Add stencil buffer usage with object layer information

#3080 #967

Source/Shaders/Stencil.hlsl

@@ -0,0 +1,23 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#ifndef __STENCIL__
+#define __STENCIL__
+
+#include "./Flax/Common.hlsl"
+
+// Stencil bits usage (must match RenderBuffers.h)
+// [0] | Object Layer
+// [1] | Object Layer
+// [2] | Object Layer
+// [3] | Object Layer
+// [4] | Object Layer
+// [5] | <unsued>
+// [6] | <unsued>
+// [7] | <unsued>
+#define STENCIL_BUFFER_OBJECT_LAYER(stencil) uint(stencil & 0x1f)
+#ifndef STENCIL_BUFFER_SWIZZLE
+#define STENCIL_BUFFER_SWIZZLE .g
+#endif
+#define STENCIL_BUFFER_LOAD(rt, pos) rt.Load(int3(pos, 0)) STENCIL_BUFFER_SWIZZLE
+
+#endif