From a6216d883fd6dc4de9339b1c61f8bb22b00c591b Mon Sep 17 00:00:00 2001
From: Allofich <rickywd@gmail.com>
Date: Wed, 31 Aug 2016 01:05:54 +0900
Subject: [PATCH] Don't allow casting Water Walking in deep water

---
 apps/openmw/mwbase/world.hpp             |  1 +
 apps/openmw/mwmechanics/spellcasting.cpp | 15 +++++++++++++++
 apps/openmw/mwworld/worldimp.cpp         | 13 +++++++++++++
 apps/openmw/mwworld/worldimp.hpp         |  1 +
 4 files changed, 30 insertions(+)

diff --git a/apps/openmw/mwbase/world.hpp b/apps/openmw/mwbase/world.hpp
index 82d5ddd5e..549931b9a 100644
--- a/apps/openmw/mwbase/world.hpp
+++ b/apps/openmw/mwbase/world.hpp
@@ -385,6 +385,7 @@ namespace MWBase
             ///Is the head of the creature underwater?
             virtual bool isSubmerged(const MWWorld::ConstPtr &object) const = 0;
             virtual bool isUnderwater(const MWWorld::CellStore* cell, const osg::Vec3f &pos) const = 0;
+            virtual bool isWaterWalkingCastableOnTarget(const MWWorld::ConstPtr &target) const = 0;
             virtual bool isOnGround(const MWWorld::Ptr &ptr) const = 0;
 
             virtual osg::Matrixf getActorHeadTransform(const MWWorld::ConstPtr& actor) const = 0;
diff --git a/apps/openmw/mwmechanics/spellcasting.cpp b/apps/openmw/mwmechanics/spellcasting.cpp
index 61365be97..19527076b 100644
--- a/apps/openmw/mwmechanics/spellcasting.cpp
+++ b/apps/openmw/mwmechanics/spellcasting.cpp
@@ -383,6 +383,21 @@ namespace MWMechanics
             }
             else
                 canCastAnEffect = true;
+          
+            if (magicEffect->mIndex == ESM::MagicEffect::WaterWalking)
+            {
+                if (target.getClass().isPureWaterCreature(target))
+                    continue;
+
+                MWBase::World *world = MWBase::Environment::get().getWorld();
+
+                if (!world->isWaterWalkingCastableOnTarget(target))
+                {
+                    if (caster == getPlayer())
+                        MWBase::Environment::get().getWindowManager()->messageBox ("#{sMagicInvalidEffect}");
+                    continue;
+                }
+            }
 
             if (!checkEffectTarget(effectIt->mEffectID, target, castByPlayer))
                 continue;
diff --git a/apps/openmw/mwworld/worldimp.cpp b/apps/openmw/mwworld/worldimp.cpp
index b178e6e52..5652b2d78 100644
--- a/apps/openmw/mwworld/worldimp.cpp
+++ b/apps/openmw/mwworld/worldimp.cpp
@@ -2077,6 +2077,19 @@ namespace MWWorld
         return pos.z() < cell->getWaterLevel();
     }
 
+    bool World::isWaterWalkingCastableOnTarget(const MWWorld::ConstPtr &target) const
+    {
+        const MWWorld::CellStore* cell = target.getCell();
+        if (!cell->getCell()->hasWater())
+            return true;
+
+        // Based on observations from the original engine, the depth
+        // limit at which water walking can still be cast on a target
+        // in water appears to be the same as what the highest swimmable
+        // z position would be with SwimHeightScale + 1.
+        return !isUnderwater(target, mSwimHeightScale + 1);
+    }
+
     bool World::isOnGround(const MWWorld::Ptr &ptr) const
     {
         return mPhysics->isOnGround(ptr);
diff --git a/apps/openmw/mwworld/worldimp.hpp b/apps/openmw/mwworld/worldimp.hpp
index aa67c9ea8..da665e27c 100644
--- a/apps/openmw/mwworld/worldimp.hpp
+++ b/apps/openmw/mwworld/worldimp.hpp
@@ -481,6 +481,7 @@ namespace MWWorld
             virtual bool isSwimming(const MWWorld::ConstPtr &object) const;
             virtual bool isUnderwater(const MWWorld::CellStore* cell, const osg::Vec3f &pos) const;
             virtual bool isWading(const MWWorld::ConstPtr &object) const;
+            virtual bool isWaterWalkingCastableOnTarget(const MWWorld::ConstPtr &target) const;
             virtual bool isOnGround(const MWWorld::Ptr &ptr) const;
 
             virtual osg::Matrixf getActorHeadTransform(const MWWorld::ConstPtr& actor) const;