From 8c1612644ed024c107bfd679120bd67fbfae8ba5 Mon Sep 17 00:00:00 2001
From: Ovahlord <dreadkiller@gmx.de>
Date: Tue, 2 Jan 2024 19:40:34 +0100
Subject: Core/Maps: restored a hack in gridmap liquid status code to solve
 precision issues (#29544)

Closes #29543
Closes #22020

(cherry picked from commit bfb9fd8a2c777651c99568ba9c6a2d4a3a468955)
---
 src/server/game/Maps/GridMap.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/server/game/Maps/GridMap.cpp b/src/server/game/Maps/GridMap.cpp
index 247a22b5d89..2d06aa25687 100644
--- a/src/server/game/Maps/GridMap.cpp
+++ b/src/server/game/Maps/GridMap.cpp
@@ -593,6 +593,8 @@ float GridMap::getLiquidLevel(float x, float y) const
     return _liquidMap[cx_int*_liquidWidth + cy_int];
 }
 
+constexpr float GROUND_LEVEL_OFFSET_HACK = 0.02f; // due to floating point precision issues, we have to resort to a small hack to fix inconsistencies in liquids
+
 // Get water state on map
 ZLiquidStatus GridMap::GetLiquidStatus(float x, float y, float z, Optional<map_liquidHeaderTypeFlags> ReqLiquidType, LiquidData* data, float collisionHeight) const
 {
@@ -656,11 +658,11 @@ ZLiquidStatus GridMap::GetLiquidStatus(float x, float y, float z, Optional<map_l
 
     // Get water level
     float liquid_level = _liquidMap ? _liquidMap[lx_int*_liquidWidth + ly_int] : _liquidLevel;
-    // Get ground level (sub 0.2 for fix some errors)
+    // Get ground level (sub 0.02 for fix some errors)
     float ground_level = getHeight(x, y);
 
     // Check water level and ground level
-    if (liquid_level < ground_level || z < ground_level)
+    if (liquid_level < (ground_level - GROUND_LEVEL_OFFSET_HACK) || z < (ground_level - GROUND_LEVEL_OFFSET_HACK))
         return LIQUID_MAP_NO_WATER;
 
     // All ok in water -> store data
-- 
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