From a69fa0b00d0a61eafa6577a61a80dcee988418fb Mon Sep 17 00:00:00 2001
From: Jean-Baptiste Perrier <jeanbapt.perrier@gmail.com>
Date: Thu, 20 May 2021 17:13:36 +0200
Subject: [PATCH] Add optional command line argument define.

---
 Source/Engine/Engine/CommandLine.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Source/Engine/Engine/CommandLine.cpp b/Source/Engine/Engine/CommandLine.cpp
index edfc9c268..eedc8d356 100644
--- a/Source/Engine/Engine/CommandLine.cpp
+++ b/Source/Engine/Engine/CommandLine.cpp
@@ -102,6 +102,23 @@ bool CommandLine::Parse(const Char* cmdLine)
 			*(end - len) = 0; \
 			end -= len; \
 		}
+    
+#define PARSE_ARG_OPT_SWITCH(text, field) \
+		pos = (Char*)StringUtils::FindIgnoreCase(buffer.Get(), TEXT(text)); \
+		if (pos) \
+		{ \
+			len = ARRAY_COUNT(text) - 1; \
+			if (ParseArg(pos + len, argStart, argEnd)) \
+				Options.field = String::Empty; \
+			else \
+            { \
+			    Options.field = String(argStart, static_cast<int32>(argEnd - argStart)); \
+			    len = static_cast<int32>((argEnd - pos) + 1); \
+			    Platform::MemoryCopy(pos, pos + len, (end - pos - len) * 2); \
+			    *(end - len) = 0; \
+			    end -= len; \
+			} \
+		}
 
     PARSE_BOOL_SWITCH("-windowed ", Windowed);
     PARSE_BOOL_SWITCH("-fullscreen ", Fullscreen);