fix macos

src/DotRecast.Recast.Demo/Draw/ModernOpenGLDraw.cs

@@ -76,7 +76,7 @@ public class ModernOpenGLDraw : OpenGLDraw
 
     public unsafe void init()
     {
-        string SHADER_VERSION = "#version 400\n";
+        string SHADER_VERSION = PlatformID.MacOSX == Environment.OSVersion.Platform ? "#version 400\n" : "#version 460\n";
         string vertex_shader = SHADER_VERSION + "uniform mat4 ProjMtx;\n" //
                                                  + "uniform mat4 ViewMtx;\n" //
                                                  + "in vec3 Position;\n" //

src/DotRecast.Recast.Demo/RecastDemo.cs

@@ -19,10 +19,8 @@ freely, subject to the following restrictions:
 */
 
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Numerics;
@@ -270,6 +268,7 @@ public class RecastDemo
         options.Position = new Vector2D<int>((resolution.X - width) / 2, (resolution.Y - height) / 2);
         options.VSync = false;
         options.ShouldSwapAutomatically = false;
+        options.PreferredDepthBufferBits = 24;
         window = Window.Create(options);
 
         if (window == null)