Attempt implement menu (unresolved symbol error)

Button.cpp

@@ -0,0 +1,48 @@
+#include "Button.h"
+#include <string>
+#include "Util.h"
+#include "Vector.h"
+
+Button::Button(std::string & text, Vec2f position, float width, float height) : MenuElement(position)
+{
+	this->width = width;
+	this->height = height;
+	this->text = text;
+
+	background = Vec3f(10, 10, 10);
+	foreground = Vec3f(255, 255, 255);
+}
+
+Button::~Button()
+{
+}
+
+void Button::draw(void)
+{
+	glColor4f(background.x, background.y, background.z, 1.0f);
+
+	glBegin(GL_QUADS);
+	glVertex2f(position.x, position.y);
+	glVertex2f(position.x, position.y + height);
+	glVertex2f(position.x + width, position.y + height);
+	glVertex2f(position.x + width, position.y);
+	glEnd();
+
+	glColor4f(foreground.x, foreground.y, foreground.z, 1.0f);
+	Util::glutBitmapString(text, position.x + (width / 2), position.y + (height / 2));
+}
+
+void Button::update(int x, int y)
+{
+	//Nothing
+}
+
+void Button::setForeground(Vec3f color)
+{
+	foreground = color;
+}
+
+void Button::setBackground(Vec3f color)
+{
+	background = color;
+}