docs: document many major functions, types, enums for important functionality

src/asset.rs

@@ -5,17 +5,28 @@
 use std::borrow::Cow;
 use strum_macros::EnumIter;
 
+/// Enumeration of all game assets with cross-platform loading support.
+///
+/// Each variant corresponds to a specific file that can be loaded either from
+/// binary-embedded data or embedded filesystem (Emscripten).
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, EnumIter)]
 pub enum Asset {
     Wav1,
     Wav2,
     Wav3,
     Wav4,
+    /// Main sprite atlas containing all game graphics (atlas.png)
     AtlasImage,
+    /// Terminal Vector font for text rendering (TerminalVector.ttf)
     Font,
 }
 
 impl Asset {
+    /// Returns the relative file path for this asset within the game's asset directory.
+    ///
+    /// Paths are consistent across platforms and used by the Emscripten backend
+    /// for filesystem loading. Desktop builds embed assets directly and don't
+    /// use these paths at runtime.
     #[allow(dead_code)]
     pub fn path(&self) -> &str {
         use Asset::*;
@@ -35,7 +46,17 @@ mod imp {
     use crate::error::AssetError;
     use crate::platform::get_platform;
 
-    /// Returns the raw bytes of the given asset.
+    /// Loads asset bytes using the appropriate platform-specific method.
+    ///
+    /// On desktop platforms, returns embedded compile-time data via `include_bytes!`.
+    /// On Emscripten, loads from the filesystem using the asset's path. The returned
+    /// `Cow` allows zero-copy access to embedded data while supporting owned data
+    /// when loaded from disk.
+    ///
+    /// # Errors
+    ///
+    /// 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)
     }