From 9d5827520a1080f218ce30a17c057c90db53d045 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Janiszewski?=
 <janisozaur@users.noreply.github.com>
Date: Tue, 31 May 2016 23:03:31 +0200
Subject: [PATCH] Replace shifting with multiplication when dragging (#3789)

`dx`, `dy` can be signed negative values, shifting them left is
undefined.
---
 src/input.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/input.c b/src/input.c
index a1416759c3..eb8a79b233 100644
--- a/src/input.c
+++ b/src/input.c
@@ -553,8 +553,8 @@ static void input_viewport_drag_continue()
 			// As the user moved the mouse, don't interpret it as right click in any case.
 			_ticksSinceDragStart = 1000;
 
-			dx <<= viewport->zoom + 1;
-			dy <<= viewport->zoom + 1;
+			dx *= 1 << (viewport->zoom + 1);
+			dy *= 1 << (viewport->zoom + 1);
 			if (gConfigGeneral.invert_viewport_drag){
 				w->saved_view_x -= dx;
 				w->saved_view_y -= dy;