From d7ae18856477f716730c8071cf33f0ce1f0e367c Mon Sep 17 00:00:00 2001
From: Michael Jumper <zhangmaike@users.sourceforge.net>
Date: Mon, 20 Aug 2012 19:19:26 -0700
Subject: [PATCH] Add magic number to hash (prevent all pure-black or
 similarly-black images from hashing to same value universally).

---
 libguac/src/hash.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libguac/src/hash.c b/libguac/src/hash.c
index 0fc8aaff..225f0def 100644
--- a/libguac/src/hash.c
+++ b/libguac/src/hash.c
@@ -101,7 +101,7 @@ unsigned int guac_hash_surface(cairo_surface_t* surface) {
 
             /* Compute next hash */
             hash_value =
-                _guac_rotate(hash_value, 1) ^ color;
+                _guac_rotate(hash_value, 1) ^ color ^ 0x1B872E69;
 
         }