Mixer.cs

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#if BROWSER
using AL = Engine.Browser.AL;
using ALContext = Engine.Browser.ALContext;
using GetSourceInteger = Engine.Browser.AL.GetSourceInteger;
using SourceState = Engine.Browser.AL.SourceState;
using ListenerFloat = Engine.Browser.AL.ListenerFloat;
using AudioError = Engine.Browser.AL.AudioError;
#else
using Silk.NET.OpenAL;
#endif
 
namespace Engine.Audio {
    public static class Mixer {
        public static AL AL;
        public static ALContext m_audioContext;
        static float m_masterVolume = 1f;
        public static readonly List<Sound> m_soundsToStop = [];
        public static HashSet<Sound> m_soundsToStopPoll = [];
        public static bool m_isInitialized;
 
        public static float MasterVolume {
            get => m_masterVolume;
            set {
                value = MathUtils.Saturate(value);
                if (value != m_masterVolume) {
                    m_masterVolume = value;
                    InternalSetMasterVolume(value);
                }
            }
        }
 
        internal static void Initialize() {
#if BROWSER
            m_audioContext = new ALContext();
            AL = new AL();
            if (!CheckALErrorFull()) {
                m_isInitialized = true;
            }
#else
#if !MOBILE
            //直接加载
            string fullPath = Path.GetDirectoryName(
                RunPath.GetExecutablePath() == "" ? RunPath.GetEntryPath() : RunPath.GetExecutablePath()
            ); //路径备选方案
            Environment.SetEnvironmentVariable("PATH", $"{fullPath};{RunPath.GetEnvironmentPath()}", EnvironmentVariableTarget.Process);
#endif
            m_audioContext = ALContext.GetApi();
            AL = AL.GetApi();
            unsafe {
                Device* device = m_audioContext.OpenDevice("");
                if (device == null) {
                    Log.Error("Could not create audio device");
                    return;
                }
                Context* c = m_audioContext.CreateContext(device, null);
                m_audioContext.MakeContextCurrent(c);
            }
            if (!CheckALErrorFull()) {
                m_isInitialized = true;
            }
#endif
        }
 
        internal static void Dispose() {
            m_isInitialized = false;
            m_audioContext?.Dispose();
        }
 
        internal static void BeforeFrame() {
            foreach (Sound item in m_soundsToStopPoll) {
                if (item.m_source != 0
                    && item.State == SoundState.Playing) {
                    AL.GetSourceProperty((uint)item.m_source, GetSourceInteger.SourceState, out int sourceState);
                    if (sourceState == (int)SourceState.Stopped) {
                        m_soundsToStop.Add(item);
                    }
                }
            }
            foreach (Sound item2 in m_soundsToStop) {
                item2.Stop();
            }
            m_soundsToStop.Clear();
        }
 
        internal static void AfterFrame() { }
 
        internal static void InternalSetMasterVolume(float volume) {
            if (m_isInitialized) {
                AL.SetListenerProperty(ListenerFloat.Gain, volume);
            }
        }
        /*
        internal static void CheckALError()
        {
            ALError error = AL.GetError();
            //if (error != 0)
            //{
            //  throw new InvalidOperationException(AL.GetErrorString(error));
            //}
        }*/
 
        public static AudioError CheckALError() {
            AudioError error = AL.GetError();
            if (error != AudioError.NoError) {
                Log.Error($"OPENAL ERROR: {error}");
            }
            return error;
        }

        public static bool CheckALErrorFull() //注意返回值为是否出错
        {
            try {
                AudioError error = AL.GetError();
                if (error != AudioError.NoError) {
                    Log.Error($"OPENAL ERROR: {error}");
                    //throw new InvalidOperationException(AL.GetErrorString(error));
                    return true;
                }
                return false;
            }
            catch (Exception e) {
                Log.Error($"Unable to load OPENAL: {e}");
                return true;
            }
        }
    }
}