Take advantage of IrrlichtMt CMake target (#11287)

With the CMake changes to IrrlichtMt, it's now possible to use a target for IrrlichtMt.
Besides greatly improving the ease of setting up IrrlichtMt for users building the client, it removes the need for Minetest's CMake to include transitive dependencies such as image libraries, cleaning it up a tiny bit. The PR works by finding the IrrlichtMt package and linking to the target it provides. If the package isn't found and it isn't building the client, it will still fall back to using just the headers of old Irrlicht or IrrlichtMt.

2 files changed, 26 insertions, 61 deletions

diff --git a/cmake/Modules/FindIrrlicht.cmake b/cmake/Modules/FindIrrlicht.cmake
deleted file mode 100644
index 1e334652b..000000000
--- a/cmake/Modules/FindIrrlicht.cmake
+++ /dev/null
@@ -1,61 +0,0 @@
-
-mark_as_advanced(IRRLICHT_DLL)
-
-# Find include directory and libraries
-
-# find our fork first, then upstream (TODO: remove this?)
-foreach(libname IN ITEMS IrrlichtMt Irrlicht)
-	string(TOLOWER "${libname}" libname2)
-
-	find_path(IRRLICHT_INCLUDE_DIR NAMES irrlicht.h
-		DOC "Path to the directory with IrrlichtMt includes"
-		PATHS
-		/usr/local/include/${libname2}
-		/usr/include/${libname2}
-		/system/develop/headers/${libname2} #Haiku
-		PATH_SUFFIXES "include/${libname2}"
-	)
-
-	find_library(IRRLICHT_LIBRARY NAMES lib${libname} ${libname}
-		DOC "Path to the IrrlichtMt library file"
-		PATHS
-		/usr/local/lib
-		/usr/lib
-		/system/develop/lib # Haiku
-	)
-
-	if(IRRLICHT_INCLUDE_DIR OR IRRLICHT_LIBRARY)
-		break()
-	endif()
-endforeach()
-
-# Handholding for users
-if(IRRLICHT_INCLUDE_DIR AND (NOT IS_DIRECTORY "${IRRLICHT_INCLUDE_DIR}" OR
-	NOT EXISTS "${IRRLICHT_INCLUDE_DIR}/irrlicht.h"))
-	message(WARNING "IRRLICHT_INCLUDE_DIR was set to ${IRRLICHT_INCLUDE_DIR} "
-		"but irrlicht.h does not exist inside. The path will not be used.")
-	unset(IRRLICHT_INCLUDE_DIR CACHE)
-endif()
-if(WIN32 OR CMAKE_SYSTEM_NAME STREQUAL "Linux" OR APPLE)
-	# (only on systems where we're sure how a valid library looks like)
-	if(IRRLICHT_LIBRARY AND (NOT EXISTS "${IRRLICHT_LIBRARY}" OR
-		NOT IRRLICHT_LIBRARY MATCHES "\\.(a|so|dylib|lib)([.0-9]+)?$"))
-		message(WARNING "IRRLICHT_LIBRARY was set to ${IRRLICHT_LIBRARY} "
-			"but is not a valid library file. The path will not be used.")
-		unset(IRRLICHT_LIBRARY CACHE)
-	endif()
-endif()
-
-# On Windows, find the DLL for installation
-if(WIN32)
-	# If VCPKG_APPLOCAL_DEPS is ON, dll's are automatically handled by VCPKG
-	if(NOT VCPKG_APPLOCAL_DEPS)
-		find_file(IRRLICHT_DLL NAMES IrrlichtMt.dll
-			DOC "Path of the IrrlichtMt dll (for installation)"
-		)
-	endif()
-endif(WIN32)
-
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(Irrlicht DEFAULT_MSG IRRLICHT_LIBRARY IRRLICHT_INCLUDE_DIR)
-
diff --git a/cmake/Modules/MinetestFindIrrlichtHeaders.cmake b/cmake/Modules/MinetestFindIrrlichtHeaders.cmake
new file mode 100644
index 000000000..d33b296d0
--- /dev/null
+++ b/cmake/Modules/MinetestFindIrrlichtHeaders.cmake
@@ -0,0 +1,26 @@
+# Locate Irrlicht or IrrlichtMt headers on system.
+
+foreach(libname IN ITEMS IrrlichtMt Irrlicht)
+	string(TOLOWER "${libname}" libname2)
+
+	find_path(IRRLICHT_INCLUDE_DIR NAMES irrlicht.h
+		DOC "Path to the directory with IrrlichtMt includes"
+		PATHS
+		/usr/local/include/${libname2}
+		/usr/include/${libname2}
+		/system/develop/headers/${libname2} #Haiku
+		PATH_SUFFIXES "include/${libname2}"
+	)
+
+	if(IRRLICHT_INCLUDE_DIR)
+		break()
+	endif()
+endforeach()
+
+# Handholding for users
+if(IRRLICHT_INCLUDE_DIR AND (NOT IS_DIRECTORY "${IRRLICHT_INCLUDE_DIR}" OR
+	NOT EXISTS "${IRRLICHT_INCLUDE_DIR}/irrlicht.h"))
+	message(WARNING "IRRLICHT_INCLUDE_DIR was set to ${IRRLICHT_INCLUDE_DIR} "
+		"but irrlicht.h does not exist inside. The path will not be used.")
+	unset(IRRLICHT_INCLUDE_DIR CACHE)
+endif()