From 692217d1fec9fb0a5d3add6fe03b473eaf61ed75 Mon Sep 17 00:00:00 2001
From: staphen <staphen@gmail.com>
Date: Wed, 3 Nov 2021 22:38:08 -0400
Subject: [PATCH] Add CMake option to use system SDL_image

---
 3rdParty/SDL_image/CMakeLists.txt |  8 ++++++-
 CMake/FindSDL2_image.cmake        | 26 +++++++++++++++++++++++
 CMakeLists.txt                    | 35 +++++++++++++++++++++++++++----
 vcpkg.json                        |  3 ++-
 4 files changed, 66 insertions(+), 6 deletions(-)
 create mode 100644 CMake/FindSDL2_image.cmake

diff --git a/3rdParty/SDL_image/CMakeLists.txt b/3rdParty/SDL_image/CMakeLists.txt
index 4cdeef000..b96650747 100644
--- a/3rdParty/SDL_image/CMakeLists.txt
+++ b/3rdParty/SDL_image/CMakeLists.txt
@@ -14,7 +14,12 @@ else()
 endif()
 FetchContent_MakeAvailableExcludeFromAll(SDL_image)
 
-add_library(SDL_image STATIC ${CMAKE_CURRENT_LIST_DIR}/IMG.c ${sdl_image_SOURCE_DIR}/IMG_png.c)
+if(DEVILUTIONX_STATIC_SDL_IMAGE)
+  add_library(SDL_image STATIC ${CMAKE_CURRENT_LIST_DIR}/IMG.c ${sdl_image_SOURCE_DIR}/IMG_png.c)
+else()
+  add_library(SDL_image SHARED ${CMAKE_CURRENT_LIST_DIR}/IMG.c ${sdl_image_SOURCE_DIR}/IMG_png.c)
+endif()
+
 target_include_directories(SDL_image PRIVATE ${sdl_image_SOURCE_DIR})
 target_compile_definitions(SDL_image PRIVATE LOAD_PNG SDL_IMAGE_USE_COMMON_BACKEND)
 target_link_libraries(SDL_image PNG::PNG)
@@ -23,4 +28,5 @@ if(USE_SDL1)
   target_link_libraries(SDL_image ${SDL_LIBRARY})
 else()
   target_link_libraries(SDL_image SDL2::SDL2)
+  add_library(SDL2::SDL2_image ALIAS SDL_image)
 endif()
diff --git a/CMake/FindSDL2_image.cmake b/CMake/FindSDL2_image.cmake
new file mode 100644
index 000000000..dd7900286
--- /dev/null
+++ b/CMake/FindSDL2_image.cmake
@@ -0,0 +1,26 @@
+find_package(PkgConfig)
+pkg_check_modules(PC_SDL2_image QUIET SDL2_image>=2.0.0)
+
+find_path(SDL2_image_INCLUDE_DIR SDL_image.h
+          HINTS ${PC_SDL2_image_INCLUDEDIR} ${PC_SDL2_image_INCLUDE_DIRS})
+          
+find_library(SDL2_image_LIBRARY
+             NAMES SDL2_image libSDL2_image
+             HINTS ${PC_SDL2_image_LIBDIR} ${PC_SDL2_image_LIBRARY_DIRS})
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(SDL2_image DEFAULT_MSG
+                                  SDL2_image_INCLUDE_DIR SDL2_image_LIBRARY)
+
+if(SDL2_image_FOUND AND NOT TARGET SDL2::SDL2_image)
+  add_library(SDL2::SDL2_image UNKNOWN IMPORTED)
+  set_target_properties(SDL2::SDL2_image PROPERTIES
+                        IMPORTED_LOCATION ${SDL2_image_LIBRARY}
+                        INTERFACE_INCLUDE_DIRECTORIES ${SDL2_image_INCLUDE_DIR})
+endif()
+
+if(SDL2_image_FOUND)
+  mark_as_advanced(SDL2_image_INCLUDE_DIR SDL2_image_LIBRARY)
+  set(SDL2_image_LIBRARIES ${SDL2_image_LIBRARY})
+  set(SDL2_image_INCLUDE_DIRS ${SDL2_image_INCLUDE_DIR})
+endif()
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2121409e9..116da573f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -93,6 +93,10 @@ option(DEVILUTIONX_SYSTEM_LIBPNG "Use system-provided libpng" ON)
 cmake_dependent_option(DEVILUTIONX_STATIC_LIBPNG "Link static libpng" OFF
                        "DEVILUTIONX_SYSTEM_LIBPNG AND NOT DIST" ON)
 
+option(DEVILUTIONX_SYSTEM_SDL_IMAGE "Use system-provided SDL_image" ON)
+cmake_dependent_option(DEVILUTIONX_STATIC_SDL_IMAGE "Link static SDL_image" OFF
+                       "DEVILUTIONX_SYSTEM_SDL_IMAGE AND NOT DIST" ON)
+
 if(NOT VERSION_NUM)
   include(CMake/git.cmake)
   get_git_tag(VERSION_NUM)
@@ -313,7 +317,29 @@ if(NOT NONET AND NOT DISABLE_TCP)
   endif()
 endif()
 
-add_subdirectory(3rdParty/SDL_image)
+if(DEVILUTIONX_SYSTEM_SDL_IMAGE)
+  if(USE_SDL1)
+    find_package(SDL_image QUIET)
+  else()
+    # vcpkg uses sdl2-image as the package name
+    find_package(sdl2-image QUIET)
+    set(SDL_image_FOUND ${sdl2-image_FOUND})
+
+    if(NOT SDL_image_FOUND)
+      # Fall back on PkgConfig via FindSDL2_image.cmake
+      find_package(SDL2_image QUIET)
+      set(SDL_image_FOUND ${SDL2_image_FOUND})
+    endif()
+  endif()
+  if(SDL_image_FOUND)
+    message("-- Found SDL_image")
+  else()
+    message("-- Suitable system SDL_image package not found, will use SDL_image from source")
+  endif()
+endif()
+if(NOT SDL_image_FOUND)
+  add_subdirectory(3rdParty/SDL_image)
+endif()
 
 if(NOT NOSOUND)
   if(DEVILUTIONX_SYSTEM_SDL_AUDIOLIB)
@@ -986,14 +1012,15 @@ endif()
 
 if(USE_SDL1)
   target_link_libraries(libdevilutionx PUBLIC
-    ${SDL_LIBRARY})
+    ${SDL_LIBRARY}
+    SDL_image)
   target_compile_definitions(libdevilutionx PUBLIC USE_SDL1)
 else()
   target_link_libraries(libdevilutionx PUBLIC
     SDL2::SDL2
-    ${SDL2_MAIN})
+    ${SDL2_MAIN}
+    SDL2::SDL2_image)
 endif()
-target_link_libraries(libdevilutionx PUBLIC SDL_image)
 
 if(NOT NOSOUND)
   target_link_libraries(libdevilutionx PUBLIC SDL_audiolib)
diff --git a/vcpkg.json b/vcpkg.json
index 0d2243d09..5719e58fe 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -4,7 +4,8 @@
     "dependencies": [
         "fmt",
         "libpng",
-        "sdl2"
+        "sdl2",
+        "sdl2-image"
     ],
     "features": {
         "encryption": {