From 3bad2eefdc59c9b89c0556ba438c054d54d95bb3 Mon Sep 17 00:00:00 2001
From: thefiddler <stapostol@gmail.com>
Date: Sat, 28 Dec 2013 01:17:56 +0100
Subject: [PATCH] [Examples] Added ExternalContext test

This test uses SDL2 to create a window and an OpenGL context. It then
uses OpenTK to render into the external SDL2 context. If everything is
working correctly, a black window should appear and gradually turn
white before disappearing.
---
 .../Examples/OpenTK/Test/ExternalContext.cs   | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 Source/Examples/OpenTK/Test/ExternalContext.cs

diff --git a/Source/Examples/OpenTK/Test/ExternalContext.cs b/Source/Examples/OpenTK/Test/ExternalContext.cs
new file mode 100644
index 00000000..cdb6d156
--- /dev/null
+++ b/Source/Examples/OpenTK/Test/ExternalContext.cs
@@ -0,0 +1,81 @@
+// This code was written for the OpenTK library and has been released
+// to the Public Domain.
+// It is provided "as is" without express or implied warranty of any kind.
+
+using System;
+using System.Runtime.InteropServices;
+using OpenTK;
+using OpenTK.Graphics;
+using OpenTK.Graphics.OpenGL;
+
+namespace Examples.Tests
+{
+    [Example("External Context Test", ExampleCategory.OpenTK, "OpenGL")]
+    class ExternalContext
+    {
+        public static void Main()
+        {
+            using (Toolkit.Init(new ToolkitOptions { Backend = PlatformBackend.PreferNative }))
+            {
+                var window = Sdl2.CreateWindow("Test", 0, 0, 640, 480, WindowFlags.AllowHighDpi | WindowFlags.OpenGL);
+                var context = Sdl2.CreateContext(window);
+                Sdl2.MakeCurrent(window, context);
+
+                using (var dummy = new GraphicsContext(new ContextHandle(context), OpenTK.Platform.Utilities.CreateDummyWindowInfo()))
+                {
+                    for (int i = 0; i < 100; i++)
+                    {
+                        Sdl2.PumpEvents();
+                        GL.ClearColor(i / 100.0f, i / 100.0f, i / 100.0f, i / 100.0f);
+                        GL.Clear(ClearBufferMask.ColorBufferBit);
+
+                        Sdl2.SwapWindow(window);
+                    }
+
+                    Sdl2.DestroyWindow(window);
+                }
+            }
+        }
+    }
+
+    #region SDL2 bindings
+
+    public enum WindowFlags
+    {
+        Default = 0,
+        OpenGL = 0x00000002,
+        AllowHighDpi = 0x00002000,
+    }
+
+    static class Sdl2
+    {
+        const string lib = "SDL2.dll";
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_CreateWindow", ExactSpelling = true)]
+        public static extern IntPtr CreateWindow(string title, int x, int y, int w, int h, WindowFlags flags);
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_GL_CreateContext", ExactSpelling = true)]
+        public static extern IntPtr CreateContext(IntPtr window);
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_DestroyWindow", ExactSpelling = true)]
+        public static extern void DestroyWindow(IntPtr window);
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_GL_GetCurrentContext", ExactSpelling = true)]
+        public static extern IntPtr GetCurrentContext();
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_GL_GetProcAddress", ExactSpelling = true)]
+        public static extern IntPtr GetAddress(string name);
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_GL_MakeCurrent", ExactSpelling = true)]
+        public static extern int MakeCurrent(IntPtr window, IntPtr context);
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_PumpEvents", ExactSpelling = true)]
+        public static extern void PumpEvents();
+
+        [DllImport(lib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SDL_GL_SwapWindow", ExactSpelling = true)]
+        public static extern void SwapWindow(IntPtr window);
+    }
+
+    #endregion
+
+}