Implement VP9 loop filtering

src/Ryujinx.Graphics.Nvdec.Vp9/TileWorkerData.cs

@@ -12,9 +12,20 @@ namespace Ryujinx.Graphics.Nvdec.Vp9
         public int BufEnd;
         public Reader BitReader;
         public Vp9BackwardUpdates Counts;
+
         public MacroBlockD Xd;
+
         /* dqcoeff are shared by all the planes. So planes must be decoded serially */
         public Array32<Array32<int>> Dqcoeff;
         public InternalErrorInfo ErrorInfo;
+
+        public int DecPartitionPlaneContext(int miRow, int miCol, int bsl)
+        {
+            ref sbyte aboveCtx = ref Xd.AboveSegContext[miCol];
+            ref sbyte leftCtx = ref Xd.LeftSegContext[miRow & Constants.MiMask];
+            int above = (aboveCtx >> bsl) & 1, left = (leftCtx >> bsl) & 1;
+
+            return (left * 2) + above + (bsl * Constants.PartitionPloffset);
+        }
     }
-}
+}