LibAudio: Allow generating sine waves

userspace/libraries/LibAudio/Audio.cpp

@@ -23,25 +23,17 @@ namespace LibAudio
 		return result;
 	}
 
-	BAN::ErrorOr<Audio> Audio::load(BAN::StringView path)
+	BAN::ErrorOr<Audio> Audio::create(BAN::UniqPtr<AudioStream>&& audio_stream)
 	{
-		Audio result(TRY(AudioStream::load(path)));
-		TRY(result.initialize(256 * 1024));
+		Audio result(BAN::move(audio_stream));
+		TRY(result.initialize(result.m_audio_stream->channels() * result.m_audio_stream->sample_rate()));
 		return result;
 	}
 
-	BAN::ErrorOr<Audio> Audio::random(uint32_t samples)
+	BAN::ErrorOr<Audio> Audio::load(BAN::StringView path)
 	{
-		Audio result;
-		TRY(result.initialize(samples));
-
-		result.m_audio_buffer->sample_rate = 48000;
-		result.m_audio_buffer->channels = 1;
-
-		for (size_t i = 0; i < samples - 1; i++)
-			result.m_audio_buffer->samples[i] = (rand() - RAND_MAX / 2) / (RAND_MAX / 2.0);
-		result.m_audio_buffer->head = samples - 1;
-
+		Audio result(TRY(AudioStream::load(path)));
+		TRY(result.initialize(result.m_audio_stream->channels() * result.m_audio_stream->sample_rate()));
 		return result;
 	}
 

userspace/libraries/LibAudio/AudioStreams/SineWaveAudioStream.cpp

@@ -0,0 +1,36 @@
+#include <LibAudio/AudioStreams/SineWaveAudioStream.h>
+
+#include <BAN/Math.h>
+
+namespace LibAudio
+{
+
+	BAN::ErrorOr<BAN::UniqPtr<AudioStream>> SineWaveAudioStream::create(uint32_t channels, uint32_t sample_rate, float frequency)
+	{
+		auto* stream_ptr = new SineWaveAudioStream(channels, sample_rate, frequency);
+		if (stream_ptr == nullptr)
+			return BAN::Error::from_errno(ENOMEM);
+		return BAN::UniqPtr<AudioStream>::adopt(stream_ptr);
+	}
+
+	SineWaveAudioStream::SineWaveAudioStream(uint32_t channels, uint32_t sample_rate, float frequency)
+		: m_channels(channels)
+		, m_sample_rate(sample_rate)
+		, m_frequency(frequency)
+		, m_phase_inc(2.0f * BAN::numbers::pi_v<float> * m_frequency / m_sample_rate)
+	{ }
+
+	float SineWaveAudioStream::get_sample()
+	{
+		if (m_sample_idx++ % m_channels == 0)
+		{
+			m_phase += m_phase_inc;
+			if (m_phase >= 2.0f * BAN::numbers::pi_v<float>)
+				m_phase -= 2.0f * BAN::numbers::pi_v<float>;
+			m_sample = BAN::Math::sin(m_phase);
+		}
+
+		return m_sample;
+	}
+
+}

userspace/libraries/LibAudio/CMakeLists.txt

@@ -2,6 +2,7 @@ set(LIBAUDIO_SOURCES
 	Audio.cpp
 	AudioStream.cpp
 	AudioStreams/WAVAudioStream.cpp
+	AudioStreams/SineWaveAudioStream.cpp
 )
 
 add_library(libaudio ${LIBAUDIO_SOURCES})

userspace/libraries/LibAudio/include/LibAudio/Audio.h

@@ -30,8 +30,8 @@ namespace LibAudio
 
 	public:
 		static BAN::ErrorOr<Audio> create(uint32_t channels, uint32_t sample_rate, uint32_t sample_frames);
+		static BAN::ErrorOr<Audio> create(BAN::UniqPtr<AudioStream>&&);
 		static BAN::ErrorOr<Audio> load(BAN::StringView path);
-		static BAN::ErrorOr<Audio> random(uint32_t samples);
 		~Audio() { clear(); }
 
 		Audio(Audio&& other) { *this = BAN::move(other); }

userspace/libraries/LibAudio/include/LibAudio/AudioStreams/SineWaveAudioStream.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <LibAudio/AudioStream.h>
+
+#include <BAN/Limits.h>
+
+namespace LibAudio
+{
+
+	class SineWaveAudioStream : public AudioStream
+	{
+	public:
+		static BAN::ErrorOr<BAN::UniqPtr<AudioStream>> create(uint32_t channels, uint32_t sample_rate, float frequency);
+
+		uint32_t channels() const override { return m_channels; }
+		uint32_t sample_rate() const override { return m_sample_rate; }
+		uint32_t samples_remaining() const override { return BAN::numeric_limits<uint32_t>::max(); }
+
+		float get_sample() override;
+
+	private:
+		SineWaveAudioStream(uint32_t channels, uint32_t sample_rate, float frequency);
+
+	private:
+		const uint32_t m_channels;
+		const uint32_t m_sample_rate;
+		const float    m_frequency;
+		const float    m_phase_inc;
+
+		uint32_t m_sample_idx { 0 };
+		float    m_sample     { 0 };
+		float    m_phase      { 0 };
+	};
+
+}