From 3da994c3b8663219be3bd9a8f3cf8a3c91fec76a Mon Sep 17 00:00:00 2001
From: Saveliy Skresanov <savask@yandex.ru>
Date: Thu, 23 Jan 2025 01:19:07 +0700
Subject: [PATCH] Prevent heat convection in liquids looking farther than 1px
 away.

---
 src/simulation/Simulation.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/simulation/Simulation.cpp b/src/simulation/Simulation.cpp
index d91697c77..92f55da07 100644
--- a/src/simulation/Simulation.cpp
+++ b/src/simulation/Simulation.cpp
@@ -2329,8 +2329,8 @@ void Simulation::UpdateParticles(int start, int end)
 				{
 					float convGravX, convGravY;
 					GetGravityField(x, y, -2.0f, -2.0f, convGravX, convGravY);
-					auto offsetX = int(std::round(convGravX + x));
-					auto offsetY = int(std::round(convGravY + y));
+					auto offsetX = std::clamp(int(std::round(convGravX + x)), x-1, x+1);
+					auto offsetY = std::clamp(int(std::round(convGravY + y)), y-1, y+1);
 					if ((offsetX != x || offsetY != y) && offsetX >= 0 && offsetX < XRES && offsetY >= 0 && offsetY < YRES) {//some heat convection for liquids
 						auto r = pmap[offsetY][offsetX];
 						if (!(!r || parts[i].type != TYP(r))) {