VU VST

plugin/CMakeLists.txt

@@ -57,6 +57,7 @@ function(add_prism_scope TARGET PRODUCT PLUGIN_CODE SCOPE_DEFINE)
         Source/PluginEditor.cpp
         ${PRISM_NATIVE_DIR}/spectrum.cpp
         ${PRISM_NATIVE_DIR}/oscilloscope.cpp
+        ${PRISM_NATIVE_DIR}/vumeter.cpp
         ${PRISM_NATIVE_DIR}/dsp_utils.cpp)
 
     target_include_directories(${TARGET} PRIVATE Source ${PRISM_NATIVE_DIR})
@@ -94,3 +95,4 @@ endfunction()
 
 add_prism_scope(PrismSpectrum     "Prism Spectrum"     Pspc "")
 add_prism_scope(PrismOscilloscope "Prism Oscilloscope" Posc "PRISM_SCOPE_OSCILLOSCOPE=1")
+add_prism_scope(PrismVUMeter      "Prism VU Meter"     Pvum "PRISM_SCOPE_VUMETER=1")

plugin/Source/PluginEditor.cpp

@@ -1,6 +1,7 @@
 #include "PluginEditor.h"
 #include "SpectrumEngine.h"
 #include "OscilloscopeEngine.h"
+#include "VUMeterEngine.h"
 #include <cstring>
 
 #if ! PRISM_USE_DEV_SERVER
@@ -18,7 +19,9 @@ namespace
 
     std::unique_ptr<ScopeEngine> makeEngine()
     {
-#if defined(PRISM_SCOPE_OSCILLOSCOPE) && PRISM_SCOPE_OSCILLOSCOPE
+#if defined(PRISM_SCOPE_VUMETER) && PRISM_SCOPE_VUMETER
+        return std::make_unique<VUMeterEngine>();
+#elif defined(PRISM_SCOPE_OSCILLOSCOPE) && PRISM_SCOPE_OSCILLOSCOPE
         return std::make_unique<OscilloscopeEngine>();
 #else
         return std::make_unique<SpectrumEngine>();

plugin/Source/VUMeterEngine.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include "ScopeEngine.h"
+#include "vumeter.h"   // reused, unmodified, from native/src
+
+/**
+ * VU meter engine. Pushes stereo audio into the reused `Visualizer::VUMeterAnalyzer`
+ * (RMS integration + ballistics + peak hold + correlation, all sample-accurate) and
+ * emits the resulting scalar snapshot each frame. No base64 needed — the frame is a
+ * handful of numbers. getSnapshot() advances peak decay on the steady clock, so the
+ * meter still settles when audio momentarily stops.
+ */
+class VUMeterEngine : public ScopeEngine
+{
+public:
+    const char* scopeId() const override { return "vumeter"; }
+    juce::Identifier frameEventId() const override { return frameId; }
+
+    void setSampleRate(double sampleRate) override
+    {
+        vu.setSampleRate((float) sampleRate);
+    }
+
+    void configure(const juce::var&) override
+    {
+        // VU settings (mode/orientation/needleChannels/referenceDb) are render-side only.
+    }
+
+    void process(const float* left, const float* right, int numSamples) override
+    {
+        if (numSamples <= 0)
+            return;
+        vu.pushSamples(left, right, (size_t) numSamples);
+    }
+
+    juce::var buildFrame(double sampleRate) override
+    {
+        const auto snap = vu.getSnapshot();
+        auto* obj = new juce::DynamicObject();
+        obj->setProperty("sampleRate", sampleRate);
+        obj->setProperty("vuLDb", snap.vuLDb);
+        obj->setProperty("vuRDb", snap.vuRDb);
+        obj->setProperty("barLDb", snap.barLDb);
+        obj->setProperty("barRDb", snap.barRDb);
+        obj->setProperty("peakLDb", snap.peakLDb);
+        obj->setProperty("peakRDb", snap.peakRDb);
+        obj->setProperty("correlation", snap.correlation);
+        return juce::var(obj);
+    }
+
+private:
+    const juce::Identifier frameId { "vumeterFrame" };
+    Visualizer::VUMeterAnalyzer vu;
+};