Add UI

src/pipewire/pipewirecontroller.cpp

@@ -21,6 +21,59 @@
 
 namespace Potato {
 
+static constexpr uint32_t kMeterRingCapacityBytes = 4096;
+
+static void writeRingValue(spa_ringbuffer *ring, std::vector<uint8_t> &buffer, float value)
+{
+    if (!ring || buffer.empty()) {
+        return;
+    }
+
+    uint32_t index = 0;
+    const uint32_t avail = spa_ringbuffer_get_write_index(ring, &index);
+    if (avail < sizeof(float)) {
+        return;
+    }
+
+    const uint32_t size = static_cast<uint32_t>(buffer.size());
+    uint32_t offset = index & (size - 1);
+    if (offset + sizeof(float) <= size) {
+        std::memcpy(buffer.data() + offset, &value, sizeof(float));
+    } else {
+        const uint32_t first = size - offset;
+        std::memcpy(buffer.data() + offset, &value, first);
+        std::memcpy(buffer.data(), reinterpret_cast<const uint8_t*>(&value) + first, sizeof(float) - first);
+    }
+    spa_ringbuffer_write_update(ring, index + sizeof(float));
+}
+
+static bool readRingLatest(spa_ringbuffer *ring, std::vector<uint8_t> &buffer, float &value)
+{
+    if (!ring || buffer.empty()) {
+        return false;
+    }
+
+    uint32_t index = 0;
+    const uint32_t avail = spa_ringbuffer_get_read_index(ring, &index);
+    if (avail < sizeof(float)) {
+        return false;
+    }
+
+    const uint32_t size = static_cast<uint32_t>(buffer.size());
+    const uint32_t latestIndex = index + (avail - sizeof(float));
+    uint32_t offset = latestIndex & (size - 1);
+    if (offset + sizeof(float) <= size) {
+        std::memcpy(&value, buffer.data() + offset, sizeof(float));
+    } else {
+        const uint32_t first = size - offset;
+        std::memcpy(&value, buffer.data() + offset, first);
+        std::memcpy(reinterpret_cast<uint8_t*>(&value) + first, buffer.data(), sizeof(float) - first);
+    }
+
+    spa_ringbuffer_read_update(ring, index + avail);
+    return true;
+}
+
 static QString toQString(const char *value)
 {
     if (!value) {
@@ -150,6 +203,9 @@ void meterProcess(void *data)
     }
 
     self->m_meterPeak.store(peak, std::memory_order_relaxed);
+    if (self->m_meterRingReady.load(std::memory_order_relaxed)) {
+        writeRingValue(&self->m_meterRing, self->m_meterRingData, peak);
+    }
     pw_stream_queue_buffer(self->m_meterStream, buf);
 }
 
@@ -217,6 +273,9 @@ PipeWireController::PipeWireController(QObject *parent)
 {
     m_registryListener = new spa_hook;
     m_coreListener = new spa_hook;
+    m_meterRingData.resize(kMeterRingCapacityBytes);
+    spa_ringbuffer_init(&m_meterRing);
+    m_meterRingReady.store(true, std::memory_order_relaxed);
 }
 
 PipeWireController::~PipeWireController()
@@ -340,6 +399,9 @@ void PipeWireController::shutdown()
     }
     
     pw_deinit();
+
+    m_meterRingReady.store(false, std::memory_order_relaxed);
+    m_meterRingData.clear();
     
     m_initialized.storeRelaxed(false);
     m_connected.storeRelaxed(false);
@@ -372,7 +434,14 @@ QVector<LinkInfo> PipeWireController::links() const
 
 float PipeWireController::meterPeak() const
 {
-    return m_meterPeak.load(std::memory_order_relaxed);
+    float peak = m_meterPeak.load(std::memory_order_relaxed);
+    if (m_meterRingReady.load(std::memory_order_relaxed)) {
+        float ringPeak = 0.0f;
+        if (readRingLatest(&m_meterRing, m_meterRingData, ringPeak)) {
+            peak = ringPeak;
+        }
+    }
+    return peak;
 }
 
 float PipeWireController::nodeMeterPeak(uint32_t nodeId) const