editor: improve switching snap modes

2 files changed, 40 insertions, 28 deletions

diff --git a/editor/editor.cpp b/editor/editor.cpp
index bb1948cc..f76a42d0 100644
--- a/editor/editor.cpp
+++ b/editor/editor.cpp
@@ -198,10 +198,6 @@ void tile_editor::set_rotation(editor_wall_rotation r)
 
 auto tile_editor::check_snap(int mods) const -> snap_mode
 {
-    enum : int {
-        KMOD_CTRL = 0x0040 | 0x0080,
-        KMOD_SHIFT = 0x0001 | 0x0002,
-    };
     const bool ctrl = mods & kmod_ctrl, shift = mods & kmod_shift;
 
     if (!(ctrl | shift))
@@ -279,46 +275,60 @@ auto editor::get_snap_value(snap_mode snap, int mods) const -> snap_mode
         return snap_mode::none;
 }
 
-void editor::on_mouse_move(world& world, global_coords& pos, int mods)
+global_coords editor::apply_snap(global_coords pos, global_coords last, snap_mode snap) noexcept
 {
-    if (!current())
-        return;
+    switch (snap)
+    {
+    default:
+        break;
+    case snap_mode::horizontal:
+        pos.y = last.y;
+        break;
+    case snap_mode::vertical:
+        pos.x = last.x;
+        break;
+    }
+    return pos;
+}
 
-    if (_last_pos)
+void editor::on_mouse_move(world& world, global_coords& pos, int mods)
+{
+    if (auto* mode = current(); mode && _last_pos && _last_pos->btn != button::none)
     {
-        auto& last_pos = *_last_pos;
-        const snap_mode snap = get_snap_value(last_pos.snap, mods);
-        switch (snap)
+        auto& last = *_last_pos;
+        Vector2i offset = pos - last.coord;
+        const snap_mode snap = get_snap_value(last.snap, mods);
+        global_coords draw_coord = apply_snap(last.draw_coord + offset, last.draw_coord, snap);
+        if (pos != _last_pos->coord)
         {
-        default:
-            break;
-        case snap_mode::horizontal:
-            pos.y = last_pos.coord.y;
-            break;
-        case snap_mode::vertical:
-            pos.x = last_pos.coord.x;
-            break;
+            _last_pos = { pos, draw_coord, snap, last.btn };
+            on_click_(world, draw_coord, mods, last.btn);
         }
-        last_pos = { pos, snap, last_pos.btn };
-        on_click(world, pos, mods, last_pos.btn);
+        pos = draw_coord;
     }
 }
 
-void editor::on_click(world& world, global_coords pos, int mods, button b)
+void editor::on_click_(world& world, global_coords pos, int mods, button b)
 {
     if (auto* mode = current(); mode != nullptr)
-    {
         if (auto opt = mode->get_selected(); opt)
         {
-            _last_pos = { pos, mode->check_snap(mods), _last_pos ? _last_pos->btn : b };
-            switch (tile_image_proto empty; b)
+            switch (b)
             {
             case button::place: return mode->place_tile(world, pos, opt);
-            case button::remove: return mode->place_tile(world, pos, empty);
+            case button::remove: return mode->place_tile(world, pos, {});
             default: break;
             }
         }
-        on_release();
+    on_release();
+}
+
+void editor::on_click(world& world, global_coords pos, int mods, button b)
+{
+    if (auto* mode = current(); mode != nullptr)
+    {
+        _last_pos = { pos, pos, mode->check_snap(mods), b };
+        on_click_(world, pos, mods, b);
     }
 }
 
diff --git a/editor/editor.hpp b/editor/editor.hpp
index 4d6b48df..66531814 100644
--- a/editor/editor.hpp
+++ b/editor/editor.hpp
@@ -88,6 +88,7 @@ struct editor final
     enum class button : std::uint8_t { none, place, remove, };
 
     void on_click(world& world, global_coords pos, int mods, button b);
+    void on_click_(world& world, global_coords pos, int mods, button b);
     void on_mouse_move(world& world, global_coords& pos, int modifiers);
     void on_release();
 
@@ -102,12 +103,13 @@ struct editor final
 
 private:
     snap_mode get_snap_value(snap_mode snap, int mods) const;
+    static global_coords apply_snap(global_coords pos, global_coords last, snap_mode snap) noexcept;
 
     tile_editor _floor{ editor_mode::floor, "floor" };
     tile_editor _wall { editor_mode::walls, "wall"  };
 
     struct drag_pos final {
-        global_coords coord;
+        global_coords coord, draw_coord;
         snap_mode snap = snap_mode::none;
         button btn;
     };