From e3fbcc9f29a1b1c83b23a4cef3819631fd3117d0 Mon Sep 17 00:00:00 2001
From: Star Rauchenberger <fefferburbia@gmail.com>
Date: Sun, 12 May 2024 18:45:21 -0400
Subject: Subway map hover detection with a quadtree

---
 src/subway_map.cpp | 37 +++++++++++++++++++++++++++++++++++++
 src/subway_map.h   | 10 ++++++++++
 2 files changed, 47 insertions(+)

(limited to 'src')

diff --git a/src/subway_map.cpp b/src/subway_map.cpp
index 0aa7df3..230a256 100644
--- a/src/subway_map.cpp
+++ b/src/subway_map.cpp
@@ -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};
+}
diff --git a/src/subway_map.h b/src/subway_map.h
index e375750..6cb5c63 100644
--- a/src/subway_map.h
+++ b/src/subway_map.h
@@ -7,8 +7,12 @@
 #include <wx/wx.h>
 #endif
 
+#include <memory>
+#include <optional>
 #include <vector>
 
+#include <quadtree/Quadtree.h>
+
 class SubwayMap : public wxPanel {
  public:
   SubwayMap(wxWindow *parent);
@@ -29,7 +33,13 @@ class SubwayMap : public wxPanel {
   int render_y_ = 0;
   int render_width_ = 0;
   int render_height_ = 0;
+
+  struct GetItemBox {
+    quadtree::Box<float> operator()(const int &id) const;
+  };
   
+  std::unique_ptr<quadtree::Quadtree<int, GetItemBox>> tree_;
+  std::optional<int> hovered_item_;
 };
 
 #endif /* end of include guard: SUBWAY_MAP_H_BD2D843E */
-- 
cgit 1.4.1