Added a white noise generator

src/sfizz/Config.h

@@ -56,6 +56,7 @@ namespace config {
     constexpr int filtersInPool { maxVoices * 2 };
     constexpr int filtersPerVoice { 2 };
     constexpr int eqsPerVoice { 3 };
+    constexpr float noiseVariance { 0.1f };
     /**
        Minimum interval in frames between recomputations of coefficients of the
        modulated filter. The lower, the more CPU resources are consumed.

src/sfizz/Voice.cpp

@@ -478,35 +478,41 @@ void sfz::Voice::fillWithData(AudioSpan<float> buffer) noexcept
 
 void sfz::Voice::fillWithGenerator(AudioSpan<float> buffer) noexcept
 {
-    if (region->sample != "*sine")
+    const auto leftSpan = buffer.getSpan(0);
-        return;
+    const auto rightSpan  = buffer.getSpan(1);
+    if (region->sample == "*noise") {
+        absl::c_generate(leftSpan, [&](){ return noiseDist(Random::randomGenerator); });
+        absl::c_generate(rightSpan, [&](){ return noiseDist(Random::randomGenerator); });
+    }
+    else if (region->sample == "*sine") {
+        // TODO: wavetables for sine and other generators
+        if (buffer.getNumFrames() == 0)
+            return;
 
-    if (buffer.getNumFrames() == 0)
+        auto jumps = tempSpan1.first(buffer.getNumFrames());
-        return;
+        auto bends = tempSpan2.first(buffer.getNumFrames());
+        auto phases = tempSpan2.first(buffer.getNumFrames());
 
-    auto jumps = tempSpan1.first(buffer.getNumFrames());
+        const float step = baseFrequency * twoPi<float> / sampleRate;
-    auto bends = tempSpan2.first(buffer.getNumFrames());
+        fill<float>(jumps, step);
-    auto phases = tempSpan2.first(buffer.getNumFrames());
 
-    const float step = baseFrequency * twoPi<float> / sampleRate;
+        if (region->bendStep > 1)
-    fill<float>(jumps, step);
+            pitchBendEnvelope.getQuantizedBlock(bends, bendStepFactor);
+        else
+            pitchBendEnvelope.getBlock(bends);
 
-    if (region->bendStep > 1)
+        applyGain<float>(bends, jumps);
-        pitchBendEnvelope.getQuantizedBlock(bends, bendStepFactor);
+        jumps[0] += phase;
-    else
+        cumsum<float>(jumps, phases);
-        pitchBendEnvelope.getBlock(bends);
+        phase = phases.back();
 
-    applyGain<float>(bends, jumps);
+        sin<float>(phases, leftSpan);
-    jumps[0] += phase;
+        copy<float>(leftSpan, rightSpan);
-    cumsum<float>(jumps, phases);
-    phase = phases.back();
 
-    sin<float>(phases, buffer.getSpan(0));
+        // Wrap the phase so we don't loose too much precision on longer notes
-    copy<float>(buffer.getSpan(0), buffer.getSpan(1));
+        const auto numTwoPiWraps = static_cast<int>(phase / twoPi<float>);
-
+        phase -= twoPi<float> * static_cast<float>(numTwoPiWraps);
-    // Wrap the phase so we don't loose too much precision on longer notes
+    }
-    const auto numTwoPiWraps = static_cast<int>(phase / twoPi<float>);
-    phase -= twoPi<float> * static_cast<float>(numTwoPiWraps);
 }
 
 bool sfz::Voice::checkOffGroup(int delay, uint32_t group) noexcept

src/sfizz/Voice.h

@@ -18,6 +18,7 @@
 #include <absl/types/span.h>
 #include <atomic>
 #include <memory>
+#include <random>
 
 namespace sfz {
 /**
@@ -308,6 +309,8 @@ private:
     MultiplicativeEnvelope<float> volumeEnvelope;
     float bendStepFactor { centsFactor(1) };
 
+    std::normal_distribution<float> noiseDist { 0, config::noiseVariance };
+
     HistoricalBuffer<float> powerHistory { config::powerHistoryLength };
     LEAK_DETECTOR(Voice);
 };