seanofw

diff --git a/src/OpenTK.Mathematics/OpenTK.Mathematics.csproj b/src/OpenTK.Mathematics/OpenTK.Mathematics.csproj
index b2f0466db..704323b26 100644
--- a/src/OpenTK.Mathematics/OpenTK.Mathematics.csproj
+++ b/src/OpenTK.Mathematics/OpenTK.Mathematics.csproj
@@ -1,13 +1,21 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;netcoreapp3.1;netstandard2.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>

seanofw

using System;
using System.Runtime.InteropServices;

public class HighPrecisionSleep : IDisposable
{
  private IntPtr _waitableTimerHandle;

  public HighPrecisionSleep()
  {
    _waitableTimerHandle = Win32.CreateWaitableTimer(IntPtr.Zero, true, null);

seanofw

using System;
using System.Runtime.InteropServices;
using System.Threading;
using OpenTK.Windowing.Common;
using OpenTK.Windowing.Desktop;

// Define this if you're running on Microsoft Windows, which supports
// high-precision sleep timers.  Enabling this can result in better CPU usage
// and power usage if your program doesn't need the CPU fully in every frame.
#define HIGH_PRECISION_SLEEP

seanofw

private static volatile int RandomSeed = 1;

private static int FastRand()
{
retry:
    int oldSeed = RandomSeed;
    int newSeed = unchecked(oldSeed * 1103515245 + 12345);
    if (Interlocked.CompareExchange(ref RandomSeed, newSeed, oldSeed) != oldSeed)
        goto retry;