[2]);                  \
    }
    ALURE_DECL_OP(+)
    ALURE_DECL_OP(-)
    ALURE_DECL_OP(*)
    ALURE_DECL_OP(/)
#undef ALURE_DECL_OP
#define ALURE_DECL_OP(op)                             \
    Vector3& operator op(const Vector3 &rhs) noexcept \
    {                                                 \
        mValue[0] op rhs.mValue[0];                   \
        mValue[1] op rhs.mValue[1];                   \
        mValue[2] op rhs.mValue[2];                   \
        return *this;                                 \
    }
    ALURE_DECL_OP(+=)
    ALURE_DECL_OP(-=)
    ALURE_DECL_OP(*=)
    ALURE_DECL_OP(/=)

#undef ALURE_DECL_OP
#define ALURE_DECL_OP(op)                                       \
    constexpr Vector3 operator op(ALfloat scale) const noexcept \
    {                                                           \
        return Vector3(mValue[0] op scale,                      \
                       mValue[1] op scale,                      \
                       mValue[2] op scale);                     \
    }
    ALURE_DECL_OP(*)
    ALURE_DECL_OP(/)
#undef ALURE_DECL_OP
#define ALURE_DECL_OP(op)                        \
    Vector3& operator op(ALfloat scale) noexcept \
    {                                            \
        mValue[0] op scale;                      \
        mValue[1] op scale;                      \
        mValue[2] op scale;                      \
        return *this;                            \
    }
    ALURE_DECL_OP(*=)
    ALURE_DECL_OP(/=)
#undef ALURE_DECL_OP

    constexpr ALfloat getLengthSquared() const noexcept
    { return mValue[0]*mValue[0] + mValue[1]*mValue[1] + mValue[2]*mValue[2]; }
    constexpr ALfloat getLength() const noexcept
    { return std::sqrt(getLengthSquared()); }

    constexpr ALfloat getDistanceSquared(const Vector3 &pos) const noexcept
    { return (pos - *this).getLengthSquared(); }
    constexpr ALfloat getDistance(const Vector3 &pos) const noexcept
    { return (pos - *this).getLength(); }
};
static_assert(sizeof(Vector3) == sizeof(ALfloat[3]), "Bad Vector3 size");


/**
 * Creates a version number value using the specified \param major and
 * \param minor values.
 */
constexpr inline ALCuint MakeVersion(ALCushort major, ALCushort minor)
{ return (major<<16) | minor; }

/**
 * Retrieves the major version of a version number value created by
 * \ref MakeVersion.
 */
constexpr inline ALCuint MajorVersion(ALCuint version)
{ return version>>16; }
/**
 * Retrieves the minor version of a version number value created by
 * \ref MakeVersion.
 */
constexpr inline ALCuint MinorVersion(ALCuint version)
{ return version&0xffff; }


enum class DeviceEnumeration {
    Basic = ALC_DEVICE_SPECIFIER,
    Complete = ALC_ALL_DEVICES_SPECIFIER,
    Capture = ALC_CAPTURE_DEVICE_SPECIFIER
};

enum class DefaultDeviceType {
    Basic = ALC_DEFAULT_DEVICE_SPECIFIER,
    Complete = ALC_DEFAULT_ALL_DEVICES_SPECIFIER,
    Capture = ALC_CAPTURE_DEFAULT_DEVICE_SPECIFIER
};

/**
 * A class managing \ref Device objects and other related functionality. This
 * class is a singleton, only one instance will exist in a process.
 */
class ALURE_API DeviceManager {
public:
    /** Retrieves the DeviceManager instance. */
    static DeviceManager &get();

    /** Queries the existence of a non-device-specific ALC extension. */
    virtual bool queryExtension(const char *extname) const = 0;

    /** Enumerates available device names of the given \param type. */
    virtual Vector<String> enumerate(DeviceEnumeration type) const = 0;
    /** Retrieves the default device of the given \param type. */
    virtual String defaultDeviceName(DefaultDeviceType type) const = 0;

    /** Opens the playback device given by \param name, or the default if empty. */
    virtual Device *openPlayback(const String &name=String()) = 0;
};


enum class PlaybackDeviceName {
    Basic = ALC_DEVICE_SPECIFIER,
    Complete = ALC_ALL_DEVICES_SPECIFIER
};

class ALURE_API Device {
public:
    /** Retrieves the device name as given by \param type. */
    virtual String getName(PlaybackDeviceName type=PlaybackDeviceName::Basic) const = 0;
    /** Queries the existence of an ALC extension on this device. */
    virtual bool queryExtension(const char *extname) const = 0;

    /**
     * Retrieves the ALC version supported by this device, as constructed by
     * \ref MakeVersion.
     */
    virtual ALCuint getALCVersion() const = 0;

    /**
     * Retrieves the EFX version supported by this device, as constructed by
     * \ref MakeVersion. If the ALC_EXT_EFX extension is unsupported, this
     * will be 0.
     */
    virtual ALCuint getEFXVersion() const = 0;

    /** Retrieves the device's playback frequency, in hz. */
    virtual ALCuint getFrequency() const = 0;

    /**
     * Retrieves the maximum number of auxiliary source sends. If ALC_EXT_EFX
     * is unsupported, this will be 0.
     */
    virtual ALCuint getMaxAuxiliarySends() const = 0;

    /**
     * Enumerates available HRTF names. The names are sorted as OpenAL gives
     * them, such that the index of a given name is the ID to use with
     * ALC_HRTF_ID_SOFT.
     *
     * Requires the ALC_SOFT_HRTF extension.
     */
    virtual Vector<String> enumerateHRTFNames() const = 0;

    /**
     * Retrieves whether HRTF is enabled on the device or not.
     *
     * Requires the ALC_SOFT_HRTF extension.
     */
    virtual bool isHRTFEnabled() const = 0;

    /**
     * Retrieves the name of the HRTF currently being used by this device.
     *
     * Requires the ALC_SOFT_HRTF extension.
     */
    virtual String getCurrentHRTF() const = 0;

    /**
     * Resets the device, using the specified \param attributes.
     *
     * Requires the ALC_SOFT_HRTF extension.
     */
    virtual void reset(const ALCint *attributes) = 0;

    /**
     * Creates a new \ref Context on this device, using the specified
     * \param attributes.
     */
    virtual Context *createContext(const ALCint *attributes=0) = 0;

    /**
     * Pauses device processing, stopping updates for its contexts. Multiple
     * calls are allowed but it is not reference counted, so the device will
     * resume after one \ref resumeDSP call.
     *
     * Requires the ALC_SOFT_pause_device extension.
     */
    virtual void pauseDSP() = 0;

    /**
     * Resumes device processing, restarting updates for its contexts. Multiple
     * calls are allowed and will no-op.
     */
    virtual void resumeDSP() = 0;

    /**
     * Closes and frees the device. All previously-created contexts must first
     * be destroyed.
     */
    virtual void close() = 0;
};


enum class DistanceModel {
    InverseClamped  = AL_INVERSE_DISTANCE_CLAMPED,
    LinearClamped   = AL_LINEAR_DISTANCE_CLAMPED,
    ExponentClamped = AL_EXPONENT_DISTANCE_CLAMPED,
    Inverse  = AL_INVERSE_DISTANCE,
    Linear   = AL_LINEAR_DISTANCE,
    Exponent = AL_EXPONENT_DISTANCE,
    None  = AL_NONE,
};

class ALURE_API Context {
public:
    /** Makes the specified \param context current for OpenAL operations. */
    static void MakeCurrent(Context *context);
    /** Retrieves the current context used for OpenAL operations. */
    static Context *GetCurrent();

    /**
     * Makes the specified \param context current for OpenAL operations on the
     * calling thread only. Requires the ALC_EXT_thread_local_context extension
     * on both the context's device and the \ref DeviceManager.
     */
    static void MakeThreadCurrent(Context *context);
    /** Retrieves the thread-specific context used for OpenAL operations. */
    static Context *GetThreadCurrent();

    /**
     * Destroys the context. The context must not be current when this is
     * called.
     */
    virtual void destroy() = 0;

    /** Retrieves the \ref Device this context was created from. */
    virtual Device *getDevice() = 0;

    virtual void startBatch() = 0;
    virtual void endBatch() = 0;

    /**
     * Retrieves a \ref Listener instance for this context. Each context will
     * only have one listener.
     */
    virtual Listener *getListener() = 0;

    /**
     * Sets a MessageHandler instance which will be used to provide certain
     * messages back to the application. Only one handler may be set for a
     * context at a time. The previously set handler will be returned.
     */
    virtual SharedPtr<MessageHandler> setMessageHandler(SharedPtr<MessageHandler> handler) = 0;

    /** Gets the currently-set message handler. */
    virtual SharedPtr<MessageHandler> getMessageHandler() const = 0;

    /**
     * Specifies the desired interval (in milliseconds) that the background
     * thread will be woken up to process tasks, e.g. keeping streaming sources
     * filled. An interval of 0 means the background thread will only be woken
     * up manually, for instance with calls to \ref update. The default is 0.
     */
    virtual void setAsyncWakeInterval(ALuint msec) = 0;

    /**
     * Retrieves the current interval used for waking up the background thread.
     */
    virtual ALuint getAsyncWakeInterval() const = 0;

    /**
     * Creates a \ref Decoder instance for the given audio file or resource
     * \param name.
     */
    virtual SharedPtr<Decoder> createDecoder(const String &name) = 0;

    // Functions below require the context to be current

    /**
     * Creates and caches a \ref Buffer for the given audio file or resource
     * \param name. Multiple calls with the same name will return the same
     * \ref Buffer object.
     */
    virtual Buffer *getBuffer(const String &name) = 0;

    /**
     * Creates and caches a \ref Buffer for the given audio file or resource
     * \param name. Multiple calls with the same name will return the same
     * \ref Buffer object.
     *
     * The returned \ref Buffer object will be scheduled for loading
     * asynchronously, and must be checked with a call to
     * \ref Buffer::getLoadStatus prior to being played.
     */
    virtual Buffer *getBufferAsync(const String &name) = 0;

    /**
     * Deletes the cached \ref Buffer object for the given audio file or
     * resource \param name. The buffer must not be in use by a \ref Source.
     */
    virtual void removeBuffer(const String &name) = 0;
    /**
     * Deletes the given cached \param buffer instance. The buffer must not be
     * in use by a \ref Source.
     */
    virtual void removeBuffer(Buffer *buffer) = 0;

    /**
     * Gets a new \ref Source. There is no practical limit to the number of
     * sources you may get.
     */
    virtual Source *getSource() = 0;

    virtual AuxiliaryEffectSlot *createAuxiliaryEffectSlot() = 0;

    virtual Effect *createEffect() = 0;

    virtual SourceGroup *createSourceGroup() = 0;

    virtual void setDopplerFactor(ALfloat factor) = 0;

    virtual void setSpeedOfSound(ALfloat speed) = 0;

    virtual void setDistanceModel(DistanceModel model) = 0;

    /**
     * Updates the context and all sources belonging to this context (you do
     * not need to call the individual sources' update method if you call this
     * function).
     */
    virtual void update() = 0;
};


enum class SampleType {
    UInt8,
    Int16,
    Float32,
    Mulaw
};
ALURE_API const char *GetSampleTypeName(SampleType type);

enum class ChannelConfig {
    /** 1-channel mono sound. */
    Mono,
    /** 2-channel stereo sound. */
    Stereo,
    /** 2-channel rear sound (back-left and back-right). */
    Rear,
    /** 4-channel surround sound. */
    Quad,
    /** 5.1 surround sound. */
    X51,
    /** 6.1 surround sound. */
    X61,
    /** 7.1 surround sound. */
    X71,
    /** 3-channel B-Format, using FuMa channel ordering and scaling. */
    BFormat2D,
    /** 4-channel B-Format, using FuMa channel ordering and scaling. */
    BFormat3D
};
ALURE_API const char *GetChannelConfigName(ChannelConfig cfg);

enum class BufferLoadStatus {
    Pending,
    Ready
};

class ALURE_API Listener {
public:
    virtual void setGain(ALfloat gain) = 0;

    virtual void setPosition(ALfloat x, ALfloat y, ALfloat z) = 0;
    virtual void setPosition(const ALfloat *pos) = 0;

    virtual void setVelocity(ALfloat x, ALfloat y, ALfloat z) = 0;
    virtual void setVelocity(const ALfloat *vel) = 0;

    virtual void setOrientation(ALfloat x1, ALfloat y1, ALfloat z1, ALfloat x2, ALfloat y2, ALfloat z2) = 0;
    virtual void setOrientation(const ALfloat *at, const ALfloat *up) = 0;
    virtual void setOrientation(const ALfloat *ori) = 0;

    virtual void setMetersPerUnit(ALfloat m_u) = 0;
};


class ALURE_API Buffer {
public:
    /**
     * Retrieves the length of the buffer in sample frames. The buffer must be
     * fully loaded before this method is called.
     */
    virtual ALuint getLength() const = 0;

    /** Retrieves the buffer's frequency in hz. */
    virtual ALuint getFrequency() const = 0;

    /** Retrieves the buffer's sample configuration. */
    virtual ChannelConfig getChannelConfig() const = 0;

    /** Retrieves the buffer's sample type. */
    virtual SampleType getSampleType() const = 0;

    /**
     * Retrieves the storage size used by the buffer, in bytes. The buffer must
     * be fully loaded before this method is called.
     */
    virtual ALuint getSize() const = 0;

    /**
     * Sets the buffer's loop points, used for looping sources. If the current
     * context does not support the AL_SOFT_loop_points extension, \param start
     * and \param end must be 0 and \ref getLength() respectively. Otherwise,
     * \param start must be less than \param end, and \param end must be less
     * than or equal to \ref getLength().
     *
     * The buffer must not be in use when this method is called, and the buffer
     * must be fully loaded.
     *
     * \param start The starting point, in sample frames (inclusive).
     * \param end The ending point, in sample frames (exclusive).
     */
    virtual void setLoopPoints(ALuint start, ALuint end) = 0;

    /**
     * Retrieves the current loop points as a [start,end) pair. The buffer must
     * be fully loaded before this method is called.
     */
    virtual std::pair<ALuint,ALuint> getLoopPoints() const = 0;

    /**
     * Retrieves the \ref Source objects currently playing the buffer. Stopping
     * the returned sources will allow the buffer to be removed from the
     * context.
     */
    virtual Vector<Source*> getSources() const = 0;

    /**
     * Queries the buffer's load status. A return of \ref BufferLoad_Pending
     * indicates the buffer is not finished loading and can't be used with a
     * call to \ref Source::play. Buffers created with \ref Context::getBuffer
     * will always return \ref BufferLoad_Ready.
     */
    virtual BufferLoadStatus getLoadStatus() = 0;

    /** Retrieves the name the buffer was created with. */
    virtual const String &getName() const = 0;

    /** Queries if the buffer is in use and can't be removed. */
    virtual bool isInUse() const = 0;
};


class ALURE_API Source {
public:
    /**
     * Plays the source using \param buffer. The same buffer may be played from
     * multiple sources simultaneously.
     */
    virtual void play(Buffer *buffer) = 0;
    /**
     * Plays the source by streaming audio from \param decoder. This will use
     * \param queuelen buffers, each with \param updatelen sample frames. The
     * given decoder must *NOT* have its read or seek methods called from
     * elsewhere while in use.
     */
    virtual void play(SharedPtr<Decoder> decoder, ALuint updatelen, ALuint queuesize) = 0;
    /**
     * Stops playback, releasing the buffer or decoder reference.
     */
    virtual void stop() = 0;

    /** Pauses the source if it is playing. */
    virtual void pause() = 0;

    /** Resumes the source if it is paused. */
    virtual void resume() = 0;

    /** Specifies if the source is currently playing. */
    virtual bool isPlaying() const = 0;

    /** Specifies if the source is currently paused. */
    virtual bool isPaused() const = 0;

    /**
     * Specifies the source's playback priority. Lowest priority sources will
     * be evicted first when higher priority sources are played.
     */
    virtual void setPriority(ALuint priority) = 0;
    /** Retrieves the source's priority. */
    virtual ALuint getPriority() const = 0;

    /**
     * Sets the source's offset, in sample frames. If the source is playing or
     * paused, it will go to that offset immediately, otherwise the source will
     * start at the specified offset the next time it's played.
     */
    virtual void setOffset(uint64_t offset) = 0;
    /**
     * Retrieves the source offset in sample frames. For streaming sources,
     * this will be the offset from the beginning of the stream based on the
     * decoder's reported position.
     *
     * \param latency If non-NULL and the device supports it, the source's
     * latency, in nanoseconds, will be written to that location.
     */
    virtual uint64_t getOffset(uint64_t *latency=0) const = 0;

    /**
     * Specifies if the source should loop on the \ref Buffer or \ref Decoder
     * object's loop points.
     */
    virtual void setLooping(bool looping) = 0;
    virtual bool getLooping() const = 0;

    /**
     * Specifies a linear pitch shift base. A value of 1.0 is the default
     * normal speed.
     */
    virtual void setPitch(ALfloat pitch) = 0;
    virtual ALfloat getPitch() const = 0;

    /**
     * Specifies the base linear gain. A value of 1.0 is the default normal
     * volume.
     */
    virtual void setGain(ALfloat gain) = 0;
    virtual ALfloat getGain() const = 0;

    /**
     * Specifies the minimum and maximum gain. The source's gain is clamped to
     * this range after distance attenuation and cone attenuation are applied
     * to the gain base, although before the filter gain adjustements.
     */
    virtual void setGainRange(ALfloat mingain, ALfloat maxgain) = 0;
    virtual ALfloat getMinGain() const = 0;
    virtual ALfloat getMaxGain() const = 0;

    /**
     * Specifies the reference distance and maximum distance the source will
     * use for the current distance model. For Clamped distance models, the
     * source's calculated distance is clamped to the specified range before
     * applying distance-related attenuation.
     *
     * For all distance models, the reference distance is the distance at which
     * the source's volume will not have any extra attenuation (an effective
     * gain multiplier of 1).
     */
    virtual void setDistanceRange(ALfloat refdist, ALfloat maxdist) = 0;
    virtual ALfloat getReferenceDistance() const = 0;
    virtual ALfloat getMaxDistance() const = 0;

    /** Specifies the source's 3D position. */
    virtual void setPosition(ALfloat x, ALfloat y, ALfloat z) = 0;
    virtual void setPosition(const ALfloat *pos) = 0;
    virtual Vector3 getPosition() const = 0;

    /**
     * Specifies the source's 3D velocity, in units per second. As with OpenAL,
     * this does not actually alter the source's position, and instead just
     * alters the pitch as determined by the doppler effect.
     */
    virtual void setVelocity(ALfloat x, ALfloat y, ALfloat z) = 0;
    virtual void setVelocity(const ALfloat *vel) = 0;
    virtual Vector3 getVelocity() const = 0;

    /**
     * Specifies the source's 3D facing direction. Deprecated in favor of
     * \ref setOrientation.
     */
    virtual void setDirection(ALfloat x, ALfloat y, ALfloat z) = 0;
    virtual void setDirection(const ALfloat *dir) = 0;
    virtual Vector3 getDirection() const = 0;

    /**
     * Specifies the source's 3D orientation. Note: unlike the AL_EXT_BFORMAT
     * extension this property comes from, this also affects the facing
     * direction, superceding \ref setDirection.
     */
    virtual void setOrientation(ALfloat x1, ALfloat y1, ALfloat z1, ALfloat x2, ALfloat y2, ALfloat z2) = 0;
    virtual void setOrientation(const ALfloat *at, const ALfloat *up) = 0;
    virtual void setOrientation(const ALfloat *ori) = 0;

    /**
     * Specifies the source's cone angles, in degrees. The inner angle is the
     * area within which the listener will hear the source with no extra
     * attenuation, while the listener being outside of the outer angle will
     * hear the source attenuated according to the outer cone gains.
     */
    virtual void setConeAngles(ALfloat inner, ALfloat outer) = 0;
    virtual ALfloat getInnerConeAngle() const = 0;
    virtual ALfloat getOuterConeAngle() const = 0;

    /**
     * Specifies the linear gain multiplier when the listener is outside of the
     * source's outer cone area. The specified \param gain applies to all
     * frequencies, while \param gainhf applies extra attenuation to high
     * frequencies.
     *
     * \param gainhf has no effect without the ALC_EXT_EFX extension.
     */
    virtual void setOuterConeGains(ALfloat gain, ALfloat gainhf=1.0f) = 0;
    virtual ALfloat getOuterConeGain() const = 0;
    virtual ALfloat getOuterConeGainHF() const = 0;

    /**
     * Specifies the rolloff factors for the direct and send paths. This is
     * effectively a distance scaling relative to the reference distance. Note:
     * the room rolloff factor is 0 by default, disabling distance attenuation
     * for send paths. This is because the reverb engine will, by default,
     * apply a more realistic room attenuation based on the reverb decay time
     * and direct path attenuation.
     */
    virtual void setRolloffFactors(ALfloat factor, ALfloat roomfactor=0.0f) = 0;
    virtual ALfloat getRolloffFactor() const = 0;
    virtual ALfloat getRoomRolloffFactor() const = 0;

    /**
     * Specifies the doppler factor for the doppler effect's pitch shift. This
     * effectively scales the source and listener velocities for the doppler
     * calculation.
     */
    virtual void setDopplerFactor(ALfloat factor) = 0;
    virtual ALfloat getDopplerFactor() const = 0;

    /** Specifies if the source properties are relative to the listener. */
    virtual void setRelative(bool relative) = 0;
    virtual bool getRelative() const = 0;

    /**
     * Specifies the source's radius. This causes the source to behave as if
     * every point within the spherical area emits sound.
     *
     * Has no effect without the AL_EXT_SOURCE_RADIUS extension.
     */
    virtual void setRadius(ALfloat radius) = 0;
    virtual ALfloat getRadius() const = 0;

    /**
     * Specifies the left and right channel angles, in radians, when playing a
     * stereo buffer or stream. The angles go counter-clockwise, with 0 being
     * in front and positive values going left.
     *
     * Has no effect without the AL_EXT_STEREO_ANGLES extension.
     */
    virtual void setStereoAngles(ALfloat leftAngle, ALfloat rightAngle) = 0;
    virtual std::pair<ALfloat,ALfloat> getStereoAngles() const = 0;

    virtual void setAirAbsorptionFactor(ALfloat factor) = 0;
    virtual ALfloat getAirAbsorptionFactor() const = 0;

    virtual void setGainAuto(bool directhf, bool send, bool sendhf) = 0;
    virtual bool getDirectGainHFAuto() const = 0;
    virtual bool getSendGainAuto() const = 0;
    virtual bool getSendGainHFAuto() const = 0;

    /** Sets the \param filter properties on the direct path signal. */
    virtual void setDirectFilter(const FilterParams &filter) = 0;
    /**
     * Sets the \param filter properties on the given \param send path signal.
     * Any auxiliary effect slot on the send path remains in place.
     */
    virtual void setSendFilter(ALuint send, const FilterParams &filter) = 0;
    /**
     * Connects the effect slot \param slot to the given \param send path. Any
     * filter properties on the send path remain as they were.
     */
    virtual void setAuxiliarySend(AuxiliaryEffectSlot *slot, ALuint send) = 0;
    /**
     * Connects the effect slot \param slot to the given \param send path,
     * using the \param filter properties.
     */
    virtual void setAuxiliarySendFilter(AuxiliaryEffectSlot *slot, ALuint send, const FilterParams &filter) = 0;

    /**
     * Updates the source, ensuring that resources are released when playback
     * is finished.
     */
    virtual void update() = 0;

    /**
     * Releases the source, stopping playback, releasing resources, and
     * returning it to the system.
     */
    virtual void release() = 0;
};


class ALURE_API SourceGroup {
public:
    /**
     * Adds \param source to the source group. A source may only be part of one
     * group at a time, and will automatically be removed from its current
     * group as needed.
     */
    virtual void addSource(Source *source) = 0;
    /** Removes \param source from the source group. */
    virtual void removeSource(Source *source) = 0;

    /** Adds a list of sources to the group at once. */
    virtual void addSources(const Vector<Source*> &sources) = 0;
    /** Removes a list of sources from the source group. */
    virtual void removeSources(const Vector<Source*> &sources) = 0;

    /**
     * Adds \param group as a subgroup of the source group. This method will
     * throw an exception if \param group is being added to a group it has as a
     * sub-group (i.e. it would create a circular sub-group chain).
     */
    virtual void addSubGroup(SourceGroup *group) = 0;
    /** Removes \param group from the source group. */
    virtual void removeSubGroup(SourceGroup *group) = 0;

    /** Returns the list of sources currently in the group. */
    virtual Vector<Source*> getSources() = 0;

    /** Returns the list of subgroups currently in the group. */
    virtual Vector<SourceGroup*> getSubGroups() = 0;

    /** Sets the source group gain, which accumulates with its sources. */
    virtual void setGain(ALfloat gain) = 0;
    /** Gets the source group gain. */
    virtual ALfloat getGain() const = 0;

    /** Sets the source group pitch, which accumulates with its sources. */
    virtual void setPitch(ALfloat pitch) = 0;
    /** Gets the source group pitch. */
    virtual ALfloat getPitch() const = 0;

    /**
     * Pauses all currently-playing sources that are under this group,
     * including sub-groups.
     */
    virtual void pauseAll() const = 0;
    /**
     * Resumes all paused sources that are under this group, including
     * sub-groups.
     */
    virtual void resumeAll() const = 0;

    /** Stops all sources that are under this group, including sub-groups. */
    virtual void stopAll() const = 0;

    /**
     * Releases the source group, removing all sources from it before being
     * freed.
     */
    virtual void release() = 0;
};


struct SourceSend {
    Source *mSource;
    ALuint mSend;
};

class ALURE_API AuxiliaryEffectSlot {
public:
    virtual void setGain(ALfloat gain) = 0;
    /**
     * If set to true, the reverb effect will automatically apply adjustments
     * to the source's send slot based on the effect properties.
     *
     * Has no effect when using non-reverb effects. Default is true.
     */
    virtual void setSendAuto(bool sendauto) = 0;

    /**
     * Updates the effect slot with a new \param effect. The given effect
     * object may be altered or destroyed without affecting the effect slot.
     */
    virtual void applyEffect(const Effect *effect) = 0;

    /**
     * Releases the effect slot, returning it to the system. It must not be in
     * use by a source.
     */
    virtual void release() = 0;

    /**
     * Retrieves each \ref Source object and its pairing send this effect slot
     * is set on. Setting a different (or null) effect slot on each source's
     * given send will allow the effect slot to be released.
     */
    virtual Vector<SourceSend> getSourceSends() const = 0;

    /** Determines if the effect slot is in use by a source. */
    virtual bool isInUse() const = 0;
};


class ALURE_API Effect {
public:
    /**
     * Updates the effect with the specified reverb properties \param props. If
     * the EAXReverb effect is not supported, it will automatically attempt to
     * downgrade to the Standard Reverb effect.
     */
    virtual void setReverbProperties(const EFXEAXREVERBPROPERTIES &props) = 0;

    virtual void destroy() = 0;
};


/**
 * Audio decoder interface. Applications may derive from this, implementing the
 * necessary methods, and use it in places the API wants a Decoder object.
 */
class ALURE_API Decoder {
public:
    virtual ~Decoder() { }

    /** Retrieves the sample frequency, in hz, of the audio being decoded. */
    virtual ALuint getFrequency() const = 0;
    /** Retrieves the channel configuration of the audio being decoded. */
    virtual ChannelConfig getChannelConfig() const = 0;
    /** Retrieves the sample type of the audio being decoded. */
    virtual SampleType getSampleType() const = 0;

    /**
     * Retrieves the total length of the audio, in sample frames. If unknown,
     * returns 0. Note that if the returned length is 0, the decoder may not be
     * used to load a \ref Buffer.
     */
    virtual uint64_t getLength() = 0;
    /**
     * Retrieves the current sample frame position (i.e. the number of sample
     * frames from the beginning).
     */
    virtual uint64_t getPosition() = 0;
    /**
     * Seek to \param pos, specified in sample frames. Returns true if the seek
     * was successful.
     */
    virtual bool seek(uint64_t pos) = 0;

    /**
     * Retrieves the loop points, in sample frames, as a [start,end) pair. If
     * start >= end, use all available data.
     */
    virtual std::pair<uint64_t,uint64_t> getLoopPoints() const = 0;

    /**
     * Decodes \param count sample frames, writing them to \param ptr, and
     * returns the number of sample frames written. Returning less than the
     * requested count indicates the end of the audio.
     */
    virtual ALuint read(ALvoid *ptr, ALuint count) = 0;
};

/**
 * Audio decoder factory interface. Applications may derive from this,
 * implementing the necessary methods, and use it in places the API wants a
 * DecoderFactory object.
 */
class ALURE_API DecoderFactory {
public:
    virtual ~DecoderFactory() { }

    /**
     * Creates and returns a \ref Decoder instance for the given resource
     * \param file. Returns NULL if a decoder can't be created from the file.
     */
    virtual SharedPtr<Decoder> createDecoder(SharedPtr<std::istream> file) = 0;
};

/**
 * Registers a decoder factory for decoding audio. Registered factories are
 * used in lexicographical order, e.g. if Factory1 is registered with name1 and
 * Factory2 is registered with name2, Factory1 will be used before Factory2 if
 * name1 < name2. Internal decoder factories are always used after registered
 * ones.
 *
 * Alure retains a reference to the DecoderFactory instance and will release it
 * (potentially destroying the object) when the library unloads.
 *
 * \param name A unique name identifying this decoder factory.
 * \param factory A DecoderFactory instance used to create Decoder instances.
 */
ALURE_API void RegisterDecoder(const String &name, UniquePtr<DecoderFactory> factory);

/**
 * Unregisters a decoder factory by name. Alure returns the instance back to
 * the application.
 *
 * \param name The unique name identifying a previously-registered decoder
 * factory.
 *
 * \return The unregistered decoder factory instance, or 0 (nullptr) if a
 * decoder factory with the given name doesn't exist.
 */
ALURE_API UniquePtr<DecoderFactory> UnregisterDecoder(const String &name);


/**
 * A file I/O factory interface. Applications may derive from this and set an
 * instance to be used by the audio decoders. By default, the library uses
 * standard I/O.
 */
class ALURE_API FileIOFactory {
public:
    /**
     * Sets the \param factory instance to be used by the audio decoders. If a
     * previous factory was set, it's returned to the application. Passing in a
     * NULL factory reverts to the default.
     */
    static UniquePtr<FileIOFactory> set(UniquePtr<FileIOFactory> factory);

    /**
     * Gets the current FileIOFactory instance being used by the audio
     * decoders.
     */
    static FileIOFactory &get();

    virtual ~FileIOFactory() { }

    /** Opens a read-only binary file for the given \param name. */
    virtual SharedPtr<std::istream> openFile(const String &name) = 0;
};


/**
 * A message handler interface. Applications may derive from this and set an
 * instance on a context to receive messages. The base methods are no-ops, so
 * derived classes only need to implement methods for relevant messages.
 *
 * It's recommended that applications mark their handler methods using the
 * override keyword, to ensure they're properly overriding the base methods in
 * case they change.
 */
class ALURE_API MessageHandler {
public:
    virtual ~MessageHandler();

    /**
     * Called when the given \param device has been disconnected and is no
     * longer usable for output. As per the ALC_EXT_disconnect specification,
     * disconnected devices remain valid, however all playing sources are
     * automatically stopped, any sources that are attempted to play will
     * immediately stop, and new contexts may not be created on the device.
     *
     * Note that connection status is checked during \ref Context::update
     * calls, so that method must be called regularly to be notified when a
     * device is disconnected. This method may not be called if the device
     * lacks support for the ALC_EXT_disconnect extension.
     *
     * WARNING: Do not attempt to clean up resources within this callback
     * method, as Alure is in the middle of doing updates. Instead, flag the
     * device as having been lost and do cleanup later.
     */
    virtual void deviceDisconnected(Device *device);

    /**
     * Called when the given \param source stops playback. If \param forced is
     * true, the source was stopped because either there were no more system
     * sources and a higher-priority source needs to play, or it's part of a
     * \ref SourceGroup (or sub-group thereof) that had its
     * \ref SourceGroup::stopAll method called.
     *
     * Sources that stopped automatically will be detected upon a call to
     * \ref Context::update or \ref Source::update, and will have \param forced
     * set to false.
     */
    virtual void sourceStopped(Source *source, bool forced);

    /**
     * Called when a new buffer is about to be created and loaded. May be
     * called asynchronously for buffers being loaded asynchronously.
     *
     * \param name The resource name, as passed to \ref Context::getBuffer.
     * \param channels Channel configuration of the given audio data.
     * \param type Sample type of the given audio data.
     * \param samplerate Sample rate of the given audio data.
     * \param data The audio data that is about to be fed to the OpenAL buffer.
     */
    virtual void bufferLoading(const String &name, ChannelConfig channels, SampleType type, ALuint samplerate, const Vector<ALbyte> &data);

    /**
     * Called when a resource isn't found, allowing the app to substitute in a
     * different resource. For buffers created with \ref Context::getBuffer or
     * \ref Context::getBufferAsync, the original name will still be used for
     * the cache map so the app doesn't have to keep track of substituted
     * resource names.
     *
     * This will be called again if the new name isn't found.
     *
     * \param name The resource name that was not found.
     * \return The resplacement resource name to use instead. Returning an
     *         empty string means to stop trying.
     */
    virtual String resourceNotFound(const String &name);
};

} // namespace alure

#endif /* AL_ALURE2_H */