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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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