Make emscripten --preload-file opt-in

README.md

@@ -102,13 +102,12 @@ For macOS, building a Universal Binary 2 (macOS 10.9+, arm64, x86_64)
 For Web, building with Emscripten
   1. Follow the installation instructions for the Emscripten SDK including
      setting up the environment with emsdk_env.
-  2. Copy or symlink your baseq3 directory into this directory so Emscripten
-     can package your game files. (Alternatively, you can build without this,
-     and provide the game data files at runtime. For this, game files should
-     be listed in `ioq3-config.json`)
-  3. Run `emmake make debug` (or release, but if you do both then you will
+  2. Run `emmake make debug` (or release, but if you do both then you will
      need to pass an extra URL parameter to the HTML file to select the
      build you want).
+  3. Copy or symlink your baseq3 pk3 files into the `build/debug-emscripten-wasm32/baseq3`
+     directory so they can be loaded at run-time. Only game files listed in
+     `ioq3-config.json` will be loaded.
   4. Start a web server serving this directory. `python3 -m http.server`
      is an easy default that you may already have installed.
   5. Open `code/web/ioquake3.html` in a web browser. Open the developer
@@ -177,6 +176,10 @@ Makefile.local:
   DEBUG_CFLAGS         - C compiler flags to use for building debug version
   COPYDIR              - the target installation directory
   TEMPDIR              - specify user defined directory for temp files
+  EMSCRIPTEN_PRELOAD_FILE - set to 1 to package 'baseq3' (BASEGAME) directory
+                            containing pk3s and loose files as a single
+                            .data file that is loaded instead of listing
+                            individual files in ioq3-config.json
 ```
 
 The defaults for these variables differ depending on the target platform.