Add: introduce CMake for project management

CMake works on all our supported platforms, like MSVC, Mingw, GCC,
Clang, and many more. It allows for a single way of doing things,
so no longer we need shell scripts and vbs scripts to work on all
our supported platforms.

Additionally, CMake allows to generate project files for like MSVC,
KDevelop, etc.

This heavily reduces the lines of code we need to support multiple
platforms from a project perspective.

Addtiionally, this heavily improves our detection of libraries, etc.

1 files changed, 84 insertions, 0 deletions

diff --git a/cmake/Options.cmake b/cmake/Options.cmake
new file mode 100644
index 000000000..b292567f0
--- /dev/null
+++ b/cmake/Options.cmake
@@ -0,0 +1,84 @@
+# Set the options for the directories (personal, shared, global).
+#
+# set_directory_options()
+#
+function(set_directory_options)
+    if (APPLE)
+        set(DEFAULT_PERSONAL_DIR "Documents/OpenTTD")
+        set(DEFAULT_SHARED_DIR "/Library/Application Support/OpenTTD")
+        set(DEFAULT_GLOBAL_DIR "(not set)")
+    elseif (WIN32)
+        set(DEFAULT_PERSONAL_DIR "OpenTTD")
+        set(DEFAULT_SHARED_DIR "(not set)")
+        set(DEFAULT_GLOBAL_DIR "(not set)")
+    elseif (UNIX)
+        set(DEFAULT_PERSONAL_DIR ".openttd")
+        set(DEFAULT_SHARED_DIR "(not set)")
+        set(DEFAULT_GLOBAL_DIR "${CMAKE_INSTALL_PREFIX}/share/games/openttd")
+    else ()
+        message(FATAL_ERROR "Unknown OS found; please consider creating a Pull Request to add support for this OS.")
+    endif ()
+
+    if (NOT PERSONAL_DIR)
+        set(PERSONAL_DIR "${DEFAULT_PERSONAL_DIR}" CACHE STRING "Personal directory")
+        message(STATUS "Detecting Personal Data directory - ${PERSONAL_DIR}")
+    endif (NOT PERSONAL_DIR)
+
+    if (NOT SHARED_DIR)
+        set(SHARED_DIR "${DEFAULT_SHARED_DIR}" CACHE STRING "Shared directory")
+        message(STATUS "Detecting Shared Data directory - ${SHARED_DIR}")
+    endif (NOT SHARED_DIR)
+
+    if (NOT GLOBAL_DIR)
+        set(GLOBAL_DIR "${DEFAULT_GLOBAL_DIR}" CACHE STRING "Global directory")
+        message(STATUS "Detecting Global Data directory - ${GLOBAL_DIR}")
+    endif (NOT GLOBAL_DIR)
+endfunction()
+
+# Set some generic options that influence what is being build.
+#
+# set_options()
+#
+function(set_options)
+    if (UNIX AND NOT APPLE)
+        set(DEFAULT_OPTION_INSTALL_FHS YES)
+    else (UNIX AND NOT APPLE)
+        set(DEFAULT_OPTION_INSTALL_FHS NO)
+    endif (UNIX AND NOT APPLE)
+
+    option(OPTION_DEDICATED "Build dedicated server only (no GUI)" NO)
+    option(OPTION_INSTALL_FHS "Install with Filesstem Hierarchy Standard folders" ${DEFAULT_OPTION_INSTALL_FHS})
+    option(OPTION_USE_ASSERTS "Use assertions; leave enabled for nightlies, betas, and RCs" YES)
+    option(OPTION_USE_THREADS "Use threads" YES)
+endfunction()
+
+# Show the values of the generic options.
+#
+# show_options()
+#
+function(show_options)
+    message(STATUS "Option Dedicated - ${OPTION_DEDICATED}")
+    message(STATUS "Option Install FHS - ${OPTION_INSTALL_FHS}")
+    message(STATUS "Option Use assert - ${OPTION_USE_ASSERTS}")
+    message(STATUS "Option Use threads - ${OPTION_USE_THREADS}")
+endfunction()
+
+# Add the definitions for the options that are selected.
+#
+# add_definitions_based_on_options()
+#
+function(add_definitions_based_on_options)
+    if (OPTION_DEDICATED)
+        add_definitions(-DDEDICATED)
+    endif (OPTION_DEDICATED)
+
+    if (NOT OPTION_USE_THREADS)
+        add_definitions(-DNO_THREADS)
+    endif (NOT OPTION_USE_THREADS)
+
+    if (OPTION_USE_ASSERTS)
+        add_definitions(-DWITH_ASSERT)
+    else (OPTION_USE_ASSERTS)
+        add_definitions(-DNDEBUG)
+    endif (OPTION_USE_ASSERTS)
+endfunction()