BFS

.gitignore

@@ -1,4 +1,4 @@
 tags
 python/.ipynb_checkpoints
-cpp/test
+cpp/build
 cpp/pathfinding

README.md

@@ -48,6 +48,6 @@ Alternatively (or if you want to edit the file), you can use the [Jupyeter Lab o
         - [x] drawing tiles
         - [x] add "terrain tiles" with different costs
     - [x] add mouse-click action
-    - [ ] add direct movement (through mouse click action, no pathfinding)
+    - [x] add direct movement (through mouse click action, no pathfinding)
     - [ ] implement pathfinding
     - [ ] windows build?

cpp/Makefile

@@ -1,9 +1,34 @@
-all: test pathfinding
-# TODO add extra warnings
-# TODO linter?
+# ---------------------------------
+# Generated by Kimi K2
+#---------- configurable ----------
+CXX      := g++
+CXXFLAGS := -std=c++23 -Wall -Wextra -Wpedantic -ggdb3
+LDFLAGS  :=
+LDLIBS   := -lSDL3 -lSDL3_image -lGLEW -lGL
 
-pathfinding: src/main.cpp src/array.hpp
-	g++ -Wall -ggdb3 -lSDL3 -lSDL3_image -std=c++23 -lGLEW -lGL -o pathfinding src/main.cpp
+SRC_DIR  := src
+BUILD_DIR:= build
+TARGET   := pathfinding
 
-test: src/test.cpp src/array.hpp
-	g++ -Wall -Wextra -Wpedantic -ggdb3 -std=c++23 -lgtest -o test src/test.cpp
+#----------------------------------
+SOURCES := $(wildcard $(SRC_DIR)/*.cpp)
+OBJECTS := $(SOURCES:$(SRC_DIR)/%.cpp=$(BUILD_DIR)/%.o)
+
+#----------------------------------
+.PHONY: all clean
+
+all: $(TARGET)
+
+# link step
+$(TARGET): $(OBJECTS)
+	$(CXX) $(LDFLAGS) -o $@ $^ $(LDLIBS)
+
+# compile step
+$(BUILD_DIR)/%.o: $(SRC_DIR)/%.cpp | $(BUILD_DIR)
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+$(BUILD_DIR):
+	mkdir -p $@
+
+clean:
+	rm -rf $(BUILD_DIR) $(TARGET)

cpp/src/entities.cpp

@@ -0,0 +1,66 @@
+#include <memory>
+
+#include "entities.hpp"
+
+#include "log.hpp"
+#include "math.hpp"
+#include "sprite.hpp"
+
+Entity::Entity(WorldPos position) : m_Position(position) {
+  LOG_DEBUG("spawning entity at position ", position);
+}
+
+std::ostream &operator<<(std::ostream &os, const Entity &obj) {
+  static constexpr std::array<std::string_view,
+                              static_cast<size_t>(Entity::Type::COUNT)>
+      type_name{"NONE", "PLAYER", "TILE"};
+  size_t idx = static_cast<size_t>(obj.GetType());
+  assert(idx < type_name.size());
+  os << type_name[idx];
+  return os;
+}
+
+void Entity::ZeroActualVelocityInDirection(WorldPos direction) {
+  // Vectors e1, e2 form the basis for a local coord system,
+  // where e1 is formed by the direction where we want to zero-out
+  // the velocity, and e2 is the orthogonal vector.
+  // Scalars q1, q2 are coordinates for e1, e2 basis.
+  WorldPos e1 = direction.normalized();
+  WorldPos e2 = e1.orthogonal();
+
+  // q1 * e1 + q2 * e2 = v, from this follows:
+  auto &v = GetActualVelocity();
+  float q2 = (v.y * e1.x - v.x * e1.y) / (e2.y * e1.x - e2.x * e1.y);
+  float q1 = (v.x - q2 * e2.x) / e1.x;
+
+  // We then zero-out the q1, but only if it's positive - meaning
+  // it is aiming in the direction of "direction", not out.
+  // (otherwise we're not able to move out from collision with
+  // another object)
+  if (q1 > 0.0f) {
+    SetActualVelocity(q2 * e2);
+  }
+}
+
+void Entity::Update(float time_delta) {
+  m_Position += m_ActualVelocity * time_delta;
+}
+
+Player::Player() {
+  LOG_DEBUG(".");
+  if (m_Sprite == nullptr) {
+    LoadResources();
+  }
+}
+
+Sprite &Player::GetSprite() {
+  assert(m_Sprite != nullptr);
+  return *m_Sprite;
+}
+
+void Player::LoadResources() {
+  m_Sprite =
+      std::make_unique<Sprite>("resources/player.png", WorldPos{38.0f, 46.0f});
+}
+
+std::unique_ptr<Sprite> Player::m_Sprite;

cpp/src/entities.hpp

@@ -0,0 +1,85 @@
+#pragma once
+
+#include <array>
+#include <cstdint>
+#include <iostream>
+#include <memory>
+#include <string_view>
+
+#include "log.hpp"
+#include "math.hpp"
+#include "sprite.hpp"
+
+class Entity {
+public:
+  enum class Type : std::uint8_t {
+    NONE,
+    PLAYER,
+    TILE,
+    COUNT // must be last
+  };
+
+  Entity(WorldPos position = {0.0f, 0.0f});
+  Entity(const Entity &) = delete;
+  Entity &operator=(const Entity &) = delete;
+  Entity(Entity &&) = delete;
+  Entity &operator=(Entity &&) = delete;
+
+  friend std::ostream &operator<<(std::ostream &os, const Entity &obj);
+
+  virtual Sprite &GetSprite() = 0;
+  virtual constexpr float GetCollisionRadius() const = 0;
+  virtual constexpr Type GetType() const = 0;
+  virtual bool IsMovable() const = 0;
+  virtual bool IsCollidable() const = 0;
+
+  virtual void Update(float time_delta);
+
+  virtual constexpr float GetCollisionRadiusSquared() const {
+    return GetCollisionRadius() * GetCollisionRadius();
+  }
+
+  void SetFlagExpired() { m_FlagExpired = true; }
+  bool IsFlaggedExpired() const { return m_FlagExpired; }
+
+  const WorldPos &GetPosition() const { return m_Position; }
+  void SetPosition(WorldPos new_pos) { m_Position = new_pos; }
+
+  const WorldPos &GetActualVelocity() const { return m_ActualVelocity; }
+  const WorldPos &GetRequestedVelocity() const { return m_RequestedVelocity; }
+  void SetActualVelocity(const WorldPos &new_velocity) {
+    m_ActualVelocity = new_velocity;
+  }
+  void SetRequestedVelocity(const WorldPos &new_velocity) {
+    m_RequestedVelocity = new_velocity;
+  }
+
+  void ZeroActualVelocityInDirection(WorldPos direction);
+
+protected:
+  WorldPos m_Position;
+  WorldPos m_ActualVelocity;
+  WorldPos m_RequestedVelocity;
+
+private:
+  bool m_FlagExpired = false;
+  static constexpr float m_CollisionRadiusSq = 1000.0f;
+};
+
+class Player final : public Entity {
+public:
+  Player();
+
+  Sprite &GetSprite() override;
+
+  constexpr Entity::Type GetType() const override {
+    return Entity::Type::PLAYER;
+  }
+  constexpr float GetCollisionRadius() const override { return 50.0f; }
+  bool IsMovable() const override { return true; }
+  bool IsCollidable() const override { return true; }
+
+private:
+  void LoadResources();
+  static std::unique_ptr<Sprite> m_Sprite;
+};

cpp/src/gameloop.cpp

@@ -0,0 +1,53 @@
+#include <thread>
+#include <memory>
+
+#include "gameloop.hpp"
+
+#include "pathfindingdemo.hpp"
+#include "window.hpp"
+#include "user_input.hpp"
+#include "log.hpp"
+#include "pathfinder.hpp"
+#include "math.hpp"
+
+void GameLoop::Run() {
+  LOG_INFO("Running the game");
+  while (!m_Game->IsExitRequested()) {
+    m_Game->HandleActions(m_UserInput->GetActions());
+    m_Game->UpdatePlayerVelocity();
+
+    m_Window->ClearWindow();
+
+    // TODO wrap all of the drawing in some function
+    // TODO rethink coupling and dependencies here
+    
+    // draw the map (terrain tiles)
+    const Map &map = m_Game->GetMap();
+    const auto &tiles = map.GetMapTiles();
+    for (size_t row = 0; row < tiles.size(); row++) {
+      for (size_t col = 0; col < tiles[row].size(); col++) {
+        // LOG_DEBUG("Drawing rect (", row, ", ", col, ")");
+        m_Window->DrawRect(
+            map.TileEdgeToWorld(TilePos{row, col}),
+            map.GetTileSize(), tiles[row][col]->R, tiles[row][col]->G,
+            tiles[row][col]->B, tiles[row][col]->A);
+      }
+    }
+
+    // draw the path, if it exists
+    WorldPos start_pos = m_Game->GetPlayer()->GetPosition();
+    for (const auto& next_pos: m_Game->GetPath()) {
+      m_Window->DrawLine(start_pos, next_pos);
+      start_pos = next_pos;
+    }
+
+    // draw all the entities (player etc)
+    for (auto &entity : m_Game->GetEntities()) {
+      m_Window->DrawSprite(entity->GetPosition(), entity->GetSprite());
+    }
+    
+    m_Window->Flush();
+    // TODO measure fps
+    std::this_thread::sleep_for(std::chrono::milliseconds(30));
+  }
+}

cpp/src/gameloop.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <memory>
+
+#include "pathfindingdemo.hpp"
+#include "window.hpp"
+#include "user_input.hpp"
+
+class GameLoop {
+public:
+  GameLoop() = default;
+  ~GameLoop() = default;
+
+  GameLoop(const GameLoop&) = delete;
+  GameLoop(GameLoop&&) = delete;
+  GameLoop& operator=(const GameLoop&) = delete;
+  GameLoop& operator=(GameLoop&&) = delete;
+ 
+  void Run();
+
+  void SetGame(std::unique_ptr<PathFindingDemo> x) {
+    m_Game = std::move(x);
+  }
+  void SetWindow(std::unique_ptr<Window> x) { m_Window = std::move(x); }
+  void SetUserInput(std::unique_ptr<UserInput> x) {
+    m_UserInput = std::move(x);
+  }
+
+private:
+  std::unique_ptr<PathFindingDemo> m_Game;
+  std::unique_ptr<Window> m_Window;
+  std::unique_ptr<UserInput> m_UserInput;
+};

cpp/src/main.cpp

@@ -1,785 +1,18 @@
-#include <cassert>
-#include <chrono>
-#include <cmath>
-#include <cstdlib>
-#include <expected>
-#include <iostream>
-#include <map>
-#include <memory>
-#include <thread>
-#include <unordered_set>
-#include <vector>
-
-#include "array.hpp"
+#include "gameloop.hpp"
 #include "log.hpp"
-#include "math.hpp"
+#include "pathfindingdemo.hpp"
+#include "user_input.hpp"
+#include "window.hpp"
+#include <memory>
 
-//
-// Utils
-//
-
-//
-// Math stuff
-//
-
-// Forward declarations
-class Sprite;
-class Sound;
-class UserAction;
-
-//
-// UI stuff. This is the part directly dependent on the SDL
-//
-
-// containers
-
-#include <GL/glew.h>
-#include <SDL3/SDL.h>
-#include <SDL3_image/SDL_image.h>
-
-class Sound {
-public:
-  Sound() { LOG_DEBUG("."); }
-  Sound(const Sound &x) { LOG_DEBUG("."); }
-  Sound(Sound &&x) noexcept { LOG_DEBUG("."); }
-  ~Sound() { LOG_DEBUG("."); }
-};
-
-class AudioOutput {
-public:
-  AudioOutput() { LOG_DEBUG("."); }
-  AudioOutput(const AudioOutput &x) = delete;
-  AudioOutput(AudioOutput &&x) = delete;
-  ~AudioOutput() { LOG_DEBUG("."); }
-
-  std::expected<void, std::string> Init() {
-    LOG_INFO("Initialing audio output");
-    return {};
-  }
-
-  void PlaySound(Sound &s);
-};
-
-class Sprite {
-public:
-  Sprite() : m_Texture(nullptr, SDL_DestroyTexture) {}
-  Sprite(std::string path, Vec2D<float> center) : Sprite() {
-    LoadImage(path, center);
-  }
-  int m_R = 0;
-  int m_G = 0;
-  int m_B = 0;
-  int m_A = 0;
-  Sprite(const Sprite &x) = delete;
-  Sprite(Sprite &&x) = delete;
-  ~Sprite() { LOG_DEBUG("."); }
-  void LoadImage(std::string path, Vec2D<float> image_center = {0.0, 0.0}) {
-    LOG_INFO("Loading image ", path);
-    assert(m_Renderer != nullptr);
-
-    auto surface = std::unique_ptr<SDL_Surface, decltype(&SDL_DestroySurface)>(
-        IMG_Load(path.c_str()), SDL_DestroySurface);
-
-    if (surface == nullptr) {
-      LOG_ERROR("IMG_Load failed to load ", path);
-      throw std::runtime_error("Failed to load resources");
-    }
-
-    m_Texture = std::unique_ptr<SDL_Texture, decltype(&SDL_DestroyTexture)>(
-        SDL_CreateTextureFromSurface(m_Renderer.get(), surface.get()),
-        SDL_DestroyTexture);
-    if (m_Texture == nullptr) {
-      LOG_ERROR("SDL_CreateTextureFromSurface failed");
-      throw std::runtime_error("Failed to load resources");
-    }
-    float w, h;
-    SDL_GetTextureSize(m_Texture.get(), &w, &h);
-    m_Size = {w, h};
-    m_ImageCenter = image_center;
-  }
-
-  // Renderer is shared for all class instances - we need it in order
-  // to create textures from images
-  static void SetRenderer(std::shared_ptr<SDL_Renderer> renderer) {
-    m_Renderer = renderer;
-  }
-
-  // GetTexture cannot return pointer to const, as SDL_RenderTexture modifies it
-  SDL_Texture *GetTexture() { return m_Texture.get(); }
-
-  Vec2D<float> GetSize() const { return m_Size; }
-  Vec2D<float> GetCenter() const { return m_ImageCenter; }
-
-private:
-  static std::shared_ptr<SDL_Renderer> m_Renderer;
-  std::unique_ptr<SDL_Texture, decltype(&SDL_DestroyTexture)> m_Texture;
-  Vec2D<float> m_Size;
-  Vec2D<float> m_ImageCenter;
-  float m_TextureWidth = 0;
-  float m_TextureHeight = 0;
-};
-std::shared_ptr<SDL_Renderer> Sprite::m_Renderer = nullptr;
-
-// User interface classes
-
-class Window {
-public:
-  Window(const Window &x) = delete;
-  Window(Window &&x) = delete;
-  Window(int width, int height) : m_Width(width), m_Height(height) {
-    LOG_DEBUG(".");
-  }
-
-  std::expected<void, std::string> Init() {
-    LOG_DEBUG(".");
-
-    if (SDL_Init(SDL_INIT_VIDEO) == false) {
-      return std::unexpected(std::string("SDL could not initialize! Error: ") +
-                             SDL_GetError());
-    }
-    m_Window = SDL_CreateWindow("SDL2 Window", m_Width, m_Height,
-                                SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
-    if (m_Window == nullptr) {
-      std::atexit(SDL_Quit);
-      return std::unexpected(
-          std::string("Window could not be created! Error: ") + SDL_GetError());
-    }
-
-    m_Context = SDL_GL_CreateContext(m_Window);
-    if (m_Context == nullptr) {
-      SDL_DestroyWindow(m_Window);
-      std::atexit(SDL_Quit);
-      return std::unexpected(
-          std::string("GL context could not be created! Error: ") +
-          SDL_GetError());
-    }
-
-    if (glewInit() != GLEW_OK) {
-      SDL_GL_DestroyContext(m_Context);
-      SDL_DestroyWindow(m_Window);
-      std::atexit(SDL_Quit);
-      return std::unexpected("GLEW init failed!");
-    }
-
-    // Resize();
-
-    m_Renderer = std::shared_ptr<SDL_Renderer>(
-        SDL_CreateRenderer(m_Window, NULL), SDL_DestroyRenderer);
-    if (m_Renderer == nullptr) {
-      SDL_DestroyWindow(m_Window);
-      std::atexit(SDL_Quit);
-      return std::unexpected(
-          std::string("Renderer could not be created! Error: ") +
-          SDL_GetError());
-    }
-
-    // Set renderer to the Sprite class
-    Sprite::SetRenderer(m_Renderer);
-
-    // TODO this needs to be tied to map size
-    SDL_SetRenderScale(m_Renderer.get(), 1.0f, 1.0f);
-
-    return {};
-  }
-
-  ~Window() {
-    // SDL_DestroyRenderer(m_Renderer); // handled by shared_ptr
-    SDL_GL_DestroyContext(m_Context);
-    SDL_DestroyWindow(m_Window);
-    std::atexit(SDL_Quit);
-    LOG_DEBUG(".");
-  }
-
-  void DrawSprite(const Vec2D<float> &position, Sprite &s) {
-    Vec2D<float> size = s.GetSize();
-    Vec2D<float> img_center = s.GetCenter();
-    SDL_FRect rect = {position.x - img_center.x, position.y - img_center.y,
-                      size.x, size.y};
-    SDL_RenderTexture(m_Renderer.get(), s.GetTexture(), nullptr, &rect);
-  }
-
-  void DrawRect(const Vec2D<float> &position, const Vec2D<float> size,
-                uint8_t R, uint8_t G, uint8_t B, uint8_t A) {
-    SDL_FRect rect = {position.x, position.y,
-                      size.x, size.y};
-    SDL_SetRenderDrawColor(m_Renderer.get(), R, G, B, A);
-    SDL_RenderFillRect(m_Renderer.get(), &rect);
-  }
-
-  void ClearWindow() {
-    SDL_SetRenderDrawColor(m_Renderer.get(), 50, 50, 50, 255);
-    SDL_RenderClear(m_Renderer.get());
-  }
-
-  void Flush() { SDL_RenderPresent(m_Renderer.get()); }
-
-  void DrawCircle(const Vec2D<float> &position, float radius) {
-    int cx = static_cast<int>(position.x);
-    int cy = static_cast<int>(position.y);
-    SDL_SetRenderDrawColor(m_Renderer.get(), 255, 0, 0, 255);
-    for (int i = 0; i < 360; ++i) {
-      double a = i * M_PI / 180.0;
-      SDL_RenderPoint(m_Renderer.get(),
-                      cx + static_cast<int>(std::round(radius * std::cos(a))),
-                      cy + static_cast<int>(std::round(radius * std::sin(a))));
-    }
-  }
-
-  std::shared_ptr<SDL_Renderer> m_Renderer = nullptr;
-  SDL_Window *m_Window;
-  SDL_GLContext m_Context;
-
-private:
-  uint32_t m_Width;
-  uint32_t m_Height;
-};
-
-class UserAction {
-public:
-  enum class Type { NONE, EXIT, MOVE, CROUCH, STAND, FIRE, MOVE_TARGET};
-
-  UserAction() = default;
-
-  UserAction(Type t) : type(t) {}
-
-  UserAction(Type t, char key) : type(t), Argument{.key = key} {}
-
-  UserAction(Type t, Vec2D<float> v) : type(t), Argument{.position = v} {}
-
-  ~UserAction() = default;
-
-  Type type;
-
-  union {
-    Vec2D<float> position;
-    char key;
-  } Argument;
-};
-
-class UserInput {
-public:
-  UserInput()
-      : // pre-alloc some space
-        m_Actions(10) {
-    LOG_DEBUG(".");
-  };
-
-  UserInput(const UserInput &x) = delete;
-  UserInput(UserInput &&x) = delete;
-  ~UserInput() { LOG_DEBUG("."); };
-
-  std::expected<void, std::string> Init() { return {}; }
-
-  const std::vector<UserAction> &GetActions() {
-    m_Actions.clear();
-    static Vec2D<float> move_direction = {0.0f, 0.0f};
-    static bool send_move_action = false;
-    SDL_Event event;
-
-    while (SDL_PollEvent(&event)) {
-      if (event.type == SDL_EVENT_KEY_DOWN || event.type == SDL_EVENT_KEY_UP) {
-        bool key_down = event.type == SDL_EVENT_KEY_DOWN ? true : false;
-        SDL_KeyboardEvent kbd_event = event.key;
-        if (kbd_event.repeat) {
-          // SDL repeats KEY_DOWN if key is held down, we ignore that
-          continue;
-        }
-        LOG_DEBUG("Key '", static_cast<char>(kbd_event.key),
-                  key_down ? "' down" : "' up");
-
-        switch (kbd_event.key) {
-        case 'q':
-          m_Actions.emplace_back(UserAction::Type::EXIT);
-          // further processing of inputs is not needed
-          return m_Actions;
-        case 'w':
-        case 's':
-        case 'a':
-        case 'd':
-        case SDLK_UP:
-        case SDLK_DOWN:
-        case SDLK_LEFT:
-        case SDLK_RIGHT: {
-          static std::map<char, Vec2D<float>> move_base{
-              {'w', {0.0, 1.0}},
-              {'s', {0.0, -1.0}},
-              {'a', {1.0, 0.0}},
-              {'d', {-1.0, 0.0}},
-              {static_cast<char>(SDLK_UP), {0.0, 1.0}},
-              {static_cast<char>(SDLK_DOWN), {0.0, -1.0}},
-              {static_cast<char>(SDLK_LEFT), {1.0, 0.0}},
-              {static_cast<char>(SDLK_RIGHT), {-1.0, 0.0}},
-          };
-
-          float direction = key_down ? -1.0f : 1.0f;
-          send_move_action = true;
-          move_direction += move_base[kbd_event.key] * direction;
-          break;
-        }
-        case SDLK_SPACE:
-          if (key_down)
-            m_Actions.emplace_back(UserAction::Type::FIRE);
-          break;
-        default:
-          LOG_INFO("Key '", static_cast<char>(kbd_event.key), "' not mapped");
-          break;
-        }
-      } else if (event.type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
-        SDL_MouseButtonEvent mouse_event = event.button;
-        LOG_DEBUG("Mouse down: ", mouse_event.x, ", ", mouse_event.y);
-        m_Actions.emplace_back(UserAction::Type::MOVE_TARGET,
-                               Vec2D<float>{mouse_event.x, mouse_event.y});
-      } else {
-        // TODO uncomment, for now too much noise
-        // LOG_WARNING("Action not processed");
-      }
-    }
-    if (send_move_action) {
-      m_Actions.emplace_back(UserAction::Type::MOVE,
-                             move_direction.normalized());
-      send_move_action = false;
-    }
-    return m_Actions;
-  }
-
-private:
-  std::vector<UserAction> m_Actions;
-};
-
-//
-// Game classes
-//
-
-class Entity {
-public:
-  enum class Type : std::uint8_t {
-    NONE,
-    PLAYER,
-    WALL,
-    TILE,
-    COUNT // must be last
-  };
-
-  Entity(Vec2D<float> position = {0.0f, 0.0f}) : m_Position(position) {
-    LOG_DEBUG("spawning entity at position ", position);
-  }
-
-  friend std::ostream &operator<<(std::ostream &os, const Entity &obj) {
-    static constexpr std::array<std::string_view,
-                                static_cast<size_t>(Entity::Type::COUNT)>
-        type_name{"NONE", "PLAYER", "WALL", "TILE"};
-    size_t idx = static_cast<size_t>(obj.GetType());
-    assert(idx < type_name.size());
-    os << type_name[idx];
-    return os;
-  }
-
-  virtual Sprite &GetSprite() = 0;
-  virtual constexpr float GetCollisionRadius() const = 0;
-  virtual constexpr float GetCollisionRadiusSquared() {
-    return GetCollisionRadius() * GetCollisionRadius();
-  }
-
-  virtual constexpr Type GetType() const = 0;
-  void SetFlagExpired() { m_FlagExpired = true; }
-  bool IsFlaggedExpired() { return m_FlagExpired; }
-
-  const Vec2D<float> &GetPosition() const { return m_Position; }
-  void SetPosition(Vec2D<float> new_pos) { m_Position = new_pos; }
-
-  const Vec2D<float> &GetActualVelocity() const { return m_ActualVelocity; }
-  const Vec2D<float> &GetRequestedVelocity() const {
-    return m_RequestedVelocity;
-  }
-  void SetActualVelocity(const Vec2D<float> &new_velocity) {
-    m_ActualVelocity = new_velocity;
-  }
-  void SetRequestedVelocity(const Vec2D<float> &new_velocity) {
-    m_RequestedVelocity = new_velocity;
-  }
-
-  void ZeroActualVelocityInDirection(Vec2D<float> direction) {
-    // Vectors e1, e2 form the basis for a local coord system,
-    // where e1 is formed by the direction where we want to zero-out
-    // the velocity, and e2 is the orthogonal vector.
-    // Scalars q1, q2 are coordinates for e1, e2 basis.
-    Vec2D<float> e1 = direction.normalized();
-    Vec2D<float> e2 = e1.orthogonal();
-
-    // q1 * e1 + q2 * e2 = v, from this follows:
-    auto &v = GetActualVelocity();
-    float q2 = (v.y * e1.x - v.x * e1.y) / (e2.y * e1.x - e2.x * e1.y);
-    float q1 = (v.x - q2 * e2.x) / e1.x;
-
-    // We then zero-out the q1, but only if it's positive - meaning
-    // it is aiming in the direction of "direction", not out.
-    // (otherwise we're not able to move out from collision with
-    // another object)
-    if (q1 > 0.0f) {
-      SetActualVelocity(q2 * e2);
-    }
-  }
-
-  virtual void Update(float time_delta) {
-    m_Position += m_ActualVelocity * time_delta;
-  }
-
-  virtual bool IsMovable() const = 0;
-  virtual bool IsCollidable() const = 0;
-
-protected:
-  Vec2D<float> m_Position;
-  Vec2D<float> m_ActualVelocity;
-  Vec2D<float> m_RequestedVelocity;
-
-private:
-  bool m_FlagExpired = false;
-  static constexpr float m_CollisionRadiusSq = 1000.0f;
-};
-
-class Wall final : public Entity {
-public:
-  Wall(Vec2D<float> pos = {0.0f, 0.0f}) : Entity(pos) {
-    LOG_DEBUG(".");
-    if (m_Sprite == nullptr) {
-      LoadResources();
-    }
-  }
-  Wall(const Wall &x) = delete;
-  Wall(Wall &&x) = delete;
-
-  Sprite &GetSprite() override {
-    assert(m_Sprite != nullptr);
-    return *m_Sprite;
-  }
-  constexpr Entity::Type GetType() const override { return Entity::Type::WALL; }
-  constexpr float GetCollisionRadius() const override { return 50.0f; }
-  bool IsMovable() const override { return false; }
-  bool IsCollidable() const override { return true; }
-
-private:
-  void LoadResources() {
-    m_Sprite = std::make_unique<Sprite>("resources/wall.png",
-                                        Vec2D<float>{50.0f, 50.0f});
-  }
-  static std::unique_ptr<Sprite> m_Sprite;
-};
-std::unique_ptr<Sprite> Wall::m_Sprite;
-
-class Player final : public Entity {
-public:
-  Player() {
-    LOG_DEBUG(".");
-    if (m_Sprite == nullptr) {
-      LoadResources();
-    }
-  }
-  Player(const Player &x) = delete;
-  Player(Player &&x) = delete;
-
-  Sprite &GetSprite() override {
-    assert(m_Sprite != nullptr);
-    return *m_Sprite;
-  }
-
-  constexpr Entity::Type GetType() const override {
-    return Entity::Type::PLAYER;
-  }
-  constexpr float GetCollisionRadius() const override { return 50.0f; }
-  bool IsMovable() const override { return true; }
-  bool IsCollidable() const override { return true; }
-
-private:
-  void LoadResources() {
-    m_Sprite = std::make_unique<Sprite>("resources/player.png",
-                                        Vec2D<float>{38.0f, 46.0f});
-  }
-  static std::unique_ptr<Sprite> m_Sprite;
-};
-
-std::unique_ptr<Sprite> Player::m_Sprite;
-
-using Collision = std::pair<std::shared_ptr<Entity>, std::shared_ptr<Entity>>;
-
-struct Tile {
-  float cost;
-  uint8_t R, G, B, A;
-};
-
-static const std::map<std::string_view, Tile> tile_types = {
-    {"Grass", {1.0, 0, 200, 0, 255}},
-    {"Mud", {2.0, 100, 100, 100, 255}},
-    {"Road", {0.5, 200, 200, 200, 255}},
-    {"Water", {10.0, 0, 50, 200, 255}},
-};
-
-using TilePos = Vec2D<int>;
-using WorldPos = Vec2D<float>;
-
-class Map {
-
-  // TODO using = ... for tile vector
-
-public:
-  static constexpr float TILE_SIZE = 100.0f; // tile size in world
-
-  Map(int width, int height) : m_Width(width), m_Height(height) {
-    bool sw = true;
-    LOG_DEBUG("width = ", width, " height = ", height);
-    m_Tiles = std::vector<std::vector<const Tile *>>{};
-    for (int i = 0; i < m_Width; i++) {
-      m_Tiles.push_back(std::vector<const Tile *>{});
-      for (int j = 0; j < m_Height; j++) {
-        if (sw)
-          m_Tiles[i].push_back(&tile_types.at("Grass"));
-        else
-          m_Tiles[i].push_back(&tile_types.at("Water"));
-        sw = !sw;
-      }
-      sw = !sw;
-    }
-  }
-  Map() : Map(0, 0) {}
-
-  const std::vector<std::vector<const Tile *>> &GetMapTiles() const {
-    return m_Tiles;
-  }
-
-  WorldPos TileToWorld(TilePos p) const {
-    return WorldPos{p.x * TILE_SIZE, p.y * TILE_SIZE};
-  }
-
-  TilePos WorldToTile(WorldPos p) const {
-    return TilePos{p.x / TILE_SIZE, p.y / TILE_SIZE};
-  }
-
-  Vec2D<float> GetTileSize() const {
-    return Vec2D<float>{TILE_SIZE, TILE_SIZE};
-  }
-
-private:
-  // std::vector<std::vector<const Tile*>> m_Tiles;
-  std::vector<std::vector<const Tile *>> m_Tiles;
-  int m_Width = 0;
-  int m_Height = 0;
-};
-
-class PathFindingDemo {
-public:
-  PathFindingDemo(int width, int height)
-      : m_Width(width), m_Height(height), // TODO delete width, height
-        m_Map(width, height) {
-    LOG_DEBUG(".");
-  }
-
-  ~PathFindingDemo() { LOG_DEBUG("."); }
-
-  PathFindingDemo(const PathFindingDemo &m) = delete;
-  PathFindingDemo(PathFindingDemo &&m) = delete;
-
-  void AddEntity(std::shared_ptr<Entity> e) {
-    // TODO emplace_back
-    m_Entities.push_back(e);
-  }
-
-  void CreateMap() {
-    m_Entities.clear();
-    m_Player = std::make_shared<Player>();
-    m_Player->SetPosition(Vec2D<float>{200.0f, 200.0f});
-    m_Entities.push_back(m_Player);
-  }
-
-  std::shared_ptr<Player> GetPlayer() { return m_Player; }
-
-  Vec2D<float> GetRandomPosition() const { return Vec2D<float>{0.0, 0.0}; }
-
-  std::vector<std::shared_ptr<Entity>> &GetEntities() { return m_Entities; }
-
-  void UpdateEntities() {
-    float time_delta = 1.0f;
-
-    // Remove entities marked as expired and handle expiry logic (e.g. bomb
-    // exploding); for all other entities, reset the actual velocity to the
-    // requested; actual velocity will be updated later with collisions
-    for (auto &entity : m_Entities) {
-      if (entity->IsFlaggedExpired()) {
-        ExpiryGameLogic(*entity);
-        auto it = std::find(m_Entities.begin(), m_Entities.end(), entity);
-        if (it != m_Entities.end()) {
-          std::swap(*it, m_Entities.back());
-          m_Entities.pop_back();
-        }
-      } else {
-        // Actual velocity might be changed later by collisions
-        entity->SetActualVelocity(entity->GetRequestedVelocity());
-      }
-    }
-
-    // Handle collisions:
-    //  - update actual velocity for colliding objects
-    //  - handle collision logic
-    auto &collisions = GetEntityCollisions();
-    //    LOG_DEBUG("number of collisions: ", collisions.size());
-    for (auto &collision : collisions) {
-      Entity &A = *std::get<0>(collision);
-      Entity &B = *std::get<1>(collision);
-      if (!A.IsMovable())
-        continue;
-      // modify actual speed
-      // LOG_DEBUG("Collision: A is ", A, ", B is ", B);
-      Vec2D<float> AB = B.GetPosition() - A.GetPosition();
-      A.ZeroActualVelocityInDirection(AB);
-      // handle logic
-      CollisionGameLogic(A, B);
-    }
-
-    // Update entities: this advances animations,
-    // internal timers, and updates positions (with velocity
-    // modified by the collision handling)
-    for (auto &entity : m_Entities) {
-      entity->Update(time_delta);
-    }
-  }
-
-  void CollisionGameLogic(Entity &A, Entity &B) {
-    // not used for path finding demo
-  }
-
-  void ExpiryGameLogic(Entity &entity) {
-    // not used for path finding demo
-  }
-
-  const std::vector<Collision> &GetEntityCollisions() {
-    static std::vector<Collision> m_Collisions;
-
-    m_Collisions.clear();
-    for (const auto &entity_A : m_Entities) {
-      for (const auto &entity_B : m_Entities) {
-        if (entity_A == entity_B)
-          continue;
-        if (!entity_A->IsCollidable() || !entity_B->IsCollidable())
-          continue;
-        // check distance of player to given entity
-        auto position_A = entity_A->GetPosition();
-        auto position_B = entity_B->GetPosition();
-        auto distance_sq = position_A.distance_squared(position_B);
-        auto collision_distance_sq =
-            entity_A->GetCollisionRadiusSquared() +
-            entity_B->GetCollisionRadiusSquared() +
-            2 * entity_A->GetCollisionRadius() * entity_B->GetCollisionRadius();
-        // TODO use vector instructions
-        if (distance_sq < collision_distance_sq) {
-          m_Collisions.emplace_back(Collision(entity_A, entity_B));
-        }
-      }
-    }
-    return m_Collisions;
-  }
-
-  void HandleActions(const std::vector<UserAction> &actions) {
-    for (const auto &action : actions) {
-      if (action.type == UserAction::Type::EXIT) {
-        LOG_INFO("Exit requested");
-        m_ExitRequested = true;
-      } else if (action.type == UserAction::Type::FIRE) {
-        LOG_INFO("Fire");
-        // AddEntity(m_Player->CreateBomb());
-      } else if (action.type == UserAction::Type::MOVE) {
-        LOG_INFO("Move direction ", action.Argument.position);
-        m_Player->SetRequestedVelocity(action.Argument.position * 4.0f);
-      } else if (action.type == UserAction::Type::MOVE_TARGET) {
-        TilePos p = m_Map.WorldToTile(action.Argument.position);
-        LOG_INFO("Move target: ", action.Argument.position, ", tile pos: ", p);
-        // TODO move
-      }
-    };
-  }
-
-  const Map &GetMap() const { return m_Map; }
-
-  bool IsCollisionBoxVisible() const { return m_DrawCollisionBox; }
-  bool IsExitRequested() const { return m_ExitRequested; }
-
-private:
-  int m_Width;
-  int m_Height;
-  bool m_ExitRequested = false;
-  bool m_DrawCollisionBox = true;
-  std::vector<std::shared_ptr<Entity>> m_Entities;
-  std::shared_ptr<Player> m_Player;
-  Map m_Map;
-};
-
-// GameLoop class handles user input and audio/video output,
-// client side only. No game logic should be handled here.
-
-class GameLoop {
-public:
-  GameLoop() = default;
-
-  void Run() {
-    LOG_INFO("Running the game");
-    while (!m_Game->IsExitRequested()) {
-      m_Game->HandleActions(m_UserInput->GetActions());
-      m_Game->UpdateEntities();
-
-      m_Window->ClearWindow();
-
-      // draw the map (terrain tiles)
-      const Map &map = m_Game->GetMap();
-      const auto &tiles = map.GetMapTiles();
-      for (int row = 0; row < tiles.size(); row++) {
-        for (int col = 0; col < tiles[row].size(); col++) {
-          // LOG_DEBUG("Drawing rect (", row, ", ", col, ")");
-          m_Window->DrawRect(
-              map.TileToWorld(TilePos{row, col}),
-              map.GetTileSize(), tiles[row][col]->R, tiles[row][col]->G,
-              tiles[row][col]->B, tiles[row][col]->A);
-        }
-      }
-
-      // draw all the entities (player etc)
-      for (auto &entity : m_Game->GetEntities()) {
-        m_Window->DrawSprite(entity->GetPosition(), entity->GetSprite());
-        if (m_Game->IsCollisionBoxVisible()) {
-          m_Window->DrawCircle(entity->GetPosition(),
-                               entity->GetCollisionRadius());
-        }
-      }
-
-      m_Window->Flush();
-      // TODO measure fps
-      std::this_thread::sleep_for(std::chrono::milliseconds(30));
-    }
-  }
-
-  inline void SetGame(std::unique_ptr<PathFindingDemo> x) {
-    m_Game = std::move(x);
-  }
-  inline void SetWindow(std::unique_ptr<Window> x) { m_Window = std::move(x); }
-  inline void SetUserInput(std::unique_ptr<UserInput> x) {
-    m_UserInput = std::move(x);
-  }
-  inline void SetAudioOutput(std::unique_ptr<AudioOutput> x) {
-    m_AudioOutput = std::move(x);
-  }
-
-private:
-  std::unique_ptr<PathFindingDemo> m_Game;
-  std::unique_ptr<Window> m_Window;
-  std::unique_ptr<UserInput> m_UserInput;
-  std::unique_ptr<AudioOutput> m_AudioOutput;
-};
-
-int main(int argc, char **argv) {
+int main() {
   constexpr int error = -1;
 
   /*
    * Initialize the input/output system
    */
 
-  auto window = std::make_unique<Window>(640, 480); // the holy resolution
-  // auto window_init = window->Init();
+  auto window = std::make_unique<Window>(640, 480);
   if (auto initialized = window->Init(); !initialized) {
     LOG_ERROR(initialized.error());
     return error;
@@ -791,12 +24,6 @@ int main(int argc, char **argv) {
     return error;
   }
 
-  auto audio_output = std::make_unique<AudioOutput>();
-  if (auto initialized = audio_output->Init(); !initialized) {
-    LOG_ERROR(initialized.error());
-    return error;
-  }
-
   /*
    * Initialize the map and run the pathfinding demo
    */
@@ -807,7 +34,7 @@ int main(int argc, char **argv) {
   auto game_loop = GameLoop{};
   game_loop.SetWindow(std::move(window));
   game_loop.SetUserInput(std::move(user_input));
-  game_loop.SetAudioOutput(std::move(audio_output));
   game_loop.SetGame(std::move(demo));
   game_loop.Run();
+  return 0;
 }

cpp/src/map.cpp

@@ -0,0 +1,86 @@
+#include <cassert>
+#include <vector>
+
+#include "log.hpp"
+#include "map.hpp"
+#include "tile.hpp"
+
+Map::Map(int rows, int cols) : m_Cols(cols), m_Rows(rows) {
+  bool sw = true;
+  LOG_DEBUG("cols = ", cols, " rows = ", rows);
+  m_Tiles = std::vector<std::vector<const Tile *>>{};
+  for (size_t row = 0; row < m_Rows; row++) {
+    m_Tiles.push_back(std::vector<const Tile *>{});
+    for (size_t col = 0; col < m_Cols; col++) {
+      if (sw)
+        m_Tiles[row].push_back(&tile_types.at("Grass"));
+      else
+        m_Tiles[row].push_back(&tile_types.at("Road"));
+      sw = !sw;
+    }
+    sw = !sw;
+  }
+}
+
+WorldPos Map::TileToWorld(TilePos p) const {
+  return WorldPos{(p.x + 0.5) * TILE_SIZE, (p.y + 0.5) * TILE_SIZE}; 
+}
+
+WorldPos Map::TileEdgeToWorld(TilePos p) const {
+  return WorldPos{p.x * TILE_SIZE, p.y * TILE_SIZE}; 
+}
+
+TilePos Map::WorldToTile(WorldPos p) const {
+  return TilePos{p.x / TILE_SIZE, p.y / TILE_SIZE};
+}
+
+WorldPos Map::GetTileSize() const { return WorldPos{TILE_SIZE, TILE_SIZE}; }
+
+const Tile *Map::GetTileAt(TilePos p) const {
+  assert(IsTilePosValid(p));
+  size_t row = p.x;
+  size_t col = p.y;
+
+  return m_Tiles[row][col];
+}
+
+const Tile *Map::GetTileAt(WorldPos p) const {
+  return GetTileAt(WorldToTile(p));
+}
+
+bool Map::IsTilePosValid(TilePos p) const {
+  size_t row = p.x;
+  size_t col = p.y;
+
+  return row < m_Tiles.size() && col < m_Tiles[0].size();
+}
+
+
+std::vector<TilePos> Map::GetNeighbors(TilePos center) const
+{
+  std::vector<TilePos> neighbours;
+  neighbours.reserve(4);
+
+  std::array<TilePos, 4> candidates = {
+    center + TilePos{1,0},
+    center + TilePos{-1,0},
+    center + TilePos{0, 1},
+    center + TilePos{0, -1},
+  };
+
+  for (const auto& c : candidates) {
+    if (IsTilePosValid(c))
+        neighbours.push_back(c);
+  }
+  return neighbours;
+}
+//  std::vector<TilePos> neighbours;
+//  neighbours.reserve(8);
+//  for (int dx = -1; dx <= 1; ++dx) {
+//      for (int dy = -1; dy <= 1; ++dy) {
+//          if (dx == 0 && dy == 0) continue;
+//          TilePos p{center.x + dx, center.y + dy};
+//          if (IsTilePosValid(p)) neighbours.push_back(std::move(p));
+//      }
+//  }
+//  return neighbours;

cpp/src/map.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <vector>
+
+#include "math.hpp"
+#include "tile.hpp"
+
+using TileGrid = std::vector<std::vector<const Tile *>>;
+
+class Map {
+public:
+  static constexpr float TILE_SIZE = 100.0f; // tile size in world
+
+  Map(int rows, int cols);
+  Map() : Map(0, 0) {}
+
+  Map(const Map&) = delete;
+  Map(Map&&) = delete;
+  Map& operator=(const Map&) = delete;
+  Map& operator=(Map&&) = delete;
+
+  const TileGrid &GetMapTiles() const { return m_Tiles; }
+
+  // coordinate conversion functions
+  WorldPos TileToWorld(TilePos p) const;
+  WorldPos TileEdgeToWorld(TilePos p) const;
+  TilePos WorldToTile(WorldPos p) const;
+
+  WorldPos GetTileSize() const;
+  const Tile *GetTileAt(TilePos p) const;
+  const Tile *GetTileAt(WorldPos p) const;
+
+  bool IsTilePosValid(TilePos p) const;
+
+
+  std::vector<TilePos> GetNeighbors(TilePos center) const;
+
+  template <typename T> double GetTileVelocityCoeff(T p) const {
+    return 1.0 / GetTileAt(p)->cost;
+  }
+
+private:
+  TileGrid m_Tiles;
+  size_t m_Cols = 0;
+  size_t m_Rows = 0;
+};

cpp/src/math.hpp

@@ -3,7 +3,11 @@
 #include <cassert>
 #include <cmath>
 #include <concepts>
+#include <initializer_list>
 #include <iostream>
+#include <utility>
+
+constexpr double EQUALITY_LIMIT = 1e-6;
 
 template <typename T> struct Vec2D {
 public:
@@ -28,6 +32,16 @@ public:
     return Vec2D{k * v.x, k * v.y};
   }
 
+  friend bool operator==(const Vec2D &a, const Vec2D &b) {
+    if constexpr (std::is_integral_v<T>) {
+      return a.x == b.x && a.y == b.y;
+    } else if constexpr (std::is_floating_point_v<T>) {
+      return a.distance(b) < EQUALITY_LIMIT;
+    } else {
+      static_assert("Unhandled comparison");
+    }
+  }
+
   Vec2D operator*(float b) const { return Vec2D{b * x, b * y}; }
 
   T distance_squared(const Vec2D &other) const {
@@ -46,7 +60,7 @@ public:
     requires std::floating_point<T>
   {
     auto length = sqrt(x * x + y * y);
-    if (length < 1e-6) {
+    if (length < EQUALITY_LIMIT) {
       x = y = 0;
     } else {
       x /= length;
@@ -86,3 +100,15 @@ public:
     return os;
   }
 };
+
+using TilePos = Vec2D<int>;
+using WorldPos = Vec2D<float>;
+
+struct TilePosHash {
+    std::size_t operator()(const TilePos& p) const noexcept {
+        std::size_t h1 = std::hash<int>{}(p.x);
+        std::size_t h2 = std::hash<int>{}(p.y);
+        return h1 ^ (h2 + 0x9e3779b9 + (h1<<6) + (h1>>2));
+    }
+};
+

cpp/src/pathfinder.cpp

@@ -0,0 +1,89 @@
+#include <memory>
+#include <cassert>
+#include <queue>
+
+#include "pathfinder.hpp"
+#include "log.hpp"
+
+namespace pathfinder {
+
+
+PathFinderBase::PathFinderBase(const Map* map) : m_Map(map) {}
+
+
+Path LinearPathFinder::CalculatePath(WorldPos start, WorldPos end)
+{
+  auto path = Path{end};
+  return path;
+}
+
+
+Path BFS::CalculatePath(WorldPos start_world, WorldPos end_world) {
+    if (m_Map == nullptr) return {};
+
+    const TilePos start = m_Map->WorldToTile(start_world);
+    const TilePos end   = m_Map->WorldToTile(end_world);
+
+    if (!m_Map->IsTilePosValid(start) || !m_Map->IsTilePosValid(end))
+        return {};
+    if (start == end) {
+        return {};
+    }
+    // clear previous run
+    m_CameFrom.clear();
+    m_Distance.clear();
+
+    std::queue<TilePos> frontier;
+    frontier.push(start);
+    m_CameFrom[start] = start;
+    m_Distance[start] = 0.0f;
+
+    // ---------------- build flow-field ----------------
+    bool early_exit = false;
+    while (!frontier.empty() && !early_exit) {
+        TilePos current = frontier.front();
+        frontier.pop();
+
+        for (TilePos next : m_Map->GetNeighbors(current)) {
+            if (m_CameFrom.find(next) == m_CameFrom.end()) {  // not visited
+                frontier.push(next);
+                m_Distance[next] = m_Distance[current] + 1.0f;
+                m_CameFrom[next] = current;
+
+                if (next == end) {          // early exit
+                    early_exit = true;
+                    break;
+                }
+            }
+        }
+    }
+
+    // --------------- reconstruct path -----------------
+    if (m_CameFrom.find(end) == m_CameFrom.end())
+        return {};                        // end not reached
+
+    Path path;
+    TilePos cur = end;
+    path.push_back(m_Map->TileToWorld(cur));
+    while (cur != start) {
+        cur = m_CameFrom[cur];
+        path.push_back(m_Map->TileToWorld(cur));
+    }
+    std::reverse(path.begin(), path.end());
+    return path;
+}
+
+std::unique_ptr<PathFinderBase> create(PathFinderType type, const Map* map) {
+  switch (type) {
+    case PathFinderType::LINEAR:
+      return std::move(std::make_unique<LinearPathFinder>(map));
+    case PathFinderType::BFS:
+      return std::move(std::make_unique<BFS>(map));
+    case PathFinderType::COUNT:
+      LOG_WARNING("Incorrect pathfinder type");
+      return nullptr;
+  };
+  return nullptr;
+}
+
+} // pathfinder namespace

cpp/src/pathfinder.hpp

@@ -0,0 +1,66 @@
+#pragma once
+
+#include <vector>
+#include <memory>
+#include <unordered_map>
+
+#include "math.hpp"
+#include "map.hpp"
+
+namespace pathfinder {
+
+using Path = std::vector<WorldPos>;
+
+enum class PathFinderType {
+  LINEAR = 1,
+  BFS,
+  COUNT,
+};
+
+class PathFinderBase {
+public:
+  PathFinderBase(const Map* m);
+  ~PathFinderBase() = default;
+
+  PathFinderBase(const PathFinderBase&) = delete;
+  PathFinderBase(PathFinderBase&&) = delete;
+  PathFinderBase& operator=(const PathFinderBase&) = delete;
+  PathFinderBase& operator=(PathFinderBase&&) = delete;
+
+  virtual const std::string_view& GetName() const = 0; 
+  virtual Path CalculatePath(WorldPos start, WorldPos end) = 0;
+
+protected:
+  const Map* m_Map;
+};
+
+
+class LinearPathFinder : public PathFinderBase {
+
+public:
+  LinearPathFinder(const Map* m): PathFinderBase(m) {}
+  Path CalculatePath(WorldPos start, WorldPos end) override;
+  const std::string_view& GetName() const override { return m_Name; }
+
+private:
+  const std::string_view m_Name = "Linear Path";
+};
+
+
+class BFS: public PathFinderBase {
+
+public:
+  BFS(const Map* m): PathFinderBase(m) {}
+  Path CalculatePath(WorldPos start, WorldPos end) override;
+  const std::string_view& GetName() const override { return m_Name; }
+
+private:
+  const std::string_view m_Name = "Breadth First Search";
+  std::unordered_map<TilePos, double, TilePosHash> m_Distance;
+  std::unordered_map<TilePos, TilePos, TilePosHash> m_CameFrom;
+};
+
+std::unique_ptr<PathFinderBase> create(PathFinderType type, const Map* map);
+
+} // pathfinder namespace
+  

cpp/src/pathfindingdemo.cpp

@@ -0,0 +1,95 @@
+#include <memory>
+#include <optional>
+#include <queue>
+#include <vector>
+
+#include "pathfindingdemo.hpp"
+
+#include "entities.hpp"
+#include "log.hpp"
+#include "map.hpp"
+#include "user_input.hpp"
+#include "pathfinder.hpp"
+
+PathFindingDemo::PathFindingDemo(int width, int height) :
+  m_Map(width, height)
+{
+  LOG_DEBUG(".");
+  // set default pathfinder method
+  m_PathFinder = pathfinder::create(pathfinder::PathFinderType::LINEAR, (const Map*)&m_Map);
+}
+
+PathFindingDemo::~PathFindingDemo() { LOG_DEBUG("."); }
+
+void PathFindingDemo::AddEntity(std::shared_ptr<Entity> e) {
+  // TODO emplace_back
+  m_Entities.push_back(e);
+}
+
+void PathFindingDemo::CreateMap() {
+  m_Entities.clear();
+  m_Player = std::make_shared<Player>();
+  m_Player->SetPosition(WorldPos{200.0f, 200.0f});
+  m_Entities.push_back(m_Player);
+}
+
+WorldPos PathFindingDemo::GetRandomPosition() const {
+  return WorldPos{0.0, 0.0};
+}
+
+std::optional<WorldPos> PathFindingDemo::GetMoveTarget() {
+  WorldPos current_player_pos = GetPlayer()->GetPosition();
+
+  if (m_Path.empty()) {
+    return {};
+  }
+
+  WorldPos next_player_pos = m_Path.front();
+
+  if (current_player_pos.distance(next_player_pos) > 10.0) {
+    // target not reached yet
+    return next_player_pos;
+  }
+  // target reached, pop it
+  //m_MoveQueue.pop();
+  m_Path.erase(m_Path.begin());
+  // return nothing - if there's next point in the queue,
+  // we'll get it in the next iteration
+  return {};
+}
+
+void PathFindingDemo::UpdatePlayerVelocity() {
+  auto player = GetPlayer();
+  auto current_pos = player->GetPosition();
+  double tile_velocity_coeff = m_Map.GetTileVelocityCoeff(current_pos);
+  auto next_pos = GetMoveTarget();
+  WorldPos velocity = WorldPos{};
+  if (next_pos) {
+    velocity = next_pos.value() - current_pos;
+    velocity.normalize();
+    LOG_DEBUG("I want to move to: ", next_pos.value(),
+              ", velocity: ", velocity);
+  }
+  player->SetActualVelocity(velocity * tile_velocity_coeff);
+  float time_delta = 1.0f;
+  player->Update(time_delta);
+}
+
+void PathFindingDemo::HandleActions(const std::vector<UserAction> &actions) {
+  for (const auto &action : actions) {
+    if (action.type == UserAction::Type::EXIT) {
+      LOG_INFO("Exit requested");
+      m_ExitRequested = true;
+    } else if (action.type == UserAction::Type::SET_MOVE_TARGET) {
+      WorldPos wp = action.Argument.position;
+      LOG_INFO("Calculating path to target: ", wp);
+      m_Path = m_PathFinder->CalculatePath(m_Player->GetPosition(), wp);
+      LOG_INFO("Done, path node count: ", m_Path.size());
+    } else if (action.type == UserAction::Type::SELECT_PATHFINDER) {
+      using namespace pathfinder;
+      PathFinderType type = static_cast<PathFinderType>(action.Argument.number);
+      m_PathFinder = pathfinder::create(type, (const Map*)&m_Map);
+      LOG_INFO("Switched to path finding method: ", m_PathFinder->GetName());
+    }
+  };
+}

cpp/src/pathfindingdemo.hpp

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <memory>
+#include <optional>
+#include <queue>
+#include <vector>
+
+#include "entities.hpp"
+#include "log.hpp"
+#include "map.hpp"
+#include "user_input.hpp"
+#include "pathfinder.hpp"
+
+class PathFindingDemo {
+public:
+  PathFindingDemo(int width, int height);
+  ~PathFindingDemo();
+
+  PathFindingDemo(const PathFindingDemo &m) = delete;
+  PathFindingDemo(PathFindingDemo &&m) = delete;
+  PathFindingDemo &operator=(const PathFindingDemo &) = delete;
+  PathFindingDemo &operator=(PathFindingDemo &&) = delete;
+
+  std::shared_ptr<Player> GetPlayer() { return m_Player; }
+  std::vector<std::shared_ptr<Entity>>& GetEntities() { return m_Entities; }
+  const Map& GetMap() const { return m_Map; }
+  const pathfinder::Path& GetPath() const { return m_Path; }
+  bool IsExitRequested() const { return m_ExitRequested; }
+
+  void AddEntity(std::shared_ptr<Entity> e);
+  void CreateMap();
+  std::optional<WorldPos> GetMoveTarget();
+  void UpdatePlayerVelocity();
+  void HandleActions(const std::vector<UserAction> &actions);
+  WorldPos GetRandomPosition() const;
+
+private:
+  bool m_ExitRequested = false;
+  Map m_Map;
+  std::vector<std::shared_ptr<Entity>> m_Entities;
+  std::shared_ptr<Player> m_Player;
+  pathfinder::Path m_Path;
+  std::unique_ptr<pathfinder::PathFinderBase> m_PathFinder;
+};

cpp/src/sprite.cpp

@@ -0,0 +1,52 @@
+#include "sprite.hpp"
+
+#include <SDL3/SDL.h>
+#include <SDL3_image/SDL_image.h>
+#include <cassert>
+#include <memory>
+#include <stdexcept>
+#include <string>
+
+#include "log.hpp"
+#include "math.hpp"
+
+Sprite::Sprite() : m_Texture(nullptr, SDL_DestroyTexture) {}
+
+Sprite::Sprite(std::string path, Vec2D<float> center) : Sprite() {
+  LoadImage(path, center);
+}
+
+Sprite::~Sprite() { LOG_DEBUG("."); }
+
+void Sprite::LoadImage(std::string path, Vec2D<float> image_center) {
+  LOG_INFO("Loading image ", path);
+  assert(m_Renderer != nullptr);
+
+  auto surface = std::unique_ptr<SDL_Surface, decltype(&SDL_DestroySurface)>(
+      IMG_Load(path.c_str()), SDL_DestroySurface);
+
+  if (surface == nullptr) {
+    LOG_ERROR("IMG_Load failed to load ", path);
+    throw std::runtime_error("Failed to load resources");
+  }
+
+  m_Texture = std::unique_ptr<SDL_Texture, decltype(&SDL_DestroyTexture)>(
+      SDL_CreateTextureFromSurface(m_Renderer.get(), surface.get()),
+      SDL_DestroyTexture);
+  if (m_Texture == nullptr) {
+    LOG_ERROR("SDL_CreateTextureFromSurface failed");
+    throw std::runtime_error("Failed to load resources");
+  }
+  float w, h;
+  SDL_GetTextureSize(m_Texture.get(), &w, &h);
+  m_Size = {w, h};
+  m_ImageCenter = image_center;
+}
+
+// Renderer is shared for all class instances - we need it in order
+// to create textures from images
+void Sprite::SetRenderer(std::shared_ptr<SDL_Renderer> renderer) {
+  m_Renderer = renderer;
+}
+
+std::shared_ptr<SDL_Renderer> Sprite::m_Renderer = nullptr;

cpp/src/sprite.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <SDL3/SDL.h>
+#include <SDL3_image/SDL_image.h>
+#include <cassert>
+#include <memory>
+#include <stdexcept>
+#include <string>
+
+#include "log.hpp"
+#include "math.hpp"
+
+class Sprite {
+public:
+  Sprite();
+  ~Sprite();
+  explicit Sprite(std::string path, WorldPos center = {0, 0});
+
+  Sprite(const Sprite &) = delete;
+  Sprite &operator=(const Sprite &) = delete;
+  Sprite(Sprite &&) = delete;
+  Sprite &operator=(Sprite &&) = delete;
+
+  static void SetRenderer(std::shared_ptr<SDL_Renderer> renderer);
+
+  // GetTexture cannot return pointer to const, as SDL_RenderTexture modifies it
+  SDL_Texture *GetTexture() { return m_Texture.get(); }
+  WorldPos GetSize() const { return m_Size; }
+  WorldPos GetCenter() const { return m_ImageCenter; }
+
+  void LoadImage(std::string path, WorldPos image_center = {0.0, 0.0});
+
+private:
+  static std::shared_ptr<SDL_Renderer> m_Renderer;
+  std::unique_ptr<SDL_Texture, decltype(&SDL_DestroyTexture)> m_Texture;
+  WorldPos m_Size;
+  WorldPos m_ImageCenter;
+  float m_TextureWidth = 0;
+  float m_TextureHeight = 0;
+};

cpp/src/tile.cpp

@@ -0,0 +1,8 @@
+#include "tile.hpp"
+
+const std::map<std::string_view, Tile> tile_types = {
+    {"Grass", {1.0, 0, 200, 0, 255}},
+    {"Mud", {2.0, 100, 100, 100, 255}},
+    {"Road", {0.5, 200, 200, 200, 255}},
+    {"Water", {10.0, 0, 50, 200, 255}},
+};

cpp/src/tile.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <cstdint>
+#include <map>
+#include <string_view>
+
+struct Tile {
+  float cost;
+  uint8_t R, G, B, A;
+};
+
+extern const std::map<std::string_view, Tile> tile_types;

cpp/src/user_input.cpp

@@ -0,0 +1,68 @@
+#include <SDL3/SDL.h>
+#include <expected>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "user_input.hpp"
+
+#include "log.hpp"
+#include "math.hpp"
+
+UserInput::UserInput()
+    : // pre-alloc some space
+      m_Actions(10) {
+  LOG_DEBUG(".");
+};
+
+UserInput::~UserInput() { LOG_DEBUG("."); };
+
+std::expected<void, std::string> UserInput::Init() { return {}; }
+
+const std::vector<UserAction> &UserInput::GetActions() {
+  m_Actions.clear();
+  static WorldPos move_direction = {0.0f, 0.0f};
+  SDL_Event event;
+
+  while (SDL_PollEvent(&event)) {
+    if (event.type == SDL_EVENT_KEY_DOWN || event.type == SDL_EVENT_KEY_UP) {
+      bool key_down = event.type == SDL_EVENT_KEY_DOWN ? true : false;
+      SDL_KeyboardEvent kbd_event = event.key;
+      if (kbd_event.repeat) {
+        // SDL repeats KEY_DOWN if key is held down, we ignore that
+        continue;
+      }
+      LOG_DEBUG("Key '", static_cast<char>(kbd_event.key),
+                key_down ? "' down" : "' up");
+
+      switch (kbd_event.key) {
+      case 'q':
+        m_Actions.emplace_back(UserAction::Type::EXIT);
+        // further processing of inputs is not needed
+        return m_Actions;
+      case '1':
+      case '2':
+      case '3':
+      case '4':
+        if (key_down) {
+          int selection = kbd_event.key - '0';
+          m_Actions.emplace_back(UserAction::Type::SELECT_PATHFINDER, selection);
+          LOG_INFO("Pathfinder selected: ", selection);
+        }
+       break;
+      default:
+        LOG_INFO("Key '", static_cast<char>(kbd_event.key), "' not mapped");
+        break;
+      }
+    } else if (event.type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
+      SDL_MouseButtonEvent mouse_event = event.button;
+      LOG_DEBUG("Mouse down: ", mouse_event.x, ", ", mouse_event.y);
+      m_Actions.emplace_back(UserAction::Type::SET_MOVE_TARGET,
+                             WorldPos{mouse_event.x, mouse_event.y});
+    } else {
+      // TODO uncomment, for now too much noise
+      // LOG_WARNING("Action not processed");
+    }
+  }
+  return m_Actions;
+}

cpp/src/user_input.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <expected>
+#include <string>
+#include <vector>
+
+#include "log.hpp"
+#include "math.hpp"
+
+class UserAction {
+public:
+  enum class Type { NONE, EXIT, SET_MOVE_TARGET, SELECT_PATHFINDER };
+
+  UserAction() = default;
+  UserAction(Type t) : type(t) {}
+  UserAction(Type t, char key) : type(t), Argument{.key = key} {}
+  UserAction(Type t, WorldPos v) : type(t), Argument{.position = v} {}
+  UserAction(Type t, int arg) : type(t), Argument{.number = arg} {}
+  ~UserAction() = default;
+
+  Type type;
+
+  union {
+    WorldPos position;
+    char key;
+    int number;
+  } Argument;
+};
+
+class UserInput {
+public:
+  UserInput();
+  ~UserInput();
+
+  UserInput(const UserInput &x) = delete;
+  UserInput(UserInput &&x) = delete;
+  UserInput &operator=(const UserInput &) = delete;
+  UserInput &operator=(UserInput &&) = delete;
+
+  std::expected<void, std::string> Init();
+
+  const std::vector<UserAction> &GetActions();
+
+private:
+  std::vector<UserAction> m_Actions;
+};

cpp/src/window.cpp

@@ -0,0 +1,118 @@
+#include <GL/glew.h>
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_opengl.h>
+#include <cmath>
+#include <cstdlib>
+#include <expected>
+#include <memory>
+#include <string>
+
+#include "window.hpp"
+
+#include "log.hpp"
+#include "math.hpp"
+#include "sprite.hpp"
+
+Window::Window(int width, int height) : m_Width(width), m_Height(height) {
+  LOG_DEBUG(".");
+}
+
+std::expected<void, std::string> Window::Init() {
+  LOG_DEBUG(".");
+
+  if (SDL_Init(SDL_INIT_VIDEO) == false) {
+    return std::unexpected(std::string("SDL could not initialize! Error: ") +
+                           SDL_GetError());
+  }
+  m_Window = SDL_CreateWindow("SDL2 Window", m_Width, m_Height,
+                              SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
+  if (m_Window == nullptr) {
+    std::atexit(SDL_Quit);
+    return std::unexpected(std::string("Window could not be created! Error: ") +
+                           SDL_GetError());
+  }
+
+  m_Context = SDL_GL_CreateContext(m_Window);
+  if (m_Context == nullptr) {
+    SDL_DestroyWindow(m_Window);
+    std::atexit(SDL_Quit);
+    return std::unexpected(
+        std::string("GL context could not be created! Error: ") +
+        SDL_GetError());
+  }
+
+  if (glewInit() != GLEW_OK) {
+    SDL_GL_DestroyContext(m_Context);
+    SDL_DestroyWindow(m_Window);
+    std::atexit(SDL_Quit);
+    return std::unexpected("GLEW init failed!");
+  }
+
+  // Resize();
+
+  m_Renderer = std::shared_ptr<SDL_Renderer>(SDL_CreateRenderer(m_Window, NULL),
+                                             SDL_DestroyRenderer);
+  if (m_Renderer == nullptr) {
+    SDL_DestroyWindow(m_Window);
+    std::atexit(SDL_Quit);
+    return std::unexpected(
+        std::string("Renderer could not be created! Error: ") + SDL_GetError());
+  }
+
+  // Set renderer to the Sprite class
+  Sprite::SetRenderer(m_Renderer);
+
+  // TODO this needs to be tied to map size
+  SDL_SetRenderScale(m_Renderer.get(), 1.0f, 1.0f);
+
+  return {};
+}
+
+Window::~Window() {
+  // SDL_DestroyRenderer(m_Renderer); // handled by shared_ptr
+  SDL_GL_DestroyContext(m_Context);
+  SDL_DestroyWindow(m_Window);
+  std::atexit(SDL_Quit);
+  LOG_DEBUG(".");
+}
+
+void Window::DrawSprite(const WorldPos &position, Sprite &s) {
+  WorldPos size = s.GetSize();
+  WorldPos img_center = s.GetCenter();
+  SDL_FRect rect = {position.x - img_center.x, position.y - img_center.y,
+                    size.x, size.y};
+  SDL_RenderTexture(m_Renderer.get(), s.GetTexture(), nullptr, &rect);
+}
+
+void Window::DrawRect(const WorldPos &position, const WorldPos size, uint8_t R,
+                      uint8_t G, uint8_t B, uint8_t A) {
+  SDL_FRect rect = {position.x, position.y, size.x, size.y};
+  SDL_SetRenderDrawColor(m_Renderer.get(), R, G, B, A);
+  SDL_RenderFillRect(m_Renderer.get(), &rect);
+}
+
+void Window::ClearWindow() {
+  SDL_SetRenderDrawColor(m_Renderer.get(), 50, 50, 50, 255);
+  SDL_RenderClear(m_Renderer.get());
+}
+
+void Window::Flush() { SDL_RenderPresent(m_Renderer.get()); }
+
+void Window::DrawCircle(const WorldPos &position, float radius) {
+  int cx = static_cast<int>(position.x);
+  int cy = static_cast<int>(position.y);
+  SDL_SetRenderDrawColor(m_Renderer.get(), 255, 0, 0, 255);
+  for (int i = 0; i < 360; ++i) {
+    double a = i * M_PI / 180.0;
+    SDL_RenderPoint(m_Renderer.get(),
+                    cx + static_cast<int>(std::round(radius * std::cos(a))),
+                    cy + static_cast<int>(std::round(radius * std::sin(a))));
+  }
+}
+
+void Window::DrawLine(const WorldPos &A, const WorldPos &B)
+{
+  SDL_SetRenderDrawColor(m_Renderer.get(), 255, 0, 0, 255);
+  SDL_RenderLine(m_Renderer.get(), A.x, A.y, B.x, B.y);
+}
+

cpp/src/window.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <GL/glew.h>
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_opengl.h>
+#include <cmath>
+#include <expected>
+#include <memory>
+#include <string>
+
+#include "math.hpp"
+#include "sprite.hpp"
+
+class Window {
+public:
+  Window(int width, int height);
+  ~Window();
+
+  Window(const Window &x) = delete;
+  Window(Window &&x) = delete;
+  Window &operator=(const Window &) = delete;
+  Window &operator=(Window &&) = delete;
+
+  std::expected<void, std::string> Init();
+  void DrawSprite(const WorldPos &position, Sprite &s);
+  void DrawRect(const WorldPos &position, const WorldPos size, uint8_t R,
+                uint8_t G, uint8_t B, uint8_t A);
+  void ClearWindow();
+  void Flush();
+  void DrawCircle(const WorldPos &position, float radius);
+  void DrawLine(const WorldPos &A, const WorldPos &B);
+
+  std::shared_ptr<SDL_Renderer> m_Renderer = nullptr;
+  SDL_Window *m_Window;
+  SDL_GLContext m_Context;
+
+private:
+  uint32_t m_Width;
+  uint32_t m_Height;
+};