VST3: Add support for defining a custom VST3 component class ID

modules/juce_audio_processors_headless/utilities/juce_VST3ClientExtensions.h

@@ -220,10 +220,42 @@ private:
 };
 
 #if DOXYGEN
+ /** An optional user defined preprocessor definition for declaring the VST3
+     plugin identifier as used by the host.
+
+     This is useful if you're creating a VST3 plugin using JUCE that needs to
+     replace a VST3 plugin that was not originally created using JUCE.
+
+     If there are multiple identifiers this plugin needs to replace take a look
+     at JUCE_VST3_COMPATIBLE_CLASSES. If required, both preprocessor definitions
+     can be used in combination for maximum compatibility.
+
+     The definition of this preprocessor must be defined at the project
+     level, normally in your CMake or Projucer project files.
+
+     If JUCE_VST3_CAN_REPLACE_VST2 is enabled, the VST3 plugin will have the
+     same identifier as the VST2 plugin and therefore this preprocessor
+     definition will have no effect!
+
+     This preprocessor definition should be defined as a string containing 32
+     hex characters, for example...
+
+     @code
+     JUCE_VST3_COMPONENT_CLASS="0F1E2D3C4B5A69788796A5B4C3D2E1F0"
+     @endcode
+
+     @see JUCE_VST3_COMPONENT_CLASS
+ */
+ #define JUCE_VST3_COMPONENT_CLASS
+
  /** An optional user defined preprocessor definition for declaring a comma
      separated list of VST2 and VST3 plugin identifiers that this VST3 plugin
      can replace in a DAW session.
 
+     At the time of writing not all hosts support this feature, if you don't
+     have multiple plugins with different identifiers already released, consider
+     using JUCE_VST3_COMPONENT_CLASS instead.
+
      The definition of this preprocessor must be defined at the project
      level, normally in your CMake or Projucer project files.
 
@@ -265,7 +297,7 @@ private:
      If the parameter IDs between compatible versions differ
      VST3ClientExtensions::getCompatibleParameterIds() should also be overridden.
 
-     @see VST3Interface VST3ClientExtensions::getCompatibleParameterIds()
+     @see JUCE_VST3_COMPONENT_CLASS, VST3Interface, VST3ClientExtensions::getCompatibleParameterIds()
  */
  #define JUCE_VST3_COMPATIBLE_CLASSES
 #endif // DOXYGEN

modules/juce_audio_processors_headless/utilities/juce_VST3Interface.h

@@ -117,18 +117,76 @@ struct VST3Interface
         return iid;
     }
 
+    /** Converts a 32-character hex notation string to a VST3 interface ID.
+
+        @see jucePluginId, vst2PluginId
+     */
+    static inline Id hexStringToId (const char* hex)
+    {
+        jassert (std::strlen (hex) == 32);
+
+        const auto getByteValue = [](const char* str)
+        {
+            const auto getCharacterValue = [](const char c)
+            {
+                if (c >= '0' && c <= '9')
+                    return (std::byte) (c - '0');
+
+                if (c >= 'A' && c <= 'F')
+                    return (std::byte) (c - 'A' + 10);
+
+                if (c >= 'a' && c <= 'f')
+                    return (std::byte) (c - 'a' + 10);
+
+                // Invalid hex character!
+                jassertfalse;
+                return std::byte{};
+            };
+
+            return getCharacterValue (str[0]) << 4
+                 | getCharacterValue (str[1]);
+        };
+
+        return { getByteValue (hex),
+                 getByteValue (hex + 2),
+                 getByteValue (hex + 4),
+                 getByteValue (hex + 6),
+                 getByteValue (hex + 8),
+                 getByteValue (hex + 10),
+                 getByteValue (hex + 12),
+                 getByteValue (hex + 14),
+                 getByteValue (hex + 16),
+                 getByteValue (hex + 18),
+                 getByteValue (hex + 20),
+                 getByteValue (hex + 22),
+                 getByteValue (hex + 24),
+                 getByteValue (hex + 26),
+                 getByteValue (hex + 28),
+                 getByteValue (hex + 30) };
+    }
+
     /** 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 vst2PluginId, hexStringToId
+        If JUCE_VST3_COMPONENT_CLASS is defined it will return this value when the
+        interface type is Type::component. This is useful if you're releasing a
+        VST3 plugin with JUCE that needs to replace a version of a VST3 plugin
+        that wasn't originally built using JUCE.
+
+        @see vst2PluginId, hexStringToId, JUCE_VST3_COMPONENT_CLASS
     */
     static inline Id jucePluginId (uint32_t manufacturerCode,
                                    uint32_t pluginCode,
                                    Type interfaceType = Type::component)
     {
+       #ifdef JUCE_VST3_COMPONENT_CLASS
+        if (interfaceType == Type::component)
+            return hexStringToId ( JUCE_VST3_COMPONENT_CLASS );
+       #endif
+
         const auto word0 = std::invoke ([&]() -> uint32_t
         {
             switch (interfaceType)
@@ -194,54 +252,6 @@ struct VST3Interface
         };
     }
 
-    /** Converts a 32-character hex notation string to a VST3 interface ID.
-
-        @see jucePluginId, vst2PluginId
-     */
-    static inline Id hexStringToId (const char* hex)
-    {
-        jassert (std::strlen (hex) == 32);
-
-        const auto getByteValue = [](const char* str)
-        {
-            const auto getCharacterValue = [](const char c)
-            {
-                if (c >= '0' && c <= '9')
-                    return (std::byte) (c - '0');
-
-                if (c >= 'A' && c <= 'F')
-                    return (std::byte) (c - 'A' + 10);
-
-                if (c >= 'a' && c <= 'f')
-                    return (std::byte) (c - 'a' + 10);
-
-                // Invalid hex character!
-                jassertfalse;
-                return std::byte{};
-            };
-
-            return getCharacterValue (str[0]) << 4
-                 | getCharacterValue (str[1]);
-        };
-
-        return { getByteValue (hex),
-                 getByteValue (hex + 2),
-                 getByteValue (hex + 4),
-                 getByteValue (hex + 6),
-                 getByteValue (hex + 8),
-                 getByteValue (hex + 10),
-                 getByteValue (hex + 12),
-                 getByteValue (hex + 14),
-                 getByteValue (hex + 16),
-                 getByteValue (hex + 18),
-                 getByteValue (hex + 20),
-                 getByteValue (hex + 22),
-                 getByteValue (hex + 24),
-                 getByteValue (hex + 26),
-                 getByteValue (hex + 28),
-                 getByteValue (hex + 30) };
-    }
-
     VST3Interface() = delete;
 };