From bd025875d452ffb8873459d8523bae227bb0806e Mon Sep 17 00:00:00 2001
From: "Phyks (Lucas Verney)" <phyks@phyks.me>
Date: Tue, 27 Nov 2018 23:03:46 +0100
Subject: [PATCH] Few fixes to travel time computation

* Takes `costfactor` into account for switching to walking mode.
* Better energy computation in hiking mode.
* Reword the `bikerMass` to make it clearer for different modes.
---
 .../src/main/java/btools/router/RoutingContext.java   |  6 +++---
 brouter-core/src/main/java/btools/router/StdPath.java | 11 ++++++++---
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/brouter-core/src/main/java/btools/router/RoutingContext.java b/brouter-core/src/main/java/btools/router/RoutingContext.java
index 9adbffa..d5a70cb 100644
--- a/brouter-core/src/main/java/btools/router/RoutingContext.java
+++ b/brouter-core/src/main/java/btools/router/RoutingContext.java
@@ -175,8 +175,8 @@ public final class RoutingContext
     turnInstructionRoundabouts = expctxGlobal.getVariableValue( "turnInstructionRoundabouts", 1.f ) != 0.f;
 
     // Speed computation model (for bikes)
-    // Mass of the biker + bike + luggages, in kg
-    bikeMass = expctxGlobal.getVariableValue( "bikeMass", 90.f );
+    // Total mass (biker + bike + luggages or hiker), in kg
+    totalMass = expctxGlobal.getVariableValue( "totalMass", 90.f );
     // Max speed (before braking), in km/h in profile and m/s in code
     maxSpeed = expctxGlobal.getVariableValue( "maxSpeed", 45.f ) / 3.6;
     // Equivalent surface for wind, S * C_x, F = -1/2 * S * C_x * v^2 = - S_C_x * v^2
@@ -225,7 +225,7 @@ public final class RoutingContext
   public boolean turnInstructionRoundabouts;
 
   // Speed computation model (for bikes)
-  public double bikeMass;
+  public double totalMass;
   public double maxSpeed;
   public double S_C_x;
   public double defaultC_r;
diff --git a/brouter-core/src/main/java/btools/router/StdPath.java b/brouter-core/src/main/java/btools/router/StdPath.java
index c299f04..4eef9d7 100644
--- a/brouter-core/src/main/java/btools/router/StdPath.java
+++ b/brouter-core/src/main/java/btools/router/StdPath.java
@@ -244,16 +244,21 @@ final class StdPath extends OsmPath
     double incline = calcIncline( dist );
 
     double speed; // Travel speed
-    double f_roll = rc.bikeMass * GRAVITY * ( rc.defaultC_r + incline );
-    if (rc.footMode )
+    double energy;
+    if (rc.footMode || rc.expctxWay.getCostfactor() > 5)
     {
       // Use Tobler's hiking function for walking sections
       speed = 6 * exp(-3.5 * Math.abs( incline + 0.05)) / 3.6;
+      energy = rc.totalMass * GRAVITY * incline * dist;
     }
     else if (rc.bikeMode)
     {
+      double f_roll = rc.totalMass * GRAVITY * ( rc.defaultC_r + incline );
       speed = solveCubic( rc.S_C_x, f_roll, rc.bikerPower );
       speed = Math.min(speed, rc.maxSpeed);
+      // Don't compute energy assuming constant biker power, as speed is capped
+      // to a max value.
+      energy = dist*(rc.S_C_x*speed*speed + f_roll);
     }
     else
     {
@@ -261,7 +266,7 @@ final class StdPath extends OsmPath
     }
     float dt = (float) ( dist / speed );
     totalTime += dt;
-    totalEnergy += dist*(rc.S_C_x*speed*speed + f_roll);
+    totalEnergy += energy;
   }
 
   private static double solveCubic( double a, double c, double d )