diff --git a/doomsday/libgui/include/de/gui/glstate.h b/doomsday/libgui/include/de/gui/glstate.h
index 6145805291..94afdaf264 100644
--- a/doomsday/libgui/include/de/gui/glstate.h
+++ b/doomsday/libgui/include/de/gui/glstate.h
@@ -157,6 +157,7 @@ class LIBGUI_PUBLIC GLState
     gl::ColorMask colorMask() const;
     GLTarget &target() const;
     Rectangleui viewport() const;
+    Rectanglef normalizedViewport() const;
     bool scissor() const;
     Rectangleui scissorRect() const;
 
diff --git a/doomsday/libgui/src/glstate.cpp b/doomsday/libgui/src/glstate.cpp
index 22acf202f7..9ba4e9dbf6 100644
--- a/doomsday/libgui/src/glstate.cpp
+++ b/doomsday/libgui/src/glstate.cpp
@@ -559,6 +559,16 @@ Rectangleui GLState::viewport() const
                        d->props[ViewportHeight]);
 }
 
+Rectanglef GLState::normalizedViewport() const
+{
+    GLTarget::Size const size = target().size();
+    Rectangleui const vp = viewport();
+    return Rectanglef(float(vp.left())   / float(size.x),
+                      float(vp.top())    / float(size.y),
+                      float(vp.width())  / float(size.x),
+                      float(vp.height()) / float(size.y));
+}
+
 bool GLState::scissor() const
 {
     return d->props.asBool(Scissor);