libakgl/CMakeLists.txt

cmake_minimum_required(VERSION 3.10)
# The single source of truth for the library version. It drives the generated
# include/akgl/version.h, the shared library's VERSION and SOVERSION, and the
# Version field in akgl.pc. Bump it here and nowhere else.
project(akgl VERSION 0.8.0 LANGUAGES C)

# Memory checking reuses the suites that already exist -- `ctest -T memcheck`
# runs every registered test under valgrind -- rather than adding programs of its
# own. The perf suites carry most of the weight there: they are the only things
# in the tree that load assets, draw a scene, and run a frame loop in one
# process, and tests/benchutil.h drops their iteration counts by three orders of
# magnitude when it finds itself under valgrind, which turns a benchmark into
# exactly the broad, once-through path coverage a leak check wants.
#
# These have to be set before include(CTest): that is what writes them into
# DartConfiguration.tcl, and a memcheck run reads them from there.
find_program(MEMORYCHECK_COMMAND valgrind)
# Set with FORCE, but only when empty. include(CTest) declares both of these as
# empty cache entries, so a build tree configured before this block existed has
# them already and a plain set(... CACHE ...) would be ignored -- the values
# would silently never reach DartConfiguration.tcl. Guarding on emptiness still
# leaves a deliberate -DMEMORYCHECK_SUPPRESSIONS_FILE=... alone.
if(NOT MEMORYCHECK_SUPPRESSIONS_FILE)
  set(MEMORYCHECK_SUPPRESSIONS_FILE
      "${CMAKE_CURRENT_SOURCE_DIR}/scripts/valgrind.supp"
      CACHE FILEPATH "Suppressions for third-party findings the memcheck run cannot fix" FORCE)
endif()
# Definite losses only. "Still reachable" is every global SDL and FreeType keeps
# for the process lifetime and says nothing about libakgl; "possibly lost" is
# dominated by interior pointers into pools and thread stacks. Neither is worth
# the false positives.
if(NOT MEMORYCHECK_COMMAND_OPTIONS)
  set(MEMORYCHECK_COMMAND_OPTIONS
      "--leak-check=full --show-leak-kinds=definite --errors-for-leak-kinds=definite --track-origins=yes --num-callers=25"
      CACHE STRING "Options passed to the memory checker" FORCE)
endif()

include(CTest)
option(AKGL_COVERAGE "Instrument libakgl and generate coverage reports with CTest" OFF)

# -Wall is always on for code this project owns. -Werror is not, and the
# distinction is deliberate.
#
# libakgl is consumed with add_subdirectory() -- akbasic does exactly that -- so
# a target-level -Werror makes every new compiler diagnostic a broken build for
# somebody else's project. The warning set is not even stable across build types
# here: an -O2 build reports ten -Wstringop-truncation warnings that -O0 and
# -fsyntax-only do not, because they need the middle end. A newer GCC or a
# switch to clang moves the line again.
#
# So the errors live in CI, where the compiler is pinned and a new warning is a
# task for the maintainer rather than an outage for a consumer.
option(AKGL_WERROR "Treat compiler warnings as errors. For CI; leave OFF when embedding." OFF)
set(AKGL_WARNING_FLAGS -Wall)
if(AKGL_WERROR)
  list(APPEND AKGL_WARNING_FLAGS -Werror)
endif()

# -Wextra is deliberately not here. It adds 22 findings, 17 of which are
# inherent to the design rather than defects: 13 -Wunused-parameter, because a
# backend vtable entry or an SDL callback has to match a signature whether it
# reads every argument or not, and 4 -Wimplicit-fallthrough from libakerror's
# own PROCESS/HANDLE/HANDLE_GROUP, which fall through between case labels by
# design. Adopting it would mean disabling both permanently to gain 5
# -Wsign-compare. See deps/libakerror/TODO.md item 8.

if(AKGL_COVERAGE)
  if(NOT CMAKE_C_COMPILER_ID MATCHES "GNU|Clang")
    message(FATAL_ERROR "AKGL_COVERAGE requires GCC or Clang")
  endif()
  find_program(GCOVR_EXECUTABLE gcovr REQUIRED)
endif()

# Vendored projects own their test suites. Suppress their CTest registration so
# the suite that runs contains only the targets built here. The override is
# lifted again below, before this project registers its own tests.
#
# **Only when this project is top-level, and that guard is load-bearing.** CMake
# exposes an overridden command as `_name` and chains exactly one level deep: a
# second override rebinds `_add_test` to the *first* override and the builtin
# becomes unreachable to everybody, forever. So two projects in one tree cannot
# both shadow add_test() -- whoever goes second breaks, and an embedding
# consumer that shadows it first sees its own registrations recurse until CMake
# stops at depth 1000.
#
# An embedded libakgl therefore leaves the override alone and lets its consumer
# suppress what it does not want; the consumer has to have that machinery
# anyway, for libakerror and libakstdlib. libakstdlib guards its own shadow the
# same way and for the same reason.
if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  set(AKGL_SUPPRESS_DEPENDENCY_TESTS TRUE)
  function(add_test)
    if(NOT AKGL_SUPPRESS_DEPENDENCY_TESTS)
      _add_test(${ARGV})
    endif()
  endfunction()
  function(set_tests_properties)
    if(NOT AKGL_SUPPRESS_DEPENDENCY_TESTS)
      _set_tests_properties(${ARGV})
    endif()
  endfunction()
endif()

set(JANSSON_WITHOUT_TESTS ON CACHE BOOL "Do not build vendored Jansson tests" FORCE)
set(JANSSON_EXAMPLES OFF CACHE BOOL "Do not build vendored Jansson examples" FORCE)
set(JANSSON_BUILD_DOCS OFF CACHE BOOL "Do not build vendored Jansson docs" FORCE)

# Add one vendored dependency, if nobody has already declared it and the
# submodule is actually checked out.
#
# A macro rather than a function on purpose: add_subdirectory() inside a
# function runs with that function's variable scope, so every cache-ish variable
# these projects set for their own subdirectories would be discarded on return.
macro(akgl_add_vendored_dependency target dir)
  if(NOT TARGET ${target})
    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${dir}/CMakeLists.txt")
      add_subdirectory(${dir} EXCLUDE_FROM_ALL)
      set(AKGL_VENDORED_DEPENDENCIES TRUE)
    endif()
  endif()
endmacro()

# Added on both paths, not just when this is the top-level project. Embedded
# with add_subdirectory(), the submodules under deps/ are sitting right there --
# the recursive clone the consumer just did put them there -- and refusing to
# configure until SDL3 is installed system-wide is a failure with its own answer
# three directories away. if(NOT TARGET ...) means a consumer that has already
# declared one of these wins; the EXISTS check means a checkout without
# submodules falls through to find_package below.
akgl_add_vendored_dependency(jansson::jansson deps/jansson)
akgl_add_vendored_dependency(akerror::akerror deps/libakerror)
akgl_add_vendored_dependency(akstdlib::akstdlib deps/libakstdlib)
akgl_add_vendored_dependency(SDL3::SDL3 deps/SDL)
akgl_add_vendored_dependency(SDL3_image::SDL3_image deps/SDL_image)
akgl_add_vendored_dependency(SDL3_mixer::SDL3_mixer deps/SDL_mixer)
akgl_add_vendored_dependency(SDL3_ttf::SDL3_ttf deps/SDL_ttf)

# libakerror sizes its own status-name registry; consumers no longer do. libakgl
# claims its status codes at runtime in akgl_heap_init() instead.
#
# The floor is 2.0.1, and it is a hard one. 2.0.0 moved __akerr_last_ignored to
# thread-local storage and made akerr_next_error() return a context that already
# holds its reference -- both of which expand at *libakgl's* call sites through
# IGNORE and the FAIL macros, and at a *consumer's* too, because akerror.h is
# part of libakgl's public interface. A tree that mixes headers and libraries
# across that line double-counts every reference and never returns a pool slot.
# The soname moved to libakerror.so.2 to stop it happening by accident; the
# #error in include/akgl/error.h catches a stale header in an install tree.

set(AKGL_SUPPRESS_DEPENDENCY_TESTS FALSE)

# Anything the vendored block did not supply has to come from the system.
if(NOT (TARGET SDL3::SDL3 AND TARGET SDL3_image::SDL3_image AND
        TARGET SDL3_mixer::SDL3_mixer AND TARGET SDL3_ttf::SDL3_ttf AND
        TARGET akerror::akerror AND TARGET akstdlib::akstdlib AND
        TARGET jansson::jansson))
  # Only needed to locate installed copies; a fully vendored build does not
  # require pkg-config to be present at all.
  find_package(PkgConfig REQUIRED)
endif()

if(NOT TARGET SDL3::SDL3)
  find_package(SDL3 REQUIRED)
endif()
if(NOT TARGET SDL3_image::SDL3_image)
  find_package(SDL3_image REQUIRED)
endif()
if(NOT TARGET SDL3_mixer::SDL3_mixer)
  find_package(SDL3_mixer REQUIRED)
endif()
if(NOT TARGET SDL3_ttf::SDL3_ttf)
  find_package(SDL3_ttf REQUIRED)
endif()
# No version here: libakerror ships no akerrorConfigVersion.cmake, so asking
# for one makes find_package reject every install. The floor is enforced by
# the #error in include/akgl/error.h instead, which feature-tests
# AKERR_FIRST_CONSUMER_STATUS and AKERR_EXIT_STATUS_UNREPRESENTABLE -- the
# latter arriving in 2.0.1, which is the version libakgl needs.
if(NOT TARGET akerror::akerror)
  find_package(akerror REQUIRED)
endif()
# 0.2 rather than bare: libakstdlib 0.2.0 ships an akstdlibConfigVersion.cmake
# with SameMinorVersion compatibility, mirroring its soname, so this accepts
# any 0.2.x and refuses 0.3 and 1.0. Unversioned, this path would silently
# accept an ABI-incompatible libakstdlib.
if(NOT TARGET akstdlib::akstdlib)
  find_package(akstdlib 0.2 REQUIRED)
endif()
if(NOT TARGET jansson::jansson)
  find_package(jansson)
endif()

# Every header installed into include/akgl/, by base name. This list is the
# single source of truth for two things that must not drift apart: what gets
# installed, and what the `headers` suite proves is self-contained. Adding a
# header here is all a new one needs. SDL_GameControllerDB.h and the generated
# version.h are installed separately -- neither is an API header.
set(AKGL_PUBLIC_HEADERS
  actor
  assets
  audio
  character
  collision
  collision_arena
  controller
  draw
  error
  game
  heap
  iterator
  json_helpers
  physics
  registry
  renderer
  sprite
  staticstring
  text
  tilemap
  types
  util
)

set(GAMECONTROLLERDB_H "include/akgl/SDL_GameControllerDB.h")
set(prefix      ${CMAKE_INSTALL_PREFIX})
set(exec_prefix "\${prefix}")
set(libdir      "\${exec_prefix}/lib")
set(includedir  "\${prefix}/include")
configure_file(${CMAKE_CURRENT_SOURCE_DIR}/akgl.pc.in ${CMAKE_CURRENT_BINARY_DIR}/akgl.pc @ONLY)
configure_file(${CMAKE_CURRENT_SOURCE_DIR}/include/akgl/version.h.in
               ${CMAKE_CURRENT_BINARY_DIR}/include/akgl/version.h @ONLY)

# Tests use both relative paths and SDL_GetBasePath(), so stage fixtures beside
# test executables in every out-of-tree build.
file(COPY "${CMAKE_CURRENT_SOURCE_DIR}/tests/assets"
     DESTINATION "${CMAKE_CURRENT_BINARY_DIR}")

# Regenerating the controller database is a deliberate act, not part of a build.
#
# This used to be an add_custom_command whose OUTPUT was the *relative* path
# "include/akgl/SDL_GameControllerDB.h", which CMake resolves against the binary
# directory while the script writes to the source directory. The declared output
# therefore never appeared, the command was permanently out of date, and every
# build re-ran it -- so every build needed network access and left the tracked
# header dirty with a fresh $(date) stamp.
#
# `cmake --build build --target controllerdb` when newer mappings are actually
# wanted. The result is its own commit, per AGENTS.md.
if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  set(AKGL_CONTROLLERDB_TARGET controllerdb)
else()
  set(AKGL_CONTROLLERDB_TARGET akgl_controllerdb)
endif()
add_custom_target(${AKGL_CONTROLLERDB_TARGET}
  COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/mkcontrollermappings.sh ${CMAKE_CURRENT_SOURCE_DIR}
  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
  USES_TERMINAL
  COMMENT "Fetching controller mappings and rewriting ${GAMECONTROLLERDB_H} ..."
)

# libccd supplies the collision narrowphase (GJK, EPA and MPR).
#
# Its sources are listed here rather than add_subdirectory()'d. Four things in
# deps/libccd/CMakeLists.txt make it unusable as a subproject, and none of them
# is ours to fix in a submodule:
#
#   - project(libccd) declares no LANGUAGES, so it enables CXX and makes a C++
#     toolchain a requirement of every build of libakgl. CI installs gcc.
#   - it declares option(BUILD_SHARED_LIBS ... ON), a global cache variable, and
#     calls include(CTest), which would register its own suites into ours and
#     build the LGPL-licensed CU framework under src/testsuites/.
#   - install(FILES "${CMAKE_BINARY_DIR}/ccd.pc") reads the *top level* binary
#     dir while configure_file writes CMAKE_CURRENT_BINARY_DIR. Those are the
#     same directory standalone and different ones embedded, so `cmake --install`
#     fails on a missing file.
#   - cmake_minimum_required(VERSION 2.8.11) warns on CMake 3.28 and is a hard
#     error on CMake 4.
#
# Compiling the sources directly, the way deps/semver/semver.c already is, sidesteps
# all four and never configures the LGPL testsuites at all.
set(CCD_SINGLE 1)
configure_file(
  ${CMAKE_CURRENT_SOURCE_DIR}/deps/libccd/src/ccd/config.h.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}/ccd/config.h)

set(AKGL_CCD_SOURCES
  deps/libccd/src/ccd.c
  deps/libccd/src/mpr.c
  deps/libccd/src/polytope.c
  deps/libccd/src/support.c
  deps/libccd/src/vec3.c)

# Add include directories
include_directories(${SDL3_INCLUDE_DIRS})
add_library(akgl SHARED
  deps/semver/semver.c
  ${AKGL_CCD_SOURCES}
  src/actor.c
  src/collision.c
  src/collision_arena.c
  src/collision_bsp.c
  src/collision_grid.c
  src/collision_shape.c
  src/actor_state_string_names.c
  src/audio.c
  src/text.c
  src/assets.c
  src/character.c
  src/draw.c
  src/error.c
  src/game.c
  src/controller.c
  src/heap.c
  src/json_helpers.c
  src/registry.c
  src/renderer.c
  src/physics.c
  src/sprite.c
  src/staticstring.c
  src/tilemap.c
  src/util.c
  src/version.c
)

# While the major version is 0 the ABI is not stable across minor releases, so
# the soname carries major.minor -- libakgl.so.0.1. A plain SOVERSION 0 would
# claim 0.1.0 and 0.2.0 are interchangeable, which is exactly the silent
# mispairing the soname is here to prevent. At 1.0.0 this becomes the major
# alone, matching libakerror.
if(PROJECT_VERSION_MAJOR EQUAL 0)
  set(AKGL_SOVERSION "${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}")
else()
  set(AKGL_SOVERSION "${PROJECT_VERSION_MAJOR}")
endif()

set_target_properties(akgl PROPERTIES
  VERSION ${PROJECT_VERSION}
  SOVERSION ${AKGL_SOVERSION}
)

target_compile_options(akgl PRIVATE ${AKGL_WARNING_FLAGS})
# deps/semver/semver.c is vendored and listed directly in add_library(), so the
# target's PRIVATE options reach it. Exempt it: a future semver update must not
# be able to fail this build. (PRIVATE options do not reach SDL, jansson,
# akerror or akstdlib -- those are separate targets.)
set_source_files_properties(deps/semver/semver.c PROPERTIES COMPILE_OPTIONS "-w")

# libccd is vendored on the same terms as semver: -w so a future bump cannot fail
# this build on a warning we do not own.
#
# src/ccd_arena_shim.h is what keeps the "libakgl does not call malloc at
# runtime" promise true with the whole of libccd compiled in. Injected with
# -include, it redirects both halves of libccd's allocation -- the
# __CCD_ALLOC_MEMORY macro every CCD_ALLOC* expands to, and the four bare free()
# calls -- at the arena in src/collision_arena.c. It applies to these five files
# and nothing else.
#
# The redirect lives in that header rather than in COMPILE_DEFINITIONS because
# CMake cannot carry a function-like macro through a -D: it dropped it silently,
# and libccd went on calling the C library while free() became a no-op. Do not
# move it back.
#
# CCD_STATIC_DEFINE plus -fvisibility=hidden keeps every ccd* symbol out of
# libakgl.so's dynamic table. That is not tidiness: AGENTS.md records a shipped
# defect where an exported `renderer` in this library was preempted by a
# same-named symbol in a test executable, and a game linking both libakgl and a
# system libccd would hit exactly that.
set_source_files_properties(${AKGL_CCD_SOURCES} PROPERTIES
  COMPILE_OPTIONS "-w;-fvisibility=hidden;-include;${CMAKE_CURRENT_SOURCE_DIR}/src/ccd_arena_shim.h"
  COMPILE_DEFINITIONS "CCD_STATIC_DEFINE")

# PRIVATE, so that ccd/*.h never reaches a consumer's include path. The `headers`
# suite compiles each public header as the first include of a translation unit
# with only include/ available, so a public header that pulled in <ccd/ccd.h>
# would fail there immediately.
target_include_directories(akgl PRIVATE
  "${CMAKE_CURRENT_SOURCE_DIR}/deps/libccd/src"
  "${CMAKE_CURRENT_BINARY_DIR}")

add_library(akgl::akgl ALIAS akgl)

add_executable(charviewer util/charviewer.c)
add_executable(akgl_test_semver_unit deps/semver/semver_unit.c)

# Every suite here is a standalone C program named tests/<name>.c, built as
# akgl_test_<name> and registered with CTest under <name>.
set(AKGL_TEST_SUITES
  actor
  audio
  bitmasks
  character
  collision
  collision_arena
  controller
  draw
  error
  game
  headers
  heap
  json_helpers
  partition
  physics
  physics_sim
  registry
  renderer
  sprite
  staticstring
  text
  tilemap
  util
  version
)

# The performance suites are built and registered exactly like the unit suites,
# but they are benchmarks: they drive hot paths for millions of iterations, print
# a table of nanoseconds per operation, and fail only when a measurement exceeds
# a budget set at roughly ten times the recorded baseline. They carry the `perf`
# label, so `ctest -L perf` runs only them and `ctest -LE perf` leaves them out
# of an ordinary run, and they get a much longer timeout for obvious reasons.
#
# Set AKGL_BENCH_SCALE in the environment to change how long they run --
# `AKGL_BENCH_SCALE=0.1 ctest -L perf` for a tenth of the iterations. Below 1.0
# the budgets are measured and reported but not enforced, because a short run is
# a noisy one.
set(AKGL_PERF_SUITES
  perf
  perf_render
)

# The executables carry an akgl_ prefix but the CTest names do not: a vendored
# dependency is free to ship its own tests/version.c, and libakstdlib now does.
# Its target is created by add_subdirectory even though EXCLUDE_FROM_ALL keeps
# it from being built, so an unprefixed test_version here is a configure error.
foreach(suite IN LISTS AKGL_TEST_SUITES AKGL_PERF_SUITES)
  add_executable(akgl_test_${suite} tests/${suite}.c)
  add_test(NAME ${suite} COMMAND akgl_test_${suite})
endforeach()

add_test(NAME semver_unit COMMAND akgl_test_semver_unit)

# Not a C program, so it is not in AKGL_TEST_SUITES: it reads the built library's
# dynamic symbol table and every public header, and fails when a function with
# external linkage is declared nowhere. That is an ABI question rather than a
# behavioural one, and nineteen symbols had drifted out of the headers before
# anything was checking.
add_test(
  NAME api_surface
  COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/scripts/check_api_surface.sh
          $<TARGET_FILE:akgl>
          ${CMAKE_CURRENT_SOURCE_DIR}/include
          ${CMAKE_CURRENT_BINARY_DIR}/include
)
set_tests_properties(api_surface PROPERTIES SKIP_RETURN_CODE 2)

# The two akerror control-flow rules whose failure mode is silent: a *_RETURN
# inside an ATTEMPT block, and a return out of a HANDLE block. Neither produces
# a compiler diagnostic and neither fails a test run until the pool it drains is
# empty, which is why both have already shipped.
#
# The mutation target below wants the same interpreter; find_package caches, so
# asking here as well costs nothing and keeps this block self-contained.
find_package(Python3 COMPONENTS Interpreter)
if(Python3_Interpreter_FOUND)
  add_test(
    NAME error_protocol
    COMMAND ${Python3_EXECUTABLE}
            ${CMAKE_CURRENT_SOURCE_DIR}/scripts/check_error_protocol.py
            ${CMAKE_CURRENT_SOURCE_DIR}/src
  )
endif()

# One translation unit per public header, each including exactly that header and
# nothing before it. This is the only shape that proves a header is
# self-contained: a second #include in the same file proves nothing about the
# second, because by then the first has dragged its dependencies in. Generated
# rather than written by hand so the check cannot fall behind
# AKGL_PUBLIC_HEADERS -- the failure being guarded against is a header nobody
# remembered to cover.
set(AKGL_HEADER_SELFTEST_SOURCES "")
foreach(header IN LISTS AKGL_PUBLIC_HEADERS)
  set(generated "${CMAKE_CURRENT_BINARY_DIR}/tests/header_${header}.c")
  file(WRITE "${generated}"
"/* Generated by CMakeLists.txt from AKGL_PUBLIC_HEADERS. Do not edit. */\n\
#include <akgl/${header}.h>\n\
\n\
/* ISO C forbids an empty translation unit; the compile is the assertion. */\n\
int akgl_header_selftest_${header}(void);\n\
int akgl_header_selftest_${header}(void)\n\
{\n\
    return 0;\n\
}\n")
  list(APPEND AKGL_HEADER_SELFTEST_SOURCES "${generated}")
endforeach()
target_sources(akgl_test_headers PRIVATE ${AKGL_HEADER_SELFTEST_SOURCES})
# Hand-written rather than generated: it checks a header's behaviour under a
# caller-supplied override, which is not something the generated shape covers.
target_sources(akgl_test_headers PRIVATE tests/header_pool_override.c)

# TIMEOUT is generous because CTest applies the same property to `ctest -T
# memcheck`, where every suite runs under valgrind at something like twenty
# times its normal cost. The unit suites finish in well under a second each
# without it; the ceiling is there for the checked run, not the ordinary one.
set_tests_properties(
  ${AKGL_TEST_SUITES} semver_unit
  PROPERTIES WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/tests" TIMEOUT 300
)

set_tests_properties(
  ${AKGL_PERF_SUITES}
  PROPERTIES
    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/tests"
    TIMEOUT 900
    LABELS perf
)

# Specify include directories for the library's headers (if applicable)
target_include_directories(akgl PUBLIC
  include/
  deps/semver/
  # akgl/version.h is generated by configure_file, so it lives in the build tree
  # rather than beside the headers it is included from.
  ${CMAKE_CURRENT_BINARY_DIR}/include/
  )

if(AKGL_COVERAGE)
  target_compile_options(akgl PRIVATE --coverage -O0 -g)
  target_link_options(akgl PRIVATE --coverage)

  set(AKGL_COVERAGE_DIR "${CMAKE_CURRENT_BINARY_DIR}/coverage")
  file(MAKE_DIRECTORY "${AKGL_COVERAGE_DIR}")

  # Both gcovr invocations take the build tree as an explicit positional search
  # path, and neither passes --object-directory.
  #
  # gcovr looks for .gcda/.gcno under its search paths, and with none given it
  # searches --root -- the source directory, which is where developers keep
  # their build trees. --object-directory does *not* narrow that: per gcovr's
  # own help it only identifies "the path between gcda files and the directory
  # where the compiler was originally run". So every instrumented tree left
  # inside the source directory was folded into the report alongside the one
  # being measured, and with two trees describing different line numbers for the
  # same function, coverage_reset failed before any test ran:
  #
  #     AssertionError: Got function akgl_game_lowfps on multiple lines: 45, 46
  #
  # The `build*/` entry in .gitignore hides those trees from git status, which
  # makes the state easy to get into and hard to notice.

  add_test(
    NAME coverage_reset
    COMMAND ${GCOVR_EXECUTABLE}
            --root "${CMAKE_CURRENT_SOURCE_DIR}"
            --delete
            "${CMAKE_CURRENT_BINARY_DIR}"
  )
  set_tests_properties(coverage_reset PROPERTIES FIXTURES_SETUP akgl_coverage)
  # Any suite missing from this list runs outside the fixture and has its
  # counters discarded by coverage_reset. The perf suites are deliberately
  # outside it: an instrumented -O0 build measures gcov, not libakgl, and the
  # lines they cover are covered by the unit suites anyway.
  set_tests_properties(
    ${AKGL_TEST_SUITES} semver_unit
    PROPERTIES FIXTURES_REQUIRED akgl_coverage
  )

  add_test(
    NAME coverage_report
    COMMAND ${GCOVR_EXECUTABLE}
            --root "${CMAKE_CURRENT_SOURCE_DIR}"
            --filter "${CMAKE_CURRENT_SOURCE_DIR}/src/"
            --xml-pretty
            --xml "${AKGL_COVERAGE_DIR}/coverage.xml"
            --html-details "${AKGL_COVERAGE_DIR}/index.html"
            "${CMAKE_CURRENT_BINARY_DIR}"
  )
  set_tests_properties(
    coverage_report
    PROPERTIES
      FIXTURES_CLEANUP akgl_coverage
      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
  )
endif()

target_link_libraries(akgl
  PUBLIC
    SDL3::SDL3
    SDL3_image::SDL3_image
    SDL3_mixer::SDL3_mixer
    SDL3_ttf::SDL3_ttf
    akstdlib::akstdlib
    akerror::akerror
    jansson::jansson
)
  
foreach(suite IN LISTS AKGL_TEST_SUITES AKGL_PERF_SUITES)
  target_link_libraries(akgl_test_${suite} PRIVATE akstdlib::akstdlib akerror::akerror akgl SDL3::SDL3 SDL3_ttf::SDL3_ttf SDL3_image::SDL3_image SDL3_mixer::SDL3_mixer  jansson::jansson -lm)
  target_include_directories(akgl_test_${suite} PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/tests")
  target_compile_options(akgl_test_${suite} PRIVATE ${AKGL_WARNING_FLAGS})
endforeach()

target_link_libraries(charviewer PRIVATE akstdlib::akstdlib akerror::akerror akgl SDL3::SDL3 SDL3_ttf::SDL3_ttf SDL3_image::SDL3_image SDL3_mixer::SDL3_mixer  jansson::jansson -lm)
target_compile_options(charviewer PRIVATE ${AKGL_WARNING_FLAGS})

# When the vendored SDL satellite libraries are built in-tree they land in per-
# project subdirectories that are not on the loader's default search path, so a
# freshly built test aborts before main() with "cannot open shared object file".
# Bake those directories into the build-tree RPATH. Installed builds resolve the
# same libraries through find_package and need no help, so this keys on whether
# anything was actually vendored rather than on being the top-level project.
if(AKGL_VENDORED_DEPENDENCIES)
  set(AKGL_VENDORED_RPATH
    "$<TARGET_FILE_DIR:SDL3::SDL3>"
    "$<TARGET_FILE_DIR:SDL3_image::SDL3_image>"
    "$<TARGET_FILE_DIR:SDL3_ttf::SDL3_ttf>"
    "$<TARGET_FILE_DIR:SDL3_mixer::SDL3_mixer>"
    "$<TARGET_FILE_DIR:akerror::akerror>"
    "$<TARGET_FILE_DIR:akstdlib::akstdlib>"
  )
  foreach(suite IN LISTS AKGL_TEST_SUITES AKGL_PERF_SUITES)
    set_target_properties(akgl_test_${suite} PROPERTIES BUILD_RPATH "${AKGL_VENDORED_RPATH}")
  endforeach()
  set_target_properties(charviewer akgl PROPERTIES BUILD_RPATH "${AKGL_VENDORED_RPATH}")

  # RPATH alone is not enough: LD_LIBRARY_PATH is searched first, so a developer
  # who has previously run rebuild.sh has an installed libakgl.so ahead of the
  # one under test. Prepend the build tree for the CTest run so the suite always
  # exercises what was just compiled.
  set(AKGL_TEST_LIBPATH
    "${CMAKE_CURRENT_BINARY_DIR}"
    "${CMAKE_CURRENT_BINARY_DIR}/deps/SDL"
    "${CMAKE_CURRENT_BINARY_DIR}/deps/SDL_image"
    "${CMAKE_CURRENT_BINARY_DIR}/deps/SDL_ttf"
    "${CMAKE_CURRENT_BINARY_DIR}/deps/SDL_mixer"
    "${CMAKE_CURRENT_BINARY_DIR}/deps/libakerror"
    "${CMAKE_CURRENT_BINARY_DIR}/deps/libakstdlib"
  )
  if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.22")
    set(AKGL_TEST_ENV_MOD "")
    foreach(dir IN LISTS AKGL_TEST_LIBPATH)
      list(APPEND AKGL_TEST_ENV_MOD "LD_LIBRARY_PATH=path_list_prepend:${dir}")
    endforeach()
    set_tests_properties(
      ${AKGL_TEST_SUITES} ${AKGL_PERF_SUITES}
      PROPERTIES ENVIRONMENT_MODIFICATION "${AKGL_TEST_ENV_MOD}"
    )
  else()
    string(REPLACE ";" ":" AKGL_TEST_LIBPATH_JOINED "${AKGL_TEST_LIBPATH}")
    set_tests_properties(
      ${AKGL_TEST_SUITES} ${AKGL_PERF_SUITES}
      PROPERTIES ENVIRONMENT "LD_LIBRARY_PATH=${AKGL_TEST_LIBPATH_JOINED}:$ENV{LD_LIBRARY_PATH}"
    )
  endif()
endif()

# ---------------------------------------------------------------------------
# The documentation's own examples.
#
# docs/ is a manual full of C snippets, asset files and shell commands, and the
# README this project started with proves what happens to samples nothing
# executes: unbalanced PASS() calls, a stray `9` inside a bitmask expression, an
# `int screenwidth = NULL`, and the exact strncpy call AGENTS.md forbids. Two
# prose claims in the headers were false against src/ as well.
#
# Documentation goes stale because the *code* moved, not because somebody edited
# a chapter, so this is an ordinary test case rather than something a docs-only
# CI job runs behind a path filter: it fails when the library changes under the
# chapter, which is exactly the case a path filter would miss.
#
# tests/docs_examples.sh reads the fence info strings; docs/MAINTENANCE.md
# documents them.
# ---------------------------------------------------------------------------

# The snippets compile against the real include path, which is transitive
# through akerror, akstdlib, SDL3, SDL3_image and jansson. Writing it out from
# the target's own INCLUDE_DIRECTORIES keeps one source of truth: a hardcoded -I
# list in the script would rot exactly the way the documentation does.
#
# INTERFACE_INCLUDE_DIRECTORIES of the linked targets as well as libakgl's own,
# because akerror.h and akstdlib.h are part of libakgl's public interface and
# neither lives under include/akgl. akgl's own INCLUDE_DIRECTORIES does not
# carry them -- they arrive at a consumer through target_link_libraries -- so
# taking only that property leaves a snippet unable to find <akerror.h>.
set(AKGL_DOCS_DEPENDENCY_TARGETS
  SDL3::SDL3
  SDL3_image::SDL3_image
  SDL3_mixer::SDL3_mixer
  SDL3_ttf::SDL3_ttf
  akstdlib::akstdlib
  akerror::akerror
  jansson::jansson
)

set(AKGL_DOCS_CFLAGS_FILE "${CMAKE_CURRENT_BINARY_DIR}/docs_cflags.txt")
# Each entry is wrapped in $<$<BOOL:...>:...>, because a target whose property
# is empty would otherwise contribute a bare `-I` line that swallows the next
# flag. $<FILTER> and $<REMOVE_DUPLICATES> would say it more directly and both
# need CMake 3.15; this file declares 3.10 and means it.
set(AKGL_DOCS_CFLAGS "$<$<BOOL:$<TARGET_PROPERTY:akgl,INCLUDE_DIRECTORIES>>:-I$<JOIN:$<TARGET_PROPERTY:akgl,INCLUDE_DIRECTORIES>,\n-I>\n>")
foreach(_docstarget IN LISTS AKGL_DOCS_DEPENDENCY_TARGETS)
  string(APPEND AKGL_DOCS_CFLAGS
    "$<$<BOOL:$<TARGET_PROPERTY:${_docstarget},INTERFACE_INCLUDE_DIRECTORIES>>:-I$<JOIN:$<TARGET_PROPERTY:${_docstarget},INTERFACE_INCLUDE_DIRECTORIES>,\n-I>\n>")
endforeach()
file(GENERATE
  OUTPUT  "${AKGL_DOCS_CFLAGS_FILE}"
  CONTENT "${AKGL_DOCS_CFLAGS}"
)

# The link line for the `c run=` and `c screenshot=` blocks. Full library paths
# plus an rpath entry per directory: a vendored build leaves the SDL satellite
# libraries in per-project subdirectories that are not on the loader's default
# search path, which is the same problem AKGL_VENDORED_RPATH solves for the test
# executables.
set(AKGL_DOCS_LDFLAGS_FILE "${CMAKE_CURRENT_BINARY_DIR}/docs_ldflags.txt")
set(AKGL_DOCS_LDFLAGS "")
foreach(_docstarget akgl ${AKGL_DOCS_DEPENDENCY_TARGETS})
  string(APPEND AKGL_DOCS_LDFLAGS "$<TARGET_LINKER_FILE:${_docstarget}>\n")
  string(APPEND AKGL_DOCS_LDFLAGS "-Wl,-rpath,$<TARGET_FILE_DIR:${_docstarget}>\n")
endforeach()
string(APPEND AKGL_DOCS_LDFLAGS "-lm\n")
file(GENERATE
  OUTPUT  "${AKGL_DOCS_LDFLAGS_FILE}"
  CONTENT "${AKGL_DOCS_LDFLAGS}"
)

# The json kind= validator: a host that brings libakgl up headless and hands the
# block to the loader that really reads that format. Not a test of its own -- it
# answers a question about a document rather than about the library -- and not
# instrumented, so a documentation run cannot flatter the coverage figure.
add_executable(akgl_docs_checkjson tools/docs_checkjson.c)
target_compile_options(akgl_docs_checkjson PRIVATE ${AKGL_WARNING_FLAGS})
target_link_libraries(akgl_docs_checkjson
  PRIVATE akstdlib::akstdlib akerror::akerror akgl SDL3::SDL3 jansson::jansson -lm)
if(AKGL_VENDORED_DEPENDENCIES)
  set_target_properties(akgl_docs_checkjson PROPERTIES BUILD_RPATH "${AKGL_VENDORED_RPATH}")
endif()

# tools/docs_screenshot.c is deliberately not a target here. It supplies main()
# for a program whose other translation unit is a block of markdown, so it is
# compiled by tools/docs_screenshots.sh together with the listing it is hosting;
# there is nothing for `all` to build.

add_test(
  NAME docs_examples
  COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/tests/docs_examples.sh
          --root         "${CMAKE_CURRENT_SOURCE_DIR}"
          --cflags-file  "${AKGL_DOCS_CFLAGS_FILE}"
          --ldflags-file "${AKGL_DOCS_LDFLAGS_FILE}"
          --checkjson    $<TARGET_FILE:akgl_docs_checkjson>
)
# Every argument is spelled out rather than assembled from a generator
# expression: an expression that evaluates to nothing still contributes an
# *empty argument*, which the script reads as the first filename. akbasic's
# suite passed having checked no documents at all that way, and was caught only
# because it reports what it ran.
set_tests_properties(docs_examples PROPERTIES
  WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
  TIMEOUT 900
  ENVIRONMENT "SDL_VIDEODRIVER=dummy;SDL_AUDIODRIVER=dummy;SDL_RENDER_DRIVER=software"
)

# Every figure in docs/ re-rendered and byte-compared against the tracked copy.
# docs_examples only asks whether the file *exists*, which catches a figure that
# was never generated and not one that stopped being of the code beside it --
# and that second failure is the one this whole arrangement is against.
#
# **A byte comparison of a rendered PNG is a deliberate bet**: that the dummy
# video driver and the software renderer are reproducible run to run and build to
# build. What is untested is an SDL upgrade that shifts one pixel of a diagonal,
# and the answer to that is to regenerate the figures in the same commit as the
# bump -- not to weaken this to a size check, which would pass for every wrong
# picture that happened to be 320x240.
add_test(
  NAME docs_screenshots
  COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/tools/docs_screenshots.sh
          --root         "${CMAKE_CURRENT_SOURCE_DIR}"
          --cflags-file  "${AKGL_DOCS_CFLAGS_FILE}"
          --ldflags-file "${AKGL_DOCS_LDFLAGS_FILE}"
          --check
)
set_tests_properties(docs_screenshots PROPERTIES
  WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
  TIMEOUT 900
  ENVIRONMENT "SDL_VIDEODRIVER=dummy;SDL_AUDIODRIVER=dummy;SDL_RENDER_DRIVER=software"
)

# Regenerating the figures is a deliberate act, never part of a build: the PNGs
# are tracked, and a rebuild that silently rewrote them would put a binary diff
# in front of anybody who happened to run `make`. Same contract as the
# controllerdb target above, and for the same reason.
if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  set(AKGL_DOCS_SCREENSHOTS_TARGET docs_screenshots)
else()
  set(AKGL_DOCS_SCREENSHOTS_TARGET akgl_docs_screenshots)
endif()
add_custom_target(${AKGL_DOCS_SCREENSHOTS_TARGET}
  COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/tools/docs_screenshots.sh"
          --root         "${CMAKE_CURRENT_SOURCE_DIR}"
          --cflags-file  "${AKGL_DOCS_CFLAGS_FILE}"
          --ldflags-file "${AKGL_DOCS_LDFLAGS_FILE}"
  DEPENDS akgl
  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
  COMMENT "Regenerating the documentation figures in docs/images"
  VERBATIM
)

# The two tutorial games. Guarded because they are written by a later pass and
# an absent directory must not break the configure -- and guarded again inside
# examples/CMakeLists.txt, one game at a time, for the same reason.
if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/examples/CMakeLists.txt")
  add_subdirectory(examples)

  # The figures at the top of chapters 20 and 21 are frames out of the games
  # themselves, taken by --screenshot between the world being drawn and the
  # frame being presented. Same contract as docs_screenshots above: deliberate,
  # never part of a build, because the PNGs are tracked.
  #
  # There is no --check counterpart. docs_screenshots can compare because its
  # figures are one deterministic frame of drawing calls; a game frame is not.
  # The sidescroller drives its physics from the wall clock, so which pixel the
  # player occupies depends on how fast the machine ran, and a byte comparison
  # would fail for reasons that have nothing to do with the documentation.
  add_custom_target(docs_game_figures
    COMMAND ${CMAKE_COMMAND} -E env
            SDL_VIDEODRIVER=dummy SDL_RENDER_DRIVER=software SDL_AUDIODRIVER=dummy
            $<TARGET_FILE:sidescroller>
            --assets "${CMAKE_CURRENT_SOURCE_DIR}/docs/tutorials/assets/sidescroller"
            --autoplay --frames 110
            --screenshot "${CMAKE_CURRENT_SOURCE_DIR}/docs/images/sidescroller.png"
            --screenshot-frame 100
    COMMAND ${CMAKE_COMMAND} -E env
            SDL_VIDEODRIVER=dummy SDL_RENDER_DRIVER=software SDL_AUDIODRIVER=dummy
            $<TARGET_FILE:jrpg>
            --demo --frames 240
            --screenshot "${CMAKE_CURRENT_SOURCE_DIR}/docs/images/jrpg.png"
            --screenshot-frame 230
    DEPENDS sidescroller jrpg
    COMMENT "Regenerating the tutorial figures in docs/images"
    VERBATIM
  )
endif()

# Mutation testing copies the repository to scratch space, applies one small
# source change at a time, and verifies that the passing tests detect it. The
# intentionally failing character test is excluded by the harness.
find_package(Python3 COMPONENTS Interpreter)
if(Python3_FOUND)
  if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
    set(AKGL_MUTATION_TARGET mutation)
  else()
    set(AKGL_MUTATION_TARGET akgl_mutation)
  endif()
  add_custom_target(${AKGL_MUTATION_TARGET}
    COMMAND ${Python3_EXECUTABLE}
            ${CMAKE_CURRENT_SOURCE_DIR}/scripts/mutation_test.py
            --source-root ${CMAKE_CURRENT_SOURCE_DIR}
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    USES_TERMINAL
    COMMENT "Running mutation tests (breaks a scratch copy, expects tests to fail)"
  )
endif()

# Memory checking runs the whole registered suite under valgrind. The wrapper
# script exists because `ctest -T memcheck` records defects and still exits 0,
# which cannot gate anything; it also forces the headless drivers, so the vendor
# GPU stack is never loaded and never has to be suppressed.
if(MEMORYCHECK_COMMAND)
  if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
    set(AKGL_MEMCHECK_TARGET memcheck)
  else()
    set(AKGL_MEMCHECK_TARGET akgl_memcheck)
  endif()
  add_custom_target(${AKGL_MEMCHECK_TARGET}
    COMMAND ${CMAKE_COMMAND} -E env
            AKGL_BUILD_DIR=${CMAKE_CURRENT_BINARY_DIR}
            ${CMAKE_CURRENT_SOURCE_DIR}/scripts/memcheck.sh
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    USES_TERMINAL
    COMMENT "Running every test suite under valgrind (slow; the perf suites scale themselves down)"
  )
endif()

install(FILES ${CMAKE_CURRENT_BINARY_DIR}/akgl.pc DESTINATION "lib/pkgconfig/")
install(FILES ${CMAKE_CURRENT_BINARY_DIR}/include/akgl/version.h DESTINATION "include/akgl/")
install(TARGETS akgl DESTINATION "lib/")
install(FILES "deps/semver/semver.h" DESTINATION "include/")
# libccd is compiled into libakgl.so, and its BSD-3 licence requires the notice
# to travel with the binary form. Nothing else in deps/ is linked in statically
# -- SDL, jansson, libakerror and libakstdlib are all separate shared objects
# that ship their own -- so this is the only third-party notice we owe.
install(FILES "deps/libccd/BSD-LICENSE" DESTINATION "share/doc/akgl/" RENAME "BSD-LICENSE.libccd")
foreach(header IN LISTS AKGL_PUBLIC_HEADERS)
  install(FILES "include/akgl/${header}.h" DESTINATION "include/akgl/")
endforeach()
install(FILES ${GAMECONTROLLERDB_H} DESTINATION "include/akgl/")