From 27e084a827f9b8a1d3f5e913694db2268acf0079 Mon Sep 17 00:00:00 2001
From: Zwip-Zwap Zapony <ZwipZwapZapony@gmail.com>
Date: Wed, 4 Mar 2020 17:31:52 +0100
Subject: [PATCH] Fix division-by-0 crash with gamepad deadzones

Fix division-by-0 crash with gamepad deadzones
The problem was that it checked if A was more than B,
then lowered A to a max value, then subtracted B from A,
then divided something by that, without checking if A minus B was 0,
allowing division by 0 if B was the same as that max value

This fixes that by making sure that A is less than the max value
---
 src/g_game.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/src/g_game.c b/src/g_game.c
index 08192bfb8..4db55329e 100644
--- a/src/g_game.c
+++ b/src/g_game.c
@@ -1045,17 +1045,14 @@ static INT32 G_BasicDeadZoneCalculation(INT32 magnitude, fixed_t deadZone)
 	const INT32 jdeadzone = (JOYAXISRANGE * deadZone) / FRACUNIT;
 	INT32 deadzoneAppliedValue = 0;
 
-	if (jdeadzone > 0)
+	if (jdeadzone > 0 && magnitude > jdeadzone && deadZone < FRACUNIT)
 	{
-		if (magnitude > jdeadzone)
-		{
-			INT32 adjustedMagnitude = abs(magnitude);
-			adjustedMagnitude = min(adjustedMagnitude, JOYAXISRANGE);
+		INT32 adjustedMagnitude = abs(magnitude);
+		adjustedMagnitude = min(adjustedMagnitude, JOYAXISRANGE);
 
-			adjustedMagnitude -= jdeadzone;
+		adjustedMagnitude -= jdeadzone;
 
-			deadzoneAppliedValue = (adjustedMagnitude * JOYAXISRANGE) / (JOYAXISRANGE - jdeadzone);
-		}
+		deadzoneAppliedValue = (adjustedMagnitude * JOYAXISRANGE) / (JOYAXISRANGE - jdeadzone);
 	}
 
 	return deadzoneAppliedValue;