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NAME
SoVRMLSound -
The SoVRMLSound class is used to represent a sound source.
The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC 14772-1:1997). It is
copyright The Web3D Consortium, and is used by permission of the Consortium:
SYNOPSIS
#include <Inventor/VRMLnodes/SoVRMLSound.h>
Inherits SoNode.
Public Member Functions
virtual SoType getTypeId (void) const
Returns the type identification of an object derived from a class inheriting SoBase. This is used for
run-time type checking and 'downward' casting.
SoVRMLSound (void)
void setDopplerVelocity (float velocity)
float getDopplerVelocity (void) const
void setDopplerFactor (float factor)
float getDopplerFactor (void) const
void startPlaying (SoPath *path, void *userdataptr)
void stopPlaying (SoPath *path, void *userdataptr)
void setBufferingProperties (int bufferLength, int numBuffers, SbTime sleepTime)
void getBufferingProperties (int &bufferLength, int &numBuffers, SbTime &sleepTime)
virtual void audioRender (SoAudioRenderAction *action)
Static Public Member Functions
static SoType getClassTypeId (void)
static void initClass (void)
static void setDefaultBufferingProperties (int bufferLength, int numBuffers, SbTime sleepTime)
Public Attributes
SoSFNode source
SoSFFloat intensity
SoSFFloat priority
SoSFVec3f location
SoSFVec3f direction
SoSFFloat minFront
SoSFFloat maxFront
SoSFFloat minBack
SoSFFloat maxBack
SoSFBool spatialize
SoSFFloat dopplerFactor
SoSFFloat dopplerVelocity
Protected Member Functions
virtual const SoFieldData * getFieldData (void) const
virtual ~SoVRMLSound (void)
Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)
Additional Inherited Members
Detailed Description
The SoVRMLSound class is used to represent a sound source.
The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC 14772-1:1997). It is
copyright The Web3D Consortium, and is used by permission of the Consortium:
Sound {
exposedField SFVec3f direction 0 0 1 # (-inf, inf)
exposedField SFFloat intensity 1 # [0,1]
exposedField SFVec3f location 0 0 0 # (-inf, inf)
exposedField SFFloat maxBack 10 # [0,inf)
exposedField SFFloat maxFront 10 # [0,inf)
exposedField SFFloat minBack 1 # [0,inf)
exposedField SFFloat minFront 1 # [0,inf)
exposedField SFFloat priority 0 # [0,1]
exposedField SFNode source NULL
field SFBool spatialize TRUE
}
The Sound node specifies the spatial presentation of a sound in a VRML scene. The sound is located at a
point in the local coordinate system and emits sound in an elliptical pattern (defined by two
ellipsoids). The ellipsoids are oriented in a direction specified by the direction field. The shape of
the ellipsoids may be modified to provide more or less directional focus from the location of the sound.
The source field specifies the sound source for the Sound node. If the source field is not specified, the
Sound node will not emit audio. The source field shall specify either an AudioClip node or a MovieTexture
node. If a MovieTexture node is specified as the sound source, the MovieTexture shall refer to a movie
format that supports sound (e.g., MPEG1-Systems).
The intensity field adjusts the loudness (decibels) of the sound emitted by the Sound node (note: this is
different from the traditional definition of intensity with respect to sound).
The intensity field has a value that ranges from 0.0 to 1.0 and specifies a factor which shall be used to
scale the normalized sample data of the sound source during playback. A Sound node with an intensity of
1.0 shall emit audio at its maximum loudness (before attenuation), and a Sound node with an intensity of
0.0 shall emit no audio. Between these values, the loudness should increase linearly from a -20 dB change
approaching an intensity of 0.0 to a 0 dB change at an intensity of 1.0.
The priority field provides a hint for the browser to choose which sounds to play when there are more
active Sound nodes than can be played at once due to either limited system resources or system load.
7.3.4, Sound priority, attenuation, and spatialization (http://www.web3d.org/x3d/specifications/vrml/ISO-
IEC-14772-VRML97/part1/concepts.html#7.3.4), describes a recommended algorithm for determining which
sounds to play under such circumstances. The priority field ranges from 0.0 to 1.0, with 1.0 being the
highest priority and 0.0 the lowest priority.
The location field determines the location of the sound emitter in the local coordinate system. A Sound
node's output is audible only if it is part of the traversed scene. Sound nodes that are descended from
LOD, Switch, or any grouping or prototype node that disables traversal (i.e., drawing) of its children
are not audible unless they are traversed. If a Sound node is disabled by a Switch or LOD node, and later
it becomes part of the traversal again, the sound shall resume where it would have been had it been
playing continuously.
The Sound node has an inner ellipsoid that defines a volume of space in which the maximum level of the
sound is audible. Within this ellipsoid, the normalized sample data is scaled by the intensity field and
there is no attenuation. The inner ellipsoid is defined by extending the direction vector through the
location.
The minBack and minFront fields specify distances behind and in front of the location along the direction
vector respectively. The inner ellipsoid has one of its foci at location (the second focus is implicit)
and intersects the direction vector at minBack and minFront. The Sound node has an outer ellipsoid that
defines a volume of space that bounds the audibility of the sound. No sound can be heard outside of this
outer ellipsoid.
The outer ellipsoid is defined by extending the direction vector through the location. The maxBack and
maxFront fields specify distances behind and in front of the location along the direction vector
respectively. The outer ellipsoid has one of its foci at location (the second focus is implicit) and
intersects the direction vector at maxBack and maxFront. The minFront, maxFront, minBack, and maxBack
fields are defined in local coordinates, and shall be greater than or equal to zero. The minBack field
shall be less than or equal to maxBack, and minFront shall be less than or equal to maxFront. The
ellipsoid parameters are specified in the local coordinate system but the ellipsoids' geometry is
affected by ancestors' transformations.
Between the two ellipsoids, there shall be a linear attenuation ramp in loudness, from 0 dB at the
minimum ellipsoid to -20 dB at the maximum ellipsoid: attenuation = -20 × (d' / d") where d' is the
distance along the location-to-viewer vector, measured from the transformed minimum ellipsoid boundary to
the viewer, and d" is the distance along the location-to-viewer vector from the transformed minimum
ellipsoid boundary to the transformed maximum ellipsoid boundary (see Figure 6.14).
Figure 6.14 -- Sound node geometry
The spatialize field specifies if the sound is perceived as being directionally located relative to the
viewer. If the spatialize field is TRUE and the viewer is located between the transformed inner and outer
ellipsoids, the viewer's direction and the relative location of the Sound node should be taken into
account during playback. Details outlining the minimum required spatialization functionality can be found
in 7.3.4, Sound priority, attenuation, and spatialization
(http://www.web3d.org/x3d/specifications/vrml/ISO-IEC-14772-VRML97/part1/concepts.html#7.3.4), If the
spatialize field is FALSE, then directional effects are ignored, but the ellipsoid dimensions and
intensity will still affect the loudness of the sound. If the sound source is multi-channel (e.g.,
stereo), then the source should retain its channel separation during playback.
Constructor & Destructor Documentation
SoVRMLSound::SoVRMLSound (void)
Constructor.
SoVRMLSound::~SoVRMLSound (void) [protected], [virtual]
Destructor.
Member Function Documentation
SoType SoVRMLSound::getTypeId (void) const [virtual]
Returns the type identification of an object derived from a class inheriting SoBase. This is used for
run-time type checking and 'downward' casting. Usage example:
void foo(SoNode * node)
{
if (node->getTypeId() == SoFile::getClassTypeId()) {
SoFile * filenode = (SoFile *)node; // safe downward cast, knows the type
}
}
For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or
others: this method needs to be overridden in all subclasses. This is typically done as part of setting
up the full type system for extension classes, which is usually accomplished by using the pre-defined
macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and
SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.
For more information on writing Coin extensions, see the class documentation of the toplevel superclasses
for the various class groups.
Implements SoBase.
const SoFieldData * SoVRMLSound::getFieldData (void) const [protected], [virtual]
Returns a pointer to the class-wide field data storage object for this instance. If no fields are
present, returns NULL.
Reimplemented from SoFieldContainer.
void SoVRMLSound::setDopplerVelocity (floatvelocity)
Sets the doppler velocity relative to the global coordinate system. Not implemented yet.
float SoVRMLSound::getDopplerVelocity (void) const
Returns the doppler velocity relative to the global coordinate system. Not implemented yet.
void SoVRMLSound::setDopplerFactor (floatfactor)
Sets the doppler factor. Not implemented yet.
float SoVRMLSound::getDopplerFactor (void) const
Returns the doppler factor. Not implemented yet.
void SoVRMLSound::startPlaying (SoPath *path, void *userdataptr)
Starts playing the sound. Not implemented yet. Please use the fields of SoVRMLAudioClip to start and stop
sounds.
void SoVRMLSound::stopPlaying (SoPath *path, void *userdataptr)
Stops playing the sound. Not implemented yet. Please use the fields of SoVRMLAudioClip to start and stop
sounds.
void SoVRMLSound::audioRender (SoAudioRenderAction *action) [virtual]
Action method for SoAudioRenderAction.
Does common processing for SoAudioRenderAction action instances.
Reimplemented from SoNode.
Member Data Documentation
SoSFNode SoVRMLSound::source
The audio stream. Either an SoVRMLAudioClip or an SoVRMLMovieTexture. Coin only supports playback of
audio from SoVRMLAudioClip, not from SoVRMLMovieTexture.
SoSFFloat SoVRMLSound::intensity
Sound intensity. A value from 0 to 1. Default value is 1.
SoSFFloat SoVRMLSound::priority
Browser hint for how important the sound is. A value from 0 to
1. Default value is 0. Coin does not yet support this field.
SoSFVec3f SoVRMLSound::location
The sound position. Default value is (0, 0, 0).
SoSFVec3f SoVRMLSound::direction
Sound direction. Default value is (0, 0, 1).
SoSFFloat SoVRMLSound::minFront
Inner ellipse front value. Default value is 1.
SoSFFloat SoVRMLSound::maxFront
Outer ellipse front value. Default value is 10.
SoSFFloat SoVRMLSound::minBack
Inner ellipse back value. Default value is 1.
SoSFFloat SoVRMLSound::maxBack
Outer ellips back value. Default value is 10.
SoSFBool SoVRMLSound::spatialize
Set to TRUE if sound should be spatialized (directional effects are applied) with respect to the viewer.
Distance attenuation is always applied. Default value is TRUE.
Author
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