Added wall bouncing logic (flawed); added bounding box computation and display

polygons.h

@@ -3,34 +3,74 @@
 
 #include "vec2d.h"
 
+#include <cmath>
 #include <gtk/gtk.h>
+#include <utility>
 #include <vector>
 
 class polygon {
+  private:
+    void update_global_points();
+
   public:
     vec2d center;
     double angle;
     std::vector<vec2d> points;
+    std::vector<vec2d> global_points = points;
+
+    vec2d speed, angular_speed;
 
     void draw(cairo_t* cr) const;
+    void draw_bounding_rect(cairo_t* cr) const;
+
+    std::pair<vec2d, vec2d> get_bounding_box() const {
+        vec2d min{INFINITY, INFINITY}, max{-INFINITY, -INFINITY};
+
+        for (auto& point : this->global_points) {
+            if (point.x < min.x)
+                min.x = point.x;
+            if (point.y < min.y)
+                min.y = point.y;
+
+            if (point.x > max.x)
+                max.x = point.x;
+            if (point.y > max.y)
+                max.y = point.y;
+        }
+        return {min, max};
+    }
 
     polygon& set_center(vec2d c) {
         center = c;
+        update_global_points();
+        return *this;
+    }
+
+    polygon& set_speed(vec2d s) {
+        speed = s;
+        return *this;
+    }
+
+    polygon& set_angular_speed(vec2d as) {
+        angular_speed = as;
         return *this;
     }
 
     polygon& set_angle(double a) {
         angle = a;
+        update_global_points();
         return *this;
     }
 
     polygon& translate(vec2d delta) {
         center += delta;
+        update_global_points();
         return *this;
     }
 
     polygon& rotate(double delta) {
         angle += delta;
+        update_global_points();
         return *this;
     }
 };