Haydn: Part 1 (#2007)

* Haydn: Part 1

Based on my reverse of audio 11.0.0.

As always, core implementation under LGPLv3 for the same reasons as for Amadeus.

This place the bases of a more flexible audio system while making audout & audin accurate.

This have the following improvements:
- Complete reimplementation of audout and audin.
- Audin currently only have a dummy backend.
- Dramatically reduce CPU usage by up to 50% in common cases (SoundIO and OpenAL).
- Audio Renderer now can output to 5.1 devices when supported.
- Audio Renderer init its backend on demand instead of keeping two up all the time.
- All backends implementation are now in their own project.
- Ryujinx.Audio.Renderer was renamed Ryujinx.Audio and was refactored because of this.

As a note, games having issues with OpenAL haven't improved and will not
because of OpenAL design (stopping when buffers finish playing causing
possible audio "pops" when buffers are very small).

* Update for latest hexkyz's edits on Switchbrew

* audren: Rollback channel configuration changes

* Address gdkchan's comments

* Fix typo in OpenAL backend driver

* Address last comments

* Fix a nit

* Address gdkchan's comments

Ryujinx.Audio/Renderer/Dsp/State/DelayState.cs

@@ -0,0 +1,73 @@
+//
+// Copyright (c) 2019-2021 Ryujinx
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+using Ryujinx.Audio.Renderer.Dsp.Effect;
+using Ryujinx.Audio.Renderer.Parameter.Effect;
+
+namespace Ryujinx.Audio.Renderer.Dsp.State
+{
+    public class DelayState
+    {
+        public DelayLine[] DelayLines { get; }
+        public float[] LowPassZ { get; set; }
+        public float FeedbackGain { get; private set; }
+        public float DelayFeedbackBaseGain { get; private set; }
+        public float DelayFeedbackCrossGain { get; private set; }
+        public float LowPassFeedbackGain { get; private set; }
+        public float LowPassBaseGain { get; private set; }
+
+        private const int FixedPointPrecision = 14;
+
+        public DelayState(ref DelayParameter parameter, ulong workBuffer)
+        {
+            DelayLines = new DelayLine[parameter.ChannelCount];
+            LowPassZ = new float[parameter.ChannelCount];
+
+            uint sampleRate = (uint)FixedPointHelper.ToInt(parameter.SampleRate, FixedPointPrecision) / 1000;
+
+            for (int i = 0; i < DelayLines.Length; i++)
+            {
+                DelayLines[i] = new DelayLine(sampleRate, parameter.DelayTimeMax);
+                DelayLines[i].SetDelay(parameter.DelayTime);
+                LowPassZ[0] = 0;
+            }
+
+            UpdateParameter(ref parameter);
+        }
+
+        public void UpdateParameter(ref DelayParameter parameter)
+        {
+            FeedbackGain = FixedPointHelper.ToFloat(parameter.FeedbackGain, FixedPointPrecision) * 0.98f;
+
+            float channelSpread = FixedPointHelper.ToFloat(parameter.ChannelSpread, FixedPointPrecision);
+
+            DelayFeedbackBaseGain = (1.0f - channelSpread) * FeedbackGain;
+
+            if (parameter.ChannelCount == 4 || parameter.ChannelCount == 6)
+            {
+                DelayFeedbackCrossGain = channelSpread * 0.5f * FeedbackGain;
+            }
+            else
+            {
+                DelayFeedbackCrossGain = channelSpread * FeedbackGain;
+            }
+
+            LowPassFeedbackGain = 0.95f * FixedPointHelper.ToFloat(parameter.LowPassAmount, FixedPointPrecision);
+            LowPassBaseGain = 1.0f - LowPassFeedbackGain;
+        }
+    }
+}