Add the effSetProcessPrecision opcode

src/common/logging/vst2.cpp

@@ -165,6 +165,9 @@ std::optional<std::string> opcode_to_string(bool is_dispatch, int opcode) {
             case effGetTailSize:
                 return "effGetTailSize";
                 break;
+            case effSetProcessPrecision:
+                return "effSetProcessPrecision";
+                break;
             default:
                 return std::nullopt;
                 break;

src/common/vst24.h

@@ -69,6 +69,26 @@
  */
 [[maybe_unused]] constexpr int effGetTailSize = 52;
 
+/**
+ * Used to indicate that the plugin is going to receive double precision audio.
+ * The name was found on the JUCE VST2 implementation linked above. REAPER seems
+ * to call this function with value set to 1 when loading a plugin that supports
+ * 64-bit double precision audio.
+ */
+[[maybe_unused]] constexpr int effSetProcessPrecision = 77;
+
+/**
+ * When passed to `effSetProcessPrecision` as the value argument, indicates that
+ * the plugin gets to process 32-bit audio. Name glanced from
+ * https://github.com/juce-framework/JUCE/blob/c0f18670f45d268ad9557bd639f14b374ce38e65/modules/juce_audio_plugin_client/VST/juce_VST_Wrapper.cpp#L1983.
+ */
+[[maybe_unused]] constexpr int kVstProcessPrecision64 = 1;
+/**
+ * Logically if 64-bit audio gets a value of 1, regular old 32-bit audio will be
+ * 0.
+ */
+[[maybe_unused]] constexpr int kVstProcessPrecision32 = 0;
+
 /**
  * The struct that's being passed through the data parameter during the
  * `effGetInputProperties` and `effGetOutputProperties` opcodes. Reverse

src/plugin/bridges/vst2.cpp

@@ -302,6 +302,7 @@ class DispatchDataConverter : public DefaultDataConverter {
             case effEndSetProgram:
             case effStartProcess:
             case effStopProcess:
+            case effSetProcessPrecision:
                 return nullptr;
             default:
                 return DefaultDataConverter::read_data(opcode, index, value,