[Add] Arrow navigation in menus.

src/UI/Button.cpp

@@ -6,6 +6,7 @@ Button::Button(void) {
   _text = "";
   _font = NULL;
   _highlighted = false;
+  _selected = false;
   _triggered = false;
   x = 0;
   y = 0;
@@ -33,7 +34,7 @@ void Button::Update(void) {
 
 void Button::Render(void) {
   if(_font) {
-    if(_highlighted) {
+    if(_highlighted || _selected) {
       _font->SetColor(1.0f, 1.0f, 1.0f, 1.0f);
     } else {
       _font->SetColor(0.5f, 0.5f, 0.5f, 1.0f);

src/UI/Button.h

@@ -19,6 +19,9 @@ public:
   bool IsHighlighted(void) const        { return _highlighted; }
   void SetHighlighted(bool highlighted) { _highlighted = highlighted; }
 
+  bool IsSelected(void) const     { return _selected; }
+  void SetSelected(bool selected) { _selected = selected; }
+
   bool Triggered(void) const { return _triggered; }
 
   int   GetX(void) const    { return x; }
@@ -35,6 +38,7 @@ private:
   String  _text;
  
   bool _highlighted;
+  bool _selected;
   bool _triggered;
 
   int x;

src/UI/Menu.cpp

@@ -1,8 +1,10 @@
 #include "Menu.h"
 #include "Button.h"
+#include "../IO/Input.h"
 
 Menu::Menu(void) {
   _triggeredButton = -1;
+  _selectedButton = 0;
   x = 0;
   y = 0;
 }
@@ -15,6 +17,11 @@ Menu::~Menu(void) {
 }
 
 void Menu::AddButton(Button* button) {
+  // Select first button.
+  if(_buttons.empty()) {
+    button->SetSelected(true);
+  }
+
   _buttons.push_back(button);
 }
 
@@ -33,6 +40,15 @@ void Menu::AlignButtons(int how) {
   }
 }
 
+void Menu::SelectButton(int index) {
+  int buttonsIndex = 0;
+  for(std::list<Button*>::iterator i = _buttons.begin(); i != _buttons.end(); ++i) {   
+    (*i)->SetSelected(buttonsIndex == index);
+    buttonsIndex++;
+  }
+  _selectedButton = index;
+}
+
 void Menu::Update(void) {
   _triggeredButton = -1;
 
@@ -52,6 +68,25 @@ void Menu::Update(void) {
 
     index++;
   }
+
+  if(KeyDown(SDLK_DOWN)) {
+    _selectedButton++;
+    if(_selectedButton == _buttons.size()) {
+      _selectedButton = 0;
+    }
+    SelectButton(_selectedButton);
+  }
+  else if(KeyDown(SDLK_UP)) {
+    _selectedButton--;
+    if(_selectedButton < 0) {
+      _selectedButton = _buttons.size() - 1;
+    }
+    SelectButton(_selectedButton);
+  }
+
+  if(KeyDown(SDLK_RETURN)) {
+    _triggeredButton = _selectedButton;
+  }
 }
 
 void Menu::Render(void) {

src/UI/Menu.h

@@ -16,6 +16,7 @@ public:
 
   void AddButton(Button* button);
   void AlignButtons(int how);
+  void SelectButton(int index);
 
   void Update(void);
   void Render(void);
@@ -31,6 +32,7 @@ public:
 private:
   std::list<Button*> _buttons;
   int _triggeredButton;
+  int _selectedButton;
   
   int x;
   int y;