Subway map hover detection with a quadtree

1 files changed, 37 insertions, 0 deletions

@@ -25,6 +25,13 @@ SubwayMap::SubwayMap(wxWindow *parent) : wxPanel(parent, wxID_ANY) {
     return;
   }
 
+  tree_ = std::make_unique<quadtree::Quadtree<int, GetItemBox>>(
+      quadtree::Box<float>{0, 0, static_cast<float>(map_image_.GetWidth()),
+                           static_cast<float>(map_image_.GetHeight())});
+  for (const SubwayItem &subway_item : GD_GetSubwayItems()) {
+    tree_->add(subway_item.id);
+  }
+
   Redraw();
 
   Bind(wxEVT_PAINT, &SubwayMap::OnPaint, this);
@@ -47,6 +54,30 @@ void SubwayMap::OnPaint(wxPaintEvent &event) {
 }
 
 void SubwayMap::OnMouseMove(wxMouseEvent &event) {
+  int mouse_x = std::clamp(
+      (event.GetX() - render_x_) * map_image_.GetWidth() / render_width_,
+      0, map_image_.GetWidth() - 1);
+  int mouse_y = std::clamp(
+      (event.GetY() - render_y_) * map_image_.GetWidth() / render_width_,
+      0, map_image_.GetHeight() - 1);
+
+  std::vector<int> hovered = tree_->query(
+      {static_cast<float>(mouse_x), static_cast<float>(mouse_y), 2, 2});
+  std::optional<int> new_hovered_item;
+  if (!hovered.empty()) {
+    new_hovered_item = hovered[0];
+  }
+
+  if (new_hovered_item != hovered_item_) {
+    if (new_hovered_item) {
+      wxLogVerbose("Hovered: %d", *new_hovered_item);
+    } else {
+      wxLogVerbose("Un-hovered: %d", *hovered_item_);
+    }
+
+    hovered_item_ = new_hovered_item;
+  }
+
   event.Skip();
 }
 
@@ -121,3 +152,9 @@ void SubwayMap::Redraw() {
     }
   }
 }
+
+quadtree::Box<float> SubwayMap::GetItemBox::operator()(const int& id) const {
+  const SubwayItem &subway_item = GD_GetSubwayItem(id);
+  return {static_cast<float>(subway_item.x), static_cast<float>(subway_item.y),
+          AREA_ACTUAL_SIZE, AREA_ACTUAL_SIZE};
+}