add gui.confirm(...)

src/graphics/ui/gui_util.cpp

@@ -50,11 +50,13 @@ void guiutil::alert(
 }
 
 void guiutil::confirm(
-        const std::shared_ptr<gui::Menu>& menu, 
-        const std::wstring& text, 
-        const runnable& on_confirm,
-        std::wstring yestext, 
-        std::wstring notext) {
+    const std::shared_ptr<gui::Menu>& menu,
+    const std::wstring& text,
+    const runnable& on_confirm,
+    const runnable& on_deny,
+    std::wstring yestext,
+    std::wstring notext
+) {
     if (yestext.empty()) yestext = langs::get(L"Yes");
     if (notext.empty()) notext = langs::get(L"No");
 
@@ -71,6 +73,8 @@ void guiutil::confirm(
     }));
 
     subpanel->add(std::make_shared<Button>(notext, glm::vec4(8.f), [=](GUI*){
+        if (on_deny)
+            on_deny();
         menu->back();
     }));
 

src/graphics/ui/gui_util.hpp

@@ -22,6 +22,7 @@ namespace guiutil {
         const std::shared_ptr<gui::Menu>& menu,
         const std::wstring& text, 
         const runnable& on_confirm=nullptr,
+        const runnable& on_deny=nullptr,
         std::wstring yestext=L"", 
         std::wstring notext=L"");