VST3ClientExtensions Struct Reference

An interface to allow an AudioProcessor to implement extended VST3-specific functionality. More...

Public Types
enum class	InterfaceType {   ara , controller , compatibility , component ,   processor }
	An enum indicating the various VST3 interface types. More...
using	InterfaceId = std::array<std::byte, 16>

Public Member Functions
virtual	~VST3ClientExtensions ()=default
virtual int32_t	queryIEditController (const Steinberg::TUID, void **obj)
	This function may be used by implementations of queryInterface() in the VST3's implementation of IEditController to return additional supported interfaces.
virtual int32_t	queryIAudioProcessor (const Steinberg::TUID, void **obj)
	This function may be used by implementations of queryInterface() in the VST3's implementation of IAudioProcessor to return additional supported interfaces.
virtual void	setIComponentHandler (Steinberg::FUnknown *)
	This may be called by the VST3 wrapper when the host sets an IComponentHandler for the plugin to use.
virtual void	setIHostApplication (Steinberg::FUnknown *)
	This may be called shortly after the AudioProcessor is constructed with the current IHostApplication.
virtual bool	getPluginHasMainInput () const
	This function will be called to check whether the first input bus should be designated as "kMain" or "kAux".
virtual std::vector< InterfaceId >	getCompatibleClasses () const
	This function should return the UIDs of any compatible VST2 or VST3 plug-ins.
virtual std::map< uint32_t, String >	getCompatibleParameterIds (const InterfaceId &compatibleClass) const
	This function should return a map of VST3 parameter IDs and the JUCE parameters they map to.

Static Public Member Functions
static InterfaceId	convertJucePluginId (uint32_t manufacturerCode, uint32_t pluginCode, InterfaceType interfaceType=InterfaceType::component)
	Returns a 16-byte array indicating the VST3 interface ID used for a given JUCE VST3 plugin.
static InterfaceId	convertVST2PluginId (uint32_t pluginCode, const String &pluginName, InterfaceType interfaceType=InterfaceType::component)
	Returns a 16-byte array indicating the VST3 interface ID used for a given VST2 plugin.
static uint32_t	convertJuceParameterId (const String &parameterId, bool studioOneCompatible=true)
	Returns the VST3 compatible parameter ID reported for a given JUCE parameter.
static InterfaceId	toInterfaceId (const String &interfaceIdString)
	Converts a 32-character hex notation string to a VST3 interface ID.

Detailed Description

An interface to allow an AudioProcessor to implement extended VST3-specific functionality.

To use this class, create an object that inherits from it, implement the methods, then return a pointer to the object in your AudioProcessor::getVST3ClientExtensions() method.

See also

AudioProcessor, AAXClientExtensions, VST2ClientExtensions

Member Typedef Documentation

InterfaceId

using VST3ClientExtensions::InterfaceId = std::array<std::byte, 16>

Member Enumeration Documentation

InterfaceType

enum class VST3ClientExtensions::InterfaceType

strong

An enum indicating the various VST3 interface types.

In most cases users shouldn't need to concern themselves with any interfaces other than the component, which is used to report the actual audio effect.

Enumerator
ara
controller
compatibility
component
processor

Constructor & Destructor Documentation

~VST3ClientExtensions()

virtual VST3ClientExtensions::~VST3ClientExtensions ( )

virtualdefault

Member Function Documentation

queryIEditController()

virtual int32_t VST3ClientExtensions::queryIEditController ( const Steinberg::TUID , void ** obj )

virtual

This function may be used by implementations of queryInterface() in the VST3's implementation of IEditController to return additional supported interfaces.

queryIAudioProcessor()

virtual int32_t VST3ClientExtensions::queryIAudioProcessor ( const Steinberg::TUID , void ** obj )

virtual

This function may be used by implementations of queryInterface() in the VST3's implementation of IAudioProcessor to return additional supported interfaces.

setIComponentHandler()

virtual void VST3ClientExtensions::setIComponentHandler ( Steinberg::FUnknown * )

virtual

This may be called by the VST3 wrapper when the host sets an IComponentHandler for the plugin to use.

You should not make any assumptions about how and when this will be called - this function may not be called at all!

setIHostApplication()

virtual void VST3ClientExtensions::setIHostApplication ( Steinberg::FUnknown * )

virtual

This may be called shortly after the AudioProcessor is constructed with the current IHostApplication.

You should not make any assumptions about how and when this will be called - this function may not be called at all!

getPluginHasMainInput()

virtual bool VST3ClientExtensions::getPluginHasMainInput ( ) const

virtual

This function will be called to check whether the first input bus should be designated as "kMain" or "kAux".

Return true if the first bus should be kMain, or false if the bus should be kAux.

All other input buses will always be designated kAux.

getCompatibleClasses()

virtual std::vector< InterfaceId > VST3ClientExtensions::getCompatibleClasses ( ) const

virtual

This function should return the UIDs of any compatible VST2 or VST3 plug-ins.

This information will be used to implement the IPluginCompatibility interface. Hosts can use this interface to determine whether this VST3 is capable of replacing a given VST2.

Each compatible class is a 16-byte array that corresponds to the VST3 interface ID for the class implementing the IComponent interface. For VST2 or JUCE plugins these IDs can be determined in the following ways:

• Use convertVST2PluginId() for VST2 plugins or JUCE VST3 plugins with JUCE_VST3_CAN_REPLACE_VST3 enabled
• Use convertJucePluginId() for any other JUCE VST3 plugins

If JUCE_VST3_CAN_REPLACE_VST2 is enabled the VST3 plugin will have the same identifier as the VST2 plugin and therefore there will be no need to implement this function.

If the parameter IDs between compatible versions differ getCompatibleParameterIds() should also be overridden. However, unlike getCompatibleParameterIds() this function should remain constant and always return the same IDs.

See also

getCompatibleParameterIds()

getCompatibleParameterIds()

virtual std::map< uint32_t, String > VST3ClientExtensions::getCompatibleParameterIds ( const InterfaceId & compatibleClass ) const

virtual

This function should return a map of VST3 parameter IDs and the JUCE parameters they map to.

This information is used to implement the IRemapParamID interface. Hosts can use this to preserve automation data when a session was saved using a compatible plugin that has different parameter IDs.

Not all hosts will take this information into account. Therefore, parameter IDs should be maintained between plugin versions. For JUCE plugins migrating from VST2 to VST3 the best method for achieving this is enabling JUCE_FORCE_LEGACY_PARAM_IDS. However, if a plugin has already been released without enabling this flag, this method offers an alternative approach that won't cause any further compatibility issues.

The key in the map is an integer which may represent a VST3 parameter identifier (Vst::ParamID) or VST2 parameter index. You should include a map entry for every parameter ID in the compatible plugin. For VST2 or JUCE plugins these IDs can be determined in the following ways.

• Use the parameter index if any of the following apply:
  • the InterfaceId argument refers to a compatible VST2 plugin, or
  • the InterfaceId argument refers to a JUCE VST3 plugin with JUCE_FORCE_LEGACY_PARAM_IDS enabled, or
  • the InterfaceId argument refers to a JUCE plugin, but the parameter in the compatible plugin doesn't inherit from HostedAudioProcessorParameter (this case is unlikely).
• Otherwise, use convertJuceParameterId() for JUCE VST3 plugins where JUCE_FORCE_LEGACY_PARAM_IDS is disabled, and where the compatible parameter derives from HostedAudioProcessorParameter.
• For non-JUCE VST3s, use the Vst::ParamIDs exported by the compatible VST3.

The value in the map is the JUCE parameter ID for the parameter to map to, or an empty string to indicate that there is no parameter to map to. If a parameter doesn't inherit from HostedAudioProcessorParameter its ID will be the parameter index as a string, for example "1". Otherwise, always use the actual parameter ID (even if JUCE_FORCE_LEGACY_PARAM_IDS is enabled).

In the unlikely event that two plugins share the same plugin ID, and both have a different parameters that share the same parameter ID, it may be possible to determine which version of the plugin is being loaded during setStateInformation(). This method will always be called after setStateInformation(), so that the map with the correct mapping can be provided when queried.

Below is an example of how you might implement this function for a JUCE VST3 plugin where JUCE_VST3_CAN_REPLACE_VST2 is enabled, but JUCE_FORCE_LEGACY_PARAM_IDS is disabled.

std::map<uint32_t, String> getCompatibleParameterIds (const InterfaceId&) const override
{
    return { { 0, "Frequency" },
             { 1, "CutOff" },
             { 2, "Gain" },
             { 3, "Bypass" } };
}

Parameters

compatibleClass

A plugin identifier, either for the current plugin or one listed in getCompatibleClasses(). This parameter allows the implementation to return a different parameter map for each compatible class. Use convertJucePluginId() and convertVST2PluginId() to determine the class IDs used by JUCE plugins. When JUCE_VST3_CAN_REPLACE_VST2 is set, the InterfaceId denoting the VST2 version of the plugin will match the InterfaceId of the VST3 that replaces it. In this case, you should only include the VST2 mappings in the returned map, assuming there are no collisions between the VST2 parameter indices and the VST3 ParamIDs. In the unlikely event of a collision between the VST2 and VST3 parameter IDs, you should inspect the state that was most recently passed to setStateInformation() to determine whether the host is loading a VST2 state that requires parameter remapping. If you determine that no remapping is necessary, you can indicate this by returning an empty map.

Returns

A map where each key is a VST3 parameter ID in the compatible plugin, and the value is the unique JUCE parameter ID in the current plugin that it should be mapped to.

See also

getCompatibleClasses, convertJucePluginId, convertVST2PluginId, convertJuceParameterId

convertJucePluginId()

static InterfaceId VST3ClientExtensions::convertJucePluginId ( uint32_t manufacturerCode, uint32_t pluginCode, InterfaceType interfaceType = InterfaceType::component )

static

Returns a 16-byte array indicating the VST3 interface ID used for a given JUCE VST3 plugin.

Internally this is what JUCE will use to assign an ID to each VST3 interface, unless JUCE_VST3_CAN_REPLACE_VST2 is enabled.

See also

convertVST2PluginId, getCompatibleClasses, getCompatibleParameterIds

References component.

convertVST2PluginId()

static InterfaceId VST3ClientExtensions::convertVST2PluginId ( uint32_t pluginCode, const String & pluginName, InterfaceType interfaceType = InterfaceType::component )

static

Returns a 16-byte array indicating the VST3 interface ID used for a given VST2 plugin.

Internally JUCE will use this method to assign an ID for the component and controller interfaces when JUCE_VST3_CAN_REPLACE_VST2 is enabled.

See also

convertJucePluginId, getCompatibleClasses, getCompatibleParameterIds

References component.

convertJuceParameterId()

static uint32_t VST3ClientExtensions::convertJuceParameterId ( const String & parameterId, bool studioOneCompatible = true )

static

Returns the VST3 compatible parameter ID reported for a given JUCE parameter.

Internally JUCE will use this method to determine the Vst::ParamID for a HostedAudioProcessorParameter, unless JUCE_FORCE_LEGACY_PARAM_IDS is enabled, in which case it will use the parameter index.

See also

getCompatibleParameterIds

toInterfaceId()

static InterfaceId VST3ClientExtensions::toInterfaceId ( const String & interfaceIdString )

static

Converts a 32-character hex notation string to a VST3 interface ID.