only supports a cone in a single-point emitter. Multi-point emitters are a convenient and efficient way to manage a related group of sound sources. Many properties are shared among all channel points, such as Doppler?the same Doppler shift is applied to all channels in the emitter. Thus, the Doppler value need only be calculated once, not per-point as would be needed with multiple separate single-point emitters. Because only has one orientation vector, a multi-point emitter cone would be of limited usefulness, forcing all channels to behave as if they were facing the same direction. If multiple independent cones are needed, multiple single-point emitters should be used, each with its own orientation.

The parameter type X3DAUDIO_VECTOR is typed to DirectX::XMFLOAT3, to provide x , y , and z floating-point values.

X3DAudio uses a left-handed Cartesian coordinate system, with values on the x-axis increasing from left to right, on the y-axis from bottom to top, and on the z-axis from near to far. Azimuths are measured clockwise from a given reference direction.

For user-defined distance curves, the distance field of the first point must be 0.0f and the distance field of the last point must be 1.0f.

If an emitter moves beyond a distance of (CurveDistanceScaler ? 1.0f), the last point on the curve is used to compute the volume output level. The last point is determined by the following:

.pPoints[PointCount-1].DSPSetting)

InnerRadius is used to specify an area of smooth transition around the origin point as a sound travels directly through, above or below the listener. Elevation is accounted for by specifying an InnerRadiusAngle, whereby a sound whose elevation increases or decreases, will eventually start to bleed the sound into more than just two speakers.

When Inner Radius and Inner Radius Angle are not used, emitters are audible in the two closest speakers to their current position/orientation (or, if directly on a line with one speaker's defined angle, solely from that one speaker).

Inner Radius and Inner Radius Angle have no effect on emitters positioned outside of the cones they describe. Inside of the cone, they will gradually cause the sound to bleed into the opposite speakers, until the sound will be equally heard in all speakers when the emitter is at the same position as (or directly above or below) the listener.

The following members must be initialized before passing this structure to the function:

• pMatrixCoefficients

• pDelayTimes

• SrcChannelCount

• DstChannelCount

The following members are returned by passing this structure to the function:

• pMatrixCoefficients

• pDelayTimes

• LPFDirectCoefficient

• LPFReverbCoefficient

• ReverbLevel

• DopplerFactor

• EmitterToListenerAngle

• EmitterToListenerDistance

• EmitterVelocityComponent

• ListenerVelocityComponent

The parameter type X3DAUDIO_VECTOR is typed to DirectX::XMFLOAT3, to provide x, y and z floating-point values.

A listener's front and top vectors must be orthonormal. To be considered orthonormal, a pair of vectors must have a magnitude of 1 +- 1x10-5 and a dot product of 0 +- 1x10-5.