Browser build: the engine compiles to WASM and runs at a URL

- mrpgi-core: ureq/tiny_http/threads are native-only deps; the AI lane
  compiles to an always-off stub on wasm32 (deterministic parser stays).
- World::from_memory + assets::cel_from_bytes — boot a game with no
  filesystem.
- mrpgi GUI on wasm: embeds games/lost-fuse via include_dir, boots
  straight into Play (Tab still opens the editor; saving needs a disk,
  so web is play + paint-only for now).
- web/: index.html shell + macroquad JS loader + build.sh producing a
  self-contained static web/dist (1.1 MB total, game included).
- .cargo/config.toml: --allow-undefined for miniquad's JS imports.

Verified in-browser: renders, typed commands reach the parser,
click-to-walk works, zero console errors.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.cargo/config.toml

@@ -0,0 +1,4 @@
+# Web builds: miniquad's JS imports (console_log, init_webgl, ...) are
+# resolved at runtime by web/mq_js_bundle.js — tell the linker to allow them.
+[target.wasm32-unknown-unknown]
+rustflags = ["-C", "link-arg=--allow-undefined"]

.gitignore

@@ -13,3 +13,4 @@
 001.jpeg
 002.png
 003.png
+web/dist/

Cargo.lock

@@ -304,6 +304,25 @@ dependencies = [
  "png",
 ]
 
+[[package]]
+name = "include_dir"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "923d117408f1e49d914f1a379a309cffe4f18c05cf4e3d12e613a15fc81bd0dd"
+dependencies = [
+ "include_dir_macros",
+]
+
+[[package]]
+name = "include_dir_macros"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cab85a7ed0bd5f0e76d93846e0147172bed2e2d3f859bcc33a8d9699cad1a75"
+dependencies = [
+ "proc-macro2",
+ "quote",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.18"
@@ -389,8 +408,10 @@ dependencies = [
 name = "mrpgi"
 version = "0.1.0"
 dependencies = [
+ "include_dir",
  "macroquad",
  "mrpgi-core",
+ "serde_json",
 ]
 
 [[package]]

mrpgi-core/Cargo.toml

@@ -8,6 +8,10 @@ description = "MRPGI headless engine core — the sim, parser, renderer and cont
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 image = { version = "0.24", default-features = false, features = ["png"] }  # PNG-only: lean builds
+
+# Native-only: the AI lane and the HTTP surface don't exist in browser builds
+# (wasm gets the deterministic parser and a baked-in game).
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ureq = { version = "2", features = ["json", "tls"] }  # AI parser lane: Ollama / OpenRouter HTTP
 tiny_http = "0.12"  # the --serve control surface; ponytail: swap for axum+WS if streaming push is ever needed
 

mrpgi-core/src/ai.rs

@@ -13,9 +13,12 @@
 //!   OPENROUTER_API_KEY (or MRPGI_AI_KEY)  for openrouter
 
 use std::sync::mpsc::{self, Receiver};
+#[cfg(not(target_arch = "wasm32"))]
 use std::thread;
+#[cfg(not(target_arch = "wasm32"))]
 use std::time::Duration;
 
+#[cfg_attr(target_arch = "wasm32", allow(dead_code))] // browser builds only ever construct Off
 #[derive(Clone, PartialEq)]
 enum Provider {
     Off,
@@ -23,6 +26,7 @@ enum Provider {
     OpenRouter,
 }
 
+#[cfg_attr(target_arch = "wasm32", allow(dead_code))] // url/key unused when the lane is compiled out
 #[derive(Clone)]
 pub struct AiConfig {
     provider: Provider,
@@ -33,6 +37,15 @@ pub struct AiConfig {
 
 impl AiConfig {
     pub fn from_env() -> Self {
+        // No HTTP client, no worker threads in the browser build.
+        #[cfg(target_arch = "wasm32")]
+        return Self::off();
+        #[cfg(not(target_arch = "wasm32"))]
+        Self::from_env_native()
+    }
+
+    #[cfg(not(target_arch = "wasm32"))]
+    fn from_env_native() -> Self {
         let which = std::env::var("MRPGI_AI").unwrap_or_else(|_| "ollama".into()).to_lowercase();
         let provider = match which.as_str() {
             "off" | "none" | "0" => Provider::Off,
@@ -84,6 +97,7 @@ Command:"
 
 /// Fire the translation on a worker thread; poll the returned receiver with
 /// `try_recv()`. The result is a sanitized command (or "" = no idea).
+#[cfg(not(target_arch = "wasm32"))]
 pub fn translate_async(cfg: AiConfig, prompt: String) -> Receiver<String> {
     let (tx, rx) = mpsc::channel();
     thread::spawn(move || {
@@ -93,6 +107,16 @@ pub fn translate_async(cfg: AiConfig, prompt: String) -> Receiver<String> {
     rx
 }
 
+/// Browser stub — never reached (the wasm AiConfig is always off), but keeps
+/// the call sites compiling without a cfg forest.
+#[cfg(target_arch = "wasm32")]
+pub fn translate_async(_cfg: AiConfig, _prompt: String) -> Receiver<String> {
+    let (tx, rx) = mpsc::channel();
+    let _ = tx.send(String::new());
+    rx
+}
+
+#[cfg(not(target_arch = "wasm32"))]
 fn sanitize(s: &str) -> String {
     s.lines()
         .map(|l| l.trim())
@@ -103,6 +127,7 @@ fn sanitize(s: &str) -> String {
         .to_lowercase()
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 fn call(cfg: &AiConfig, prompt: &str) -> Result<String, Box<dyn std::error::Error>> {
     let agent = ureq::AgentBuilder::new()
         .timeout_connect(Duration::from_secs(5))

mrpgi-core/src/assets.rs

@@ -67,6 +67,11 @@ pub fn quantize(img: &image::RgbaImage, dither: bool) -> Cel {
     Cel { w, h, pixels }
 }
 
+/// Quantize a PNG already in memory (the browser build's sprite path).
+pub fn cel_from_bytes(bytes: &[u8], dither: bool) -> Option<Cel> {
+    image::load_from_memory(bytes).ok().map(|img| quantize(&img.to_rgba8(), dither))
+}
+
 /// Load a PNG and quantize it. Returns a small magenta placeholder on failure
 /// so missing art is obvious rather than a crash.
 pub fn load_cel(path: &str, dither: bool) -> Cel {

mrpgi-core/src/world.rs

@@ -278,6 +278,28 @@ impl World {
         w
     }
 
+    /// Build a World entirely from memory — no filesystem. This is how the
+    /// browser build boots: the game folder is baked into the binary and
+    /// handed over here as parsed rooms + quantized sprites.
+    pub fn from_memory(
+        manifest: GameManifest,
+        rooms: impl IntoIterator<Item = (u32, RoomDoc)>,
+        sprites: Vec<(String, Cel)>,
+    ) -> Self {
+        let mut w = World {
+            base: PathBuf::from("."),
+            current: manifest.start_room,
+            manifest,
+            doc: RoomDoc::default(),
+            fb: FrameBuffer::new(),
+            sprites,
+            overlay: rooms.into_iter().collect(),
+        };
+        let start = w.current;
+        w.goto_room(start);
+        w
+    }
+
     pub fn room_path(&self, n: u32) -> PathBuf {
         self.base.join(format!("rooms/room{}.json", n))
     }

mrpgi/Cargo.toml

@@ -7,3 +7,8 @@ description = "Monster Robot Party Game Interpreter — macroquad GUI front-end
 [dependencies]
 mrpgi-core = { path = "../mrpgi-core" }
 macroquad = "0.4"
+
+# Browser builds bake a game folder into the binary (no filesystem on the web).
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+include_dir = "0.7"
+serde_json = "1"

mrpgi/src/main.rs

@@ -34,28 +34,70 @@ enum Mode {
     Play,
 }
 
+/// Browser boot: the game folder is compiled into the binary (there is no
+/// filesystem on the web) and handed to the core fully parsed.
+#[cfg(target_arch = "wasm32")]
+fn embedded_world() -> World {
+    static GAME: include_dir::Dir = include_dir::include_dir!("$CARGO_MANIFEST_DIR/../games/lost-fuse");
+    let manifest = GAME
+        .get_file("game.json")
+        .and_then(|f| serde_json::from_slice(f.contents()).ok())
+        .unwrap_or_default();
+    let rooms = (0u32..64).filter_map(|n| {
+        let f = GAME.get_file(format!("rooms/room{}.json", n))?;
+        Some((n, serde_json::from_slice(f.contents()).ok()?))
+    });
+    let mut sprites: Vec<(String, mrpgi_core::view::Cel)> = GAME
+        .get_dir("sprites")
+        .map(|d| {
+            d.files()
+                .filter_map(|f| {
+                    let name = f.path().file_stem()?.to_str()?.to_string();
+                    Some((name, mrpgi_core::assets::cel_from_bytes(f.contents(), false)?))
+                })
+                .collect()
+        })
+        .unwrap_or_default();
+    sprites.sort_by(|a, b| a.0.cmp(&b.0));
+    World::from_memory(manifest, rooms, sprites)
+}
+
 #[macroquad::main(window_conf)]
 async fn main() {
     let game_dir = std::env::args()
         .skip_while(|a| a != "--game")
         .nth(1)
         .unwrap_or_else(|| ".".to_string());
-    if std::env::args().any(|a| a == "--sample") {
-        mrpgi_core::kit::write_sample_world(&game_dir);
+    #[cfg(not(target_arch = "wasm32"))]
+    {
+        if std::env::args().any(|a| a == "--sample") {
+            mrpgi_core::kit::write_sample_world(&game_dir);
+        }
+        if std::env::args().any(|a| a == "--kit") {
+            mrpgi_core::kit::write_kit(&game_dir);
+        }
+        mrpgi_core::assets::ensure_sample_sprites(
+            &std::path::Path::new(&game_dir).join("sprites").to_string_lossy(),
+        );
     }
-    if std::env::args().any(|a| a == "--kit") {
-        mrpgi_core::kit::write_kit(&game_dir);
-    }
-    mrpgi_core::assets::ensure_sample_sprites(
-        &std::path::Path::new(&game_dir).join("sprites").to_string_lossy(),
-    );
 
     let ai_cfg = AiConfig::from_env();
     let ai_label = ai_cfg.label();
-    let mut gs = GameState::new(World::load_game(&game_dir), ai_cfg);
+    #[cfg(not(target_arch = "wasm32"))]
+    let world = World::load_game(&game_dir);
+    #[cfg(target_arch = "wasm32")]
+    let world = embedded_world();
+    let mut gs = GameState::new(world, ai_cfg);
     let mut ed = Editor::new(&game_dir);
 
+    // Native boots into the editor; the web build boots straight into the game.
+    #[cfg(not(target_arch = "wasm32"))]
     let mut mode = Mode::Edit;
+    #[cfg(target_arch = "wasm32")]
+    let mut mode = Mode::Play;
+    #[cfg(target_arch = "wasm32")]
+    let _ = gs.apply(Command::NewGame { room: None });
+
     let mut play_img = Image::gen_image_color(PIC_W as u16, PIC_H as u16, BLACK);
     let play_tex = Texture2D::from_image(&play_img);
     play_tex.set_filter(FilterMode::Nearest);

web/build.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+# Build the browser version of MRPGI into web/dist/ (self-contained, static).
+# Requires the wasm target: rustup target add wasm32-unknown-unknown
+set -e
+cd "$(dirname "$0")/.."
+cargo build -p mrpgi --release --target wasm32-unknown-unknown
+mkdir -p web/dist
+cp target/wasm32-unknown-unknown/release/mrpgi.wasm web/dist/
+cp web/index.html web/mq_js_bundle.js web/dist/
+echo "web build ready: $(du -sh web/dist | cut -f1) in web/dist/"

web/index.html

@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>MRPGI — Monster Robot Party Game Interpreter</title>
+  <meta name="description" content="A new-school reimagining of Sierra's AGI adventure engine. Play The DJ's Lost Fuse in your browser.">
+  <style>
+    html, body { margin: 0; padding: 0; height: 100%; background: #0b0d11; overflow: hidden; }
+    canvas {
+      position: absolute; inset: 0;
+      width: 100%; height: 100%;
+      image-rendering: pixelated;
+      background: #0b0d11;
+    }
+    #boot {
+      position: absolute; inset: 0; display: flex; flex-direction: column;
+      align-items: center; justify-content: center; gap: 12px;
+      color: #5fffd7; font-family: ui-monospace, Menlo, monospace; font-size: 14px;
+      pointer-events: none; transition: opacity .4s;
+    }
+    #boot b { font-size: 22px; letter-spacing: 2px; color: #ff87d7; }
+  </style>
+</head>
+<body>
+  <div id="boot"><b>MRPGI</b><span>booting the party&hellip;</span></div>
+  <canvas id="glcanvas" tabindex="1"></canvas>
+  <script src="mq_js_bundle.js"></script>
+  <script>
+    load("mrpgi.wasm");
+    // hide the boot splash once the engine is drawing frames
+    const t = setInterval(() => {
+      if (typeof wasm_exports !== "undefined" && wasm_exports) {
+        document.getElementById("boot").style.opacity = "0";
+        clearInterval(t);
+      }
+    }, 250);
+  </script>
+</body>
+</html>