From b9b35e546c33259f48e916e964f84062fbf51067 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Sat, 20 Mar 2010 17:39:36 +0000
Subject: [PATCH] Fix gradient calculations

---
 maps/uphill/uphill.bin | Bin 4364 -> 4364 bytes
 maps/uphill/uphill.xml |   2 +-
 src/Engine.cpp         |  14 +++++++-------
 src/Train.cpp          |  18 +++++++++++++++---
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/maps/uphill/uphill.bin b/maps/uphill/uphill.bin
index 26e62a856d397d82752dc149e33f16012af5c3cf..8e53c717cb917803388c01fd6cce9e9b79b96fbd 100644
GIT binary patch
delta 124
zcmeBC>QUOD!f4D@cfyvd&cm)FZkipCZPzpR7mzJx@0q7>4-~gQ-J59NGq=iq`L#}a
apc?y(XNxA^X4IYB!l*)y-p#ie4fz4rBr-Vw

delta 124
zcmeBC>QUOD!f3o__io!gyRGfcp6Rgzvh7x{dIe<j*n=<w!v{MMK6l2*e$LEXdsE{n
XKzifk+l;!CTNqWy(YyIJqai;4A?G;%

diff --git a/maps/uphill/uphill.xml b/maps/uphill/uphill.xml
index e43047e..5458933 100644
--- a/maps/uphill/uphill.xml
+++ b/maps/uphill/uphill.xml
@@ -2,7 +2,7 @@
 <map width="32" height="32">
 <name>No Name</name>
 
-<start x="11" y="14" dirX="0" dirY="-1"/>
+<start x="22" y="2" dirX="1" dirY="0"/>
 
 <heightmap>uphill.bin</heightmap>
 
diff --git a/src/Engine.cpp b/src/Engine.cpp
index 2d64809..2706333 100644
--- a/src/Engine.cpp
+++ b/src/Engine.cpp
@@ -205,15 +205,15 @@ void Engine::update(int delta, float gradient)
    const double P = tractiveEffort();
    const double Q = resistance();
    const double B = isBrakeOn ? brakeForce() : 0.0;
-   const double G = 0;//gravity(gradient);   
+   const double G = gravity(gradient);   
 
-#if 0
-   if (gradient * P > 0.001f)
-      debug() << "D";
-   else if (gradient * P < -0.001f)
-      debug() << "U";
+#if 1
+   if (gradient > 0.01f)
+      debug() << "U = " << gradient;
+   else if (gradient < -0.01f)
+      debug() << "D =" << gradient;
    else
-      debug() << "F";
+      debug() << "F =" << gradient;
 #endif
    
    // The applied tractive effort is controlled by the throttle
diff --git a/src/Train.cpp b/src/Train.cpp
index e0a6e31..314b000 100644
--- a/src/Train.cpp
+++ b/src/Train.cpp
@@ -283,9 +283,21 @@ void Train::update(int delta)
    int oldSpeedSign = engine().vehicle->speed() >= 0.0 ? 1 : 0;
    
    for (list<Part>::iterator it = parts.begin();
-        it != parts.end(); ++it)
-      (*it).vehicle->update(delta,
-         (*it).travelToken.gradient((*it).segmentDelta));
+        it != parts.end(); ++it) {
+      float gradient = (*it).travelToken.gradient((*it).segmentDelta);
+
+         
+      debug() << "dir=" << (*it).direction << " ms=" << (*it).movementSign
+              << " g=" << gradient;
+      
+      if ((*it).direction.x < 0 || (*it).direction.z < 0)
+         gradient *= -1.0f;
+
+      gradient *= (*it).movementSign;
+      
+      
+      (*it).vehicle->update(delta, gradient);
+   }
 
    int newSpeedSign = engine().vehicle->speed() >= 0.0 ? 1 : 0;
 
-- 
2.39.2