Initial helper functions for PacMan AI. Not complete.

lib/Board.cpp

@@ -6,14 +6,14 @@ const std::size_t ROWS = 31;
 const std::size_t COLUMNS = 28;
 
 enum class Cell {
-    wall = 0,
-    pellet = 1,
-    // nothing = 2,
-    // missing 3,
-    power_pellet = 4,
-    pen = 5,
-    left_portal = 6,
-    right_portal = 7
+  wall = 0,
+  pellet = 1,
+  // nothing = 2,
+  // missing 3,
+  power_pellet = 4,
+  pen = 5,
+  left_portal = 6,
+  right_portal = 7
 };
 
 // clang-format off
@@ -124,4 +124,60 @@ std::vector<GridPosition> initialSuperPelletPositions() {
   return positions;
 }
 
+// AI
+
+bool isIntersection(GridPosition point) {
+  if (!isWalkableForPacMan(point) || cellAtPosition(point) == Cell::left_portal || cellAtPosition(point) == Cell::right_portal) {
+    return false;
+  }
+
+  const GridPosition right{ point.x + 1, point.y };
+  const bool rightWalkable = isWalkableForPacMan(right);
+
+  const GridPosition left{ point.x - 1, point.y };
+  const bool leftWalkable = isWalkableForPacMan(left);
+
+  const GridPosition top{ point.x, point.y - 1 };
+  const bool topWalkable = isWalkableForPacMan(top);
+
+  const GridPosition bottom{ point.x, point.y + 1 };
+  const bool bottomWalkable = isWalkableForPacMan(bottom);
+
+  return (topWalkable && rightWalkable) || (rightWalkable && bottomWalkable) || (bottomWalkable && leftWalkable) || (leftWalkable && topWalkable);
+}
+
+bool isWalkableStraightLine(GridPosition pointA, GridPosition pointB) {
+  // Points with no shared x,y have no straight line between them
+  if (pointA.x != pointB.x && pointA.y != pointB.y) {
+    return false;
+  }
+
+  // this is std::all_of
+  if (pointA.x == pointB.x) {
+    const size_t startY = (pointA.y > pointB.y ? pointB.y : pointA.y);
+    const size_t endY = (pointA.y > pointB.y ? pointA.y : pointB.y);
+    for (size_t y = startY; y <= endY; y++) {
+      const GridPosition test{ pointA.x, y };
+      if (!isWalkableForPacMan(test)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  if (pointA.y == pointB.y) {
+    const size_t startX = (pointA.x > pointB.x ? pointB.x : pointA.x);
+    const size_t endX = (pointA.x > pointB.x ? pointA.x : pointB.x);
+    for (size_t x = startX; x <= endX; x++) {
+      const GridPosition test{ x, pointA.y };
+      if (!isWalkableForPacMan(test)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  return false;
+}
+
 } // namespace pacman

lib/Ghost.cpp

@@ -1,8 +1,8 @@
 #include "Ghost.hpp"
+#include <algorithm>
 #include <array>
 #include <cmath>
 #include <numeric>
-#include <algorithm>
 
 namespace pacman {
 
@@ -13,7 +13,8 @@ Ghost::Ghost(Atlas::Ghost spriteSet)
 void Ghost::frighten() {
   if (state > State::Scatter)
     return;
-  direction = oppositeDirection(direction);
+
+  dir = oppositeDirection(dir);
   state = State::Frightened;
   timeFrighten = {};
 }
@@ -29,7 +30,8 @@ bool Ghost::isEyes() const {
 void Ghost::die() {
   if (state == State::Eyes)
     return;
-  direction = oppositeDirection(direction);
+
+  dir = oppositeDirection(dir);
   state = State::Eyes;
   timeFrighten = {};
   timeChase = {};
@@ -42,12 +44,12 @@ void Ghost::reset() {
   timeChase = {};
 }
 
- GridPosition Ghost::currentSprite() const {
+GridPosition Ghost::currentSprite() const {
   switch (state) {
     default:
-      return Atlas::ghostSprite(spriteSet, direction, (animationIndex % 2) == 0);
+      return Atlas::ghostSprite(spriteSet, dir, (animationIndex % 2) == 0);
     case State::Eyes:
-      return Atlas::eyeSprite(direction);
+      return Atlas::eyeSprite(dir);
     case State::Frightened:
       if (timeFrighten.count() < 3500)
         return Atlas::initialFrightened(animationIndex);
@@ -64,6 +66,10 @@ GridPosition Ghost::positionInGrid() const {
   return positionToGridPosition(pos);
 }
 
+Direction Ghost::direction() const {
+  return dir;
+}
+
 void Ghost::update(std::chrono::milliseconds time_delta, const GameState & gameState) {
   if (state == State::Eyes && isInPen())
     state = State::Scatter;
@@ -78,7 +84,7 @@ void Ghost::update(std::chrono::milliseconds time_delta, const GameState & gameS
     timeChase += time_delta;
     const auto newState = defaultStateAtDuration(std::chrono::duration_cast<std::chrono::seconds>(timeChase));
     if (newState != state) {
-      direction = oppositeDirection(direction);
+      dir = oppositeDirection(dir);
       state = newState;
     }
   }
@@ -99,7 +105,7 @@ void Ghost::updatePosition(std::chrono::milliseconds time_delta, const GameState
   const auto old_position = pos;
   const GridPosition old_grid_position = positionToGridPosition(old_position);
 
-  switch (direction) {
+  switch (dir) {
     case Direction::NONE:
       break;
     case Direction::LEFT:
@@ -120,12 +126,11 @@ void Ghost::updatePosition(std::chrono::milliseconds time_delta, const GameState
       break;
   }
 
-  if (isPortal(positionInGrid(), direction)) {
+  if (isPortal(positionInGrid(), dir)) {
     pos = gridPositionToPosition(teleport(positionInGrid()));
-  }
-  else if (!isWalkableForGhost(positionInGrid(), old_grid_position, isEyes())) {
+  } else if (!isWalkableForGhost(positionInGrid(), old_grid_position, isEyes())) {
     pos = old_position;
-    direction = oppositeDirection(direction);
+    dir = oppositeDirection(dir);
   }
 }
 
@@ -175,7 +180,7 @@ void Ghost::updateDirection(const GameState & gameState) {
     if (invalid_position)
       continue;
 
-    const bool opposite_direction = (move.direction == oppositeDirection(direction));
+    const bool opposite_direction = (move.direction == oppositeDirection(dir));
     if (opposite_direction)
       continue;
 
@@ -192,7 +197,7 @@ void Ghost::updateDirection(const GameState & gameState) {
   });
 
   const auto & move = *optimal_move;
-  direction = move.direction;
+  dir = move.direction;
   last_grid_position = current_grid_position;
 }
 

lib/PacManAI.cpp

@@ -0,0 +1,4 @@
+#include "PacManAI.hpp"
+
+namespace pacman {
+}

lib/include/GameState.hpp

@@ -2,15 +2,16 @@
 
 #include "Blinky.hpp"
 #include "Clyde.hpp"
+#include "Fruits.hpp"
 #include "Ghost.hpp"
 #include "Inky.hpp"
+#include "InputState.hpp"
 #include "PacMan.hpp"
+#include "PacManAI.hpp"
 #include "Pellets.hpp"
 #include "Pinky.hpp"
 #include "Score.hpp"
 #include "SuperPellets.hpp"
-#include "Fruits.hpp"
-#include "InputState.hpp"
 
 namespace pacman {
 
@@ -23,6 +24,7 @@ struct GameState {
   Clyde clyde;
 
   PacMan pacMan;
+  PacManAI pacManAI;
   InputState inputState;
   Pellets pellets;
   SuperPellets superPellets;

lib/include/Ghost.hpp

@@ -25,6 +25,7 @@ public:
   GridPosition currentSprite() const;
   Position position() const;
   GridPosition positionInGrid() const;
+  Direction direction() const;
 
   void update(std::chrono::milliseconds time_delta, const GameState & gameState);
   void frighten();
@@ -40,7 +41,7 @@ private:
 
 protected:
   Atlas::Ghost spriteSet;
-  Direction direction = Direction::NONE;
+  Direction dir = Direction::NONE;
   double timeForAnimation = 0;
   std::size_t animationIndex = 0;
   State state = State::Chase;

lib/include/PacManAI.hpp

@@ -0,0 +1,9 @@
+#pragma once
+
+namespace pacman {
+
+class PacManAI {
+public:
+};
+
+} // namespace pacman