Account for viewports when converting from screen to view space.

src/input.rs

@@ -135,10 +135,14 @@ impl EditorCamInputEvent {
         let screen_to_view_space = |camera: &Camera,
                                     proj: &Projection,
                                     controller: &EditorCam,
-                                    viewport_position: Vec2|
+                                    target_position: Vec2|
          -> Option<DVec3> {
+            let mut viewport_position = if let Some(rect) = camera.logical_viewport_rect() {
+                target_position.as_dvec2() - rect.min.as_dvec2()
+            } else {
+                target_position.as_dvec2()
+            };
             let target_size = camera.logical_viewport_size()?.as_dvec2();
-            let mut viewport_position = viewport_position.as_dvec2();
             // Flip the Y co-ordinate origin from the top to the bottom.
             viewport_position.y = target_size.y - viewport_position.y;
             let ndc = viewport_position * 2. / target_size - DVec2::ONE;