Godot-cpp compile for Android

README.md

@@ -76,8 +76,16 @@ $ cd godot-cpp
 $ scons platform=<your platform> generate_bindings=yes
 $ cd ..
 ```
+For android:
+Download the latest [Android NDK](https://developer.android.com/ndk/downloads) from the official website and set NDK path.
+```
+$ scons platform=android generate_bindings=yes ANDROID_NDK_ROOT="/PATH-TO-ANDROID-NDK/" android_arch=<  >
+```
+`android_arch` can be `armv7, arm64v8, x86, x86_64`.
+`ANDROID_NDK_ROOT` can also be set in the environment variables of your computer if you do not want to include it in your Scons call.
+
 
-> Replace `<your platform>` with either `windows`, `linux` or `osx`.
+> Replace `<your platform>` with either `windows`, `linux`, `osx` or `android`.
 
 > Include `use_llvm=yes` for using clang++
 
@@ -189,6 +197,19 @@ $ link /nologo /dll /out:bin\libtest.dll /implib:bin\libsimple.lib src\init.obj
 *macOS*
 For OSX you need to find out what compiler flags need to be used.
 
+*Android*
+```
+$ cd SimpleLibrary
+$ aarch64-linux-android29-clang -fPIC -o src/init.os -c src/init.cpp -g -O3 -std=c++14 -Igodot-cpp/include -Igodot-cpp/include/core -Igodot-cpp/include/gen -Igodot-cpp/godot_headers
+$ aarch64-linux-android29-clang -o bin/libtest.so -shared src/init.os -Lgodot-cpp/bin -l<name of the godot-cpp>
+```
+> use `armv7a-linux-androideabi29-clang` for 32 bit armeabi-v7a library
+
+> This creates the file `libtest.so` in your `SimpleLibrary/bin` directory.
+
+> You will need to replace `<name of the godot-cpp>` with the file that was created in [**Compiling the cpp bindings library**](#compiling-the-cpp-bindings-library)
+
+
 ### Creating `.gdnlib` and `.gdns` files
 follow [godot_header/README.md](https://github.com/GodotNativeTools/godot_headers/blob/master/README.md#how-do-i-use-native-scripts-from-the-editor) to create the `.gdns` 
 

SConstruct

@@ -3,6 +3,41 @@
 import os
 import sys
 
+# Workaround for MinGW. See:
+# http://www.scons.org/wiki/LongCmdLinesOnWin32
+if (os.name=="nt"):
+    import subprocess
+
+    def mySubProcess(cmdline,env):
+        #print "SPAWNED : " + cmdline
+        startupinfo = subprocess.STARTUPINFO()
+        startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
+        proc = subprocess.Popen(cmdline, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE, startupinfo=startupinfo, shell = False, env = env)
+        data, err = proc.communicate()
+        rv = proc.wait()
+        if rv:
+            print("=====")
+            print(err.decode("utf-8"))
+            print("=====")
+        return rv
+
+    def mySpawn(sh, escape, cmd, args, env):
+
+        newargs = ' '.join(args[1:])
+        cmdline = cmd + " " + newargs
+
+        rv=0
+        if len(cmdline) > 32000 and cmd.endswith("ar") :
+            cmdline = cmd + " " + args[1] + " " + args[2] + " "
+            for i in range(3,len(args)) :
+                rv = mySubProcess( cmdline + args[i], env )
+                if rv :
+                    break	
+        else:				
+            rv = mySubProcess( cmdline, env )
+
+        return rv
 
 def add_sources(sources, dir, extension):
     for f in os.listdir(dir):
@@ -29,7 +64,7 @@ opts.Add(EnumVariable(
     'platform',
     'Target platform',
     host_platform,
-    allowed_values=('linux', 'osx', 'windows'),
+    allowed_values=('linux', 'osx', 'windows', 'android'),
     ignorecase=2
 ))
 opts.Add(EnumVariable(
@@ -73,16 +108,33 @@ opts.Add(BoolVariable(
     'Generate GDNative API bindings',
     False
 ))
+opts.Add(EnumVariable(
+    'android_arch',
+    'Target Android architecture',
+    'armv7',
+    ['armv7','arm64v8','x86','x86_64']
+))
+opts.Add(
+    'android_api_level',
+    'Target Android API level',
+    '18' if ARGUMENTS.get("android_arch", 'armv7') in ['armv7', 'x86'] else '21'
+)
+opts.Add(
+    'ANDROID_NDK_ROOT',
+    'Path to your Android NDK installation. By default, uses ANDROID_NDK_ROOT from your defined environment variables.',
+    os.environ.get("ANDROID_NDK_ROOT", None)
+)
 
-env = Environment()
+env = Environment(ENV = os.environ)
 opts.Update(env)
 Help(opts.GenerateHelpText(env))
 
 is64 = sys.maxsize > 2**32
 if (
     env['TARGET_ARCH'] == 'amd64' or
     env['TARGET_ARCH'] == 'emt64' or
-    env['TARGET_ARCH'] == 'x86_64'
+    env['TARGET_ARCH'] == 'x86_64' or
+    env['TARGET_ARCH'] == 'arm64-v8a'
 ):
     is64 = True
 
@@ -92,7 +144,7 @@ if env['bits'] == 'default':
 # This makes sure to keep the session environment variables on Windows.
 # This way, you can run SCons in a Visual Studio 2017 prompt and it will find
 # all the required tools
-if host_platform == 'windows':
+if host_platform == 'windows' and env['platform'] != 'android':
     if env['bits'] == '64':
         env = Environment(TARGET_ARCH='amd64')
     elif env['bits'] == '32':
@@ -173,6 +225,62 @@ elif env['platform'] == 'windows':
             '-static-libgcc',
             '-static-libstdc++',
         ])
+elif env['platform'] == 'android':
+    if host_platform == 'windows':
+        env = env.Clone(tools=['mingw'])
+        env["SPAWN"] = mySpawn
+
+    # Verify NDK root
+    if not 'ANDROID_NDK_ROOT' in env:
+        raise ValueError("To build for Android, ANDROID_NDK_ROOT must be defined. Please set ANDROID_NDK_ROOT to the root folder of your Android NDK installation.")
+
+    # Validate API level
+    api_level = int(env['android_api_level'])
+    if env['android_arch'] in ['x86_64', 'arm64v8'] and api_level < 21:
+        print("WARN: 64-bit Android architectures require an API level of at least 21; setting android_api_level=21")
+        env['android_api_level'] = '21'
+        api_level = 21
+
+    # Setup toolchain
+    toolchain = env['ANDROID_NDK_ROOT'] + "/toolchains/llvm/prebuilt/"
+    if host_platform == "windows":
+        toolchain += "windows"
+        import platform as pltfm
+        if pltfm.machine().endswith("64"):
+            toolchain += "-x86_64"
+    elif host_platform == "linux":
+        toolchain += "linux-x86_64"
+    elif host_platform == "osx":
+        toolchain += "darwin-x86_64"
+    env.PrependENVPath('PATH', toolchain + "/bin") # This does nothing half of the time, but we'll put it here anyways
+
+    # Get architecture info
+    arch_info_table = {
+        "armv7" : {
+            "march":"armv7-a", "target":"armv7a-linux-androideabi", "tool_path":"arm-linux-androideabi", "compiler_path":"armv7a-linux-androideabi",
+            "ccflags" : ['-mfpu=neon']
+            },
+        "arm64v8" : {
+            "march":"armv8-a", "target":"aarch64-linux-android", "tool_path":"aarch64-linux-android", "compiler_path":"aarch64-linux-android",
+            "ccflags" : []
+            },
+        "x86" : {
+            "march":"i686", "target":"i686-linux-android", "tool_path":"i686-linux-android", "compiler_path":"i686-linux-android",
+            "ccflags" : ['-mstackrealign']
+            },
+        "x86_64" : {"march":"x86-64", "target":"x86_64-linux-android", "tool_path":"x86_64-linux-android", "compiler_path":"x86_64-linux-android",
+            "ccflags" : []
+        }
+    }
+    arch_info = arch_info_table[env['android_arch']]
+
+    # Setup tools
+    env['CC'] = toolchain + "/bin/clang"
+    env['CXX'] = toolchain + "/bin/clang++"
+    env['AR'] = toolchain + "/bin/" + arch_info['tool_path'] + "-ar"
+
+    env.Append(CCFLAGS=['--target=' + arch_info['target'] + env['android_api_level'], '-march=' + arch_info['march'], '-fPIC'])#, '-fPIE', '-fno-addrsig', '-Oz'])
+    env.Append(CCFLAGS=arch_info['ccflags'])
 
 env.Append(CPPPATH=[
     '.',
@@ -202,10 +310,11 @@ add_sources(sources, 'src/core', 'cpp')
 add_sources(sources, 'src/gen', 'cpp')
 
 library = env.StaticLibrary(
-    target='bin/' + 'libgodot-cpp.{}.{}.{}'.format(
+    target='bin/' + 'libgodot-cpp.{}.{}.{}{}'.format(
         env['platform'],
         env['target'],
-        env['bits'],
+        env['bits'] if env['platform'] != 'android' else env['android_arch'],
+        env['LIBSUFFIX']
     ), source=sources
 )
 Default(library)