From c775e05d7a5e2f4b723164cedcfbc2f0fa76f0d8 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Sun, 24 Aug 2014 19:15:02 +0200
Subject: [PATCH] Show encumbrance preview when trading (Fixes #1793)

---
 apps/openmw/mwgui/inventorywindow.cpp |  1 +
 apps/openmw/mwgui/tradeitemmodel.cpp  | 15 +++++++++++++++
 apps/openmw/mwgui/tradeitemmodel.hpp  |  4 ++++
 3 files changed, 20 insertions(+)

diff --git a/apps/openmw/mwgui/inventorywindow.cpp b/apps/openmw/mwgui/inventorywindow.cpp
index a044d014f..441d8c28f 100644
--- a/apps/openmw/mwgui/inventorywindow.cpp
+++ b/apps/openmw/mwgui/inventorywindow.cpp
@@ -493,6 +493,7 @@ namespace MWGui
 
         float capacity = player.getClass().getCapacity(player);
         float encumbrance = player.getClass().getEncumbrance(player);
+        mTradeModel->adjustEncumbrance(encumbrance);
         mEncumbranceBar->setValue(encumbrance, capacity);
     }
 
diff --git a/apps/openmw/mwgui/tradeitemmodel.cpp b/apps/openmw/mwgui/tradeitemmodel.cpp
index 5fdf604da..7ac14f7b5 100644
--- a/apps/openmw/mwgui/tradeitemmodel.cpp
+++ b/apps/openmw/mwgui/tradeitemmodel.cpp
@@ -93,6 +93,21 @@ namespace MWGui
         unborrowImpl(item, count, mBorrowedFromUs);
     }
 
+    void TradeItemModel::adjustEncumbrance(float &encumbrance)
+    {
+        for (std::vector<ItemStack>::iterator it = mBorrowedToUs.begin(); it != mBorrowedToUs.end(); ++it)
+        {
+            MWWorld::Ptr item = it->mBase;
+            encumbrance += item.getClass().getWeight(item) * it->mCount;
+        }
+        for (std::vector<ItemStack>::iterator it = mBorrowedFromUs.begin(); it != mBorrowedFromUs.end(); ++it)
+        {
+            MWWorld::Ptr item = it->mBase;
+            encumbrance -= item.getClass().getWeight(item) * it->mCount;
+        }
+        encumbrance = std::max(0.f, encumbrance);
+    }
+
     void TradeItemModel::abort()
     {
         mBorrowedFromUs.clear();
diff --git a/apps/openmw/mwgui/tradeitemmodel.hpp b/apps/openmw/mwgui/tradeitemmodel.hpp
index 5cfaaafc7..1bfee9b2a 100644
--- a/apps/openmw/mwgui/tradeitemmodel.hpp
+++ b/apps/openmw/mwgui/tradeitemmodel.hpp
@@ -34,6 +34,10 @@ namespace MWGui
         /// Aborts trade
         void abort();
 
+        /// Adjusts the given encumbrance by adding weight for items that have been lent to us,
+        /// and removing weight for items we've lent to someone else.
+        void adjustEncumbrance (float& encumbrance);
+
         std::vector<ItemStack> getItemsBorrowedToUs();
 
     private: