Fix audio module: implement WAV parsing and audio playback

- Implement ParseWAVData and ParseWAVHeader in AudioLoader to properly
  parse WAV file headers (sample rate, channels, bits per sample, duration)
- Modify Load() to call ParseWAVData for WAV files during loading
- Add DecodeAudioData() to AudioSourceComponent to decode PCM bytes to float
- Update SetClip() to trigger audio decoding
- Fix ProcessAudio() to read from decoded data instead of empty output buffer
- Add WAV parsing unit tests (ParseWAV_Mono44100_16bit, ParseWAV_Stereo48000_16bit)

Fixes issues:
- AudioLoader::ParseWAVData was a stub returning true without parsing
- AudioLoader::Load didn't extract audio metadata from WAV headers
- AudioSourceComponent::ProcessAudio read from empty m_outputBuffer

All 167 tests pass.

engine/include/XCEngine/Components/AudioSourceComponent.h

@@ -82,6 +82,7 @@ public:
     std::string GetName() const override { return "AudioSource"; }
 
 private:
+    void DecodeAudioData();
     void Apply3DAttenuation(const Math::Vector3& listenerPosition);
     void UpdateEnergy(const float* buffer, Audio::uint32 sampleCount);
 

engine/src/Components/AudioSourceComponent.cpp

@@ -52,7 +52,7 @@ void AudioSourceComponent::SetClip(Resources::AudioClip* clip) {
     m_clip = clip;
     m_isDecoded = false;
     if (clip && clip->IsValid()) {
-        m_decodedData.resize(clip->GetAudioData().Size() / 2);
+        DecodeAudioData();
     }
 }
 
@@ -168,10 +168,60 @@ void AudioSourceComponent::OnDestroy() {
     Stop();
 }
 
+void AudioSourceComponent::DecodeAudioData() {
+    if (!m_clip || !m_clip->IsValid()) {
+        return;
+    }
+
+    if (m_isDecoded) {
+        return;
+    }
+
+    const auto& audioData = m_clip->GetAudioData();
+    if (audioData.Empty()) {
+        return;
+    }
+
+    Audio::uint32 channels = m_clip->GetChannels();
+    Audio::uint32 bitsPerSample = m_clip->GetBitsPerSample();
+    uint32_t bytesPerSample = bitsPerSample / 8;
+    uint32_t totalSamples = static_cast<uint32_t>(audioData.Size()) / bytesPerSample;
+
+    m_decodedData.resize(totalSamples);
+
+    const uint8_t* rawData = audioData.Data();
+
+    if (bitsPerSample == 16) {
+        const int16_t* samples16 = reinterpret_cast<const int16_t*>(rawData);
+        for (uint32_t i = 0; i < totalSamples; ++i) {
+            m_decodedData[i] = samples16[i] / 32768.0f;
+        }
+    } else if (bitsPerSample == 8) {
+        for (uint32_t i = 0; i < totalSamples; ++i) {
+            m_decodedData[i] = (rawData[i] - 128) / 128.0f;
+        }
+    } else if (bitsPerSample == 24) {
+        for (uint32_t i = 0; i < totalSamples; ++i) {
+            int32_t sample = (rawData[i * 3] | (rawData[i * 3 + 1] << 8) | (rawData[i * 3 + 2] << 16));
+            if (sample & 0x800000) {
+                sample |= 0xFF000000;
+            }
+            m_decodedData[i] = sample / 8388608.0f;
+        }
+    } else if (bitsPerSample == 32) {
+        const int32_t* samples32 = reinterpret_cast<const int32_t*>(rawData);
+        for (uint32_t i = 0; i < totalSamples; ++i) {
+            m_decodedData[i] = samples32[i] / 2147483648.0f;
+        }
+    }
+
+    m_isDecoded = true;
+}
+
 void AudioSourceComponent::ProcessAudio(float* buffer, Audio::uint32 sampleCount, Audio::uint32 channels,
                                       const Math::Vector3& listenerPosition,
                                       const Math::Quaternion& listenerRotation) {
-    if (m_playState != Audio::PlayState::Playing || !m_clip) {
+    if (m_playState != Audio::PlayState::Playing || !m_clip || !m_isDecoded) {
         return;
     }
 
@@ -179,18 +229,53 @@ void AudioSourceComponent::ProcessAudio(float* buffer, Audio::uint32 sampleCount
         return;
     }
 
+    if (m_decodedData.empty()) {
+        return;
+    }
+
     float volume = m_volume;
     if (m_spatialize) {
         Apply3DAttenuation(listenerPosition);
         volume *= m_volume;
     }
 
-    for (Audio::uint32 i = 0; i < sampleCount && i < BufferSize * 2; ++i) {
-        buffer[i] += m_outputBuffer[i] * volume;
+    Audio::uint32 clipChannels = m_clip->GetChannels();
+    Audio::uint64 totalSamples = static_cast<Audio::uint64>(m_decodedData.size());
+    Audio::uint64 samplesPerFrame = sampleCount * channels;
+
+    for (Audio::uint32 i = 0; i < sampleCount; ++i) {
+        for (Audio::uint32 ch = 0; ch < channels; ++ch) {
+            Audio::uint64 outputIndex = m_samplePosition + i * channels + ch;
+
+            if (outputIndex >= totalSamples) {
+                if (m_isLooping && totalSamples > 0) {
+                    outputIndex = outputIndex % totalSamples;
+                } else {
+                    buffer[i * channels + ch] += 0.0f;
+                    continue;
+                }
+            }
+
+            Audio::uint64 decodedChannel = (ch < clipChannels) ? ch : (clipChannels - 1);
+            Audio::uint64 decodedIndex = (outputIndex / channels) * clipChannels + decodedChannel;
+            float sample = m_decodedData[decodedIndex];
+
+            buffer[i * channels + ch] += sample * volume;
+        }
+    }
+
+    m_samplePosition += samplesPerFrame;
+
+    if (m_samplePosition >= totalSamples) {
+        if (m_isLooping) {
+            m_samplePosition = m_samplePosition % totalSamples;
+        } else {
+            Stop();
+        }
     }
 
     if (m_isEnergyDetecting) {
-        UpdateEnergy(buffer, sampleCount);
+        UpdateEnergy(buffer, sampleCount * channels);
     }
 }
 

engine/src/Resources/AudioLoader.cpp

@@ -1,10 +1,68 @@
 #include "Resources/AudioLoader.h"
 #include "Resources/ResourceManager.h"
 #include "Resources/ResourceTypes.h"
+#include <cstring>
 
 namespace XCEngine {
 namespace Resources {
 
+namespace {
+
+struct WAVHeader {
+    uint32_t sampleRate = 44100;
+    uint32_t channels = 2;
+    uint32_t bitsPerSample = 16;
+    uint32_t dataSize = 0;
+    uint32_t dataOffset = 44;
+};
+
+bool ParseWAVHeader(const uint8_t* data, size_t size, WAVHeader& header) {
+    if (size < 44) {
+        return false;
+    }
+
+    if (data[0] != 'R' || data[1] != 'I' || data[2] != 'F' || data[3] != 'F') {
+        return false;
+    }
+
+    if (data[8] != 'W' || data[9] != 'A' || data[10] != 'V' || data[11] != 'E') {
+        return false;
+    }
+
+    if (data[12] != 'f' || data[13] != 'm' || data[14] != 't' || data[15] != ' ') {
+        return false;
+    }
+
+    uint32_t subchunk1Size = *reinterpret_cast<const uint32_t*>(&data[16]);
+    if (subchunk1Size < 16) {
+        return false;
+    }
+
+    uint16_t audioFormat = *reinterpret_cast<const uint16_t*>(&data[20]);
+    if (audioFormat != 1) {
+        return false;
+    }
+
+    header.channels = *reinterpret_cast<const uint16_t*>(&data[22]);
+    header.sampleRate = *reinterpret_cast<const uint32_t*>(&data[24]);
+    header.bitsPerSample = *reinterpret_cast<const uint16_t*>(&data[34]);
+
+    if (data[36] != 'd' || data[37] != 'a' || data[38] != 't' || data[39] != 'a') {
+        return false;
+    }
+
+    header.dataSize = *reinterpret_cast<const uint32_t*>(&data[40]);
+    header.dataOffset = 44;
+
+    if (header.dataOffset + header.dataSize > size) {
+        return false;
+    }
+
+    return true;
+}
+
+} // namespace
+
 AudioLoader::AudioLoader() = default;
 
 AudioLoader::~AudioLoader() = default;
@@ -38,6 +96,12 @@ LoadResult AudioLoader::Load(const Containers::String& path, const ImportSetting
     audioClip->m_guid = ResourceGUID::Generate(path);
     
     AudioFormat format = DetectAudioFormat(path, data);
+    if (format == AudioFormat::WAV) {
+        if (!ParseWAVData(data, audioClip)) {
+            delete audioClip;
+            return LoadResult("Failed to parse WAV data");
+        }
+    }
     audioClip->SetAudioFormat(format);
     audioClip->SetAudioData(data);
     
@@ -53,6 +117,20 @@ ImportSettings* AudioLoader::GetDefaultSettings() const {
 }
 
 bool AudioLoader::ParseWAVData(const Containers::Array<Core::uint8>& data, AudioClip* audioClip) {
+    WAVHeader header;
+    if (!ParseWAVHeader(data.Data(), data.Size(), header)) {
+        return false;
+    }
+
+    audioClip->SetSampleRate(header.sampleRate);
+    audioClip->SetChannels(header.channels);
+    audioClip->SetBitsPerSample(header.bitsPerSample);
+
+    uint32_t bytesPerSample = header.bitsPerSample / 8;
+    uint32_t totalSamples = header.dataSize / (bytesPerSample * header.channels);
+    float duration = static_cast<float>(totalSamples) / (header.sampleRate * header.channels);
+    audioClip->SetDuration(duration);
+
     return true;
 }
 

tests/Resources/test_audio_loader.cpp

@@ -2,12 +2,93 @@
 #include <XCEngine/Resources/AudioLoader.h>
 #include <XCEngine/Resources/ResourceTypes.h>
 #include <XCEngine/Containers/Array.h>
+#include <XCEngine/Resources/ResourceManager.h>
+#include <fstream>
+#include <cstring>
 
 using namespace XCEngine::Resources;
 using namespace XCEngine::Containers;
 
 namespace {
 
+#pragma pack(push, 1)
+struct WAVFileHeader {
+    char riff[4];
+    uint32_t fileSize;
+    char wave[4];
+    char fmt[4];
+    uint32_t fmtSize;
+    uint16_t audioFormat;
+    uint16_t numChannels;
+    uint32_t sampleRate;
+    uint32_t byteRate;
+    uint16_t blockAlign;
+    uint16_t bitsPerSample;
+    char data[4];
+    uint32_t dataSize;
+};
+#pragma pack(pop)
+
+void CreateTestWAVFile(const char* filepath, uint16_t channels, uint32_t sampleRate, uint16_t bitsPerSample, uint32_t numSamples) {
+    WAVFileHeader header = {};
+    header.riff[0] = 'R'; header.riff[1] = 'I'; header.riff[2] = 'F'; header.riff[3] = 'F';
+    header.wave[0] = 'W'; header.wave[1] = 'A'; header.wave[2] = 'V'; header.wave[3] = 'E';
+    header.fmt[0] = 'f'; header.fmt[1] = 'm'; header.fmt[2] = 't'; header.fmt[3] = ' ';
+    header.fmtSize = 16;
+    header.audioFormat = 1;
+    header.numChannels = channels;
+    header.sampleRate = sampleRate;
+    header.bitsPerSample = bitsPerSample;
+    header.blockAlign = channels * bitsPerSample / 8;
+    header.byteRate = sampleRate * header.blockAlign;
+    header.data[0] = 'd'; header.data[1] = 'a'; header.data[2] = 't'; header.data[3] = 'a';
+    header.dataSize = numSamples * header.blockAlign;
+    header.fileSize = 36 + header.dataSize;
+
+    std::vector<uint8_t> wavData(sizeof(WAVFileHeader) + header.dataSize, 0);
+    std::memcpy(wavData.data(), &header, sizeof(WAVFileHeader));
+
+    std::ofstream file(filepath, std::ios::binary);
+    file.write(reinterpret_cast<const char*>(wavData.data()), wavData.size());
+}
+
+TEST(AudioLoader, ParseWAV_Mono44100_16bit) {
+    const char* testPath = "test_mono_44100.wav";
+    CreateTestWAVFile(testPath, 1, 44100, 16, 44100);
+
+    AudioLoader loader;
+    LoadResult result = loader.Load(testPath);
+
+    EXPECT_TRUE(result);
+    if (result) {
+        AudioClip* clip = static_cast<AudioClip*>(result.resource);
+        EXPECT_EQ(clip->GetSampleRate(), 44100u);
+        EXPECT_EQ(clip->GetChannels(), 1u);
+        EXPECT_EQ(clip->GetBitsPerSample(), 16u);
+        EXPECT_GT(clip->GetDuration(), 0.0f);
+    }
+
+    std::remove(testPath);
+}
+
+TEST(AudioLoader, ParseWAV_Stereo48000_16bit) {
+    const char* testPath = "test_stereo_48000.wav";
+    CreateTestWAVFile(testPath, 2, 48000, 16, 4800);
+
+    AudioLoader loader;
+    LoadResult result = loader.Load(testPath);
+
+    EXPECT_TRUE(result);
+    if (result) {
+        AudioClip* clip = static_cast<AudioClip*>(result.resource);
+        EXPECT_EQ(clip->GetSampleRate(), 48000u);
+        EXPECT_EQ(clip->GetChannels(), 2u);
+        EXPECT_EQ(clip->GetBitsPerSample(), 16u);
+    }
+
+    std::remove(testPath);
+}
+
 TEST(AudioLoader, GetResourceType) {
     AudioLoader loader;
     EXPECT_EQ(loader.GetResourceType(), ResourceType::AudioClip);