Potential fix for promotion detection.

game/src/game/mod.rs

@@ -70,6 +70,12 @@ impl Game {
                             if piece.player == target.player {
                                 swap = true;
                                 target.tile = play.from;
+
+                                // Check for target promotion.
+                                let hex = Hex::from_tile(play.to);
+                                if !target.promoted && !Hex::is_back(hex.x(), hex.y(), target.player) {
+                                    target.promoted = true;
+                                }
                             }
                             
                             // Add captured piece to pool.
@@ -82,6 +88,7 @@ impl Game {
                         if !swap { self.board.pieces[tid as usize] = None; }
                     }
 
+                    // Set tile/piece associations.
                     if swap {
                         self.board.tiles[play.from as usize].piece = self.board.tiles[play.to as usize].piece;
                     } else {
@@ -92,10 +99,9 @@ impl Game {
 
                     self.board.pieces[pid as usize] = Some(piece);
 
-                    // Check if piece is promoted.
+                    // Check for piece promotion.
                     let hex = Hex::from_tile(play.from);
-                    let offset = -(piece.player as i8 * 2) + 1;
-                    if !piece.promoted && !Hex::is_valid(hex.x() as i8, hex.y() as i8 + offset) {
+                    if !piece.promoted && !Hex::is_back(hex.x(), hex.y(), piece.player) {
                         if let Some(piece) = &mut self.board.pieces[pid as usize] {
                             piece.promoted = true;
                         }

game/src/util/hex.rs

@@ -41,7 +41,7 @@ impl Hex {
         }
     }
 
-    pub fn is_valid(x:i8, y:i8) -> bool
+    /*pub fn is_valid(x:i8, y:i8) -> bool
     {
         const COLUMNS :[(i8, i8); 9] = [
             (0, 4),
@@ -60,6 +60,24 @@ impl Hex {
             let (min, max) = COLUMNS[x as usize];
             y >= min && y <= max
         } else { false }
+    }*/
+
+    pub fn is_back(x:u8, y:u8, player:u8) -> bool
+    {
+        const COLUMNS :[[u8; 2]; 9] = [
+            [0, 4],
+            [0, 5],
+            [0, 6],
+            [0, 7],
+            [0, 8],
+            [1, 8],
+            [2, 8],
+            [3, 8],
+            [4, 8],
+        ];
+        if x > 0 && x < 9 {
+            y == COLUMNS[x as usize][1 ^ player as usize]
+        } else { false }
     }
 
     pub fn x(&self) -> u8 { self.x }

www/js/interface.js

@@ -771,6 +771,8 @@ const INTERFACE = {
     },
 
     message(code, data) {
+        if(data === null) { return; }
+        
         switch(code) {
             case OpCode.GameState: {
                 INTERFACE_DATA.player = data.player;