refactor: use small_rng for Emscripten only, simplify platform to top-level functions only, no trait/struct

Cargo.lock

@@ -722,6 +722,15 @@ dependencies = [
  "portable-atomic",
 ]
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "pretty_assertions"
 version = "1.4.1"
@@ -762,6 +771,17 @@ version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
 dependencies = [
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
  "rand_core",
 ]
 
@@ -1529,3 +1549,23 @@ name = "yansi"
 version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cfe53a6657fd280eaa890a3bc59152892ffa3e30101319d168b781ed6529b049"
+
+[[package]]
+name = "zerocopy"
+version = "0.8.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1039dd0d3c310cf05de012d8a39ff557cb0d23087fd44cad61df08fc31907a2f"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ecf5b4cc5364572d7f4c329661bcc82724222973f2cab6f050a4e5c22f75181"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]

Cargo.toml

@@ -25,7 +25,6 @@ tracing-error = "0.2.0"
 tracing-subscriber = {version = "0.3.20", features = ["env-filter"]}
 thiserror = "2.0.16"
 anyhow = "1.0"
-rand = { version = "0.9.2", default-features = false, features = ["small_rng", "os_rng"] }
 smallvec = "1.15.1"
 bitflags = "2.9.4"
 micromap = "0.1.0"
@@ -48,6 +47,7 @@ windows-sys = { version = "0.60.2", features = ["Win32_System_Console"] }
 [target.'cfg(not(target_os = "emscripten"))'.dependencies]
 # On desktop platforms, build SDL2 with cargo-vcpkg
 sdl2 = { version = "0.38", default-features = false, features = ["image", "ttf", "gfx", "mixer", "unsafe_textures", "static-link", "use-vcpkg"] }
+rand = { version = "0.9.2", default-features = false, features = ["thread_rng"] }
 spin_sleep = "1.3.2"
 
 # Browser-specific dependencies
@@ -55,6 +55,7 @@ spin_sleep = "1.3.2"
 # On Emscripten, we don't use cargo-vcpkg
 sdl2 = { version = "0.38", default-features = false, features = ["image", "ttf", "gfx", "mixer", "unsafe_textures"] }
 # TODO: Document why Emscripten cannot use `os_rng`.
+rand = { version = "0.9.2", default-features = false, features = ["small_rng", "os_rng"] }
 libc = "0.2.175"  # TODO: Describe why this is required.
 
 [dev-dependencies]

src/app.rs

@@ -4,7 +4,7 @@ use crate::error::{GameError, GameResult};
 
 use crate::constants::{CANVAS_SIZE, LOOP_TIME, SCALE};
 use crate::game::Game;
-use crate::platform::get_platform;
+use crate::platform;
 use sdl2::{AudioSubsystem, Sdl};
 
 /// Main application wrapper that manages SDL initialization, window lifecycle, and the game loop.
@@ -101,7 +101,7 @@ impl App {
             if start.elapsed() < LOOP_TIME {
                 let time = LOOP_TIME.saturating_sub(start.elapsed());
                 if time != Duration::ZERO {
-                    get_platform().sleep(time, self.focused);
+                    platform::sleep(time, self.focused);
                 }
             }
 

src/asset.rs

@@ -44,7 +44,7 @@ impl Asset {
 mod imp {
     use super::*;
     use crate::error::AssetError;
-    use crate::platform::get_platform;
+    use crate::platform;
 
     /// Loads asset bytes using the appropriate platform-specific method.
     ///
@@ -58,7 +58,7 @@ mod imp {
     /// Returns `AssetError::NotFound` if the asset file cannot be located (Emscripten only),
     /// or `AssetError::Io` for filesystem I/O failures.
     pub fn get_asset_bytes(asset: Asset) -> Result<Cow<'static, [u8]>, AssetError> {
-        get_platform().get_asset_bytes(asset)
+        platform::get_asset_bytes(asset)
     }
 }
 

src/main.rs

@@ -22,13 +22,12 @@ mod texture;
 /// This function initializes SDL, the window, the game state, and then enters
 /// the main game loop.
 pub fn main() {
-    let platform = platform::get_platform();
-    if platform.requires_console() {
+    if platform::requires_console() {
         // Setup buffered tracing subscriber that will buffer logs until console is ready
         let switchable_writer = platform::tracing_buffer::setup_switchable_subscriber();
 
         // Initialize platform-specific console
-        platform.init_console().expect("Could not initialize console");
+        platform::init_console().expect("Could not initialize console");
 
         // Now that console is initialized, flush buffered logs and switch to direct output
         debug!("Switching to direct logging mode and flushing buffer...");

src/platform/desktop.rs

@@ -1,17 +1,15 @@
 //! Desktop platform implementation.
 
 use std::borrow::Cow;
-use std::time::Duration;
+use std::time::{Duration, Instant};
+
+use rand::rngs::ThreadRng;
 
 use crate::asset::Asset;
 use crate::error::{AssetError, PlatformError};
-use crate::platform::CommonPlatform;
 
 /// Desktop platform implementation.
-pub struct Platform;
-
-impl CommonPlatform for Platform {
-    fn sleep(&self, duration: Duration, focused: bool) {
+pub fn sleep(duration: Duration, focused: bool) {
     if focused {
         spin_sleep::sleep(duration);
     } else {
@@ -19,11 +17,11 @@ impl CommonPlatform for Platform {
     }
 }
 
-    fn get_time(&self) -> f64 {
-        std::time::Instant::now().elapsed().as_secs_f64()
+pub fn get_time() -> f64 {
+    Instant::now().elapsed().as_secs_f64()
 }
 
-    fn init_console(&self) -> Result<(), PlatformError> {
+pub fn init_console() -> Result<(), PlatformError> {
     #[cfg(windows)]
     {
         use tracing::{debug, info};
@@ -37,13 +35,13 @@ impl CommonPlatform for Platform {
             debug!("No existing console window found");
         }
 
-            if let Some(file_type) = Self::is_output_setup()? {
+        if let Some(file_type) = is_output_setup()? {
             debug!(r#type = file_type, "Existing output detected");
         } else {
             debug!("No existing output detected");
 
             // Try to attach to parent console for direct cargo run
-                Self::attach_to_parent_console()?;
+            attach_to_parent_console()?;
             info!("Successfully attached to parent console");
         }
     }
@@ -51,15 +49,15 @@ impl CommonPlatform for Platform {
     Ok(())
 }
 
-    fn requires_console(&self) -> bool {
+pub fn requires_console() -> bool {
     cfg!(windows)
 }
 
-    fn get_canvas_size(&self) -> Option<(u32, u32)> {
+pub fn get_canvas_size() -> Option<(u32, u32)> {
     None // Desktop doesn't need this
 }
 
-    fn get_asset_bytes(&self, asset: Asset) -> Result<Cow<'static, [u8]>, AssetError> {
+pub fn get_asset_bytes(asset: Asset) -> Result<Cow<'static, [u8]>, AssetError> {
     match asset {
         Asset::Wav1 => Ok(Cow::Borrowed(include_bytes!("../../assets/game/sound/waka/1.ogg"))),
         Asset::Wav2 => Ok(Cow::Borrowed(include_bytes!("../../assets/game/sound/waka/2.ogg"))),
@@ -69,11 +67,16 @@ impl CommonPlatform for Platform {
         Asset::Font => Ok(Cow::Borrowed(include_bytes!("../../assets/game/TerminalVector.ttf"))),
     }
 }
+
+pub fn rng() -> ThreadRng {
+    rand::rng()
 }
 
-#[cfg(windows)]
-impl Platform {
+/* Internal functions */
+
 /// Check if the output stream has been setup by a parent process
+/// Windows-only
+#[cfg(windows)]
 fn is_output_setup() -> Result<Option<&'static str>, PlatformError> {
     use tracing::{debug, warn};
 
@@ -117,6 +120,8 @@ impl Platform {
 }
 
 /// Try to attach to parent console
+/// Windows-only
+#[cfg(windows)]
 fn attach_to_parent_console() -> Result<(), PlatformError> {
     use windows::{
         core::PCSTR,
@@ -170,4 +175,3 @@ impl Platform {
 
     Ok(())
 }
-}

src/platform/emscripten.rs

@@ -5,35 +5,47 @@ use std::time::Duration;
 
 use crate::asset::Asset;
 use crate::error::{AssetError, PlatformError};
-use crate::platform::CommonPlatform;
+use rand::{rngs::SmallRng, SeedableRng};
 
-/// Emscripten platform implementation.
-pub struct Platform;
+// Emscripten FFI functions
+extern "C" {
+    fn emscripten_get_now() -> f64;
+    fn emscripten_sleep(ms: u32);
+    fn emscripten_get_element_css_size(target: *const u8, width: *mut f64, height: *mut f64) -> i32;
+}
 
-impl CommonPlatform for Platform {
-    fn sleep(&self, duration: Duration, _focused: bool) {
+pub fn sleep(duration: Duration, _focused: bool) {
     unsafe {
         emscripten_sleep(duration.as_millis() as u32);
     }
 }
 
-    fn get_time(&self) -> f64 {
+pub fn get_time() -> f64 {
     unsafe { emscripten_get_now() }
 }
 
-    fn init_console(&self) -> Result<(), PlatformError> {
+pub fn init_console() -> Result<(), PlatformError> {
     Ok(()) // No-op for Emscripten
 }
 
-    fn requires_console(&self) -> bool {
+pub fn requires_console() -> bool {
     false
 }
 
-    fn get_canvas_size(&self) -> Option<(u32, u32)> {
-        Some(unsafe { get_canvas_size() })
+pub fn get_canvas_size() -> Option<(u32, u32)> {
+    let mut width = 0.0;
+    let mut height = 0.0;
+
+    unsafe {
+        emscripten_get_element_css_size(c"canvas".as_ptr().cast(), &mut width, &mut height);
+        if width == 0.0 || height == 0.0 {
+            return None;
+        }
+    }
+    Some((width as u32, height as u32))
 }
 
-    fn get_asset_bytes(&self, asset: Asset) -> Result<Cow<'static, [u8]>, AssetError> {
+pub fn get_asset_bytes(asset: Asset) -> Result<Cow<'static, [u8]>, AssetError> {
     use sdl2::rwops::RWops;
     use std::io::Read;
 
@@ -49,18 +61,7 @@ impl CommonPlatform for Platform {
 
     Ok(Cow::Owned(buf))
 }
-}
 
-// Emscripten FFI functions
-extern "C" {
-    fn emscripten_get_now() -> f64;
-    fn emscripten_sleep(ms: u32);
-    fn emscripten_get_element_css_size(target: *const u8, width: *mut f64, height: *mut f64) -> i32;
-}
-
-unsafe fn get_canvas_size() -> (u32, u32) {
-    let mut width = 0.0;
-    let mut height = 0.0;
-    emscripten_get_element_css_size(c"canvas".as_ptr().cast(), &mut width, &mut height);
-    (width as u32, height as u32)
+pub fn rng() -> SmallRng {
+    SmallRng::from_os_rng()
 }

src/platform/mod.rs

@@ -1,52 +1,13 @@
 //! Platform abstraction layer for cross-platform functionality.
-
-use crate::asset::Asset;
-use crate::error::{AssetError, PlatformError};
-use std::borrow::Cow;
-use std::time::Duration;
-
-#[cfg(not(target_os = "emscripten"))]
-mod desktop;
-#[cfg(target_os = "emscripten")]
-mod emscripten;
-
 pub mod buffered_writer;
 pub mod tracing_buffer;
 
-/// Cross-platform abstraction layer providing unified APIs for platform-specific operations.
-pub trait CommonPlatform {
-    /// Platform-specific sleep function (required due to Emscripten's non-standard sleep requirements).
-    ///
-    /// Provides access to current window focus state, useful for changing sleep algorithm conditionally.
-    fn sleep(&self, duration: Duration, focused: bool);
-
-    #[allow(dead_code)]
-    fn get_time(&self) -> f64;
-
-    /// Configures platform-specific console and debugging output capabilities.
-    fn init_console(&self) -> Result<(), PlatformError>;
-
-    /// Retrieves the actual display canvas dimensions.
-    #[allow(dead_code)]
-    fn get_canvas_size(&self) -> Option<(u32, u32)>;
-
-    /// Loads raw asset data using the appropriate platform-specific method.
-    fn get_asset_bytes(&self, asset: Asset) -> Result<Cow<'static, [u8]>, AssetError>;
-
-    /// Whether the platform requires a console to be initialized.
-    fn requires_console(&self) -> bool;
-}
-
-/// Returns the appropriate platform implementation based on compile-time target.
-#[allow(dead_code)]
-pub fn get_platform() -> &'static dyn CommonPlatform {
 #[cfg(not(target_os = "emscripten"))]
-    {
-        &desktop::Platform
-    }
+mod desktop;
+#[cfg(not(target_os = "emscripten"))]
+pub use desktop::*;
 
 #[cfg(target_os = "emscripten")]
-    {
-        &emscripten::Platform
-    }
-}
+pub use emscripten::*;
+#[cfg(target_os = "emscripten")]
+mod emscripten;

src/systems/ghost.rs

@@ -1,3 +1,4 @@
+use crate::platform;
 use crate::systems::components::{DirectionalAnimation, Frozen, GhostAnimation, GhostState, LastAnimationState, LinearAnimation};
 use crate::{
     map::{
@@ -14,9 +15,7 @@ use crate::{
 use crate::systems::GhostAnimations;
 use bevy_ecs::query::Without;
 use bevy_ecs::system::{Commands, Query, Res};
-use rand::rngs::SmallRng;
 use rand::seq::IndexedRandom;
-use rand::SeedableRng;
 use smallvec::SmallVec;
 
 /// Autonomous ghost AI system implementing randomized movement with backtracking avoidance.
@@ -49,7 +48,7 @@ pub fn ghost_movement_system(
                             break;
                         }
                     } else {
-                        *non_opposite_options.choose(&mut SmallRng::from_os_rng()).unwrap()
+                        *non_opposite_options.choose(&mut platform::rng()).unwrap()
                     };
 
                     velocity.direction = new_edge.direction;