Preliminar "parameter value change request" support

Signed-off-by: falkTX <falktx@falktx.com>

distrho/DistrhoInfo.hpp

@@ -488,20 +488,20 @@ START_NAMESPACE_DISTRHO
 #define DISTRHO_PLUGIN_URI "urn:distrho:name"
 
 /**
-   Wherever the plugin has a custom %UI.
+   Whether the plugin has a custom %UI.
    @see DISTRHO_UI_USE_NANOVG
    @see UI
  */
 #define DISTRHO_PLUGIN_HAS_UI 1
 
 /**
-   Wherever the plugin processing is realtime-safe.@n
+   Whether the plugin processing is realtime-safe.@n
    TODO - list rtsafe requirements
  */
 #define DISTRHO_PLUGIN_IS_RT_SAFE 1
 
 /**
-   Wherever the plugin is a synth.@n
+   Whether the plugin is a synth.@n
    @ref DISTRHO_PLUGIN_WANT_MIDI_INPUT is automatically enabled when this is too.
    @see DISTRHO_PLUGIN_WANT_MIDI_INPUT
  */
@@ -516,39 +516,47 @@ START_NAMESPACE_DISTRHO
 #define DISTRHO_PLUGIN_WANT_DIRECT_ACCESS 0
 
 /**
-   Wherever the plugin introduces latency during audio or midi processing.
+   Whether the plugin introduces latency during audio or midi processing.
    @see Plugin::setLatency(uint32_t)
  */
 #define DISTRHO_PLUGIN_WANT_LATENCY 1
 
 /**
-   Wherever the plugin wants MIDI input.@n
+   Whether the plugin wants MIDI input.@n
    This is automatically enabled if @ref DISTRHO_PLUGIN_IS_SYNTH is true.
  */
 #define DISTRHO_PLUGIN_WANT_MIDI_INPUT 1
 
 /**
-   Wherever the plugin wants MIDI output.
+   Whether the plugin wants MIDI output.
    @see Plugin::writeMidiEvent(const MidiEvent&)
  */
 #define DISTRHO_PLUGIN_WANT_MIDI_OUTPUT 1
 
 /**
-   Wherever the plugin provides its own internal programs.
+   Whether the plugin wants to change its own parameter inputs.@n
+   Not all hosts or plugin formats support this,
+   so Plugin::canRequestParameterValueChanges() can be used to query support at runtime.
+   @see Plugin::requestParameterValueChange(uint32_t, float)
+ */
+#define DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST 1
+
+/**
+   Whether the plugin provides its own internal programs.
    @see Plugin::initProgramName(uint32_t, String&)
    @see Plugin::loadProgram(uint32_t)
  */
 #define DISTRHO_PLUGIN_WANT_PROGRAMS 1
 
 /**
-   Wherever the plugin uses internal non-parameter data.
+   Whether the plugin uses internal non-parameter data.
    @see Plugin::initState(uint32_t, String&, String&)
    @see Plugin::setState(const char*, const char*)
  */
 #define DISTRHO_PLUGIN_WANT_STATE 1
 
 /**
-   Wherever the plugin implements the full state API.
+   Whether the plugin implements the full state API.
    When this macro is enabled, the plugin must implement a new getState(const char* key) function, which the host calls when saving its session/project.
    This is useful for plugins that have custom internal values not exposed to the host as key-value state pairs or parameters.
    Most simple effects and synths will not need this.
@@ -558,13 +566,13 @@ START_NAMESPACE_DISTRHO
 #define DISTRHO_PLUGIN_WANT_FULL_STATE 1
 
 /**
-   Wherever the plugin wants time position information from the host.
+   Whether the plugin wants time position information from the host.
    @see Plugin::getTimePosition()
  */
 #define DISTRHO_PLUGIN_WANT_TIMEPOS 1
 
 /**
-   Wherever the %UI uses a custom toolkit implementation based on OpenGL.@n
+   Whether the %UI uses a custom toolkit implementation based on OpenGL.@n
    When enabled, the macros @ref DISTRHO_UI_CUSTOM_INCLUDE_PATH and @ref DISTRHO_UI_CUSTOM_WIDGET_TYPE are required.
  */
 #define DISTRHO_UI_USE_CUSTOM 1
@@ -586,13 +594,13 @@ START_NAMESPACE_DISTRHO
 #define DISTRHO_UI_CUSTOM_WIDGET_TYPE
 
 /**
-   Wherever the %UI uses NanoVG for drawing instead of the default raw OpenGL calls.@n
+   Whether the %UI uses NanoVG for drawing instead of the default raw OpenGL calls.@n
    When enabled your %UI instance will subclass @ref NanoWidget instead of @ref Widget.
  */
 #define DISTRHO_UI_USE_NANOVG 1
 
 /**
-   Wherever the %UI is resizable to any size by the user.@n
+   Whether the %UI is resizable to any size by the user.@n
    By default this is false, and resizing is only allowed under the plugin UI control,@n
    Enabling this options makes it possible for the user to resize the plugin UI at anytime.
    @see UI::setGeometryConstraints(uint, uint, bool, bool)

distrho/DistrhoPlugin.hpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -746,6 +746,22 @@ public:
     bool writeMidiEvent(const MidiEvent& midiEvent) noexcept;
 #endif
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+   /**
+      Check if parameter value change requests will work with the current plugin host.
+      @note This function is only available if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST is enabled.
+    */
+    bool canRequestParameterValueChanges() const noexcept;
+
+   /**
+      Request a parameter value change from the host.
+      This function can fail, for example if the host is busy with the parameter for read-only automation.
+      Some hosts simply do not have this functionality, which can be verified with canRequestParameterValueChanges().
+      @note This function is only available if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST is enabled.
+    */
+    bool requestParameterValueChange(uint32_t index, float value) noexcept;
+#endif
+
 protected:
    /* --------------------------------------------------------------------------------------------------------
     * Information */

distrho/src/DistrhoPlugin.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2018 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -109,6 +109,18 @@ bool Plugin::writeMidiEvent(const MidiEvent& midiEvent) noexcept
 }
 #endif
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+bool Plugin::canRequestParameterValueChanges() const noexcept
+{
+    return pData->requestParameterValueChangeCallbackFunc != nullptr;
+}
+
+bool Plugin::requestParameterValueChange(const uint32_t index, const float value) noexcept
+{
+    return pData->requestParameterValueChangeCallback(index, value);
+}
+#endif
+
 /* ------------------------------------------------------------------------------------------------------------
  * Init */
 

distrho/src/DistrhoPluginCarla.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2018 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -22,6 +22,10 @@
 
 #include "CarlaNative.hpp"
 
+// TODO
+#undef DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+#define DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST 0
+
 // -----------------------------------------------------------------------
 
 START_NAMESPACE_DISTRHO
@@ -29,6 +33,9 @@ START_NAMESPACE_DISTRHO
 #if ! DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
 static const writeMidiFunc writeMidiCallback = nullptr;
 #endif
+#if ! DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+static const requestParameterValueChangeFunc requestParameterValueChangeCallback = nullptr;
+#endif
 
 #if DISTRHO_PLUGIN_HAS_UI
 // -----------------------------------------------------------------------
@@ -184,7 +191,7 @@ class PluginCarla : public NativePluginClass
 public:
     PluginCarla(const NativeHostDescriptor* const host)
         : NativePluginClass(host),
-          fPlugin(this, writeMidiCallback),
+          fPlugin(this, writeMidiCallback, requestParameterValueChangeCallback),
           fScalePointsCache(nullptr)
     {
 #if DISTRHO_PLUGIN_HAS_UI
@@ -512,6 +519,19 @@ private:
     }
 #endif
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+    bool requestParameterValueChange(const uint32_t index, const float value)
+    {
+        // TODO implementation
+        return false;
+    }
+
+    static bool requestParameterValueChangeCallback(void* ptr, const uint32_t index, const float value)
+    {
+        return thisPtr->requestParameterValueChange(index, value);
+    }
+#endif
+
     CARLA_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginCarla)
 
     // -------------------------------------------------------------------

distrho/src/DistrhoPluginChecks.h

@@ -69,6 +69,10 @@
 # define DISTRHO_PLUGIN_WANT_MIDI_OUTPUT 0
 #endif
 
+#ifndef DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+# define DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST 0
+#endif
+
 #ifndef DISTRHO_PLUGIN_WANT_PROGRAMS
 # define DISTRHO_PLUGIN_WANT_PROGRAMS 0
 #endif

distrho/src/DistrhoPluginInternal.hpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2018 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -36,6 +36,7 @@ extern double   d_lastSampleRate;
 // DSP callbacks
 
 typedef bool (*writeMidiFunc) (void* ptr, const MidiEvent& midiEvent);
+typedef bool (*requestParameterValueChangeFunc) (void* ptr, uint32_t index, float value);
 
 // -----------------------------------------------------------------------
 // Plugin private data
@@ -73,6 +74,7 @@ struct Plugin::PrivateData {
     // Callbacks
     void*         callbacksPtr;
     writeMidiFunc writeMidiCallbackFunc;
+    requestParameterValueChangeFunc requestParameterValueChangeCallbackFunc;
 
     uint32_t bufferSize;
     double   sampleRate;
@@ -99,6 +101,7 @@ struct Plugin::PrivateData {
 #endif
           callbacksPtr(nullptr),
           writeMidiCallbackFunc(nullptr),
+          requestParameterValueChangeCallbackFunc(nullptr),
           bufferSize(d_lastBufferSize),
           sampleRate(d_lastSampleRate)
     {
@@ -170,6 +173,16 @@ struct Plugin::PrivateData {
         return false;
     }
 #endif
+
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+    bool requestParameterValueChangeCallback(const uint32_t index, const float value)
+    {
+        if (requestParameterValueChangeCallbackFunc != nullptr)
+            return requestParameterValueChangeCallbackFunc(callbacksPtr, index, value);
+
+        return false;
+    }
+#endif
 };
 
 // -----------------------------------------------------------------------
@@ -178,7 +191,9 @@ struct Plugin::PrivateData {
 class PluginExporter
 {
 public:
-    PluginExporter(void* const callbacksPtr, const writeMidiFunc writeMidiCall)
+    PluginExporter(void* const callbacksPtr,
+                   const writeMidiFunc writeMidiCall,
+                   const requestParameterValueChangeFunc requestParameterValueChangeCall)
         : fPlugin(createPlugin()),
           fData((fPlugin != nullptr) ? fPlugin->pData : nullptr),
           fIsActive(false)
@@ -213,8 +228,9 @@ public:
             fPlugin->initState(i, fData->stateKeys[i], fData->stateDefValues[i]);
 #endif
 
-        fData->callbacksPtr          = callbacksPtr;
+        fData->callbacksPtr = callbacksPtr;
         fData->writeMidiCallbackFunc = writeMidiCall;
+        fData->requestParameterValueChangeCallbackFunc = requestParameterValueChangeCall;
     }
 
     ~PluginExporter()

distrho/src/DistrhoPluginJack.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -31,6 +31,10 @@
 # include <signal.h>
 #endif
 
+// TODO
+#undef DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+#define DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST 0
+
 // -----------------------------------------------------------------------
 
 START_NAMESPACE_DISTRHO
@@ -41,6 +45,9 @@ static const setStateFunc setStateCallback = nullptr;
 #if ! DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
 static const writeMidiFunc writeMidiCallback = nullptr;
 #endif
+#if ! DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+static const requestParameterValueChangeFunc requestParameterValueChangeCallback = nullptr;
+#endif
 
 // -----------------------------------------------------------------------
 
@@ -90,7 +97,7 @@ class PluginJack
 {
 public:
     PluginJack(jack_client_t* const client)
-        : fPlugin(this, writeMidiCallback),
+        : fPlugin(this, writeMidiCallback, requestParameterValueChangeCallback),
 #if DISTRHO_PLUGIN_HAS_UI
           fUI(this, 0,
               nullptr, // edit param
@@ -472,18 +479,6 @@ protected:
     }
 #endif
 
-#if DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
-    bool writeMidi(const MidiEvent& midiEvent)
-    {
-        DISTRHO_SAFE_ASSERT_RETURN(fPortMidiOutBuffer != nullptr, false);
-
-        return jack_midi_event_write(fPortMidiOutBuffer,
-                                     midiEvent.frame,
-                                     midiEvent.size > MidiEvent::kDataSize ? midiEvent.dataExt : midiEvent.data,
-                                     midiEvent.size) == 0;
-    }
-#endif
-
     // NOTE: no trigger support for JACK, simulate it here
     void updateParameterTriggers()
     {
@@ -584,7 +579,30 @@ private:
     }
 #endif
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+    bool requestParameterValueChange(const uint32_t index, const float value)
+    {
+        // TODO implementation
+        return false;
+    }
+
+    static bool requestParameterValueChangeCallback(void* ptr, const uint32_t index, const float value)
+    {
+        return thisPtr->requestParameterValueChange(index, value);
+    }
+#endif
+
 #if DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
+    bool writeMidi(const MidiEvent& midiEvent)
+    {
+        DISTRHO_SAFE_ASSERT_RETURN(fPortMidiOutBuffer != nullptr, false);
+
+        return jack_midi_event_write(fPortMidiOutBuffer,
+                                     midiEvent.frame,
+                                     midiEvent.size > MidiEvent::kDataSize ? midiEvent.dataExt : midiEvent.data,
+                                     midiEvent.size) == 0;
+    }
+
     static bool writeMidiCallback(void* ptr, const MidiEvent& midiEvent)
     {
         return thisPtr->writeMidi(midiEvent);

distrho/src/DistrhoPluginLADSPA+DSSI.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -16,6 +16,9 @@
 
 #include "DistrhoPluginInternal.hpp"
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+# error Cannot use parameter value change request with LADSPA or DSSI
+#endif
 #if DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
 # error Cannot use MIDI Output with LADSPA or DSSI
 #endif
@@ -47,7 +50,7 @@ class PluginLadspaDssi
 {
 public:
     PluginLadspaDssi()
-        : fPlugin(nullptr, nullptr),
+        : fPlugin(nullptr, nullptr, nullptr),
           fPortControls(nullptr),
           fLastControlValues(nullptr)
     {
@@ -550,7 +553,7 @@ static const struct DescriptorInitializer
         // Create dummy plugin to get data from
         d_lastBufferSize = 512;
         d_lastSampleRate = 44100.0;
-        const PluginExporter plugin(nullptr, nullptr);
+        const PluginExporter plugin(nullptr, nullptr, nullptr);
         d_lastBufferSize = 0;
         d_lastSampleRate = 0.0;
 

distrho/src/DistrhoPluginLV2.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -31,6 +31,7 @@
 #include "lv2/worker.h"
 #include "lv2/lv2_kxstudio_properties.h"
 #include "lv2/lv2_programs.h"
+#include "lv2/control-input-port-change-request.h"
 
 #ifdef DISTRHO_PLUGIN_LICENSED_FOR_MOD
 # include "libmodla.h"
@@ -61,6 +62,9 @@ typedef std::map<const LV2_URID, String> UridToStringMap;
 #if ! DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
 static const writeMidiFunc writeMidiCallback = nullptr;
 #endif
+#if ! DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+static const requestParameterValueChangeFunc requestParameterValueChangeCallback = nullptr;
+#endif
 
 // -----------------------------------------------------------------------
 
@@ -70,8 +74,9 @@ public:
     PluginLv2(const double sampleRate,
               const LV2_URID_Map* const uridMap,
               const LV2_Worker_Schedule* const worker,
+              const LV2_ControlInputPort_Change_Request* const ctrlInPortChangeReq,
               const bool usingNominal)
-        : fPlugin(this, writeMidiCallback),
+        : fPlugin(this, writeMidiCallback, requestParameterValueChangeCallback),
           fUsingNominal(usingNominal),
 #ifdef DISTRHO_PLUGIN_LICENSED_FOR_MOD
           fRunCount(0),
@@ -81,7 +86,8 @@ public:
           fSampleRate(sampleRate),
           fURIDs(uridMap),
           fUridMap(uridMap),
-          fWorker(worker)
+          fWorker(worker),
+          fCtrlInPortChangeReq(ctrlInPortChangeReq)
     {
 #if DISTRHO_PLUGIN_NUM_INPUTS > 0
         for (uint32_t i=0; i < DISTRHO_PLUGIN_NUM_INPUTS; ++i)
@@ -1174,6 +1180,7 @@ private:
     // LV2 features
     const LV2_URID_Map* const fUridMap;
     const LV2_Worker_Schedule* const fWorker;
+    const LV2_ControlInputPort_Change_Request* const fCtrlInPortChangeReq;
 
 #if DISTRHO_PLUGIN_WANT_STATE
     StringToStringMap fStateMap;
@@ -1231,6 +1238,20 @@ private:
 #endif
     }
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+    bool requestParameterValueChange(const uint32_t index, const float value)
+    {
+        if (fCtrlInPortChangeReq == nullptr)
+            return false;
+        return fCtrlInPortChangeReq->request_change(fCtrlInPortChangeReq->handle, index, value);
+    }
+
+    static bool requestParameterValueChangeCallback(void* const ptr, const uint32_t index, const float value)
+    {
+        return (((PluginLv2*)ptr)->requestParameterValueChange(index, value) == 0);
+    }
+#endif
+
 #if DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
     bool writeMidi(const MidiEvent& midiEvent)
     {
@@ -1271,6 +1292,7 @@ static LV2_Handle lv2_instantiate(const LV2_Descriptor*, double sampleRate, cons
     const LV2_Options_Option* options = nullptr;
     const LV2_URID_Map*       uridMap = nullptr;
     const LV2_Worker_Schedule* worker = nullptr;
+    const LV2_ControlInputPort_Change_Request* ctrlInPortChangeReq = nullptr;
 
     for (int i=0; features[i] != nullptr; ++i)
     {
@@ -1280,6 +1302,8 @@ static LV2_Handle lv2_instantiate(const LV2_Descriptor*, double sampleRate, cons
             uridMap = (const LV2_URID_Map*)features[i]->data;
         else if (std::strcmp(features[i]->URI, LV2_WORKER__schedule) == 0)
             worker = (const LV2_Worker_Schedule*)features[i]->data;
+        else if (std::strcmp(features[i]->URI, LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_URI) == 0)
+            ctrlInPortChangeReq = (const LV2_ControlInputPort_Change_Request*)features[i]->data;
     }
 
     if (options == nullptr)
@@ -1344,7 +1368,7 @@ static LV2_Handle lv2_instantiate(const LV2_Descriptor*, double sampleRate, cons
 
     d_lastSampleRate = sampleRate;
 
-    return new PluginLv2(sampleRate, uridMap, worker, usingNominal);
+    return new PluginLv2(sampleRate, uridMap, worker, ctrlInPortChangeReq, usingNominal);
 }
 
 #define instancePtr ((PluginLv2*)instance)

distrho/src/DistrhoPluginLV2export.cpp

@@ -226,7 +226,7 @@ void lv2_generate_ttl(const char* const basename)
     // Dummy plugin to get data from
     d_lastBufferSize = 512;
     d_lastSampleRate = 44100.0;
-    PluginExporter plugin(nullptr, nullptr);
+    PluginExporter plugin(nullptr, nullptr, nullptr);
     d_lastBufferSize = 0;
     d_lastSampleRate = 0.0;
 

distrho/src/DistrhoPluginVST.cpp

@@ -25,7 +25,7 @@
 #if DISTRHO_PLUGIN_HAS_UI
 # undef DISTRHO_UI_USER_RESIZABLE
 # define DISTRHO_UI_USER_RESIZABLE 0
-# define DISTRHO_UI_IS_STANDALONE 0
+# define DISTRHO_UI_IS_STANDALONE false
 # include "DistrhoUIInternal.hpp"
 #endif
 
@@ -73,6 +73,9 @@ static const int kVstMidiEventSize = static_cast<int>(sizeof(VstMidiEvent));
 #if ! DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
 static const writeMidiFunc writeMidiCallback = nullptr;
 #endif
+#if ! DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+static const requestParameterValueChangeFunc requestParameterValueChangeCallback = nullptr;
+#endif
 
 // -----------------------------------------------------------------------
 
@@ -429,7 +432,7 @@ class PluginVst : public ParameterCheckHelper
 {
 public:
     PluginVst(const audioMasterCallback audioMaster, AEffect* const effect)
-        : fPlugin(this, writeMidiCallback),
+        : fPlugin(this, writeMidiCallback, requestParameterValueChangeCallback),
           fAudioMaster(audioMaster),
           fEffect(effect)
     {
@@ -1184,6 +1187,19 @@ private:
     }
 #endif
 
+#if DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
+    bool requestParameterValueChange(const uint32_t index, const float value)
+    {
+        hostCallback(audioMasterAutomate, index, 0, nullptr, value);
+        return true;
+    }
+
+    static bool requestParameterValueChangeCallback(void* const ptr, const uint32_t index, const float value)
+    {
+        return ((PluginVst*)ptr)->requestParameterValueChange(index, value);
+    }
+#endif
+
 #if DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
     bool writeMidi(const MidiEvent& midiEvent)
     {
@@ -1273,7 +1289,7 @@ static intptr_t vst_dispatcherCallback(AEffect* effect, int32_t opcode, int32_t
     }
 
     // Create dummy plugin to get data from
-    static PluginExporter plugin(nullptr, nullptr);
+    static PluginExporter plugin(nullptr, nullptr, nullptr);
 
     if (doInternalInit)
     {

distrho/src/DistrhoUIDSSI.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2016 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -14,7 +14,7 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define DISTRHO_UI_IS_STANDALONE 1
+#define DISTRHO_UI_IS_STANDALONE true
 #include "DistrhoUIInternal.hpp"
 
 #if DISTRHO_PLUGIN_WANT_DIRECT_ACCESS

distrho/src/DistrhoUILV2.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -14,7 +14,7 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define DISTRHO_UI_IS_STANDALONE 0
+#define DISTRHO_UI_IS_STANDALONE false
 #include "DistrhoUIInternal.hpp"
 
 #include "../extra/String.hpp"

distrho/src/lv2/control-input-port-change-request.h

@@ -0,0 +1,84 @@
+/*
+  LV2 ControlInputPort change request extension
+  Copyright 2020 Filipe Coelho <falktx@falktx.com>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+/**
+   @file control-input-port-change-request.h
+   C header for the LV2 ControlInputPort change request extension <http://kx.studio/ns/lv2ext/control-input-port-change-request>.
+*/
+
+#ifndef LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_H
+#define LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_H
+
+#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
+
+#define LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_URI    "http://kx.studio/ns/lv2ext/control-input-port-change-request"
+#define LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_PREFIX LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_URI "#"
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#else
+#include <stdbool.h>
+#endif
+
+/** A status code for LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_URI functions. */
+typedef enum {
+	LV2_CONTROL_INPUT_PORT_CHANGE_SUCCESS           = 0,  /**< Completed successfully. */
+	LV2_CONTROL_INPUT_PORT_CHANGE_ERR_UNKNOWN       = 1,  /**< Unknown error. */
+	LV2_CONTROL_INPUT_PORT_CHANGE_ERR_INVALID_INDEX = 2   /**< Failed due to invalid port index. */
+} LV2_ControlInputPort_Change_Status;
+
+/**
+ *  Opaque handle for LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_URI feature.
+ */
+typedef void* LV2_ControlInputPort_Change_Request_Handle;
+
+/**
+ * On instantiation, host must supply LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_URI feature.
+ * LV2_Feature::data must be pointer to LV2_ControlInputPort_Change_Request.
+*/
+typedef struct _LV2_ControlInputPort_Change_Request {
+    /**
+     *  Opaque host data.
+     */
+    LV2_ControlInputPort_Change_Request_Handle handle;
+
+    /**
+     * request_change()
+     *
+     * Ask the host to change a plugin's control input port value.
+     * Parameter handle MUST be the 'handle' member of this struct.
+     * Parameter index is port index to change.
+     * Parameter value is the requested value to change the control port input to.
+     *
+     * Returns status of the request.
+     * The host may decline this request, if e.g. it is currently automating this port.
+     *
+     * The plugin MUST call this function during run().
+     */
+    LV2_ControlInputPort_Change_Status (*request_change)(LV2_ControlInputPort_Change_Request_Handle handle,
+                                                         uint32_t index,
+                                                         float value);
+
+} LV2_ControlInputPort_Change_Request;
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* LV2_CONTROL_INPUT_PORT_CHANGE_REQUEST_H */