From d3d356c9c157e7a8f5665714a88c64686cfd2caf Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Sat, 6 Mar 2010 17:48:34 +0000
Subject: [PATCH] Compute effect of gravity correctly

---
 src/Engine.cpp | 10 +++++-----
 src/Train.cpp  |  4 +++-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/Engine.cpp b/src/Engine.cpp
index 10550a5..a16cdb7 100644
--- a/src/Engine.cpp
+++ b/src/Engine.cpp
@@ -161,8 +161,8 @@ double Engine::resistance() const
    const double sign = mySpeed < 0.0 ? -1.0 : 1.0;
    
    const double a = 0.0;
-   const double b = 0.09;
-   const double c = 0.02;
+   const double b = 0.1;
+   const double c = 0.04;
 
    const double absSpeed = abs(mySpeed);
    
@@ -173,7 +173,7 @@ double Engine::resistance() const
 double Engine::gravity(float gradient) const
 {
    const double g = 9.78;
-   return -g * gradient;
+   return -g * gradient * myMass;
 }
 
 // Calculate the magnitude of the braking force
@@ -184,9 +184,9 @@ double Engine::brakeForce() const
 
    // Brake always acts against direction of motion
    double dir;
-   if (abs(mySpeed) < STOP_SPEED)
+   /*if (abs(mySpeed) < STOP_SPEED)
       dir = 0.0;
-   else if (mySpeed < 0.0)
+      else*/ if (mySpeed < 0.0)
       dir = -1.0;
    else
       dir = 1.0;
diff --git a/src/Train.cpp b/src/Train.cpp
index 93b39e8..facfa40 100644
--- a/src/Train.cpp
+++ b/src/Train.cpp
@@ -115,9 +115,11 @@ Train::Train(IMapPtr aMap)
 
    // Bit of a hack to put the engine in the right place
    move(0.275);
-   
+
+#if 0
    for (int i = 1; i <= 4; i++)
       addPart(loadWaggon("coal_truck"));
+#endif
 
    smokeTrail = makeSmokeTrail();
 }
-- 
2.39.2