From 7b96144716e1c133aa89e473efac2533ae12395e Mon Sep 17 00:00:00 2001
From: Vasilis Narain <79228641+Vasilis-Narain@users.noreply.github.com>
Date: Fri, 29 May 2026 18:18:18 +0200
Subject: [PATCH] [rcore] `GetCurrentMonitor()`, fix for integer overflow in
 distance calculation (#5842)

* Fix signed integer overflow in GetCurrentMonitor distance calc

* Revert "Fix signed integer overflow in GetCurrentMonitor distance calc"

This reverts commit e0083bc7fe8a4dab23e6c1783402e37aec2661d2.

* fix GetCurrentMonitor() distance calc overflow

* fix GetCurrentMonitor() distance calc
---
 src/platforms/rcore_desktop_glfw.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/platforms/rcore_desktop_glfw.c b/src/platforms/rcore_desktop_glfw.c
index 6def8e77a..16f22f605 100644
--- a/src/platforms/rcore_desktop_glfw.c
+++ b/src/platforms/rcore_desktop_glfw.c
@@ -839,7 +839,7 @@ int GetCurrentMonitor(void)
             // this is probably an overengineered solution for a side case
             // trying to match SDL behaviour
 
-            int closestDist = 0x7FFFFFFF;
+            unsigned int closestDist = 0xFFFFFFFFu;
 
             // Window center position
             int wcx = 0;
@@ -883,7 +883,14 @@ int GetCurrentMonitor(void)
 
                     int dx = wcx - xclosest;
                     int dy = wcy - yclosest;
-                    int dist = (dx*dx) + (dy*dy);
+
+                    // Unsigned to dodge signed overflow UB; (-x)^2 == x^2 mod 2^32 so sign drops out.
+                    // If |dx| or |dy| >= 65536, dist wraps and the wrong monitor may win.
+                    // Not a concern for realistic monitor layouts.
+                    unsigned int ux = (unsigned int)dx;
+                    unsigned int uy = (unsigned int)dy;
+                    unsigned int dist = ux*ux + uy*uy;
+
                     if (dist < closestDist)
                     {
                         index = i;