ShepardToneSource Class Reference

A WaveSource that constructs a special looped waveform reminiscent of a Shepard tone. More...

#include <shepard_tone_source.h>

Inheritance diagram for ShepardToneSource:

Public Member Functions
	ShepardToneSource ()
	Constructs a ShepardToneSource with a loop frame for seamless frequency content.
virtual	~ShepardToneSource ()
virtual void	render (vital::WaveFrame *wave_frame, float position) override
	Renders a frame of the Shepard tone wavetable at a given position.
virtual WavetableComponentFactory::ComponentType	getType () override
	Returns the component type associated with this source.
virtual bool	hasKeyframes () override
	Indicates whether this component has keyframes.
Public Member Functions inherited from WaveSource
	WaveSource ()
	Constructs a WaveSource with a default frequency-domain interpolation mode.
virtual	~WaveSource ()
WavetableKeyframe *	createKeyframe (int position) override
	Creates a new keyframe at a given position.
void	render (vital::WaveFrame *wave_frame, float position) override
	Renders the waveform at a given position into a WaveFrame.
WavetableComponentFactory::ComponentType	getType () override
	Returns the type of this WavetableComponent.
json	stateToJson () override
	Serializes the component’s state and all keyframes to a JSON object.
void	jsonToState (json data) override
	Restores the component’s state from a JSON object.
vital::WaveFrame *	getWaveFrame (int index)
	Gets a WaveFrame from a specified keyframe index.
WaveSourceKeyframe *	getKeyframe (int index)
	Retrieves a WaveSourceKeyframe by index.
void	setInterpolationMode (InterpolationMode mode)
	Sets the interpolation mode for morphing between keyframes.
InterpolationMode	getInterpolationMode () const
	Gets the current interpolation mode.
Public Member Functions inherited from WavetableComponent
	WavetableComponent ()
	Constructs a WavetableComponent with a default linear interpolation style.
virtual	~WavetableComponent ()
virtual void	prerender ()
	Called before rendering to perform any needed precomputation.
void	reset ()
	Clears all keyframes and inserts a default one at position 0.
void	interpolate (WavetableKeyframe *dest, float position)
	Interpolates a destination keyframe at a given position.
WavetableKeyframe *	insertNewKeyframe (int position)
	Inserts a new keyframe at the given position, creating and sorting it into the array.
void	reposition (WavetableKeyframe *keyframe)
	Repositions a keyframe in the keyframe list after its position changed.
void	remove (WavetableKeyframe *keyframe)
	Removes a specific keyframe from the component.
int	numFrames () const
	Gets the number of keyframes.
int	indexOf (WavetableKeyframe *keyframe) const
	Finds the index of a given keyframe.
WavetableKeyframe *	getFrameAt (int index) const
	Gets a keyframe by index.
int	getIndexFromPosition (int position) const
	Finds the insertion index for a given position to keep keyframes sorted.
WavetableKeyframe *	getFrameAtPosition (int position)
	Gets a keyframe by position if one matches exactly, or nullptr otherwise.
int	getLastKeyframePosition ()
	Gets the highest position among all keyframes.
void	setInterpolationStyle (InterpolationStyle type)
	Sets the global interpolation style.
InterpolationStyle	getInterpolationStyle () const
	Gets the current global interpolation style.

Protected Attributes
std::unique_ptr< WaveSourceKeyframe >	loop_frame_
	A loop frame used to create the repetitive Shepard effect.
Protected Attributes inherited from WaveSource
std::unique_ptr< WaveSourceKeyframe >	compute_frame_
	A keyframe for intermediate interpolation computations.
InterpolationMode	interpolation_mode_
	The mode of interpolation.
Protected Attributes inherited from WavetableComponent
std::vector< std::unique_ptr< WavetableKeyframe > >	keyframes_
	The list of keyframes sorted by position.
InterpolationStyle	interpolation_style_
	Current interpolation style (none, linear, cubic).

Additional Inherited Members
Public Types inherited from WaveSource
enum	InterpolationMode { kTime , kFrequency }
	Defines how keyframes should be interpolated. More...
Public Types inherited from WavetableComponent
enum	InterpolationStyle { kNone , kLinear , kCubic , kNumInterpolationStyles }
	Defines how interpolation is performed between keyframes. More...

Detailed Description

A WaveSource that constructs a special looped waveform reminiscent of a Shepard tone.

ShepardToneSource uses a single keyframe and loops the spectrum in a manner that can create an auditory illusion similar to a Shepard tone—where the tone seems to continually ascend (or descend) without actually changing pitch. Internally, it duplicates and interleaves frequency components to produce a repetitive, seamless effect when traversing frames.

Constructor & Destructor Documentation

ShepardToneSource()

ShepardToneSource::ShepardToneSource

(

)

Constructs a ShepardToneSource with a loop frame for seamless frequency content.

~ShepardToneSource()

ShepardToneSource::~ShepardToneSource ( )

virtual

Member Function Documentation

getType()

WavetableComponentFactory::ComponentType ShepardToneSource::getType ( )

overridevirtual

Returns the component type associated with this source.

Returns

The ComponentType enumerated value representing a Shepard tone source.

Implements WavetableComponent.

hasKeyframes()

virtual bool ShepardToneSource::hasKeyframes ( )

inlineoverridevirtual

Indicates whether this component has keyframes.

ShepardToneSource uses a single keyframe and a looping frame; it effectively doesn't operate on multiple keyframes.

Returns

False since it does not rely on a series of keyframes.

Reimplemented from WavetableComponent.

render()

void ShepardToneSource::render ( vital::WaveFrame * wave_frame, float position )

overridevirtual

Renders a frame of the Shepard tone wavetable at a given position.

The ShepardToneSource reads from its single keyframe, duplicates frequency bins in a certain pattern, and interpolates between the base and loop frames to create a continuous tone effect.

Parameters

wave_frame	The WaveFrame to render into.
position	The normalized position along the wavetable (0 to 1).

Implements WavetableComponent.

Member Data Documentation

loop_frame_

std::unique_ptr<WaveSourceKeyframe> ShepardToneSource::loop_frame_

protected

A loop frame used to create the repetitive Shepard effect.

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The documentation for this class was generated from the following files:

• /Users/davidvogel/repos/VitalHelp/src/common/wavetable/shepard_tone_source.h
• /Users/davidvogel/repos/VitalHelp/src/common/wavetable/shepard_tone_source.cpp