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/Command/MixRampCommand.cs

@@ -0,0 +1,83 @@
+//
+// 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.Common;
+using System;
+
+namespace Ryujinx.Audio.Renderer.Dsp.Command
+{
+    public class MixRampCommand : ICommand
+    {
+        public bool Enabled { get; set; }
+
+        public int NodeId { get; }
+
+        public CommandType CommandType => CommandType.MixRamp;
+
+        public ulong EstimatedProcessingTime { get; set; }
+
+        public ushort InputBufferIndex { get; }
+        public ushort OutputBufferIndex { get; }
+
+        public float Volume0 { get; }
+        public float Volume1 { get; }
+
+        public Memory<VoiceUpdateState> State { get; }
+
+        public int LastSampleIndex { get; }
+
+        public MixRampCommand(float volume0, float volume1, uint inputBufferIndex, uint outputBufferIndex, int lastSampleIndex, Memory<VoiceUpdateState> state, int nodeId)
+        {
+            Enabled = true;
+            NodeId = nodeId;
+
+            InputBufferIndex = (ushort)inputBufferIndex;
+            OutputBufferIndex = (ushort)outputBufferIndex;
+
+            Volume0 = volume0;
+            Volume1 = volume1;
+
+            State = state;
+            LastSampleIndex = lastSampleIndex;
+        }
+
+        private float ProcessMixRamp(Span<float> outputBuffer, ReadOnlySpan<float> inputBuffer, int sampleCount)
+        {
+            float ramp = (Volume1 - Volume0) / sampleCount;
+            float volume = Volume0;
+            float state = 0;
+
+            for (int i = 0; i < sampleCount; i++)
+            {
+                state = FloatingPointHelper.MultiplyRoundUp(inputBuffer[i], volume);
+
+                outputBuffer[i] += state;
+                volume += ramp;
+            }
+
+            return state;
+        }
+
+        public void Process(CommandList context)
+        {
+            ReadOnlySpan<float> inputBuffer = context.GetBuffer(InputBufferIndex);
+            Span<float> outputBuffer = context.GetBuffer(OutputBufferIndex);
+
+            State.Span[0].LastSamples[LastSampleIndex] = ProcessMixRamp(outputBuffer, inputBuffer, (int)context.SampleCount);
+        }
+    }
+}