Tic Tac Toe done

src/dawn/games/tictactoe/TicTacToeLogic.cpp

@@ -17,7 +17,7 @@ enum TicTacToeTileState Dawn::ticTacToeDetermineWinner(
   // Check rows
   for(i = 0; i < 9; i += 3) {
     if(board.at(i) == board.at(i + 1) && board.at(i) == board.at(i + 2) && board.at(i) != 0) {
-      *winningCombo = { i, (uint8_t)i + 1, (uint8_t)i + 2 };
+      *winningCombo = { i, (uint8_t)(i + 0x01), (uint8_t)(i + 0x02) };
       return board.at(i);
     }
   }
@@ -25,21 +25,102 @@ enum TicTacToeTileState Dawn::ticTacToeDetermineWinner(
   // Check columns
   for(i = 0; i < 3; i++) {
     if(board.at(i) == board.at(i + 3) && board.at(i) == board.at(i + 6) && board.at(i) != 0) {
-      *winningCombo = { i, (uint8_t)i + 3, (uint8_t)i + 6 };
+      *winningCombo = { i, (uint8_t)(i + 0x03), (uint8_t)(i + 0x06) };
       return board.at(i);
     }
   }
 
   // Check diagonals
   if(board.at(0) == board.at(4) && board.at(0) == board.at(8) && board.at(0) != 0) {
-    *winningCombo = {0, 4, 8};
+    *winningCombo = { 0, 0x04, 0x08 };
     return board.at(0);
   }
 
   if(board.at(2) == board.at(4) && board.at(2) == board.at(6) && board.at(2) != 0) {
-    *winningCombo = { 2, 4, 6 };
+    *winningCombo = { 0x02, 0x04, 0x06 };
     return board.at(2);
   }
 
   return TIC_TAC_TOE_EMPTY;
-}
+}
+
+int32_t Dawn::ticTacToeGetBoardScore(
+  std::map<uint8_t, enum TicTacToeTileState> board,
+  enum TicTacToeTileState player
+) {
+  int32_t score = 0;
+  uint8_t lines[8][3] = {
+    {0, 1, 2}, {3, 4, 5}, {6, 7, 8},
+    {0, 3, 6}, {1, 4, 7}, {2, 5, 8},
+    {0, 4, 8}, {2, 4, 6}
+  };
+
+  for (uint8_t i = 0; i < 8; i++) {
+    uint8_t countPlayer = 0;
+    uint8_t countEmpty = 0;
+
+    for (uint8_t j = 0; j < 3; j++) {
+      if (board[lines[i][j]] == player) {
+        countPlayer++;
+      } else if (board[lines[i][j]] == TIC_TAC_TOE_EMPTY) {
+        countEmpty++;
+      }
+    }
+
+    if (countPlayer == 2 && countEmpty == 1) {
+      score += 10;
+    } else if (countPlayer == 1 && countEmpty == 2) {
+      score += 1;
+    }
+  }
+
+  return score;
+}
+
+
+uint8_t Dawn::ticTacToeGetAiMove(
+  std::map<uint8_t, enum TicTacToeTileState> board,
+  enum TicTacToeTileState player
+) {
+  std::vector<uint8_t> winningCombo;
+
+  // First, check if there's an immediate winning move for the AI
+  for(uint8_t i = 0; i < 9; i++) {
+    if(board[i] != TIC_TAC_TOE_EMPTY) continue;
+    board[i] = player;
+    if(ticTacToeDetermineWinner(board, &winningCombo) == player) {
+      board[i] = TIC_TAC_TOE_EMPTY;
+      return i;
+    }
+    board[i] = TIC_TAC_TOE_EMPTY;
+  }
+
+  // Next, check if the player has an immediate winning move and block it
+  auto opponent = (player == TIC_TAC_TOE_NOUGHT) ? TIC_TAC_TOE_CROSS : TIC_TAC_TOE_NOUGHT;
+  for(uint8_t i = 0; i < 9; i++) {
+    if(board[i] != TIC_TAC_TOE_EMPTY) continue;
+    board[i] = opponent;
+    if(ticTacToeDetermineWinner(board, &winningCombo) == opponent) {
+      board[i] = TIC_TAC_TOE_EMPTY;
+      return i;
+    }
+    board[i] = TIC_TAC_TOE_EMPTY;
+  }
+
+  // If neither player has an immediate winning move, use the simple heuristic to choose a move
+  uint8_t bestMove = -1;
+  int32_t bestScore = -1000;
+  for(uint8_t i = 0; i < 9; i++) {
+    if(board[i] != TIC_TAC_TOE_EMPTY) continue;
+    board[i] = player;
+    auto score = ticTacToeGetBoardScore(board, player);
+    board[i] = TIC_TAC_TOE_EMPTY;
+
+    if(score > bestScore) {
+      bestMove = i;
+      bestScore = score;
+    }
+  }
+
+  return bestMove;
+}

src/dawn/games/tictactoe/TicTacToeLogic.hpp

@@ -13,12 +13,41 @@ namespace Dawn {
     TIC_TAC_TOE_CROSS
   };
 
+  /**
+   * Determine the winner of the given board.
+   * 
+   * @param board Tic tac toe board.
+   * @param winningCombo The output winning combo (if any).
+   * @return The winning player, or EMPTY if no winner is present.
+   */
   enum TicTacToeTileState ticTacToeDetermineWinner(
     const std::map<uint8_t, enum TicTacToeTileState> board,
     std::vector<uint8_t> *winningCombo
   );
 
-  int32_t ticTacToeGetAiMove(
+  /**
+   * Returns the score / value of a given board for the given player. Mostly
+   * used by the AI to determine whether a given board is better or worse than
+   * any other.
+   * 
+   * @param board Board to get the score of.
+   * @param player Player to get the score for.
+   * @return The weighted score of this board.
+   */
+  int32_t ticTacToeGetBoardScore(
+    std::map<uint8_t, enum TicTacToeTileState> board,
+    enum TicTacToeTileState player
+  );
+
+  /**
+   * Returns which cell should be used by the given player for their AI as the
+   * best move for them.
+   * 
+   * @param board Tic tac toe board.
+   * @param player Player to get the AI move for.
+   * @return The recommended cell to fill.
+   */
+  uint8_t ticTacToeGetAiMove(
     std::map<uint8_t, enum TicTacToeTileState> board,
     enum TicTacToeTileState player
   );

src/dawntictactoe/components/TicTacToeGame.cpp

@@ -13,8 +13,10 @@ using namespace Dawn;
 TicTacToeGame::TicTacToeGame(SceneItem *item) :
   SceneItemComponent(item),
   winner(TIC_TAC_TOE_EMPTY),
-  nextMove(TIC_TAC_TOE_NOUGHT)
-{}
+  nextMove(TIC_TAC_TOE_NOUGHT),
+  gameOver(false)
+{
+}
 
 void TicTacToeGame::onStart() {
   // Map tiles by tile number = tile
@@ -26,71 +28,98 @@ void TicTacToeGame::onStart() {
   }
 
   useEffect([&]{
-    if(nextMove != TIC_TAC_TOE_CROSS) return;
-    std::cout << "AI Move" << std::endl;
-  }, nextMove);
-
-  useEffect([&]{
-    if(winner == TIC_TAC_TOE_NOUGHT) return;
     std::cout << "Winner is " << winner << std::endl;
-  }, winner);
+  }, gameOver);
 
   useEvent([&](float_t delta) {
     // Only allow player input if it's their turn.
-    if(nextMove != TIC_TAC_TOE_NOUGHT) return;
-
-    // Get mouse in screen space.
-    auto mouse = getGame()->inputManager.getAxis2D(INPUT_BIND_MOUSE_X, INPUT_BIND_MOUSE_Y);
-    mouse *= 2.0f;
-    mouse -= glm::vec2(1, 1);
+    if(winner != TIC_TAC_TOE_EMPTY) return;
 
     Camera *camera = getScene()->findComponent<Camera>();
     if(camera == nullptr) return;
 
-    struct Ray3D ray;
-    ray.origin = camera->transform->getWorldPosition();
-    ray.direction = camera->getRayDirectionFromScreenSpace(mouse);
-    
-
-    // Find the hovered tile (if any)
     TicTacToeTile *hovered = nullptr;
-    auto results = getPhysics()->raycast3DAll(ray);
-    auto itResult = results.begin();
-    while(itResult != results.end()) {
-      auto result = *itResult;
-      auto tile = result.collider->item->getComponent<TicTacToeTile>();
-      if(tile == nullptr) {
-        ++itResult;
-        continue;
+    bool_t isPlayerMove = nextMove == TIC_TAC_TOE_NOUGHT;
+
+    // Get hovered tile (for player move only)
+    if(isPlayerMove) {
+      // Get mouse in screen space.
+      auto mouse = getGame()->inputManager.getAxis2D(INPUT_BIND_MOUSE_X, INPUT_BIND_MOUSE_Y);
+      mouse *= 2.0f;
+      mouse -= glm::vec2(1, 1);
+
+      struct Ray3D ray;
+      ray.origin = camera->transform->getWorldPosition();
+      ray.direction = camera->getRayDirectionFromScreenSpace(mouse);
+
+      // Find the hovered tile (if any)
+      auto results = getPhysics()->raycast3DAll(ray);
+      auto itResult = results.begin();
+      while(itResult != results.end()) {
+        auto result = *itResult;
+        auto tile = result.collider->item->getComponent<TicTacToeTile>();
+        if(tile == nullptr) {
+          ++itResult;
+          continue;
+        }
+        
+        hovered = tile;
+        break;
       }
-      
-      hovered = tile;
-      break;
     }
 
-    // Now update the state of each tile, also get the state while we are at it
-    std::map<uint8_t, enum TicTacToeTileState> tileMap;
-
+    // Now update the hover state(s)
     auto itTiles = tiles.begin();
+    uint8_t tilesLeft = 0;
     while(itTiles != tiles.end()) {
       auto t = itTiles->second;
-
       if(t == hovered) {
-        if(t->tileState == TIC_TAC_TOE_EMPTY && getGame()->inputManager.isPressed(INPUT_BIND_MOUSE_CLICK)) {
-          t->tileState = nextMove;
-          nextMove = nextMove == TIC_TAC_TOE_NOUGHT ? TIC_TAC_TOE_CROSS : TIC_TAC_TOE_NOUGHT;
-        } else if(t->tileState == TIC_TAC_TOE_EMPTY) {
-          t->hovered = true;
-        }
+        t->hovered = true;
       } else {
         t->hovered = false;
       }
-      tileMap[itTiles->second->tile] = itTiles->second->tileState;
+      if(t->tileState == TIC_TAC_TOE_EMPTY) tilesLeft++;
       ++itTiles;
     }
 
+    if(tilesLeft == 0) {
+      winner = TIC_TAC_TOE_EMPTY;
+      gameOver = true;
+      return;
+    }
+
+    if(isPlayerMove) {
+      if(getGame()->inputManager.isPressed(INPUT_BIND_MOUSE_CLICK)) {
+        this->makeMove(hovered->tile, nextMove);
+      }
+    } else if(nextMove != TIC_TAC_TOE_NOUGHT) {
+      auto board = this->getBoard();
+      auto move = ticTacToeGetAiMove(board, nextMove);
+      this->makeMove(move, nextMove);
+    }
+
     // Determine winner
+    auto board = this->getBoard();
     std::vector<uint8_t> winningCombo;
-    winner = ticTacToeDetermineWinner(tileMap, &winningCombo);
+    winner = ticTacToeDetermineWinner(board, &winningCombo);
+    if(winner != TIC_TAC_TOE_EMPTY) gameOver = true;
   }, getScene()->eventSceneUpdate);
-}
+}
+
+std::map<uint8_t, enum TicTacToeTileState> TicTacToeGame::getBoard() {
+  std::map<uint8_t, enum TicTacToeTileState> tileMap;
+
+  auto itTiles = tiles.begin();
+  while(itTiles != tiles.end()) {
+    auto t = itTiles->second;
+    tileMap[t->tile] = t->tileState;
+    ++itTiles;
+  }
+
+  return tileMap;
+}
+
+void TicTacToeGame::makeMove(uint8_t tile, enum TicTacToeTileState player) {
+  this->tiles[tile]->tileState = player;
+  nextMove = player == TIC_TAC_TOE_NOUGHT ? TIC_TAC_TOE_CROSS : TIC_TAC_TOE_NOUGHT;
+}

src/dawntictactoe/components/TicTacToeGame.hpp

@@ -11,12 +11,16 @@
 namespace Dawn {
   class TicTacToeGame : public SceneItemComponent {
     public:
-      StateProperty<TicTacToeTileState> winner;
+      enum TicTacToeTileState winner;
+      StateProperty<bool_t> gameOver;
       std::map<int32_t, TicTacToeTile*> tiles;
       StateProperty<enum TicTacToeTileState> nextMove;
 
       TicTacToeGame(SceneItem *item);
 
+      std::map<uint8_t, enum TicTacToeTileState> getBoard();
+      void makeMove(uint8_t tile, enum TicTacToeTileState player);
+
       void onStart() override;
   };
 }

src/dawntictactoe/components/TicTacToeTile.cpp

@@ -5,6 +5,7 @@
 
 #include "TicTacToeTile.hpp"
 #include "scene/SceneItem.hpp"
+#include "game/DawnGame.hpp"
 
 using namespace Dawn;
 
@@ -18,13 +19,13 @@ TicTacToeTile::TicTacToeTile(SceneItem *item) :
 void TicTacToeTile::onStart() {
   auto cb = [&]{
     auto sprite = this->item->getComponent<TiledSprite>();
-    if(this->hovered) {
+    if(this->hovered && tileState == TIC_TAC_TOE_EMPTY) {
       sprite->setTile(0x03);
     } else {
       sprite->setTile(tileState);
     }
   };
-
-  useEffect(cb, { &tileState, &hovered });
-  cb();
-}
+  
+  useEffect(cb, tileState);
+  useEffect(cb, hovered)();
+}

src/dawntictactoe/components/TicTacToeTile.hpp

@@ -16,7 +16,6 @@ namespace Dawn {
       uint8_t tile;
 
       TicTacToeTile(SceneItem *item);
-
       void onStart() override;
   };
 }