docs: Add DCO

Signed-off-by: Slendi <slendi@socopon.com>

.github/workflows/format.yml

@@ -0,0 +1,24 @@
+name: Format checks
+
+on:
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  format:
+    name: Format
+    runs-on: ubuntu-22.04
+    permissions:
+      contents: read
+    steps:
+      - name: git checkout
+        uses: actions/checkout@v4
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+      - name: Check clang-format
+        run: |
+          nix develop -c sh -lc 'git ls-files "*.cpp" "*.hpp" "*.cppm" | xargs clang-format --dry-run --Werror'
+      - name: Check cmake-format
+        run: |
+          nix develop -c sh -lc 'cmake-format --check CMakeLists.txt src/modules/CMakeLists.txt cmake/smathConfig.cmake.in'

AGENTS.md

@@ -0,0 +1,11 @@
+# AGENTS.md
+
+Instructions for agents working in this repo.
+
+See the [`CONTRIBUTING.md`](CONTRIBUTING.md) file. Said file **must** be read, examined,
+and understood before any change is made by agents.
+
+For agents that understand `@`-inclusion of other markdown files, said inclusion line for
+`CONTRIBUTING.md` follows, such that explicit reading of the file is not necessary:
+
+@CONTRIBUTING.md

CLAUDE.md

@@ -0,0 +1,7 @@
+# CLAUDE.md
+
+This project's agent guidance lives in [AGENTS.md](AGENTS.md), the single source of truth
+shared with other tools. Claude Code does not load `AGENTS.md` automatically, so it is
+imported here:
+
+@AGENTS.md

CMakeLists.txt

@@ -1,5 +1,8 @@
 cmake_minimum_required(VERSION 3.15)
-project(SmathExamples LANGUAGES CXX VERSION 1.0.0)
+project(
+  SmathExamples
+  LANGUAGES CXX
+  VERSION 1.0.0)
 
 set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -11,105 +14,90 @@ option(SMATH_ENABLE_LEGACY_HEADER "Install legacy include <smath.hpp> shim" OFF)
 option(SMATH_INSTALL_INTEROP_HEADERS "Install interop headers" OFF)
 
 if(SMATH_BUILD_MODULES)
-	message(STATUS "Building smath C++ module")
-	add_subdirectory(src/modules)
+  message(STATUS "Building smath C++ module")
+  add_subdirectory(src/modules)
 endif()
 
 add_library(smath INTERFACE)
-target_include_directories(smath
-	INTERFACE
-		$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-		$<$<BOOL:${SMATH_ENABLE_LEGACY_HEADER}>:$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>>
-		$<INSTALL_INTERFACE:include>
-)
+target_include_directories(
+  smath
+  INTERFACE
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<$<BOOL:${SMATH_ENABLE_LEGACY_HEADER}>:$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>>
+    $<INSTALL_INTERFACE:include>)
 add_library(smath::smath ALIAS smath)
 
 include(CMakePackageConfigHelpers)
-install(TARGETS smath
-	EXPORT smathTargets
-)
+install(TARGETS smath EXPORT smathTargets)
 install(FILES include/smath/smath.hpp DESTINATION include/smath)
 
 if(SMATH_INSTALL_INTEROP_HEADERS)
-	install(DIRECTORY include/smath/interop DESTINATION include/smath)
+  install(DIRECTORY include/smath/interop DESTINATION include/smath)
 endif()
 
 if(SMATH_ENABLE_LEGACY_HEADER)
-	file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/include")
-	configure_file(
-		"${CMAKE_CURRENT_SOURCE_DIR}/cmake/smath_legacy_header.hpp.in"
-		"${CMAKE_CURRENT_BINARY_DIR}/include/smath.hpp"
-		@ONLY
-	)
-	install(FILES "${CMAKE_CURRENT_BINARY_DIR}/include/smath.hpp" DESTINATION include)
+  file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/include")
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/cmake/smath_legacy_header.hpp.in"
+                 "${CMAKE_CURRENT_BINARY_DIR}/include/smath.hpp" @ONLY)
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/include/smath.hpp"
+          DESTINATION include)
 endif()
 
-install(EXPORT smathTargets
-	NAMESPACE smath::
-	FILE smathTargets.cmake
-	DESTINATION lib/cmake/smath
-)
+install(
+  EXPORT smathTargets
+  NAMESPACE smath::
+  FILE smathTargets.cmake
+  DESTINATION lib/cmake/smath)
 
 write_basic_package_version_file(
-	"${CMAKE_CURRENT_BINARY_DIR}/smathConfigVersion.cmake"
-	VERSION ${PROJECT_VERSION}
-	COMPATIBILITY SameMajorVersion
-)
+  "${CMAKE_CURRENT_BINARY_DIR}/smathConfigVersion.cmake"
+  VERSION ${PROJECT_VERSION}
+  COMPATIBILITY SameMajorVersion)
 
 configure_package_config_file(
-	"${CMAKE_CURRENT_SOURCE_DIR}/cmake/smathConfig.cmake.in"
-	"${CMAKE_CURRENT_BINARY_DIR}/smathConfig.cmake"
-	INSTALL_DESTINATION "lib/cmake/smath"
-)
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/smathConfig.cmake.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/smathConfig.cmake"
+  INSTALL_DESTINATION "lib/cmake/smath")
 
-configure_file(
-	"${CMAKE_CURRENT_SOURCE_DIR}/cmake/smath.pc.in"
-	"${CMAKE_CURRENT_BINARY_DIR}/smath.pc"
-	@ONLY
-)
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/cmake/smath.pc.in"
+               "${CMAKE_CURRENT_BINARY_DIR}/smath.pc" @ONLY)
 
-install(FILES "${CMAKE_CURRENT_BINARY_DIR}/smath.pc"
-	DESTINATION lib/pkgconfig
-)
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/smath.pc" DESTINATION lib/pkgconfig)
 
-install(FILES
-	"${CMAKE_CURRENT_BINARY_DIR}/smathConfig.cmake"
-	"${CMAKE_CURRENT_BINARY_DIR}/smathConfigVersion.cmake"
-	DESTINATION lib/cmake/smath
-)
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/smathConfig.cmake"
+              "${CMAKE_CURRENT_BINARY_DIR}/smathConfigVersion.cmake"
+        DESTINATION lib/cmake/smath)
 
 if(SMATH_BUILD_EXAMPLES)
-	file(GLOB EXAMPLE_SOURCES "${CMAKE_SOURCE_DIR}/examples/*.cpp")
-	foreach(EXAMPLE_FILE ${EXAMPLE_SOURCES})
-		get_filename_component(EXAMPLE_NAME ${EXAMPLE_FILE} NAME_WE)
-		add_executable(${EXAMPLE_NAME} ${EXAMPLE_FILE})
-		target_link_libraries(${EXAMPLE_NAME} PRIVATE smath::smath)
-	endforeach()
+  file(GLOB EXAMPLE_SOURCES "${CMAKE_SOURCE_DIR}/examples/*.cpp")
+  foreach(EXAMPLE_FILE ${EXAMPLE_SOURCES})
+    get_filename_component(EXAMPLE_NAME ${EXAMPLE_FILE} NAME_WE)
+    add_executable(${EXAMPLE_NAME} ${EXAMPLE_FILE})
+    target_link_libraries(${EXAMPLE_NAME} PRIVATE smath::smath)
+  endforeach()
 endif()
 
 if(SMATH_BUILD_TESTS)
-	enable_testing()
+  enable_testing()
 
-	find_package(GTest QUIET)
+  find_package(GTest QUIET)
 
-	if(NOT GTest_FOUND)
-		include(FetchContent)
-		FetchContent_Declare(
-			googletest
-			URL https://github.com/google/googletest/archive/refs/tags/v1.15.2.zip
-		)
-		set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
-		FetchContent_MakeAvailable(googletest)
-	endif()
+  if(NOT GTest_FOUND)
+    include(FetchContent)
+    FetchContent_Declare(
+      googletest
+      URL https://github.com/google/googletest/archive/refs/tags/v1.15.2.zip)
+    set(gtest_force_shared_crt
+        ON
+        CACHE BOOL "" FORCE)
+    FetchContent_MakeAvailable(googletest)
+  endif()
 
-	file(GLOB TEST_SOURCES "${CMAKE_SOURCE_DIR}/tests/*.cpp")
+  file(GLOB TEST_SOURCES "${CMAKE_SOURCE_DIR}/tests/*.cpp")
 
-	add_executable(smath_tests ${TEST_SOURCES})
-	target_link_libraries(smath_tests PRIVATE
-		smath::smath
-		GTest::gtest_main
-	)
+  add_executable(smath_tests ${TEST_SOURCES})
+  target_link_libraries(smath_tests PRIVATE smath::smath GTest::gtest_main)
 
-	include(GoogleTest)
-	gtest_discover_tests(smath_tests)
+  include(GoogleTest)
+  gtest_discover_tests(smath_tests)
 endif()

CONTRIBUTING.md

@@ -2,7 +2,9 @@
 
 Welcome to `smath` contributors!
 
-This document contains a set of guidelines to contribute to the project. If you feel like there's a mistake or something can be improved to this document, feel free to propose changes in a pull request.
+This document contains a set of guidelines to contribute to the project. If you
+feel like there's a mistake or something can be improved to this document, feel
+free to propose changes in a pull request.
 
 ## Philosophy
 
@@ -52,6 +54,51 @@ This project uses `clang-format` to maintain a consistent code style. Before ope
 git ls-files '*.hpp' '*.cpp' | xargs clang-format -i
 ```
 
+## Sign-off (DCO)
+
+Every commit must be signed off by at least one (1) human contributor:
+
+```
+git commit -s
+```
+
+This adds a `Signed-off-by: Your Name <your@email>` trailer certifying that you
+wrote the change (or otherwise have reviewed the commit and have the right to
+submit it) and agree to contribute it under the project's license, per the
+Developer Certificate of Origin (the DCO file in this repository - also at
+https://developercertificate.org).
+
+## AI-assisted contributions
+
+AI-assisted contributions are allowed, subject to the following:
+
+- A human must be in the loop at all times. AI tools may assist, but a human
+  contributor must drive the work, review and understand every generated
+  change, and take full responsibility for it. Do not submit code you have not
+  read and understood.
+
+- The assistance must be disclosed. Any commit produced with material AI help
+  must carry an `Assisted-by:` trailer using a format similar to the Linux
+  kernel's AI coding assistant format:
+
+  ```
+  Assisted-by: AGENT_NAME:MODEL_VERSION
+  ```
+
+  `AGENT_NAME` is the AI tool or framework (e.g. Codex, Claude, ...).
+  `MODEL_VERSION` is the full model identifier, all lowercase, including any
+  numeric, snapshot, or version suffix. Do not shorten it to the model family
+  (e.g. use gpt-5-5, not gpt-5; use claude-opus-4-8, not claude-opus).
+
+- Do not add `Co-authored-by:` trailers for the AI assistant. The
+  `Assisted-by:` trailer already serves that purpose.
+
+- The human contributor still signs off (see above). `Signed-off-by:` is the
+  human's certification of, and responsibility for, the change.
+  `Assisted-by:` only records which tool helped. It does not replace the sign-off or the human review.
+
+Unreviewed, bulk, or fully-automated submissions are not accepted.
+
 ## Pull requests
 
 - Keep changes focused and scoped to one topic.

DCO

@@ -0,0 +1,35 @@
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
+

flake.nix

@@ -23,6 +23,7 @@
         devShells.default = pkgs.mkShell {
           packages = with pkgs; [
             cmake
+            cmake-format
             ninja
             clang-tools
             lldb

src/modules/CMakeLists.txt

@@ -5,4 +5,3 @@ target_sources(smath_modules PUBLIC FILE_SET CXX_MODULES FILES smath.cppm)
 target_link_libraries(smath_modules PUBLIC smath::smath)
 
 target_compile_features(smath_modules PUBLIC cxx_std_20)
-

src/modules/smath.cppm

@@ -4,51 +4,52 @@ module;
 
 export module smath;
 
-export namespace smath {
-export using ::smath::Vec;
-export using ::smath::VecOrScalar;
-export using ::smath::Quaternion;
-export using ::smath::Mat;
+export namespace smath
+{
+using ::smath::Mat;
+using ::smath::Quaternion;
+using ::smath::Vec;
+using ::smath::VecOrScalar;
 
-export using ::smath::Vec2;
-export using ::smath::Vec3;
-export using ::smath::Vec4;
+using ::smath::Vec2;
+using ::smath::Vec3;
+using ::smath::Vec4;
 
-export using ::smath::Vec2d;
-export using ::smath::Vec3d;
-export using ::smath::Vec4d;
+using ::smath::Vec2d;
+using ::smath::Vec3d;
+using ::smath::Vec4d;
 
-export using ::smath::Mat2;
-export using ::smath::Mat3;
-export using ::smath::Mat4;
+using ::smath::Mat2;
+using ::smath::Mat3;
+using ::smath::Mat4;
 
-export using ::smath::Mat2d;
-export using ::smath::Mat3d;
-export using ::smath::Mat4d;
+using ::smath::Mat2d;
+using ::smath::Mat3d;
+using ::smath::Mat4d;
 
-export using ::smath::swizzle;
+using ::smath::swizzle;
 
-export using ::smath::deg;
-export using ::smath::rad;
-export using ::smath::turns;
+using ::smath::deg;
+using ::smath::rad;
+using ::smath::turns;
 
-export using ::smath::pack_unorm4x8;
-export using ::smath::pack_snorm4x8;
-export using ::smath::unpack_unorm4x8;
-export using ::smath::unpack_snorm4x8;
+using ::smath::pack_snorm4x8;
+using ::smath::pack_unorm4x8;
+using ::smath::unpack_snorm4x8;
+using ::smath::unpack_unorm4x8;
 
-export using ::smath::operator*;
+using ::smath::operator*;
 
-export using ::smath::translate;
-export using ::smath::rotate;
-export using ::smath::scale;
+using ::smath::rotate;
+using ::smath::scale;
+using ::smath::translate;
 
-export using ::smath::shear_x;
-export using ::smath::shear_y;
-export using ::smath::shear_z;
+using ::smath::shear_x;
+using ::smath::shear_y;
+using ::smath::shear_z;
 
-export using ::smath::matrix_ortho3d;
-export using ::smath::matrix_perspective;
-export using ::smath::matrix_infinite_perspective;
-export using ::smath::matrix_look_at;
-}
+using ::smath::matrix_infinite_perspective;
+using ::smath::matrix_look_at;
+using ::smath::matrix_ortho3d;
+using ::smath::matrix_perspective;
+} // namespace smath