wow

ADOFAIRenderer/Renderer/RenderClock.cs

@@ -0,0 +1,28 @@
+using System;
+
+namespace ADOFAIRenderer.Renderer
+{
+    public sealed class RenderClock
+    {
+        public int Fps { get; }
+        public long FrameIndex { get; private set; }
+        public double Time => FrameIndex / (double)Fps;
+        // A fixed DSP origin also keeps scheduling independent of the audio device.
+        public double DspOrigin { get; private set; } = 1000.0;
+        public double DspTime => DspOrigin + Time;
+        public void AnchorDsp(double origin)
+        {
+            if (FrameIndex != 0 || double.IsNaN(origin) || double.IsInfinity(origin))
+                throw new InvalidOperationException("DSP origin must be anchored before frame zero.");
+            DspOrigin = origin;
+        }
+        public RenderClock(int fps = 60)
+        {
+            if (fps <= 0) throw new ArgumentOutOfRangeException(nameof(fps));
+            Fps = fps;
+        }
+        public double SongPosition(double scheduledStart, double pitch, double offset, double calibration)
+            => (DspTime - scheduledStart - calibration) * pitch - offset;
+        public void Advance() { checked { FrameIndex++; } }
+    }
+}