diff --git a/client/bvh.js b/client/bvh.js
index b1d43e4..c913a6f 100644
--- a/client/bvh.js
+++ b/client/bvh.js
@@ -219,7 +219,7 @@ function bvh_clip(state, context) {
     const screen = {'x1': screen_topleft.x, 'y1': screen_topleft.y, 'x2': screen_bottomright.x, 'y2': screen_bottomright.y};
 
     const stroke_indices = bvh_intersect_quad(state.bvh, screen);
-    stroke_indices.sort();
+    stroke_indices.sort((a, b) => a - b);
 
     for (const i of stroke_indices) {
         if (state.debug.limit_to && i >= state.debug.render_to) break;