texture offsets

samples/ControlCatalog.NetCore/Properties/launchSettings.json

@@ -0,0 +1,8 @@
+{
+  "profiles": {
+    "ControlCatalog.NetCore": {
+      "commandName": "Project",
+      "nativeDebugging": true
+    }
+  }
+}

src/Avalonia.OpenGL/Angle/AngleEglInterface.cs

@@ -7,8 +7,8 @@ namespace Avalonia.OpenGL.Angle
 {
     public class AngleEglInterface : EglInterface
     {
-        [DllImport("libegl.dll", CharSet = CharSet.Ansi)]
-        static extern IntPtr eglGetProcAddress(string proc);
+        [DllImport("libglesv2.dll", CharSet = CharSet.Ansi)]
+        static extern IntPtr EGL_GetProcAddress(string proc);
 
         public AngleEglInterface() : base(LoadAngle())
         {
@@ -20,10 +20,10 @@ namespace Avalonia.OpenGL.Angle
             if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                 throw new PlatformNotSupportedException();
             {
-                var disp = eglGetProcAddress("eglGetPlatformDisplayEXT");
+                var disp = EGL_GetProcAddress("eglGetPlatformDisplayEXT");
                 if (disp == IntPtr.Zero)
                     throw new OpenGlException("libegl.dll doesn't have eglGetPlatformDisplayEXT entry point");
-                return eglGetProcAddress;
+                return EGL_GetProcAddress;
             }
         }
 

src/Avalonia.OpenGL/Angle/AngleWin32EglDisplay.cs

@@ -78,11 +78,11 @@ namespace Avalonia.OpenGL.Angle
             return d3dDeviceHandle;
         }
 
-        public EglSurface WrapDirect3D11Texture(IntPtr handle)
+        public EglSurface WrapDirect3D11Texture(IntPtr handle, int offsetX, int offsetY)
         {
             if (PlatformApi != AngleOptions.PlatformApi.DirectX11)
                 throw new InvalidOperationException("Current platform API is " + PlatformApi);
-            return CreatePBufferFromClientBuffer(EGL_D3D_TEXTURE_ANGLE, handle, new[] { EGL_NONE, EGL_NONE });
+            return CreatePBufferFromClientBuffer(EGL_D3D_TEXTURE_ANGLE, handle, new[] { EGL_TEXTURE_OFFSET_X_ANGLE, offsetX, EGL_TEXTURE_OFFSET_Y_ANGLE, offsetY, EGL_NONE, EGL_NONE });
         }
     }
 }

src/Avalonia.OpenGL/EglConsts.cs

@@ -205,5 +205,9 @@ namespace Avalonia.OpenGL
 
         public const int EGL_D3D_TEXTURE_2D_SHARE_HANDLE_ANGLE = 0x3200;
         public const int EGL_D3D_TEXTURE_ANGLE = 0x33A3;
+
+
+        public const int EGL_TEXTURE_OFFSET_X_ANGLE = 0x3490;
+        public const int EGL_TEXTURE_OFFSET_Y_ANGLE = 0x3491;
     }
 }

src/Windows/Avalonia.Win32/Composition/CompositionHost.cs

@@ -94,7 +94,7 @@ namespace Avalonia.Win32
                     ref iid,
                     out IntPtr texture, ref offset);
 
-                var surface = (_display as AngleWin32EglDisplay).WrapDirect3D11Texture(texture);
+                var surface = (_display as AngleWin32EglDisplay).WrapDirect3D11Texture(texture, offset.X, offset.Y);
 
                 return base.BeginDraw(surface, _info, () => { _surfaceInterop.EndDraw(); Marshal.Release(texture); surface.Dispose();  }, true);
             }