From 77753c85395861be639ff872f69b5d54d9de5c54 Mon Sep 17 00:00:00 2001
From: Cameron Cawley <ccawley2011@gmail.com>
Date: Mon, 5 Jul 2021 16:35:43 +0100
Subject: [PATCH] Resolve WinMain linking issues with CMake

---
 cmake/FindSDL2.cmake            | 25 +++++++++++++------------
 skeleton/CMakeLists.txt         | 15 ++++++++++++++-
 skeleton/sdl2.cpp               |  3 +++
 skeleton/win.cpp                |  3 ++-
 tools/dumprwtree/dumprwtree.cpp |  1 +
 tools/ska2anm/ska2anm.cpp       |  1 +
 6 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/cmake/FindSDL2.cmake b/cmake/FindSDL2.cmake
index 24288b4..38e420c 100644
--- a/cmake/FindSDL2.cmake
+++ b/cmake/FindSDL2.cmake
@@ -1,22 +1,21 @@
-find_package(PkgConfig QUIET)
-if(PKG_CONFIG_FOUND)
-    pkg_check_modules(SDL2 IMPORTED_TARGET "sdl2")
-    if(TARGET PkgConfig::SDL2 AND NOT TARGET SDL2::SDL2)
-        add_library(SDL2::SDL2 INTERFACE IMPORTED)
-        set_property(TARGET SDL2::SDL2 PROPERTY INTERFACE_LINK_LIBRARIES PkgConfig::SDL2)
+# On Windows, SDL2main is included as part of the pkg-config output, which isn't desirable when linking.
+if(NOT WIN32)
+    find_package(PkgConfig QUIET)
+    if(PKG_CONFIG_FOUND)
+        pkg_check_modules(SDL2 IMPORTED_TARGET "sdl2")
+        if(TARGET PkgConfig::SDL2 AND NOT TARGET SDL2::SDL2)
+            add_library(SDL2::SDL2 INTERFACE IMPORTED)
+            set_property(TARGET SDL2::SDL2 PROPERTY INTERFACE_LINK_LIBRARIES PkgConfig::SDL2)
+        endif()
     endif()
 endif()
 
-find_library(SDL2main_LIBRARY SDL2main)
-
 if(NOT SDL2_FOUND)
-    find_path(SDL2_INCLUDE_DIR sdl2.h)
+    find_path(SDL2_INCLUDE_DIR SDL.h PATH_SUFFIXES SDL2)
     find_library(SDL2_LIBRARY SDL2 SDL2d)
 
-    find_library(SDL2main_LIBRARY SDL2main)
-
     include(FindPackageHandleStandardArgs)
-    find_package_handle_standard_args(libuv
+    find_package_handle_standard_args(SDL2
         REQUIRED_VARS SDL2_INCLUDE_DIR SDL2_LIBRARY
     )
 
@@ -29,6 +28,8 @@ if(NOT SDL2_FOUND)
     endif()
 endif()
 
+find_library(SDL2main_LIBRARY SDL2main)
+
 if(SDL2main_LIBRARY AND NOT TARGET SDL2::SDL2main)
     add_library(SDL2::SDL2main UNKNOWN IMPORTED)
     set_target_properties(SDL2::SDL2main PROPERTIES
diff --git a/skeleton/CMakeLists.txt b/skeleton/CMakeLists.txt
index 1c7c031..0492f05 100644
--- a/skeleton/CMakeLists.txt
+++ b/skeleton/CMakeLists.txt
@@ -19,7 +19,6 @@ add_library(librw_skeleton
     imgui/stb_textedit.h
     imgui/stb_truetype.h
 )
-add_library(librw::skeleton ALIAS librw_skeleton)
 
 set_target_properties(librw_skeleton
     PROPERTIES
@@ -38,6 +37,20 @@ target_include_directories(librw_skeleton
         $<INSTALL_INTERFACE:${LIBRW_INSTALL_INCLUDEDIR}/skeleton>
 )
 
+# HACK: When building with MinGW, it's necessary to link to libmingw32.a *before* the library
+# that provides WinMain. To work around this, an intermediate target is created when using MinGW
+# that specifies the correct linking order.
+#
+# TODO: Use SDL_main on platforms that require it
+if(MINGW AND LIBRW_PLATFORM_D3D9)
+    add_library(librw_skeleton_main INTERFACE)
+    find_library(MINGW32_LIBRARY NAMES mingw32)
+    target_link_libraries(librw_skeleton_main INTERFACE ${MINGW32_LIBRARY} librw_skeleton)
+    add_library(librw::skeleton ALIAS librw_skeleton_main)
+else()
+    add_library(librw::skeleton ALIAS librw_skeleton)
+endif()
+
 if(LIBRW_INSTALL)
     install(
         FILES
diff --git a/skeleton/sdl2.cpp b/skeleton/sdl2.cpp
index 4cb7c0f..e65bf4f 100644
--- a/skeleton/sdl2.cpp
+++ b/skeleton/sdl2.cpp
@@ -1,5 +1,8 @@
 #ifdef LIBRW_SDL2
 
+#ifdef _WIN32
+#define SDL_MAIN_HANDLED
+#endif
 #include <rw.h>
 #include "skeleton.h"
 
diff --git a/skeleton/win.cpp b/skeleton/win.cpp
index 9f1ee5a..53c6807 100644
--- a/skeleton/win.cpp
+++ b/skeleton/win.cpp
@@ -1,4 +1,5 @@
 #ifdef _WIN32
+#define SDL_MAIN_HANDLED
 #include <windows.h>
 #include <rw.h>
 #include "skeleton.h"
@@ -291,7 +292,7 @@ SetMousePosition(int x, int y)
 
 #endif
 
-#ifdef RW_OPENGL
+#if defined(RW_OPENGL) && !defined(__MINGW32__)
 int main(int argc, char *argv[]);
 
 int WINAPI
diff --git a/tools/dumprwtree/dumprwtree.cpp b/tools/dumprwtree/dumprwtree.cpp
index ca86d3c..595a57a 100644
--- a/tools/dumprwtree/dumprwtree.cpp
+++ b/tools/dumprwtree/dumprwtree.cpp
@@ -3,6 +3,7 @@
 #include <cstring>
 #include <cassert>
 
+#define SDL_MAIN_HANDLED
 #include <rw.h>
 
 using namespace std;
diff --git a/tools/ska2anm/ska2anm.cpp b/tools/ska2anm/ska2anm.cpp
index 900ba82..71b2572 100644
--- a/tools/ska2anm/ska2anm.cpp
+++ b/tools/ska2anm/ska2anm.cpp
@@ -3,6 +3,7 @@
 #include <string.h>
 #include <assert.h>
 
+#define SDL_MAIN_HANDLED
 #include <rw.h>
 #include <args.h>