From 40a4456a54fd72d7340696f682e98aa204cee3bb Mon Sep 17 00:00:00 2001
From: Mark Satterthwaite <mark.satterthwaite@epicgames.com>
Date: Wed, 14 Aug 2019 10:54:18 -0400
Subject: [PATCH] Fix conversion of the SampleMask intrinsic from SPIRV, where
 it is an array to Metal where it isn't.

---
 spirv_msl.cpp | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/spirv_msl.cpp b/spirv_msl.cpp
index 694c792d..9ab847c2 100644
--- a/spirv_msl.cpp
+++ b/spirv_msl.cpp
@@ -5161,6 +5161,19 @@ void CompilerMSL::emit_instruction(const Instruction &instruction)
 
 	switch (opcode)
 	{
+	/* UE Change Begin: Sample mask input for Metal is not an array */
+	case OpLoad:
+	{
+		uint32_t id = ops[1];
+		uint32_t ptr = ops[2];
+		if (ir.meta[ptr].decoration.builtin_type == BuiltInSampleMask)
+		{
+			ir.meta[id].decoration.builtin_type = BuiltInSampleMask;
+		}
+		CompilerGLSL::emit_instruction(instruction);
+		break;
+	}
+	/* UE Change End: Sample mask input for Metal is not an array */
 
 	// Comparisons
 	case OpIEqual:
@@ -11844,7 +11857,9 @@ std::string CompilerMSL::access_chain_internal(uint32_t base, const uint32_t *in
 				if (!pending_array_enclose)
 					expr += "]";
 			}
-			else
+			/* UE Change Begin: Sample mask input for Metal is not an array */
+			else if (ir.meta[base].decoration.builtin_type != BuiltInSampleMask)
+			/* UE Change End: Sample mask input for Metal is not an array */
 			{
 				append_index(index);
 			}