Class TSoundEngine

Unit

Declaration

type TSoundEngine = class(TSoundAllocator)

Description

Sound engine, responsible for loading and playing sounds. See manual about sound in Castle Game Engine for an overview of sound support.

There should always be only one instance of this class, accessed through the global SoundEngine routine.

Hierarchy

Overview

Fields

Public nested const DefaultVolume = 1.0;
Public nested const DefaultDistanceModel = dmInverse;
Public nested const DefaultDevice = '';
Public nested const DefaultEnabled = true;
Public class var LogVerbose: Boolean;

Methods

Public constructor Create;
Public destructor Destroy; override;
Public procedure ContextOpen;
Public procedure ContextClose;
Public procedure Play(const ASound: TCastleSound); overload;
Public procedure Play(const PlayingSound: TCastlePlayingSound); overload;
Public procedure ParseParameters;
Public function ParseParametersHelp: string;
Public function Devices: TSoundDeviceList;
Public function DeviceCaption: string;

Properties

Public property InternalBackend: TSoundEngineBackend read Backend write SetInternalBackend;
Public property IsContextOpen: boolean read FIsContextOpen;
Public property Information: string read FInformation;
Public property InformationSummary: string read FInformationSummary;
Public property OnOpenClose: TNotifyEventList read FOnOpenClose;
Public class property LogSoundLoading: Boolean read GetLogSoundLoading write SetLogSoundLoading;
Public property Volume: Single read FVolume write SetVolume default DefaultVolume;
Public property Device: string read FDevice write SetDevice;
Public property Enabled: boolean read FEnabled write SetEnabled default DefaultEnabled;
Public property DistanceModel: TSoundDistanceModel read FDistanceModel write SetDistanceModel default DefaultDistanceModel;
Public property DopplerFactor: Single read FDopplerFactor write SetDopplerFactor default 0.0;

Description

Fields

Public nested const DefaultVolume = 1.0;

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Public nested const DefaultDistanceModel = dmInverse;

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Public nested const DefaultDevice = '';

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Public nested const DefaultEnabled = true;

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Public class var LogVerbose: Boolean;

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Methods

Public constructor Create;

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Public destructor Destroy; override;

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Public procedure ContextOpen;

Initialize sound backend. Sets IsContextOpen, IsContextOpenSuccess, Information.

You don't usually need to call this – everything will be initialized automatically when you first load a sound (or try to load and play it).

You can set Device before calling this.

Note that we continue (without any exception) if the initialization failed for any reason (e.g. OpenAL library is not available, or no sound output device is available). You can check IsContextOpenSuccess and Information to know if the initialization was actually successful. But you can also ignore it, the sound engine will silently (literally) keep working even if OpenAL could not be initialized.

Public procedure ContextClose;

Close the sound backend, releasing all sound resources and stopping playback. This sets IsContextOpen and IsContextOpenSuccess to False. It's allowed and harmless to call this when one of them is already False.

You don't usually need to call this – everything will be released automatically when the sound engine is destroyed (at program finalization).

Public procedure Play(const ASound: TCastleSound); overload;

Play given sound once (not looping).

This is the simplest method to just play the sound and "forget about it" (no need to manage the playback afterwards).

It is allowed to set ASound to Nil. Nothing will be played then.

Note: Instead of this method, use Play(TCastlePlayingSound) overload to have more control over the sound (before and after it starts playing).

This only plays non-spatial sounds, as it doesn't give any control over the sound 3D position. Instead of this method, use TCastleSoundSource (attached to some TCastleTransform) for spatial sounds to control their 3D position.

Public procedure Play(const PlayingSound: TCastlePlayingSound); overload;

Play given sound.

Set TCastlePlayingSound.Sound before passing it to this method. Otherwise, if TCastlePlayingSound.Sound is left Nil, nothing will be played.

Use the PlayingSound (TCastlePlayingSound) properties to provide additional information about the sound playback. E.g. assign TCastlePlayingSound.Loop TCastlePlayingSound.OnStop or control sound afterwards by TCastlePlayingSound.Stop, TCastlePlayingSound.Offset.

Consider using TCastlePlayingSound.FreeOnStop if you don't want to manage the lifetime of the TCastlePlayingSound instance.

This only plays non-spatial sounds, as it doesn't give any control over the sound 3D position. Instead of this method, use TCastleSoundSource (attached to some TCastleTransform) for spatial sounds to control their 3D position.

Public procedure ParseParameters;

Parse parameters in Parameters and interpret and remove recognized options. Internally it uses Parameters.Parse with ParseOnlyKnownLongOptions = True. Recognized options:

--audio-device DEVICE-NAME

Set Device variable to given argument.

--no-sound

Disable any sound (sets Enabled to False).

More user-oriented documentation for the above options is here: [https://castle-engine.io/openal_notes.php#section_options]

Public function ParseParametersHelp: string;

Help string for options parsed by ParseParameters.

Note that it also lists the available sound output Devices, as they are valid arguments for the --audio-device option.

Public function Devices: TSoundDeviceList;

List of available sound devices. Read-only.

Use Devices[].Name as Device values.

On some backend implementations, also some other Device values may be possible. E.g. old Loki implementation of OpenAL allowed some hints to be encoded in Lisp-like language inside the Device string.

Public function DeviceCaption: string;

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Properties

Public property InternalBackend: TSoundEngineBackend read Backend write SetInternalBackend;

Sound backend, like OpenAL or FMOD or SOX. See OpenAL or FMOD.

Do not change or access this yourself. You can change this only by calling procedure like UseFMODSoundBackend from CastleFMODSoundBackend unit.

Public property IsContextOpen: boolean read FIsContextOpen;

Did we attempt to initialize sound rendering context. This indicates that ContextOpen was called, and not closed with ContextClose yet. Contrary to IsContextOpenSuccess, this doesn't care if ContextOpen was a success.

Public property Information: string read FInformation;

Multiline information about the currently initialized sound backend (OpenAL, FMOD etc.).

Public property InformationSummary: string read FInformationSummary;

One-line information about the currently initialized sound backend (OpenAL, FMOD etc.).

Public property OnOpenClose: TNotifyEventList read FOnOpenClose;

Events fired after sound context is being open or closed. More precisely, when IsContextOpen changes (and so, possibly, IsContextOpenSuccess changed).

Public class property LogSoundLoading: Boolean read GetLogSoundLoading write SetLogSoundLoading;

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Public property Volume: Single read FVolume write SetVolume default DefaultVolume;

Sound volume, affects all sounds (effects and music). Must be within 0..1 range.

Setting volume to 0.0 means that there is no sound output (this case should be optimized). The sounds played are still tracked.

Public property Device: string read FDevice write SetDevice;

Sound output device, used when initializing sound context.

You can change it even when context is already initialized. Then we'll close the old device (ContextClose), change Device value, and initialize context again (ContextOpen). Note that you will need to reload your buffers and sources again.

Public property Enabled: boolean read FEnabled write SetEnabled default DefaultEnabled;

Enable sound. Value True, the default, means that we will initialize sound backend and play all sounds as you expect.

If this is False, then we will not initialize any sound backend even if you try to load or play some sound. This is useful if you simply want to disable any sound output (or backend, like OpenAL, usage), even when sound library (like OpenAL) is available.

Setting this to False when the sound backend is already initialized will close it, stopping the playback of all existing sound sources.

Note that when sound backend is not initialized, sounds are not tracked, and non-looping sounds are just discarded. So toggling this property between False and True will simply restart all looping sounds from the beginning. So setting this to False is not a way to "pause" or "mute" sound playback, it's a way to "stop" sound playback. If you want to mute all sounds, but be able to unmute them when necessary, set the Volume to zero.

Public property DistanceModel: TSoundDistanceModel read FDistanceModel write SetDistanceModel default DefaultDistanceModel;

How does the distance affect spatial sounds (with TCastleSoundSource.Spatial). See TSoundDistanceModel for the description of possible options.

Public property DopplerFactor: Single read FDopplerFactor write SetDopplerFactor default 0.0;

Emphasize or deemphasize the Doppler effect. See https://en.wikipedia.org/wiki/Doppler_effect and CGE demo examples/audio/doppler_effect to see what it is.

Allowed values are anything > 0. Value 0 disables the Doppler effect. This is the default, otherwise the Doppler effect would be way too audible in 2D games. Value 1 makes a correct Doppler effect if the distance in your world of 1 unit corresponds to 1 meter. Larger values allow to emphasize the effect more.


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