From 0f8e61797f0acec556e0dec454b00659d9cead75 Mon Sep 17 00:00:00 2001
From: "Zed A. Shaw" <zed.shaw@gmail.com>
Date: Sun, 18 May 2025 14:37:43 -0400
Subject: [PATCH] Now using a hunt-and-kill maze algorithm.

---
 maze.cpp         | 125 +++++++++++++++++++++++++++++++++++++++++++++--
 maze.hpp         |   2 +
 tests/mazes.cpp  |  16 +++++-
 worldbuilder.cpp |   5 +-
 4 files changed, 138 insertions(+), 10 deletions(-)

diff --git a/maze.cpp b/maze.cpp
index ec5b069..0711e57 100644
--- a/maze.cpp
+++ b/maze.cpp
@@ -107,11 +107,11 @@ void divide(Matrix& map, std::vector<Room> &rooms,
   }
 
   if(punch_room) {
-    for(size_t j = jCoords.x; j <= jCoords.y; j++) {
-      for(size_t i = iCoords.x; i <= iCoords.y; i++) {
-        map[j][i] = 0;
-      }
-    }
+    // for(size_t j = jCoords.x; j <= jCoords.y; j++) {
+    //   for(size_t i = iCoords.x; i <= iCoords.y; i++) {
+    //     map[j][i] = 0;
+    //   }
+    // }
 
     Room room{iCoords.x, jCoords.x, iCoords.y - iCoords.x + 1, jCoords.y - jCoords.x + 1};
 
@@ -143,3 +143,118 @@ void maze::recursive_div(Matrix& map, std::vector<Room>& rooms) {
 
   divide(map, rooms, {1, height - 2}, {1, width - 2}, split_dir(1, 1));
 }
+
+
+bool complete(Matrix& maze) {
+  size_t width = matrix::width(maze);
+  size_t height = matrix::height(maze);
+
+  for(size_t row = 1; row < height; row += 2) {
+    for(size_t col = 1; col < width; col += 2) {
+      if(maze[row][col] != 0) return false;
+    }
+  }
+
+  // dbc::sentinel("LOL it's complete eh?");
+  return true;
+}
+
+std::vector<Point> neighborsAB(Matrix& maze, Point on) {
+  std::vector<Point> result;
+
+  std::array<Point, 4> points{{
+    {on.x, on.y - 2},
+    {on.x, on.y + 2},
+    {on.x - 2, on.y},
+    {on.x + 2, on.y}
+  }};
+
+  for(auto point : points) {
+    if(matrix::inbounds(maze, point.x, point.y)) {
+      result.push_back(point);
+    }
+  }
+
+  return result;
+}
+
+std::vector<Point> neighbors(Matrix& maze, Point on) {
+  std::vector<Point> result;
+
+  std::array<Point, 4> points{{
+    {on.x, on.y - 2},
+    {on.x, on.y + 2},
+    {on.x - 2, on.y},
+    {on.x + 2, on.y}
+  }};
+
+  for(auto point : points) {
+    if(matrix::inbounds(maze, point.x, point.y)) {
+      if(maze[point.y][point.x] == WALL_PATH_LIMIT) {
+        result.push_back(point);
+      }
+    }
+  }
+
+  return result;
+}
+
+std::pair<Point, Point> findCoord(Matrix& maze) {
+  size_t width = matrix::width(maze);
+  size_t height = matrix::height(maze);
+
+  for(size_t y = 1; y < height; y += 2) {
+    for(size_t x = 1; x < width; x += 2) {
+      if(maze[y][x] == WALL_PATH_LIMIT) {
+        auto found = neighborsAB(maze, {x, y});
+
+        for(auto point : found) {
+          if(maze[point.y][point.x] == 0) {
+            return {{x, y}, point};
+          }
+        }
+      }
+    }
+  }
+
+  matrix::dump("BAD MAZE", maze);
+  dbc::sentinel("failed to find coord?");
+}
+
+void maze::hunt_and_kill(Matrix& maze, std::vector<Room>& rooms) {
+  size_t width = matrix::width(maze);
+  size_t height = matrix::height(maze);
+  matrix::assign(maze, WALL_PATH_LIMIT);
+
+  Room start{2, 2, 3, 3};
+  rooms.push_back(start);
+  Room goal{width-4, height-4, 3, 3};
+  rooms.push_back(goal);
+
+  for(auto& room : rooms) {
+    for(matrix::box it{maze, room.x, room.y, 1}; it.next();) {
+      maze[it.y][it.x] = 0;
+    }
+  }
+
+  Point on{1,1};
+  while(!complete(maze)) {
+    auto n = neighbors(maze, on);
+    if(n.size() == 0) {
+      auto t = findCoord(maze);
+      on = t.first;
+      maze[on.y][on.x] = 0;
+      size_t row = (on.y + t.second.y) / 2;
+      size_t col = (on.x + t.second.x) / 2;
+      maze[row][col] = 0;
+    } else {
+      auto nb = n[Random::uniform(size_t(0), n.size() - 1)];
+      maze[nb.y][nb.x] = 0;
+
+      size_t row = (nb.y + on.y) / 2;
+      size_t col = (nb.x + on.x) / 2;
+      maze[row][col] = 0;
+      on = nb;
+    }
+  }
+}
diff --git a/maze.hpp b/maze.hpp
index 2a4a8ef..6fdce07 100644
--- a/maze.hpp
+++ b/maze.hpp
@@ -4,4 +4,6 @@
 
 namespace maze {
   void recursive_div(matrix::Matrix& map, std::vector<Room>& rooms);
+
+  void hunt_and_kill(Matrix& maze, std::vector<Room>& rooms);
 }
diff --git a/tests/mazes.cpp b/tests/mazes.cpp
index 7d1cc1b..8332409 100644
--- a/tests/mazes.cpp
+++ b/tests/mazes.cpp
@@ -9,7 +9,8 @@
 using std::string;
 using matrix::Matrix;
 
-TEST_CASE("simple maze first attempt", "[maze-gen]") {
+
+TEST_CASE("recursive division (garbage)", "[mazes]") {
   auto map = matrix::make(21, 21);
   std::vector<Room> rooms;
 
@@ -21,3 +22,16 @@ TEST_CASE("simple maze first attempt", "[maze-gen]") {
         room.x, room.y, room.width, room.height);
   }
 }
+
+TEST_CASE("hunt-and-kill", "[maze-gen]") {
+  auto map = matrix::make(21, 21);
+  std::vector<Room> rooms;
+
+  maze::hunt_and_kill(map, rooms);
+  matrix::dump("MAZE?", map);
+
+  for(auto& room : rooms) {
+    fmt::println("room: {},{}; {},{}",
+        room.x, room.y, room.width, room.height);
+  }
+}
diff --git a/worldbuilder.cpp b/worldbuilder.cpp
index db412da..1bdd275 100644
--- a/worldbuilder.cpp
+++ b/worldbuilder.cpp
@@ -137,10 +137,7 @@ void WorldBuilder::generate_rooms() {
 }
 
 void WorldBuilder::generate_map() {
-  matrix::dump("BEFORE MAZE:", $map.$walls);
-  maze::recursive_div($map.$walls, $map.$rooms);
-  matrix::dump("AFTER MAZE:", $map.$walls);
-
+  maze::hunt_and_kill($map.$walls, $map.$rooms);
   $map.expand();
   $map.load_tiles();