sdl3

This module builds SDL 3 from source with rules_cc, as a static library. It has no shared library target. overlay/BUILD.bazel documents the build.

Targets

The module supplies these targets. The CMake name of each target is in parentheses:

@sdl3 (SDL3::SDL3-static)
@sdl3//:sdl3_headers (SDL3::Headers)
@sdl3//:sdl3_test (SDL3::SDL3_test)

A consumer depends on @sdl3 alone and includes <SDL3/SDL.h>. That target carries the public headers, so the build satisfies layering_check.

The module supports Linux, macOS and Windows. On other platforms @sdl3 is incompatible, and a wildcard build therefore skips it. The module needs Bazel 7.4.0 or newer, because rules_cc_autoconf uses attr.string_keyed_label_dict.

On macOS, cc_library compiles SDL's Objective-C sources. A consumer needs no apple_support dependency and no special bazel_dep order.

What the module builds

On Windows and macOS, the module uses the build configuration headers that SDL supplies in include/build_config/. On Linux, the module generates that header with rules_cc_autoconf, from the checks in sdl3_config_checks.bzl, which copy SDL's own CMake checks.

On Linux the module enables the ALSA audio driver and the X11 and Wayland video drivers. It also enables OpenGL through EGL, OpenGL ES 2, Vulkan, the V4L2 camera driver, and the evdev joystick and haptic drivers.

The module disables each backend that has no Bazel module: PulseAudio, PipeWire, JACK, sndio, OSS, KMSDRM, libdecor, D-Bus, libudev, libusb, liburing, GLX, XScrnSaver, XTest, fribidi and libthai.

Runtime requirements

SDL loads X11, Wayland, ALSA and xkbcommon at runtime by soname, and Bazel links none of them into a consumer. Two of them have a minimum version on the machine that runs the program:

libwayland-client 1.20 or newer. The generated protocol code calls wl_proxy_marshal_flags. If that symbol is absent, SDL does not use the Wayland driver.
libxkbcommon 0.5.0 or newer, which is the minimum version in SDL's pkg-config specification.

Patches

The module applies one patch, upstream commit 32c19b9dc. That commit stops a read past the end of a buffer in test/testprocess.c. No 3.4.x release contains it. Delete patches/ and the patches entry in source.json when a release contains it.

Tests

The @sdl3//test package runs the non-interactive programs of test/CMakeLists.txt headless, on the dummy video driver and the dummy audio driver. The one program left out is pretest, which upstream builds for 32-bit Windows only. The presubmit matrix also builds overlay/test_module, which links @sdl3 as a consumer links it.

Upgrading

Compare include/build_config/SDL_build_config.h.cmake between the two releases. Write a check in sdl3_config_checks.bzl for each new #cmakedefine. Delete the check for each entry that upstream removed.
Compare the sdl_glob_sources and sdl_sources calls in CMakeLists.txt with the source lists in overlay/BUILD.bazel. Add a glob for each new backend directory. testsymbols fails to link if a source file is absent.
Examine test/testprocess.c in the new release. If that file limits the EOF search with SDL_strnstr, delete the patch as above.
Set the new version in MODULE.bazel and in overlay/MODULE.bazel. Keep the two files identical, because bcr_validation compares them.
Change the release-3.4.16 links in overlay/ to the new release tag. Correct each line anchor that moved.
Update the hashes with bazel run //tools:update_integrity -- sdl3 --version=<new>. Then start the presubmit matrix.

sdl3_config_checks.bzl gives the procedure to compare the generated Linux header with the output of SDL's own configure step.

License

SDL 3 is under the zlib license. @sdl3//:LICENSE.txt has the text.