Check doxygen in the CI to avoid errors in projects using this

The ddnet CI has this so any ddnet based project with the default
github actions setup will throw errors in caused by twbl
so we should keep it clean here.

Author: ChillerDragon

.github/workflows/style.yml

@@ -18,12 +18,32 @@ jobs:
       run: |
         sudo apt-get update -y
         sudo apt-get install -y pkg-config cmake cmake build-essential shellcheck
+        mkdir -p ~/.local/bin/
+
+        # clang-format
         wget https://github.com/muttleyxd/clang-tools-static-binaries/releases/download/master-796e77c/clang-format-20_linux-amd64
         echo "bbb30a777d075dfbe91aa146a1ea1fa0c1d4745efa9c5490ebf9f5a7a7dec679c22f1c6015d5c85cb5b5b22964d86ae65002f1d4145bfdd7f27022d981b58979  clang-format-20_linux-amd64" | sha512sum -c
-        mkdir -p ~/.local/bin/
         mv clang-format-20_linux-amd64 ~/.local/bin/clang-format
         chmod +x ~/.local/bin/clang-format
+
+        # doxygen
+        wget -O doxygen.tar.gz https://www.doxygen.nl/files/doxygen-1.16.1.linux.bin.tar.gz
+        tar xf doxygen.tar.gz
+        mv doxygen-1.16.1/bin/doxygen ~/.local/bin
+        rm -f doxygen.tar.gz
+        rm -rf doxygen-1.16.1
     - name: Check fix_style
       run: scripts/fix_style.py --dry-run
     # - name: Shellcheck
     #   run: find . -type f -name '*.sh' -not -path './deps/*' -print0 | xargs -0 shellcheck
+
+    - name: Check documentation style (Doxygen)
+      run: |
+        doxygen --version
+        doxygen -q
+        if [ -s docs/warn.log ]; then
+          echo "--------------------------------------------------"
+          echo "Doxygen warnings:"
+          cat docs/warn.log
+          exit 1
+        fi

.gitignore

@@ -10,6 +10,8 @@ log.txt
 *.exe
 *.dll
 *.pyc
+docs/html
+docs/warn.log
 build/
 build-tidy/
 build-*/

Doxyfile

@@ -0,0 +1,30 @@
+PROJECT_NAME           = "DDNet documentation"
+PROJECT_LOGO           = other/icons/DDNet_48x48x32.png
+OUTPUT_DIRECTORY       = docs
+BUILTIN_STL_SUPPORT    = YES
+NUM_PROC_THREADS       = 0
+EXTRACT_ALL            = YES
+EXTRACT_PRIVATE        = YES
+EXTRACT_PRIV_VIRTUAL   = YES
+EXTRACT_STATIC         = YES
+CASE_SENSE_NAMES       = YES
+WARN_LOGFILE           = docs/warn.log
+INPUT                  = src
+RECURSIVE              = YES
+EXCLUDE                = src/engine/external \
+                         src/masterping/target \
+                         src/mastersrv/target
+USE_MDFILE_AS_MAINPAGE = src/README.md
+GENERATE_LATEX         = NO
+MACRO_EXPANSION        = YES
+PREDEFINED             = CONF_FAMILY_UNIX \
+                         CONF_MYSQL \
+                         CONF_DISCORD \
+                         CONF_OPENSSL \
+                         CONF_UPNP \
+                         CONF_VIDEORECORDER \
+                         CONF_ANTIBOT
+DOT_IMAGE_FORMAT       = svg
+INTERACTIVE_SVG        = YES
+DOT_GRAPH_MAX_NODES    = 200
+DOT_MULTI_TARGETS      = YES