Introduce Widget and Screen classes

src/Screen.cpp

@@ -0,0 +1,33 @@
+#include "Screen.h"
+
+Screen::Screen(Framebuffer *framebuffer, ShaderProgram *shaderProgram) :
+    framebuffer(framebuffer), shaderProgram(shaderProgram)
+{
+    
+}
+
+Screen::~Screen()
+{
+    
+}
+
+void Screen::addWidget(Widget* widget)
+{
+    widgets.push_back(widget);
+}
+
+void Screen::draw()
+{
+    framebuffer->setExposureCorrection(false);
+    framebuffer->bind();
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    
+    for(auto it = widgets.begin(); it != widgets.end(); it++) {
+        (*it)->draw(shaderProgram);
+    }
+
+    framebuffer->unbind();
+    framebuffer->render();
+    framebuffer->setExposureCorrection(true);
+}
+