From 2d83fff5815d319091d9433b9e19580c3365ec66 Mon Sep 17 00:00:00 2001
From: Castor215 <132155746+Castor215@users.noreply.github.com>
Date: Tue, 17 Oct 2023 19:02:50 +0100
Subject: [PATCH] externals: allow user to use system glslang (#7075)

---
 CMakeLists.txt           |  1 +
 externals/CMakeLists.txt | 25 ++++++++++++++++++-------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 65b16f44e3..393df00d53 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -103,6 +103,7 @@ option(USE_SYSTEM_XBYAK "Use the system xbyak (instead of the bundled one)" OFF)
 option(USE_SYSTEM_INIH "Use the system inih (instead of the bundled one)" OFF)
 option(USE_SYSTEM_FDK_AAC_HEADERS "Use the system fdk-aac headers (instead of the bundled one)" OFF)
 option(USE_SYSTEM_FFMPEG_HEADERS "Use the system FFmpeg headers (instead of the bundled one)" OFF)
+option(USE_SYSTEM_GLSLANG "Use the system glslang and SPIR-V libraries (instead of the bundled ones)" OFF)
 
 if (CITRA_USE_PRECOMPILED_HEADERS)
     message(STATUS "Using Precompiled Headers.")
diff --git a/externals/CMakeLists.txt b/externals/CMakeLists.txt
index f9b24f1b3d..527929b156 100644
--- a/externals/CMakeLists.txt
+++ b/externals/CMakeLists.txt
@@ -117,13 +117,24 @@ endif()
 add_subdirectory(glad)
 
 # glslang
-set(SKIP_GLSLANG_INSTALL ON CACHE BOOL "")
-set(ENABLE_GLSLANG_BINARIES OFF CACHE BOOL "")
-set(ENABLE_SPVREMAPPER OFF CACHE BOOL "")
-set(ENABLE_CTEST OFF CACHE BOOL "")
-set(ENABLE_HLSL OFF CACHE BOOL "")
-set(BUILD_EXTERNAL OFF CACHE BOOL "")
-add_subdirectory(glslang)
+if(USE_SYSTEM_GLSLANG)
+    find_package(glslang REQUIRED)
+    add_library(glslang INTERFACE)
+    add_library(SPIRV INTERFACE)
+    target_link_libraries(glslang INTERFACE glslang::glslang)
+    target_link_libraries(SPIRV INTERFACE glslang::SPIRV)
+    # System include path is different from submodule include path
+    get_target_property(GLSLANG_PREFIX glslang::SPIRV INTERFACE_INCLUDE_DIRECTORIES)
+    target_include_directories(SPIRV SYSTEM INTERFACE "${GLSLANG_PREFIX}/glslang")
+else()
+    set(SKIP_GLSLANG_INSTALL ON CACHE BOOL "")
+    set(ENABLE_GLSLANG_BINARIES OFF CACHE BOOL "")
+    set(ENABLE_SPVREMAPPER OFF CACHE BOOL "")
+    set(ENABLE_CTEST OFF CACHE BOOL "")
+    set(ENABLE_HLSL OFF CACHE BOOL "")
+    set(BUILD_EXTERNAL OFF CACHE BOOL "")
+    add_subdirectory(glslang)
+endif()
 
 # inih
 if(USE_SYSTEM_INIH)