spectrogram VST

2026-08-12 13:20:53 +02:00 · 2026-05-27 19:56:09 -04:00
parent 7da5f62c5e
commit 4de676a8ad
11 changed files with 453 additions and 3 deletions
@@ -0,0 +1,121 @@
+#pragma once
+
+#include "ScopeEngine.h"
+#include "spectrogram.h"   // reused, unmodified, from native/src
+#include <vector>
+#include <algorithm>
+
+/**
+ * Spectrogram engine. The reused Visualizer::SpectrogramAnalyzer runs in C++ and
+ * produces finished display+heat columns. Unlike the other scopes, its DSP needs
+ * the canvas-derived rowCount (and fft/freq/db/scale/orientation), which only the
+ * webview knows — the UI pushes the full native config via "prismSpectrogramConfig",
+ * routed here through configureNative(). process() mixes to mono and runs the DSP;
+ * buildFrame() emits the columns produced since the last frame (base64) tagged with
+ * rowCount, so the bridge can match them to the config the UI currently expects.
+ * configure() (scope settings) is a no-op — every DSP parameter arrives in the
+ * native config. The host sample rate (from setSampleRate) overrides whatever the
+ * UI believed, so frequency mapping is always correct.
+ */
+class SpectrogramEngine : public ScopeEngine
+{
+public:
+    const char* scopeId() const override { return "spectrogram"; }
+    juce::Identifier frameEventId() const override { return frameId; }
+
+    void setSampleRate(double sampleRate) override
+    {
+        if (sampleRate > 0.0 && (float) sampleRate != config.sampleRate)
+        {
+            config.sampleRate = (float) sampleRate;
+            if (hasConfig)
+                spectro.configure(config);
+        }
+    }
+
+    void configure(const juce::var&) override {}
+
+    void configureNative(const juce::var& opts) override
+    {
+        if (! opts.isObject())
+            return;
+
+        config.fftSize         = (size_t) std::max(0, (int) opts.getProperty("fftSize", 4096));
+        config.rowCount        = (size_t) std::max(0, (int) opts.getProperty("rowCount", 0));
+        config.minFrequency    = (float) opts.getProperty("minFrequency", 20.0);
+        config.maxFrequency    = (float) opts.getProperty("maxFrequency", 20000.0);
+        config.minDecibels     = (float) opts.getProperty("minDecibels", -90.0);
+        config.maxDecibels     = (float) opts.getProperty("maxDecibels", -12.0);
+        config.scrollSpeed     = (float) opts.getProperty("scrollSpeed", 2.0);
+        config.contrast        = (float) opts.getProperty("contrast", 1.0);
+        config.tiltDbPerOctave = (float) opts.getProperty("tiltDbPerOctave", 4.0);
+        config.clarityMode     = opts.getProperty("clarityMode", "sharper").toString().toStdString();
+        config.scaleMode       = opts.getProperty("scaleMode", "log").toString().toStdString();
+        config.orientation     = opts.getProperty("orientation", "horizontal").toString().toStdString();
+
+        // Host rate (from setSampleRate) is authoritative; the UI may still hold a
+        // stale default before it has seen a frame. Only fall back to the UI value
+        // if we have not yet learned the host rate.
+        if (config.sampleRate <= 0.0f)
+            config.sampleRate = (float) opts.getProperty("sampleRate", 48000.0);
+
+        hasConfig = config.rowCount > 0 && config.fftSize > 0;
+        if (hasConfig)
+            spectro.configure(config);
+
+        // The config changed: drop any half-built column batch so the next frame
+        // starts clean at the new rowCount.
+        pendingDisplay.clear();
+        pendingHeat.clear();
+        pendingColumns = 0;
+    }
+
+    void process(const float* left, const float* right, int numSamples) override
+    {
+        if (! hasConfig || numSamples <= 0)
+            return;
+        if ((int) mono.size() < numSamples)
+            mono.resize((size_t) numSamples);
+        for (int i = 0; i < numSamples; ++i)
+            mono[(size_t) i] = 0.5f * (left[i] + right[i]);
+
+        auto result = spectro.process(mono.data(), (size_t) numSamples);
+        if (result.columnCount > 0 && result.rowCount == config.rowCount)
+        {
+            pendingDisplay.insert(pendingDisplay.end(), result.display.begin(), result.display.end());
+            pendingHeat.insert(pendingHeat.end(), result.heat.begin(), result.heat.end());
+            pendingColumns += result.columnCount;
+        }
+    }
+
+    juce::var buildFrame(double sampleRate) override
+    {
+        auto* obj = new juce::DynamicObject();
+        obj->setProperty("sampleRate", sampleRate);
+        obj->setProperty("rowCount", (int) config.rowCount);
+        obj->setProperty("columnCount", (int) pendingColumns);
+        if (pendingColumns > 0)
+        {
+            obj->setProperty("display", juce::Base64::toBase64(pendingDisplay.data(), pendingDisplay.size() * sizeof(float)));
+            obj->setProperty("heat", juce::Base64::toBase64(pendingHeat.data(), pendingHeat.size() * sizeof(float)));
+        }
+        else
+        {
+            obj->setProperty("display", juce::String());
+            obj->setProperty("heat", juce::String());
+        }
+        pendingDisplay.clear();
+        pendingHeat.clear();
+        pendingColumns = 0;
+        return juce::var(obj);
+    }
+
+private:
+    const juce::Identifier frameId { "spectrogramFrame" };
+    Visualizer::SpectrogramAnalyzer spectro;
+    Visualizer::SpectrogramConfig config;
+    bool hasConfig = false;
+    std::vector<float> mono;
+    std::vector<float> pendingDisplay, pendingHeat;
+    size_t pendingColumns = 0;
+};