Fonts: bundle Liberation Sans and register it with fontconfig

- ship assets/LiberationSans-Regular.ttf (+ OFL license/README)
- at startup, resolve the .so path via dladdr, add assets/...ttf to the
  current fontconfig config with FcConfigAppFontAddFile, and fall back to
  the system Liberation path if the asset is missing
- font creation tries Liberation Sans, then DejaVu Sans/Noto/Tahoma/Verdana/
  Arial, so the overlay still renders on installs without the bundled font

1 files changed, 77 insertions, 10 deletions

diff --git a/src/menu.cpp b/src/menu.cpp
index 9537e05..1ef8638 100644
--- a/src/menu.cpp
+++ b/src/menu.cpp
@@ -4,7 +4,9 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <dlfcn.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 // ---------------------------------------------------------------------------
 // ConMsg (tier0 console printer — prints to in-game console)
@@ -217,6 +219,63 @@ static std::string config_path() {
   return dir + "/config";
 }
 
+// Register the bundled Liberation Sans with fontconfig so the VGUI overlay
+// does not depend on the host/game install having it. The font file lives in
+// assets/ next to the .so (or the system path as a fallback).
+void register_bundled_font() {
+  static bool done = false;
+  if (done)
+    return;
+  done = true;
+
+  std::string path;
+  Dl_info info;
+  if (dladdr((void *)&register_bundled_font, &info) && info.dli_fname) {
+    char resolved[4096];
+    const char *lib = realpath(info.dli_fname, resolved);
+    std::string p = lib ? resolved : info.dli_fname;
+    size_t slash = p.find_last_of('/');
+    if (slash != std::string::npos)
+      p.resize(slash + 1);
+    else
+      p = "./";
+    p += "assets/LiberationSans-Regular.ttf";
+    if (access(p.c_str(), R_OK) == 0)
+      path = p;
+  }
+  if (path.empty()) {
+    const char *sys = "/usr/share/fonts/liberation/LiberationSans-Regular.ttf";
+    if (access(sys, R_OK) == 0)
+      path = sys;
+  }
+  if (path.empty()) {
+    logf("font: bundled LiberationSans-Regular.ttf not found");
+    return;
+  }
+
+  void *fc = dlopen("libfontconfig.so.1", RTLD_LAZY | RTLD_GLOBAL);
+  if (!fc) {
+    logf("font: libfontconfig.so.1 not available");
+    return;
+  }
+  using InitFn = int (*)();
+  using GetCurrentFn = void *(*)();
+  using AddFileFn = int (*)(void *, const char *);
+  auto init = (InitFn)dlsym(fc, "FcInit");
+  auto get = (GetCurrentFn)dlsym(fc, "FcConfigGetCurrent");
+  auto add = (AddFileFn)dlsym(fc, "FcConfigAppFontAddFile");
+  if (!init || !get || !add) {
+    logf("font: fontconfig symbols missing");
+    return;
+  }
+  init();
+  void *cfg = get();
+  if (cfg && add(cfg, path.c_str()))
+    logf("font: registered %s", path.c_str());
+  else
+    logf("font: failed to register %s", path.c_str());
+}
+
 static void config_save() {
   FILE *f = fopen(config_path().c_str(), "w");
   if (!f)
@@ -671,17 +730,24 @@ void outer_draw() {
   if (!g_surface || (!g_menu_open && !draw_test && !esp_on))
     return;
   if (!g_font) {
-    g_font = surf_create_font();
-    if (!g_font) {
-      logf("outer_draw: CreateFont failed");
-      return;
+    static const char *families[] = {
+        "Liberation Sans", "DejaVu Sans", "Noto Sans", "Tahoma",
+        "Verdana",         "Arial",      nullptr};
+    bool font_ok = false;
+    for (int fi = 0; families[fi] && !font_ok; fi++) {
+      g_font = surf_create_font();
+      if (!g_font)
+        continue;
+      if (surf_set_font_glyph_set(g_font, families[fi], 16, 400, 0, 0, 0x400,
+                                  0x20, 0xFF)) {
+        logf("outer_draw: font family %s", families[fi]);
+        font_ok = true;
+      } else {
+        g_font = 0;
+      }
     }
-    // FONTFLAG_CUSTOM only; Liberation Sans is an installed real TTF (Verdana
-    // substitutes to Noto). Raw glyphs, ASCII range pinned.
-    if (!surf_set_font_glyph_set(g_font, "Liberation Sans", 16, 400, 0, 0,
-                                 0x400, 0x20, 0xFF)) {
-      logf("outer_draw: SetFontGlyphSet failed");
-      g_font = 0;
+    if (!font_ok) {
+      logf("outer_draw: no usable font");
       return;
     }
   }
@@ -789,6 +855,7 @@ static ISurface *find_surface_interface() {
 
 void install_menu() {
   build_tree();
+  register_bundled_font();
   logf("config: %s", config_path().c_str());
   config_load();
   // resolve ISurface once (used by the DrawPrintText hook in hl2h.cpp and