diff --git a/dotscape b/dotscape
index 3ce5387..ce4b4db 100755
Binary files a/dotscape and b/dotscape differ
diff --git a/ffi/export.h b/ffi/export.h
index a18c4d2..a697dec 100644
--- a/ffi/export.h
+++ b/ffi/export.h
@@ -159,6 +159,7 @@ extern "C" {
 
 MLLIB_PUBLIC(void mltonMouseMoveCallback (Real32 x0, Real32 x1);)
 MLLIB_PUBLIC(void mltonMouseClickCallback (Int32 x0, Int32 x1);)
+MLLIB_PUBLIC(void mltonFramebufferSizeCallback (Int32 x0, Int32 x1);)
 
 #undef MLLIB_PRIVATE
 #undef MLLIB_PUBLIC
diff --git a/ffi/glfw-input.c b/ffi/glfw-input.c
index 296bf10..b42ab21 100644
--- a/ffi/glfw-input.c
+++ b/ffi/glfw-input.c
@@ -10,16 +10,21 @@ void mouseMoveCallback(GLFWwindow *window, double xpos, double ypos) {
   mltonMouseMoveCallback((float)xpos, (float)ypos);
 }
 
-void mouseClickCallback(GLFWwindow *window, int button, int action, int mods) {
-  mltonMouseClickCallback(button, action);
-}
-
-// Call this from MLton to register key callback with GLFW.
+// Call this from MLton to register callback with GLFW.
 void setMouseMoveCallback(GLFWwindow *window) {
   glfwSetCursorPosCallback(window, mouseMoveCallback);
 }
 
+void mouseClickCallback(GLFWwindow *window, int button, int action, int mods) {
+  mltonMouseClickCallback(button, action);
+}
 void setMouseClickCallback(GLFWwindow *window) {
   glfwSetMouseButtonCallback(window, mouseClickCallback);
 }
 
+void framebufferSizeCallback(GLFWwindow *window, int width, int height) {
+  mltonFramebufferSizeCallback(width, height);
+}
+void setFramebufferSizeCallback(GLFWwindow *window, int width, int height) {
+  glfwSetFramebufferSizeCallback(window, framebufferSizeCallback);
+}
diff --git a/ffi/glfw-input.sml b/ffi/glfw-input.sml
index 87b7126..72ddb5e 100644
--- a/ffi/glfw-input.sml
+++ b/ffi/glfw-input.sml
@@ -11,9 +11,13 @@ struct
 
   val exportMouseClickCallback =
     _export "mltonMouseClickCallback" public : (int * int -> unit) -> unit;
-
   val setMouseClickCallback = _import "setMouseClickCallback" public reentrant : window -> unit;
 
+  val exportFramebufferSizeCallback =
+    _export "mltonFramebufferSizeCallback" public : (int * int -> unit) -> unit;
+  val setFramebufferSizeCallback = 
+    _import "setFramebufferSizeCallback" public reentrant : window -> unit;
+
   (* Constants for mouse input. *)
   val (MOUSE_PRESSED, _) =
     _symbol "MOUSE_PRESSED" public : ( unit -> int ) * ( int -> unit );
diff --git a/functional-core/app-update.sml b/functional-core/app-update.sml
index f423464..c97678c 100644
--- a/functional-core/app-update.sml
+++ b/functional-core/app-update.sml
@@ -161,7 +161,7 @@ struct
           in
             (model, drawMsg, mouseX, mouseY)
           end
-      | MUSE_LEFT_CLICK =>
+      | MOUSE_LEFT_CLICK =>
           let
             val (buttonVec, hpos, vpos) = getClickPos
               (#clickPoints model, mouseX, mouseY, 0.0, 0.0, 1.0)
@@ -205,5 +205,11 @@ struct
             else
               (model, NO_DRAW, mouseX, mouseY)
           end
+      | RESIZE_WINDOW {width, height} => 
+          let
+            val _ = print "resized window \n"
+          in
+            (model, NO_DRAW, mouseX, mouseY)
+          end
     end
 end
diff --git a/imperative-shell/input-callbacks.sml b/imperative-shell/input-callbacks.sml
index d1bfbb5..d516970 100644
--- a/imperative-shell/input-callbacks.sml
+++ b/imperative-shell/input-callbacks.sml
@@ -15,6 +15,11 @@ struct
     else
       ()
 
+  fun framebufferSizeCallback mailbox (width, height) =
+    let val _ = Gles3.viewport (width, height)
+    in Mailbox.send (mailbox, RESIZE_WINDOW {width = width, height = height})
+    end
+
   fun registerCallbacks (window, inputMailbox) =
     let
       val mouseMoveCallback = mouseMoveCallback inputMailbox
@@ -24,6 +29,10 @@ struct
       val mouseClickCallback = mouseClickCallback inputMailbox
       val _ = Input.exportMouseClickCallback mouseClickCallback
       val _ = Input.setMouseClickCallback window
+
+      val resizeCallback = framebufferSizeCallback inputMailbox
+      val _ = Input.exportFramebufferSizeCallback resizeCallback
+      val _ = Input.setFramebufferSizeCallback window
     in
       ()
     end
diff --git a/message-types/input-msg.sml b/message-types/input-msg.sml
index 7b2ebac..a73eaef 100644
--- a/message-types/input-msg.sml
+++ b/message-types/input-msg.sml
@@ -4,6 +4,7 @@ sig
     MOUSE_MOVE of {x: Real32.real, y: Real32.real}
   | MOUSE_LEFT_CLICK
   | MOUSE_LEFT_RELEASE
+  | RESIZE_WINDOW of {width: int, height: int}
 end
 
 structure InputMessage :> INPUT_MESSAGE =
@@ -12,4 +13,5 @@ struct
     MOUSE_MOVE of {x: Real32.real, y: Real32.real}
   | MOUSE_LEFT_CLICK
   | MOUSE_LEFT_RELEASE
+  | RESIZE_WINDOW of {width: int, height: int}
 end