import os from emscripten_helpers import run_closure_compiler, create_engine_file, add_js_libraries from SCons.Util import WhereIs def is_active(): return True def get_name(): return "JavaScript" def can_build(): return WhereIs("emcc") is not None def get_opts(): from SCons.Variables import BoolVariable return [ # eval() can be a security concern, so it can be disabled. BoolVariable("javascript_eval", "Enable JavaScript eval interface", True), BoolVariable("threads_enabled", "Enable WebAssembly Threads support (limited browser support)", False), BoolVariable("gdnative_enabled", "Enable WebAssembly GDNative support (produces bigger binaries)", False), BoolVariable("use_closure_compiler", "Use closure compiler to minimize JavaScript code", False), ] def get_flags(): return [ ("tools", False), ("builtin_pcre2_with_jit", False), # Disabling the mbedtls module reduces file size. # The module has little use due to the limited networking functionality # in this platform. For the available networking methods, the browser # manages TLS. ("module_mbedtls_enabled", False), ] def configure(env): ## Build type if env["target"] == "release": # Use -Os to prioritize optimizing for reduced file size. This is # particularly valuable for the web platform because it directly # decreases download time. # -Os reduces file size by around 5 MiB over -O3. -Oz only saves about # 100 KiB over -Os, which does not justify the negative impact on # run-time performance. env.Append(CCFLAGS=["-Os"]) env.Append(LINKFLAGS=["-Os"]) elif env["target"] == "release_debug": env.Append(CCFLAGS=["-Os"]) env.Append(LINKFLAGS=["-Os"]) env.Append(CPPDEFINES=["DEBUG_ENABLED"]) # Retain function names for backtraces at the cost of file size. env.Append(LINKFLAGS=["--profiling-funcs"]) else: # "debug" env.Append(CPPDEFINES=["DEBUG_ENABLED"]) env.Append(CCFLAGS=["-O1", "-g"]) env.Append(LINKFLAGS=["-O1", "-g"]) env.Append(LINKFLAGS=["-s", "ASSERTIONS=1"]) if env["tools"]: if not env["threads_enabled"]: raise RuntimeError( "Threads must be enabled to build the editor. Please add the 'threads_enabled=yes' option" ) # Tools need more memory. Initial stack memory in bytes. See `src/settings.js` in emscripten repository (will be renamed to INITIAL_MEMORY). env.Append(LINKFLAGS=["-s", "TOTAL_MEMORY=33554432"]) elif env["builtin_icu"]: env.Append(CCFLAGS=["-frtti"]) else: # Disable exceptions and rtti on non-tools (template) builds # These flags help keep the file size down. env.Append(CCFLAGS=["-fno-exceptions", "-fno-rtti"]) # Don't use dynamic_cast, necessary with no-rtti. env.Append(CPPDEFINES=["NO_SAFE_CAST"]) ## Copy env variables. env["ENV"] = os.environ # LTO if env["use_lto"]: env.Append(CCFLAGS=["-flto=full"]) env.Append(LINKFLAGS=["-flto=full"]) # Closure compiler if env["use_closure_compiler"]: # For emscripten support code. env.Append(LINKFLAGS=["--closure", "1"]) # Register builder for our Engine files jscc = env.Builder(generator=run_closure_compiler, suffix=".cc.js", src_suffix=".js") env.Append(BUILDERS={"BuildJS": jscc}) # Add helper method for adding libraries. env.AddMethod(add_js_libraries, "AddJSLibraries") # Add method that joins/compiles our Engine files. env.AddMethod(create_engine_file, "CreateEngineFile") # Closure compiler extern and support for ecmascript specs (const, let, etc). env["ENV"]["EMCC_CLOSURE_ARGS"] = "--language_in ECMASCRIPT6" env["CC"] = "emcc" env["CXX"] = "em++" env["AR"] = "emar" env["RANLIB"] = "emranlib" # Use TempFileMunge since some AR invocations are too long for cmd.exe. # Use POSIX-style paths, required with TempFileMunge. env["ARCOM_POSIX"] = env["ARCOM"].replace("$TARGET", "$TARGET.posix").replace("$SOURCES", "$SOURCES.posix") env["ARCOM"] = "${TEMPFILE(ARCOM_POSIX)}" # All intermediate files are just LLVM bitcode. env["OBJPREFIX"] = "" env["OBJSUFFIX"] = ".bc" env["PROGPREFIX"] = "" # Program() output consists of multiple files, so specify suffixes manually at builder. env["PROGSUFFIX"] = "" env["LIBPREFIX"] = "lib" env["LIBSUFFIX"] = ".bc" env["LIBPREFIXES"] = ["$LIBPREFIX"] env["LIBSUFFIXES"] = ["$LIBSUFFIX"] env.Prepend(CPPPATH=["#platform/javascript"]) env.Append(CPPDEFINES=["JAVASCRIPT_ENABLED", "UNIX_ENABLED"]) if env["javascript_eval"]: env.Append(CPPDEFINES=["JAVASCRIPT_EVAL_ENABLED"]) if env["threads_enabled"] and env["gdnative_enabled"]: raise Exception("Threads and GDNative support can't be both enabled due to WebAssembly limitations") # Thread support (via SharedArrayBuffer). if env["threads_enabled"]: env.Append(CPPDEFINES=["PTHREAD_NO_RENAME"]) env.Append(CCFLAGS=["-s", "USE_PTHREADS=1"]) env.Append(LINKFLAGS=["-s", "USE_PTHREADS=1"]) env.Append(LINKFLAGS=["-s", "PTHREAD_POOL_SIZE=8"]) env.Append(LINKFLAGS=["-s", "WASM_MEM_MAX=2048MB"]) env.extra_suffix = ".threads" + env.extra_suffix else: env.Append(CPPDEFINES=["NO_THREADS"]) if env["gdnative_enabled"]: env.Append(CCFLAGS=["-s", "RELOCATABLE=1"]) env.Append(LINKFLAGS=["-s", "RELOCATABLE=1"]) env.extra_suffix = ".gdnative" + env.extra_suffix # Reduce code size by generating less support code (e.g. skip NodeJS support). env.Append(LINKFLAGS=["-s", "ENVIRONMENT=web,worker"]) # Wrap the JavaScript support code around a closure named Godot. env.Append(LINKFLAGS=["-s", "MODULARIZE=1", "-s", "EXPORT_NAME='Godot'"]) # Allow increasing memory buffer size during runtime. This is efficient # when using WebAssembly (in comparison to asm.js) and works well for # us since we don't know requirements at compile-time. env.Append(LINKFLAGS=["-s", "ALLOW_MEMORY_GROWTH=1"]) # This setting just makes WebGL 2 APIs available, it does NOT disable WebGL 1. env.Append(LINKFLAGS=["-s", "USE_WEBGL2=1"]) # Do not call main immediately when the support code is ready. env.Append(LINKFLAGS=["-s", "INVOKE_RUN=0"]) # Allow use to take control of swapping WebGL buffers. env.Append(LINKFLAGS=["-s", "OFFSCREEN_FRAMEBUFFER=1"]) # callMain for manual start. env.Append(LINKFLAGS=["-s", "EXTRA_EXPORTED_RUNTIME_METHODS=['callMain']"]) # Add code that allow exiting runtime. env.Append(LINKFLAGS=["-s", "EXIT_RUNTIME=1"])