SConstruct

#!/usr/bin/env python

EnsureSConsVersion(0, 98, 1)

# System
import glob
import os
import pickle
import sys
from collections import OrderedDict

# Local
import methods
import gles_builders
from platform_methods import run_in_subprocess

# scan possible build platforms

platform_list = []  # list of platforms
platform_opts = {}  # options for each platform
platform_flags = {}  # flags for each platform

active_platforms = []
active_platform_ids = []
platform_exporters = []
platform_apis = []

for x in sorted(glob.glob("platform/*")):
    if not os.path.isdir(x) or not os.path.exists(x + "/detect.py"):
        continue
    tmppath = "./" + x

    sys.path.insert(0, tmppath)
    import detect

    if os.path.exists(x + "/export/export.cpp"):
        platform_exporters.append(x[9:])
    if os.path.exists(x + "/api/api.cpp"):
        platform_apis.append(x[9:])
    if detect.is_active():
        active_platforms.append(detect.get_name())
        active_platform_ids.append(x)
    if detect.can_build():
        x = x.replace("platform/", "")  # rest of world
        x = x.replace("platform\\", "")  # win32
        platform_list += [x]
        platform_opts[x] = detect.get_opts()
        platform_flags[x] = detect.get_flags()
    sys.path.remove(tmppath)
    sys.modules.pop("detect")

methods.save_active_platforms(active_platforms, active_platform_ids)

custom_tools = ["default"]

platform_arg = ARGUMENTS.get("platform", ARGUMENTS.get("p", False))

if os.name == "nt" and (platform_arg == "android" or methods.get_cmdline_bool("use_mingw", False)):
    custom_tools = ["mingw"]
elif platform_arg == "javascript":
    # Use generic POSIX build toolchain for Emscripten.
    custom_tools = ["cc", "c++", "ar", "link", "textfile", "zip"]

# We let SCons build its default ENV as it includes OS-specific things which we don't
# want to have to pull in manually.
# Then we prepend PATH to make it take precedence, while preserving SCons' own entries.
env_base = Environment(tools=custom_tools)
env_base.PrependENVPath("PATH", os.getenv("PATH"))
env_base.PrependENVPath("PKG_CONFIG_PATH", os.getenv("PKG_CONFIG_PATH"))
if "TERM" in os.environ:  # Used for colored output.
    env_base["ENV"]["TERM"] = os.environ["TERM"]

env_base.disabled_modules = []
env_base.use_ptrcall = False
env_base.module_version_string = ""
env_base.msvc = False

env_base.__class__.disable_module = methods.disable_module

env_base.__class__.add_module_version_string = methods.add_module_version_string

env_base.__class__.add_source_files = methods.add_source_files
env_base.__class__.use_windows_spawn_fix = methods.use_windows_spawn_fix
env_base.__class__.split_lib = methods.split_lib

env_base.__class__.add_shared_library = methods.add_shared_library
env_base.__class__.add_library = methods.add_library
env_base.__class__.add_program = methods.add_program
env_base.__class__.CommandNoCache = methods.CommandNoCache
env_base.__class__.disable_warnings = methods.disable_warnings

env_base["x86_libtheora_opt_gcc"] = False
env_base["x86_libtheora_opt_vc"] = False

# avoid issues when building with different versions of python out of the same directory
env_base.SConsignFile(".sconsign{0}.dblite".format(pickle.HIGHEST_PROTOCOL))

# Build options

customs = ["custom.py"]

profile = ARGUMENTS.get("profile", "")
if profile:
    if os.path.isfile(profile):
        customs.append(profile)
    elif os.path.isfile(profile + ".py"):
        customs.append(profile + ".py")

opts = Variables(customs, ARGUMENTS)

# Target build options
opts.Add("p", "Platform (alias for 'platform')", "")
opts.Add("platform", "Target platform (%s)" % ("|".join(platform_list),), "")
opts.Add(BoolVariable("tools", "Build the tools (a.k.a. the Godot editor)", True))
opts.Add(EnumVariable("target", "Compilation target", "debug", ("debug", "release_debug", "release")))
opts.Add("arch", "Platform-dependent architecture (arm/arm64/x86/x64/mips/...)", "")
opts.Add(EnumVariable("bits", "Target platform bits", "default", ("default", "32", "64")))
opts.Add(EnumVariable("optimize", "Optimization type", "speed", ("speed", "size", "none")))
opts.Add(BoolVariable("production", "Set defaults to build Godot for use in production", False))
opts.Add(BoolVariable("use_lto", "Use link-time optimization", False))

# Components
opts.Add(BoolVariable("deprecated", "Enable deprecated features", True))
opts.Add(BoolVariable("gdscript", "Enable GDScript support", True))
opts.Add(BoolVariable("minizip", "Enable ZIP archive support using minizip", True))
opts.Add(BoolVariable("xaudio2", "Enable the XAudio2 audio driver", False))
opts.Add("custom_modules", "A list of comma-separated directory paths containing custom modules to build.", "")
opts.Add(BoolVariable("custom_modules_recursive", "Detect custom modules recursively for each specified path.", True))

# Advanced options
opts.Add(BoolVariable("dev", "If yes, alias for verbose=yes warnings=extra werror=yes", False))
opts.Add(BoolVariable("progress", "Show a progress indicator during compilation", True))
opts.Add(BoolVariable("verbose", "Enable verbose output for the compilation", False))
opts.Add(EnumVariable("warnings", "Level of compilation warnings", "all", ("extra", "all", "moderate", "no")))
opts.Add(BoolVariable("werror", "Treat compiler warnings as errors", False))
opts.Add("extra_suffix", "Custom extra suffix added to the base filename of all generated binary files", "")
opts.Add(BoolVariable("vsproj", "Generate a Visual Studio solution", False))
opts.Add(
    BoolVariable(
        "split_libmodules",
        "Split intermediate libmodules.a in smaller chunks to prevent exceeding linker command line size (forced to True when using MinGW)",
        False,
    )
)
opts.Add(BoolVariable("disable_3d", "Disable 3D nodes for a smaller executable", False))
opts.Add(BoolVariable("disable_advanced_gui", "Disable advanced GUI nodes and behaviors", False))
opts.Add(BoolVariable("no_editor_splash", "Don't use the custom splash screen for the editor", False))
opts.Add("system_certs_path", "Use this path as SSL certificates default for editor (for package maintainers)", "")
opts.Add(BoolVariable("use_precise_math_checks", "Math checks use very precise epsilon (debug option)", False))

# Thirdparty libraries
opts.Add(BoolVariable("builtin_bullet", "Use the built-in Bullet library", True))
opts.Add(BoolVariable("builtin_certs", "Use the built-in SSL certificates bundles", True))
opts.Add(BoolVariable("builtin_embree", "Use the built-in Embree library", True))
opts.Add(BoolVariable("builtin_enet", "Use the built-in ENet library", True))
opts.Add(BoolVariable("builtin_freetype", "Use the built-in FreeType library", True))
opts.Add(BoolVariable("builtin_libogg", "Use the built-in libogg library", True))
opts.Add(BoolVariable("builtin_libpng", "Use the built-in libpng library", True))
opts.Add(BoolVariable("builtin_libtheora", "Use the built-in libtheora library", True))
opts.Add(BoolVariable("builtin_libvorbis", "Use the built-in libvorbis library", True))
opts.Add(BoolVariable("builtin_libvpx", "Use the built-in libvpx library", True))
opts.Add(BoolVariable("builtin_libwebp", "Use the built-in libwebp library", True))
opts.Add(BoolVariable("builtin_wslay", "Use the built-in wslay library", True))
opts.Add(BoolVariable("builtin_mbedtls", "Use the built-in mbedTLS library", True))
opts.Add(BoolVariable("builtin_miniupnpc", "Use the built-in miniupnpc library", True))
opts.Add(BoolVariable("builtin_opus", "Use the built-in Opus library", True))
opts.Add(BoolVariable("builtin_pcre2", "Use the built-in PCRE2 library", True))
opts.Add(BoolVariable("builtin_pcre2_with_jit", "Use JIT compiler for the built-in PCRE2 library", True))
opts.Add(BoolVariable("builtin_recast", "Use the built-in Recast library", True))
opts.Add(BoolVariable("builtin_squish", "Use the built-in squish library", True))
opts.Add(BoolVariable("builtin_xatlas", "Use the built-in xatlas library", True))
opts.Add(BoolVariable("builtin_zlib", "Use the built-in zlib library", True))
opts.Add(BoolVariable("builtin_zstd", "Use the built-in Zstd library", True))

# Compilation environment setup
opts.Add("CXX", "C++ compiler")
opts.Add("CC", "C compiler")
opts.Add("LINK", "Linker")
opts.Add("CCFLAGS", "Custom flags for both the C and C++ compilers")
opts.Add("CFLAGS", "Custom flags for the C compiler")
opts.Add("CXXFLAGS", "Custom flags for the C++ compiler")
opts.Add("LINKFLAGS", "Custom flags for the linker")

# Update the environment to have all above options defined
# in following code (especially platform and custom_modules).
opts.Update(env_base)

# Platform selection: validate input, and add options.

selected_platform = ""

if env_base["platform"] != "":
    selected_platform = env_base["platform"]
elif env_base["p"] != "":
    selected_platform = env_base["p"]
else:
    # Missing `platform` argument, try to detect platform automatically
    if (
        sys.platform.startswith("linux")
        or sys.platform.startswith("dragonfly")
        or sys.platform.startswith("freebsd")
        or sys.platform.startswith("netbsd")
        or sys.platform.startswith("openbsd")
    ):
        selected_platform = "x11"
    elif sys.platform == "darwin":
        selected_platform = "osx"
    elif sys.platform == "win32":
        selected_platform = "windows"
    else:
        print("Could not detect platform automatically. Supported platforms:")
        for x in platform_list:
            print("\t" + x)
        print("\nPlease run SCons again and select a valid platform: platform=<string>")

    if selected_platform != "":
        print("Automatically detected platform: " + selected_platform)

if selected_platform in ["linux", "bsd", "linuxbsd"]:
    if selected_platform == "linuxbsd":
        # Alias for forward compatibility.
        print('Platform "linuxbsd" is still called "x11" in Godot 3.x. Building for platform "x11".')
    # Alias for convenience.
    selected_platform = "x11"

# Make sure to update this to the found, valid platform as it's used through the buildsystem as the reference.
# It should always be re-set after calling `opts.Update()` otherwise it uses the original input value.
env_base["platform"] = selected_platform

# Add platform-specific options.
if selected_platform in platform_opts:
    for opt in platform_opts[selected_platform]:
        opts.Add(opt)

# Update the environment to take platform-specific options into account.
opts.Update(env_base)
env_base["platform"] = selected_platform  # Must always be re-set after calling opts.Update().

# Detect modules.
modules_detected = OrderedDict()
module_search_paths = ["modules"]  # Built-in path.

if env_base["custom_modules"]:
    paths = env_base["custom_modules"].split(",")
    for p in paths:
        try:
            module_search_paths.append(methods.convert_custom_modules_path(p))
        except ValueError as e:
            print(e)
            sys.exit(255)

for path in module_search_paths:
    if path == "modules":
        # Built-in modules don't have nested modules,
        # so save the time it takes to parse directories.
        modules = methods.detect_modules(path, recursive=False)
    else:  # Custom.
        modules = methods.detect_modules(path, env_base["custom_modules_recursive"])
        # Provide default include path for both the custom module search `path`
        # and the base directory containing custom modules, as it may be different
        # from the built-in "modules" name (e.g. "custom_modules/summator/summator.h"),
        # so it can be referenced simply as `#include "summator/summator.h"`
        # independently of where a module is located on user's filesystem.
        env_base.Prepend(CPPPATH=[path, os.path.dirname(path)])
    # Note: custom modules can override built-in ones.
    modules_detected.update(modules)

# Add module options
for name, path in modules_detected.items():
    enabled = True
    sys.path.insert(0, path)
    import config

    try:
        enabled = config.is_enabled()
    except AttributeError:
        pass
    sys.path.remove(path)
    sys.modules.pop("config")
    opts.Add(BoolVariable("module_" + name + "_enabled", "Enable module '%s'" % (name,), enabled))

methods.write_modules(modules_detected)

# Update the environment again after all the module options are added.
opts.Update(env_base)
env_base["platform"] = selected_platform  # Must always be re-set after calling opts.Update().
Help(opts.GenerateHelpText(env_base))

# add default include paths

env_base.Prepend(CPPPATH=["#"])

# configure ENV for platform
env_base.platform_exporters = platform_exporters
env_base.platform_apis = platform_apis

if env_base["use_precise_math_checks"]:
    env_base.Append(CPPDEFINES=["PRECISE_MATH_CHECKS"])

if env_base["target"] == "debug":
    env_base.Append(CPPDEFINES=["DEBUG_MEMORY_ALLOC", "DISABLE_FORCED_INLINE"])

    # The two options below speed up incremental builds, but reduce the certainty that all files
    # will properly be rebuilt. As such, we only enable them for debug (dev) builds, not release.

    # To decide whether to rebuild a file, use the MD5 sum only if the timestamp has changed.
    # http://scons.org/doc/production/HTML/scons-user/ch06.html#idm139837621851792
    env_base.Decider("MD5-timestamp")
    # Use cached implicit dependencies by default. Can be overridden by specifying `--implicit-deps-changed` in the command line.
    # http://scons.org/doc/production/HTML/scons-user/ch06s04.html
    env_base.SetOption("implicit_cache", 1)

if env_base["no_editor_splash"]:
    env_base.Append(CPPDEFINES=["NO_EDITOR_SPLASH"])

if not env_base["deprecated"]:
    env_base.Append(CPPDEFINES=["DISABLE_DEPRECATED"])

if selected_platform in platform_list:
    tmppath = "./platform/" + selected_platform
    sys.path.insert(0, tmppath)
    import detect

    if "create" in dir(detect):
        env = detect.create(env_base)
    else:
        env = env_base.Clone()

    # Generating the compilation DB (`compile_commands.json`) requires SCons 4.0.0 or later.
    from SCons import __version__ as scons_raw_version

    scons_ver = env._get_major_minor_revision(scons_raw_version)

    if scons_ver >= (4, 0, 0):
        env.Tool("compilation_db")
        env.Alias("compiledb", env.CompilationDatabase())

    # 'dev' and 'production' are aliases to set default options if they haven't been set
    # manually by the user.
    if env["dev"]:
        env["verbose"] = methods.get_cmdline_bool("verbose", True)
        env["warnings"] = ARGUMENTS.get("warnings", "extra")
        env["werror"] = methods.get_cmdline_bool("werror", True)
    if env["production"]:
        env["use_static_cpp"] = methods.get_cmdline_bool("use_static_cpp", True)
        env["use_lto"] = methods.get_cmdline_bool("use_lto", True)
        print("use_lto is: " + str(env["use_lto"]))
        env["debug_symbols"] = methods.get_cmdline_bool("debug_symbols", False)
        if not env["tools"] and env["target"] == "debug":
            print(
                "WARNING: Requested `production` build with `tools=no target=debug`, "
                "this will give you a full debug template (use `target=release_debug` "
                "for an optimized template with debug features)."
            )
        if env.msvc:
            print(
                "WARNING: For `production` Windows builds, you should use MinGW with GCC "
                "or Clang instead of Visual Studio, as they can better optimize the "
                "GDScript VM in a very significant way. MSVC LTO also doesn't work "
                "reliably for our use case."
                "If you want to use MSVC nevertheless for production builds, set "
                "`debug_symbols=no use_lto=no` instead of the `production=yes` option."
            )
            Exit(255)

    env.extra_suffix = ""

    if env["extra_suffix"] != "":
        env.extra_suffix += "." + env["extra_suffix"]

    # Environment flags
    CCFLAGS = env.get("CCFLAGS", "")
    env["CCFLAGS"] = ""
    env.Append(CCFLAGS=str(CCFLAGS).split())

    CFLAGS = env.get("CFLAGS", "")
    env["CFLAGS"] = ""
    env.Append(CFLAGS=str(CFLAGS).split())

    CXXFLAGS = env.get("CXXFLAGS", "")
    env["CXXFLAGS"] = ""
    env.Append(CXXFLAGS=str(CXXFLAGS).split())

    LINKFLAGS = env.get("LINKFLAGS", "")
    env["LINKFLAGS"] = ""
    env.Append(LINKFLAGS=str(LINKFLAGS).split())

    # Platform specific flags
    flag_list = platform_flags[selected_platform]
    for f in flag_list:
        if not (f[0] in ARGUMENTS):  # allow command line to override platform flags
            env[f[0]] = f[1]

    # Must happen after the flags definition, so that they can be used by platform detect
    detect.configure(env)

    # Set our C and C++ standard requirements.
    # Prepending to make it possible to override
    # This needs to come after `configure`, otherwise we don't have env.msvc.
    if not env.msvc:
        # Specifying GNU extensions support explicitly, which are supported by
        # both GCC and Clang. This mirrors GCC and Clang's current default
        # compile flags if no -std is specified.
        env.Prepend(CFLAGS=["-std=gnu11"])
        env.Prepend(CXXFLAGS=["-std=gnu++14"])
    else:
        # MSVC doesn't have clear C standard support, /std only covers C++.
        # We apply it to CCFLAGS (both C and C++ code) in case it impacts C features.
        env.Prepend(CCFLAGS=["/std:c++14"])

    # Configure compiler warnings
    if env.msvc:  # MSVC
        # Truncations, narrowing conversions, signed/unsigned comparisons...
        disable_nonessential_warnings = ["/wd4267", "/wd4244", "/wd4305", "/wd4018", "/wd4800"]
        if env["warnings"] == "extra":
            env.Append(CCFLAGS=["/Wall"])  # Implies /W4
        elif env["warnings"] == "all":
            env.Append(CCFLAGS=["/W3"] + disable_nonessential_warnings)
        elif env["warnings"] == "moderate":
            env.Append(CCFLAGS=["/W2"] + disable_nonessential_warnings)
        else:  # 'no'
            env.Append(CCFLAGS=["/w"])
        # Set exception handling model to avoid warnings caused by Windows system headers.
        env.Append(CCFLAGS=["/EHsc"])

        if env["werror"]:
            env.Append(CCFLAGS=["/WX"])
    else:  # GCC, Clang
        version = methods.get_compiler_version(env) or [-1, -1]

        common_warnings = []

        if methods.using_gcc(env):
            common_warnings += ["-Wno-misleading-indentation"]
            if version[0] >= 7:
                common_warnings += ["-Wshadow-local"]
        elif methods.using_clang(env) or methods.using_emcc(env):
            # We often implement `operator<` for structs of pointers as a requirement
            # for putting them in `Set` or `Map`. We don't mind about unreliable ordering.
            common_warnings += ["-Wno-ordered-compare-function-pointers"]

        if env["warnings"] == "extra":
            # Note: enable -Wimplicit-fallthrough for Clang (already part of -Wextra for GCC)
            # once we switch to C++11 or later (necessary for our FALLTHROUGH macro).
            env.Append(CCFLAGS=["-Wall", "-Wextra", "-Wwrite-strings", "-Wno-unused-parameter"] + common_warnings)
            env.Append(CXXFLAGS=["-Wctor-dtor-privacy", "-Wnon-virtual-dtor"])
            if methods.using_gcc(env):
                env.Append(
                    CCFLAGS=[
                        "-Walloc-zero",
                        "-Wduplicated-branches",
                        "-Wduplicated-cond",
                        "-Wstringop-overflow=4",
                        "-Wlogical-op",
                    ]
                )
                env.Append(CXXFLAGS=["-Wnoexcept", "-Wplacement-new=1"])
                if version[0] >= 9:
                    env.Append(CCFLAGS=["-Wattribute-alias=2"])
        elif env["warnings"] == "all":
            env.Append(CCFLAGS=["-Wall"] + common_warnings)
        elif env["warnings"] == "moderate":
            env.Append(CCFLAGS=["-Wall", "-Wno-unused"] + common_warnings)
        else:  # 'no'
            env.Append(CCFLAGS=["-w"])

        if env["werror"]:
            env.Append(CCFLAGS=["-Werror"])
        else:  # always enable those errors
            env.Append(CCFLAGS=["-Werror=return-type"])

    if hasattr(detect, "get_program_suffix"):
        suffix = "." + detect.get_program_suffix()
    else:
        suffix = "." + selected_platform

    if env["target"] == "release":
        if env["tools"]:
            print("Tools can only be built with targets 'debug' and 'release_debug'.")
            sys.exit(255)
        suffix += ".opt"
        env.Append(CPPDEFINES=["NDEBUG"])

    elif env["target"] == "release_debug":
        if env["tools"]:
            suffix += ".opt.tools"
        else:
            suffix += ".opt.debug"
    else:
        if env["tools"]:
            suffix += ".tools"
        else:
            suffix += ".debug"

    if env["arch"] != "":
        suffix += "." + env["arch"]
    elif env["bits"] == "32":
        suffix += ".32"
    elif env["bits"] == "64":
        suffix += ".64"

    suffix += env.extra_suffix

    sys.path.remove(tmppath)
    sys.modules.pop("detect")

    modules_enabled = OrderedDict()
    env.module_icons_paths = []
    env.doc_class_path = {}

    for name, path in modules_detected.items():
        if not env["module_" + name + "_enabled"]:
            continue
        sys.path.insert(0, path)
        env.current_module = name
        import config

        # can_build changed number of arguments between 3.0 (1) and 3.1 (2),
        # so try both to preserve compatibility for 3.0 modules
        can_build = False
        try:
            can_build = config.can_build(env, selected_platform)
        except TypeError:
            print(
                "Warning: module '%s' uses a deprecated `can_build` "
                "signature in its config.py file, it should be "
                "`can_build(env, platform)`." % x
            )
            can_build = config.can_build(selected_platform)
        if can_build:
            config.configure(env)
            # Get doc classes paths (if present)
            try:
                doc_classes = config.get_doc_classes()
                doc_path = config.get_doc_path()
                for c in doc_classes:
                    env.doc_class_path[c] = path + "/" + doc_path
            except Exception:
                pass
            # Get icon paths (if present)
            try:
                icons_path = config.get_icons_path()
                env.module_icons_paths.append(path + "/" + icons_path)
            except Exception:
                # Default path for module icons
                env.module_icons_paths.append(path + "/" + "icons")
            modules_enabled[name] = path

        sys.path.remove(path)
        sys.modules.pop("config")

    env.module_list = modules_enabled

    methods.update_version(env.module_version_string)

    env["PROGSUFFIX"] = suffix + env.module_version_string + env["PROGSUFFIX"]
    env["OBJSUFFIX"] = suffix + env["OBJSUFFIX"]
    # (SH)LIBSUFFIX will be used for our own built libraries
    # LIBSUFFIXES contains LIBSUFFIX and SHLIBSUFFIX by default,
    # so we need to append the default suffixes to keep the ability
    # to link against thirdparty libraries (.a, .so, .lib, etc.).
    if os.name == "nt":
        # On Windows, only static libraries and import libraries can be
        # statically linked - both using .lib extension
        env["LIBSUFFIXES"] += [env["LIBSUFFIX"]]
    else:
        env["LIBSUFFIXES"] += [env["LIBSUFFIX"], env["SHLIBSUFFIX"]]
    env["LIBSUFFIX"] = suffix + env["LIBSUFFIX"]
    env["SHLIBSUFFIX"] = suffix + env["SHLIBSUFFIX"]

    if env.use_ptrcall:
        env.Append(CPPDEFINES=["PTRCALL_ENABLED"])
    if env["tools"]:
        env.Append(CPPDEFINES=["TOOLS_ENABLED"])
    if env["disable_3d"]:
        if env["tools"]:
            print(
                "Build option 'disable_3d=yes' cannot be used with 'tools=yes' (editor), "
                "only with 'tools=no' (export template)."
            )
            sys.exit(255)
        else:
            env.Append(CPPDEFINES=["_3D_DISABLED"])
    if env["gdscript"]:
        env.Append(CPPDEFINES=["GDSCRIPT_ENABLED"])
    if env["disable_advanced_gui"]:
        if env["tools"]:
            print(
                "Build option 'disable_advanced_gui=yes' cannot be used with 'tools=yes' (editor), "
                "only with 'tools=no' (export template)."
            )
            sys.exit(255)
        else:
            env.Append(CPPDEFINES=["ADVANCED_GUI_DISABLED"])
    if env["minizip"]:
        env.Append(CPPDEFINES=["MINIZIP_ENABLED"])

    editor_module_list = ["freetype", "regex"]
    for x in editor_module_list:
        if not env["module_" + x + "_enabled"]:
            if env["tools"]:
                print(
                    "Build option 'module_" + x + "_enabled=no' cannot be used with 'tools=yes' (editor), "
                    "only with 'tools=no' (export template)."
                )
                sys.exit(255)

    if not env["verbose"]:
        methods.no_verbose(sys, env)

    if not env["platform"] == "server":  # FIXME: detect GLES3
        env.Append(
            BUILDERS={
                "GLES3_GLSL": env.Builder(
                    action=run_in_subprocess(gles_builders.build_gles3_headers), suffix="glsl.gen.h", src_suffix=".glsl"
                )
            }
        )
        env.Append(
            BUILDERS={
                "GLES2_GLSL": env.Builder(
                    action=run_in_subprocess(gles_builders.build_gles2_headers), suffix="glsl.gen.h", src_suffix=".glsl"
                )
            }
        )

    scons_cache_path = os.environ.get("SCONS_CACHE")
    if scons_cache_path != None:
        CacheDir(scons_cache_path)
        print("Scons cache enabled... (path: '" + scons_cache_path + "')")

    if env["vsproj"]:
        env.vs_incs = []
        env.vs_srcs = []

    Export("env")

    # build subdirs, the build order is dependent on link order.

    SConscript("core/SCsub")
    SConscript("servers/SCsub")
    SConscript("scene/SCsub")
    SConscript("editor/SCsub")
    SConscript("drivers/SCsub")

    SConscript("platform/SCsub")
    SConscript("modules/SCsub")
    SConscript("main/SCsub")

    SConscript("platform/" + selected_platform + "/SCsub")  # build selected platform

    # Microsoft Visual Studio Project Generation
    if env["vsproj"]:
        env["CPPPATH"] = [Dir(path) for path in env["CPPPATH"]]
        methods.generate_vs_project(env, GetOption("num_jobs"))
        methods.generate_cpp_hint_file("cpp.hint")

    # Check for the existence of headers
    conf = Configure(env)
    if "check_c_headers" in env:
        for header in env["check_c_headers"]:
            if conf.CheckCHeader(header[0]):
                env.AppendUnique(CPPDEFINES=[header[1]])

elif selected_platform != "":
    if selected_platform == "list":
        print("The following platforms are available:\n")
    else:
        print('Invalid target platform "' + selected_platform + '".')
        print("The following platforms were detected:\n")

    for x in platform_list:
        print("\t" + x)

    print("\nPlease run SCons again and select a valid platform: platform=<string>")

    if selected_platform == "list":
        # Exit early to suppress the rest of the built-in SCons messages
        sys.exit(0)
    else:
        sys.exit(255)

# The following only makes sense when the 'env' is defined, and assumes it is.
if "env" in locals():
    methods.show_progress(env)
    # TODO: replace this with `env.Dump(format="json")`
    # once we start requiring SCons 4.0 as min version.
    methods.dump(env)