Audio device pt 2

include/audio/audio_device.hpp

@@ -8,17 +8,17 @@
 class AudioDeviceInterface {
   protected:
 	using Samples = Common::RingBuffer<s16, 0x2000 * 2>;
+	using RenderBatchCallback = usize (*)(const s16*, usize);
+
 	Samples* samples = nullptr;
 
 	const AudioDeviceConfig& audioSettings;
+	// Store the last stereo sample we output. We play this when underruning to avoid pops.
+	std::array<s16, 2> lastStereoSample{};
 
   public:
 	AudioDeviceInterface(Samples* samples, const AudioDeviceConfig& audioSettings) : samples(samples), audioSettings(audioSettings) {}
 
-	// Store the last stereo sample we output. We play this when underruning to avoid pops.
-	// TODO: Make this protected again before merging!!!
-	std::array<s16, 2> lastStereoSample{};
-
 	bool running = false;
 	Samples* getSamples() { return samples; }
 
@@ -28,4 +28,7 @@ class AudioDeviceInterface {
 
 	virtual void start() = 0;
 	virtual void stop() = 0;
+
+	// Only used for audio devices that render multiple audio frames in one go, eg the libretro audio device.
+	virtual void renderBatch(RenderBatchCallback callback) {}
 };

include/audio/libretro_audio_device.hpp

@@ -1,7 +1,5 @@
 #pragma once
-#include <atomic>
-#include <string>
-#include <vector>
+#include <cstring>
 
 #include "audio/audio_device.hpp"
 
@@ -28,6 +26,35 @@ class LibretroAudioDevice : public AudioDeviceInterface {
 	void start() override { running = true; }
 	void stop() override { running = false; };
 
+	void renderBatch(RenderBatchCallback callback) override {
+		if (running) {
+			static constexpr int frameCount = 547;
+			static constexpr int channelCount = 2;
+			static s16 audioBuffer[frameCount * channelCount];
+
+			usize samplesWritten = 0;
+			samplesWritten += samples->pop(audioBuffer, frameCount * channelCount);
+
+			// Get the last sample for underrun handling
+			if (samplesWritten != 0) {
+				std::memcpy(&lastStereoSample[0], &audioBuffer[(samplesWritten - 1) * 2], sizeof(lastStereoSample));
+			}
+
+			// If underruning, copy the last output sample
+			{
+				s16* pointer = &audioBuffer[samplesWritten * 2];
+				s16 l = lastStereoSample[0];
+				s16 r = lastStereoSample[1];
+
+				for (usize i = samplesWritten; i < frameCount; i++) {
+					*pointer++ = l;
+					*pointer++ = r;
+				}
+			}
+
+			callback(audioBuffer, sizeof(audioBuffer) / (2 * sizeof(s16)));
+		}
+	}
+
 	bool isInitialized() const { return initialized; }
-	bool isRunning() const { return running; }
 };

include/emulator.hpp

@@ -60,7 +60,7 @@ class Emulator {
 	static constexpr u32 width = 400;
 	static constexpr u32 height = 240 * 2;  // * 2 because 2 screens
 	ROMType romType = ROMType::None;
-	bool running = false;         // Is the emulator running a game?
+	bool running = false;  // Is the emulator running a game?
 
   private:
 #ifdef PANDA3DS_ENABLE_HTTP_SERVER