Don't scale camera path speed if no duration was given

Just using the current distance for camera speed works better than setting a default duration based on the path length

include/openspace/navigation/path.h

@@ -57,12 +57,6 @@ public:
     Waypoint startPoint() const;
     Waypoint endPoint() const;
 
-    /**
-     * Return the specified duration for the path, in seconds. Note that the time it
-     * takes to actually traverse the path will not exactly match the provided duration 
-     */
-    double duration() const;
-
     /**
      * Return the total length of the the curve for the path, in meters
      */
@@ -128,7 +122,6 @@ private:
 
     Waypoint _start;
     Waypoint _end;
-    double _duration; // seconds
     Type _type;
 
     std::unique_ptr<PathCurve> _curve;

src/navigation/path.cpp

@@ -107,19 +107,19 @@ Path::Path(Waypoint start, Waypoint end, Type type,
             throw ghoul::MissingCaseException();
     }
 
-    _duration = duration.value_or(std::log(pathLength()));
+    // Compute speed factor to match any given duration, by traversing the path and
+    // computing how much faster/slower it should be
+    _speedFactorFromDuration = 1.0;
+    if (duration.has_value()) {
+        constexpr const double dt = 0.05; // 20 fps
+        while (!hasReachedEnd()) {
+            traversePath(dt);
+        }
 
-    // Compute speed factor to match the generated path length and duration, by
-    // traversing the path and computing how much faster/slower it should be
-    const int nSteps = 500;
-    const double dt = (_duration / nSteps) > 0.01 ? (_duration / nSteps) : 0.01;
-
-    while (!hasReachedEnd()) {
-        traversePath(dt);
+        // We now know how long it took to traverse the path. Use that
+        _speedFactorFromDuration = _progressedTime / *duration;
     }
 
-    _speedFactorFromDuration = _progressedTime / _duration;
-
     // Reset playback variables
     _traveledDistance = 0.0;
     _progressedTime = 0.0;
@@ -129,8 +129,6 @@ Waypoint Path::startPoint() const { return _start; }
 
 Waypoint Path::endPoint() const { return _end; }
 
-double Path::duration() const { return _duration; }
-
 double Path::pathLength() const { return _curve->length(); }
 
 std::vector<glm::dvec3> Path::controlPoints() const {