Some improvements for nvnflinger (#555)

* Initial fixes for last release of libnx

For now, the framebuffer aren't okay but it will not crash/

* Improve code reaadability in NvFlinger parsing

* Make surfaces access more userfriendly

* Add ColorFormat

* Fix code style in ColorFormat.cs

* Add multiple framebuffer support in nvnflinger

This fix libnx console rendering

* Move ReadStruct/WriteStruct to Ryujinx.Common

* fix the last nit

* Fix inverted color for R5G6B5

Also add some other format that libnx might uses.

* Remove hardcoded BlockHeight in nvflinger

Ryujinx.Common/StructIOExtension.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace Ryujinx.Common
+{
+    public static class StructIOExtension
+    {
+        public unsafe static T ReadStruct<T>(this BinaryReader reader) where T : struct
+        {
+            int size = Marshal.SizeOf<T>();
+
+            byte[] data = reader.ReadBytes(size);
+
+            fixed (byte* ptr = data)
+            {
+                return Marshal.PtrToStructure<T>((IntPtr)ptr);
+            }
+        }
+
+        public unsafe static void WriteStruct<T>(this BinaryWriter writer, T value) where T : struct
+        {
+            long size = Marshal.SizeOf<T>();
+
+            byte[] data = new byte[size];
+
+            fixed (byte* ptr = data)
+            {
+                Marshal.StructureToPtr<T>(value, (IntPtr)ptr, false);
+            }
+
+            writer.Write(data);
+        }
+    }
+}