diff --git a/src/rl.clj b/src/rl.clj
index 58c4877..6351b4c 100644
--- a/src/rl.clj
+++ b/src/rl.clj
@@ -166,6 +166,8 @@
 (def ^:const key-kp-equal 336)
 
 (def ^:const mouse-button-left 0)
+(def ^:const mouse-button-right 1)
+(def ^:const mouse-button-middle 2)
 (def ^:const log-warning 4)
 (def ^:const pixelformat-r8g8b8a8 7)
 (def ^:const texture-filter-point 0)
@@ -189,6 +191,8 @@
 (defcfn mouse-button-pressed?  "IsMouseButtonPressed"  [::mem/int] ::bool)
 (defcfn mouse-button-released? "IsMouseButtonReleased" [::mem/int] ::bool)
 (defcfn get-mouse-position     "GetMousePosition"      [] ::vector-2)
+(defcfn get-mouse-wheel-move   "GetMouseWheelMove"     [] ::mem/float)
+(defcfn get-mouse-wheel-move-v "GetMouseWheelMoveV"    [] ::vector-2)
 
 ;; The !* forms take pre-serialized struct segments and allocate nothing per
 ;; call. Everything in a per-frame path uses these.
diff --git a/src/sprite_atlas.clj b/src/sprite_atlas.clj
index 90bac9a..7e3102d 100644
--- a/src/sprite_atlas.clj
+++ b/src/sprite_atlas.clj
@@ -10,18 +10,47 @@
   (let [path (:sprite-path @state)]
     (if (.exists (io/file path))
       {:atlas (rl/load-texture path)}
-      (println "Unable to load " path))))
+      {})))
 
-(defn handle-sprite-atlas-input [config game]
-  game)
+(defn handle-sprite-atlas-input [_ game]
+  (cond-> game
+    (rl/mouse-button-pressed? rl/mouse-button-left)
+    (assoc :drag-start (rl/get-mouse-position))
 
-(defn update-sprite-atlas [config game]
-  game)
+    (rl/mouse-button-released? rl/mouse-button-left)
+    (assoc :event-drag-ended true)
 
-(defn draw-sprite-atlas [config game]
+    :always
+    (as-> g (cond-> g
+              (contains? g :drag-start)
+              (assoc :current-mouse-pos (rl/get-mouse-position))))))
+
+(defn- get-selection-rect [{ax :x ay :y} {bx :x by :y}]
+  (let [start-x (min ax bx)
+        start-y (min ay by)
+        end-x (max ax bx)
+        end-y (max ay by)]
+    {:x start-x :y start-y :w (- end-x start-x) :h (- end-y start-y)}))
+
+(defn update-sprite-atlas [_ game]
+  (cond-> game
+    (contains? game :event-drag-ended)
+    (-> (assoc :selected-sprite (get-selection-rect (:drag-start game) (:current-mouse-pos game)))
+        (dissoc :event-drag-ended :drag-start :current-mouse-pos))))
+
+(defn draw-sprite-atlas [_ {:keys [atlas drag-start current-mouse-pos selected-sprite]}]
   (rl/clear-background!* rl/black)
-  (when-let [atlas (:atlas game)]
+  (when atlas
     (rl/draw-texture!* (:seg atlas) 0 0 rl/white)
+    (when drag-start
+      (let [start-x (:x drag-start)
+            start-y (:y drag-start)
+            end-x (:x current-mouse-pos)
+            end-y (:y current-mouse-pos)]
+        (rl/draw-rectangle-lines!* start-x start-y (- end-x start-x) (- end-y start-y) rl/white)))
+    (when selected-sprite
+      (let [{:keys [x y w h]} selected-sprite]
+        (rl/draw-texture-rec!* (:seg atlas) (rl/rect-seg x y w h) (rl/vec2-seg 30 30) rl/white)))
     (rl/draw-fps 10 10)))
 
 (defn watch-sprite-atlas [config game]