updated README.md

diff --git a/README.md b/README.md
index 83dfa3a..4e73ce5 100644 (file)
--- a/README.md
+++ b/README.md
@@ -23,3 +23,6 @@ $ ./demo -vulkan
 Default:
 $ ./demo
 (uses the OpenGL backend)
+
+Use mouse motion + left click to rotate the camera and
+right click + mouse motion to zoom in/out.