AudioListener

DirectXTK	Audio

AudioListener is a helper object derived from X3DAUDIO_LISTENER that can be used by the Apply3D method of SoundEffectInstance, SoundStreamInstance, and DynamicSoundEffectInstance.

See AudioEmitter.

Related tutorial: Using positional audio

classDiagram
direction LR
class AudioListener{
   +ListenerCone
   +SetPosition()
   +SetVelocity()
   +SetOrientation()
   +Update()
}
class X3DAUDIO_LISTENER
X3DAUDIO_LISTENER <|-- AudioListener

Header

#include <Audio.h>

Initialization

The default constructor creates an omnidirectional listener located at 0,0,0 facing -z and an up vector of +y.

When using left-handed coordinates, be sure to set OrientFront

Helpers

In addition to setting the members of X3DAUDIO_LISTENER directly, these helper functions are provided:

SetPosition (XMVECTOR) or (XMFLOAT3): Sets the Position of the listener.
SetVelocity (XMVECTOR) or (XMFLOAT3): Sets the Velocity of the listener.
SetOrientation (XMVECTOR forward, XMVECTOR up) or (XMFLOAT3 forward, XMFLOAT3 up)
SetOrientationFromQuaternion (XMVECTOR): Sets the OrientFront/OrientTop of the listener.
Update (XMVECTOR newPos, XMVECTOR upDir, float dt): Computes a direction and velocity for the listener based on the current Position value, the new position, and the provided delta time (Δt). This updates the OrientFront/OrientTop to match, and then sets the Position to the new position. If dt is 0, the update is skipped.

Directional Listener

AudioListener defaults to an omnidirectional listener. To create a sound-cone, set the pCone member to point to a X3DAUDIO_CONE structure. The pointer must point to valid memory at the time Apply3D is called.

SetOmnidirectional sets the pCone value to nullptr indicating an omnidirectional listener (the default).
SetCone (X3DAUDIO_CONE) sets the pCone value to point to ListenerCone and copies the passed in cone parameters.

Example

float dt = static_cast<float>(timer.GetElapsedSeconds());

emitter.Update(soundPosition, Vector3::Up, dt);
listener.Update(playerPosiiton, Vector3::Up, dt);
if (soundSource)
{
    soundSource->Apply3D(listener, emitter);
}