Update board.hpp, forces.hpp, forces.cpp, main.cpp, pedestrian.hpp: correct some bugs in implementation

board.hpp

@@ -1,9 +1,41 @@
 #pragma once
 #include "vector2d.hpp"
 
+struct Obstacle {
+  Vector2d start;
+  Vector2d end;
+
+  Obstacle() : start(0, 0), end(0, 0) {}
+  Obstacle(Vector2d s, Vector2d e) : start(s), end(e) {}
+  // find the point of the obstacle that is nearest to p
+  Vector2d find_nearest_obstacle_point(Vector2d p) {
+    Vector2d obstacle_v = end - start;
+    double projection = (p - start).dot(obstacle_v) / obstacle_v.dot(obstacle_v);
+    if (projection < 0.0)
+      projection = 0.0;
+    if (projection > 1.0)
+      projection = 1.0;
+    return start + obstacle_v * projection;
+  }
+};
+
 struct Board {
   double length, width;
-  Vector2d *borders; // array containing the position of each obstacle
-  int n_borders;     // number of obstacles
-  Board(double l, double w, int n, Vector2d *border) : length(l), width(w), n_borders(n), borders(border) {}
+  Obstacle *obstacles; // array of obstacles (represented as lines) that are present on the board
+  int n_obstacles;     // number of obstacles
+
+  Board(double l, double w, int n, Obstacle *o) : length(l), width(w), n_obstacles(n + 4) {
+    obstacles = new Obstacle[n + 4];
+    for (int i = 0; i < n; i++) {
+      obstacles[i] = o[i];
+    }
+
+    // borders of the board: bottom, right, top, left
+    obstacles[n] = Obstacle(Vector2d(0, 0), Vector2d(l, 0));
+    obstacles[n + 1] = Obstacle(Vector2d(l, 0), Vector2d(l, w));
+    obstacles[n + 2] = Obstacle(Vector2d(l, w), Vector2d(0, w));
+    obstacles[n + 3] = Obstacle(Vector2d(0, w), Vector2d(0, 0));
+  }
+
+  ~Board() { delete[] obstacles; }
 };