refactor: add WABox::from_value and struct constructors for DDKeyboard/Palette

Add WABox::from_value(val) to allocate on WA's heap and write a
fully-initialized value in one step. Add DDKeyboard::new() and
Palette::new() that return Self with all fields set, replacing
multi-line alloc+field-write sequences with one-liners.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/openwa-core/src/ddkeyboard.rs

@@ -41,3 +41,27 @@ pub struct DDKeyboard {
 }
 
 const _: () = assert!(core::mem::size_of::<DDKeyboard>() == 0x33C);
+
+impl DDKeyboard {
+    /// Create a new DDKeyboard with inline construction (no native C++ ctor).
+    ///
+    /// All fields are zero-initialized, then known fields are set.
+    ///
+    /// # Safety
+    /// `vtable_addr` must be a valid rebased vtable pointer.
+    /// `input_ptr` must be the address of `GameInfo.input_state_f918`.
+    pub unsafe fn new(vtable_addr: u32, input_ptr: u32) -> Self {
+        Self {
+            vtable: vtable_addr as *mut u8,
+            game_info_input_ptr: input_ptr,
+            _field_008: 1,
+            _unknown_00c: [0; 8],
+            _field_014: 0,
+            _field_018: 0,
+            _unknown_01c: [0; 0x100],
+            key_state: [0; 256],
+            prev_state: [0; 256],
+            _unknown_31c: [0; 0x20],
+        }
+    }
+}

crates/openwa-core/src/palette.rs

@@ -36,6 +36,18 @@ pub struct PaletteVtable {
 }
 
 impl Palette {
+    /// Create a new Palette with inline construction (no native C++ ctor).
+    ///
+    /// # Safety
+    /// `vtable_addr` must be a valid rebased vtable pointer.
+    pub unsafe fn new(vtable_addr: u32) -> Self {
+        Self {
+            vtable: vtable_addr as *const PaletteVtable,
+            _field_004: 0xFFFF_FFFF,
+            _unknown_008: [0; 0x20],
+        }
+    }
+
     /// Vtable[4]: Reset palette state.
     pub unsafe fn reset(&mut self) { vcall!(self, reset) }
     /// Vtable[3]: Initialize palette.

crates/openwa-core/src/wa_alloc.rs

@@ -56,6 +56,26 @@ impl<T> WABox<T> {
         self.ptr.as_ptr()
     }
 
+    /// Allocate space for `T` on WA's heap and write `val` into it.
+    ///
+    /// Equivalent to `alloc(size_of::<T>(), 0)` followed by `ptr::write(ptr, val)`.
+    /// The value is fully initialized on the stack first, then moved to the heap.
+    ///
+    /// # Safety
+    /// Must only be called from within the WA.exe process.
+    pub unsafe fn from_value(val: T) -> Self {
+        let size = core::mem::size_of::<T>() as u32;
+        let raw = wa_malloc(size);
+        if raw.is_null() {
+            panic!("wa_malloc({size}) returned null");
+        }
+        let ptr = raw as *mut T;
+        core::ptr::write(ptr, val);
+        Self {
+            ptr: core::ptr::NonNull::new_unchecked(ptr),
+        }
+    }
+
     /// Consume the box and return the raw pointer, relinquishing Rust ownership.
     ///
     /// The caller is now responsible for the memory — typically by storing the pointer

crates/openwa-wormkit/src/replacements/hardware_init.rs

@@ -49,7 +49,7 @@ use openwa_core::ddgame_wrapper::DDGameWrapper;
 use openwa_core::ddkeyboard::DDKeyboard;
 use openwa_core::dddisplay::DDDisplay;
 use openwa_core::dssound::DSSound;
-use openwa_core::palette::{Palette, PaletteVtable};
+use openwa_core::palette::Palette;
 use openwa_core::input_ctrl::{InputCtrl, InputCtrlVtable};
 use openwa_core::game_timer::GameTimer;
 use openwa_core::game_stats::GameStats;
@@ -360,20 +360,14 @@ unsafe extern "cdecl" fn impl_init_hardware(
         }
 
         // ── DDKeyboard (inline construction) ──────────────────────────────────
-        // WABox zeroes the first 0x31C bytes, covering key_state (+0x11C) and
-        // prev_state (+0x21C) — no separate zeroing needed.
-        let kb = WABox::<DDKeyboard>::alloc(0x33C, 0x31C).leak();
-        (*kb).vtable = rb(va::DDKEYBOARD_VTABLE) as *mut u8;
-        (*kb).game_info_input_ptr = &raw mut gi.input_state_f918 as u32;
-        (*kb)._field_008 = 1;
-        (*kb)._field_014 = 0;
-        (*kb)._field_018 = 0;
+        let kb = WABox::from_value(DDKeyboard::new(
+            rb(va::DDKEYBOARD_VTABLE),
+            &raw mut gi.input_state_f918 as u32,
+        )).leak();
         (*session).keyboard = kb;
 
         // ── Palette (inline construction) ─────────────────────────────────────
-        let pal = WABox::<Palette>::alloc(0x28, 0).leak();
-        (*pal).vtable = rb(va::PALETTE_VTABLE_MAYBE) as *const PaletteVtable;
-        (*pal)._field_004 = 0xFFFF_FFFF;
+        let pal = WABox::from_value(Palette::new(rb(va::PALETTE_VTABLE_MAYBE))).leak();
         (*session).palette = pal;
 
         // ── DSSound ───────────────────────────────────────────────────────────