Work on fetch sdl

CMakeLists.txt

@@ -228,6 +228,7 @@ endif()
 #------------------------------------------------------------------------------
 if (EMSCRIPTEN AND NOT HELLOIMGUI_USE_SDL_OPENGL3 AND NOT HELLOIMGUI_USE_GLFW_OPENGL3)
     set(HELLOIMGUI_USE_SDL_OPENGL3 ON)
+    set(HELLOIMGUI_USE_GLFW_OPENGL3 OFF)
 endif()
 
 

external/CMakeLists.txt

@@ -45,17 +45,3 @@ if (HELLOIMGUI_BUILD_IMGUI)
     endif()
 endif()
 
-if (HELLOIMGUI_USE_SDL_OPENGL3)
-    # On desktop (linux, windows, osx) sdl is provided via vcpkg
-    # On iOS, the build is done externally via tools/ios/sdl_compile_ios.sh
-
-    if (ANDROID OR IOS)
-        # if the folder SDL is not present, it means that the user did not download the submodule
-        # we download it for him
-        if(NOT IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/SDL)
-            message(FATAL_ERROR "Please download SDL by running ${HELLOIMGUI_BASEPATH}/tools/sdl_download.sh")
-        endif()
-
-        add_subdirectory(SDL)
-    endif()
-endif()

hello_imgui_cmake/android/apkCMake/templates/sdl/apkCMake_makeSymLinks.cmake

@@ -2,4 +2,7 @@ function(apkCMake_makeSymLinks)
     set(links_folder ${apkCMake_outputProjectFolder}/app/jni)
     file(CREATE_LINK ${HELLOIMGUI_BASEPATH} ${links_folder}/hello_imgui_subrepo SYMBOLIC)
     file(CREATE_LINK ${CMAKE_CURRENT_SOURCE_DIR} ${links_folder}/appDir SYMBOLIC)
+
+    # apkCMake_sdl_symlink_target was filled by _him_prepare_android_sdl_symlink() is src/hello_imgui/CMakeLists.txt
+    file(CREATE_LINK ${apkCMake_sdl_symlink_target} ${links_folder}/SDL SYMBOLIC)
 endfunction()

hello_imgui_cmake/android/apkCMake/templates/sdl/gradle_template/app/jni/CMakeLists.txt.in

@@ -17,3 +17,4 @@ add_subdirectory(appDir)
 if (NOT TARGET hello_imgui)
     add_subdirectory(hello_imgui_subrepo)
 endif()
+add_subdirectory(SDL)

src/hello_imgui/CMakeLists.txt

@@ -1,6 +1,7 @@
 ###################################################################################################
 # Global variables and + objective-c++ for apple
 ###################################################################################################
+include(FetchContent)
 
 # Set target name
 set(helloimgui_target hello_imgui)
@@ -16,13 +17,6 @@ endif()
 # Global variable for this file
 set(imgui_backends_dir ${HELLOIMGUI_IMGUI_SOURCE_DIR}/backends)
 
-# Force emscripten to use opengl3 + sdl
-# (this is dirty, maybe this should be done at the root CMakeLists.txt, to be more visible)
-if (EMSCRIPTEN)
-    set(HELLOIMGUI_USE_SDL_OPENGL3 ON)
-    set(HELLOIMGUI_USE_GLFW_OPENGL3 OFF)
-endif()
-
 
 ###################################################################################################
 # Add library and sources: API = him_add_target
@@ -90,6 +84,7 @@ function(him_add_linux_options)
     endif()
 endfunction()
 
+
 ###################################################################################################
 # Windows related options: API = him_add_windows_options
 ###################################################################################################
@@ -185,14 +180,59 @@ endfunction()
 # SDL backend: API = him_use_sdl2_backend
 ###################################################################################################
 function (him_use_sdl2_backend target)
+    _him_fetch_sdl_if_needed()
+    _him_link_sdl(${helloimgui_target})
+
     target_sources(${target} PRIVATE
         ${imgui_backends_dir}/imgui_impl_sdl2.h
         ${imgui_backends_dir}/imgui_impl_sdl2.cpp
     )
-    _him_link_sdl(${helloimgui_target})
     target_compile_definitions(${helloimgui_target} PUBLIC HELLOIMGUI_USE_SDL)
 endfunction()
 
+
+function(_him_fetch_sdl_if_needed)
+    if (HELLOIMGUI_USE_SDL_OPENGL3 AND (IOS OR ANDROID))
+        _him_fetch_declare_sdl()
+        if(ANDROID)
+            FetchContent_Populate(sdl)
+            _him_prepare_android_sdl_symlink()
+        endif()
+        if(IOS)
+            FetchContent_MakeAvailable(sdl)
+        endif()
+    endif()
+endfunction()
+
+function(_him_prepare_android_sdl_symlink)
+    # We now have SDL in _deps/sdl-src
+    set(sdl_location ${CMAKE_BINARY_DIR}/_deps/sdl-src)
+    # We need to communicate this location to the function apkCMake_makeSymLinks()
+    # so that it can create the symlinks in the right place:
+    # it will use the variable apkCMake_sdl_symlink_target
+    set(apkCMake_sdl_symlink_target ${CMAKE_BINARY_DIR}/_deps/sdl-src CACHE STRING "" FORCE)
+endfunction()
+
+function(_him_fetch_declare_sdl)
+    # iOS and Android were tested with SDL 2.28.5
+    # other platforms, not yet
+    if (IOS OR ANDROID)
+        set(sdl_version 2.28.5)
+    else()
+        set(sdl_version 2.24.2)
+    endif()
+
+    message(STATUS "Fetching SDL version ${sdl_version}")
+    include(FetchContent)
+    Set(FETCHCONTENT_QUIET FALSE)
+    FetchContent_Declare(sdl
+        GIT_REPOSITORY    https://github.com/libsdl-org/SDL.git
+        GIT_TAG           release-${sdl_version}
+        GIT_PROGRESS TRUE
+    )
+endfunction()
+
+
 function(_him_link_sdl target)
     if (need_fetch_make_available_sdl)
         FetchContent_MakeAvailable(sdl)