Files are now in a src directory and I'm using a src/meson.build and tests/meson.build to specify what to build.

src/pathing.hpp

@@ -0,0 +1,40 @@
+#pragma once
+#include "point.hpp"
+#include "matrix.hpp"
+#include <functional>
+
+using matrix::Matrix;
+
+constexpr const int PATHING_TOWARD=1;
+constexpr const int PATHING_AWAY=-1;
+
+enum class PathingResult {
+  FAIL=0,
+  FOUND=1,
+  CONTINUE=2
+};
+
+class Pathing {
+public:
+  size_t $width;
+  size_t $height;
+  Matrix $paths;
+  Matrix $input;
+
+  Pathing(size_t width, size_t height) :
+    $width(width),
+    $height(height),
+    $paths(height, matrix::Row(width, 1)),
+    $input(height, matrix::Row(width, 1))
+  {}
+
+  void compute_paths(Matrix &walls);
+  void set_target(const Point &at, int value=0);
+  void clear_target(const Point &at);
+  Matrix &paths() { return $paths; }
+  Matrix &input() { return $input; }
+  int distance(Point to) { return $paths[to.y][to.x];}
+  PathingResult find_path(Point &out, int direction, bool diag);
+
+  bool INVARIANT();
+};