Add Doxyfile and generate Doxygen docs in CI

.github/workflows/doxygen_deploy.yml

@@ -0,0 +1,45 @@
+name: doxygen_deploy
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+on:
+  push:
+    paths:
+      - '.github/workflows/doxygen_deploy.yml'
+      - 'doc/'
+      - 'src/src/'
+      - 'src/tms/'
+    branches:
+      - master
+
+jobs:
+  build:
+    if: github.repository == 'Bithack/principia'
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install deps
+        run: |
+          sudo apt-get install -y doxygen graphviz wget
+
+      - name: Generate Doxygen documentation
+        run: |
+          wget https://raw.githubusercontent.com/rollerozxa/doxygen-awesome-css/main/doxygen-awesome.css -O doc/doxygen-awesome.css
+          doxygen Doxyfile
+          touch doc/doxy/html/.nojekyll
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: 'doc/doxy/html/'
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

.gitignore

@@ -10,6 +10,10 @@ opengl32.dll
 .cache/
 compile_commands.json
 
+# Doxygen documentation
+doc/doxy/
+doc/doxygen-awesome.css
+
 # Model junk files
 *.blend1
 *.blend2

Doxyfile

@@ -0,0 +1,39 @@
+# Project properties
+PROJECT_NAME           = Principia
+PROJECT_LOGO           = packaging/principia.png
+
+# Parsing
+JAVADOC_AUTOBRIEF      = YES
+EXTRACT_ALL            = YES
+EXTRACT_PRIVATE        = YES
+EXTRACT_STATIC         = YES
+SORT_MEMBERS_CTORS_1ST = YES
+WARN_IF_UNDOCUMENTED   = NO
+BUILTIN_STL_SUPPORT    = YES
+
+# Input
+RECURSIVE              = YES
+STRIP_FROM_PATH        = src
+INPUT                  = doc/main_page.dox \
+                         src/src/ src/tms/
+EXCLUDE                = src/src/Box2D/
+
+# Dot graphs
+HAVE_DOT               = YES
+CALL_GRAPH             = YES
+CALLER_GRAPH           = YES
+MAX_DOT_GRAPH_DEPTH    = 3
+DOT_MULTI_TARGETS      = YES
+DOT_IMAGE_FORMAT       = svg
+
+# Output
+OUTPUT_DIRECTORY       = doc/doxy/  # /tmp/doxy/
+GENERATE_LATEX         = NO
+REFERENCED_BY_RELATION = YES
+REFERENCES_RELATION    = YES
+SEARCHENGINE           = YES
+DISABLE_INDEX          = YES
+GENERATE_TREEVIEW      = YES
+HTML_DYNAMIC_SECTIONS  = YES
+HTML_TIMESTAMP         = YES
+HTML_EXTRA_STYLESHEET  = doc/doxygen-awesome.css

doc/main_page.dox

@@ -0,0 +1,5 @@
+/** @mainpage Principia documentation
+
+This site contains automatically generated documentation by Doxygen for Principia and its engine.
+
+*/