From 847a3a1f9e1fc914e45a5900fbcbedadb17097d7 Mon Sep 17 00:00:00 2001
From: danij <danij@dengine.net>
Date: Wed, 11 Sep 2013 18:41:52 +0100
Subject: [PATCH] World|Plane|Client: Continuously interpolate plane movement

It would seem the plane height delta must be continuously updated to
ensure smooth movement. Naturally this means that change notification
will run a little behind the actual interpolation.
---
 doomsday/client/src/world/plane.cpp | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/doomsday/client/src/world/plane.cpp b/doomsday/client/src/world/plane.cpp
index 99899fe147..3518473dbc 100644
--- a/doomsday/client/src/world/plane.cpp
+++ b/doomsday/client/src/world/plane.cpp
@@ -226,39 +226,39 @@ coord_t Plane::heightSmoothedDelta() const
 
 void Plane::lerpSmoothedHeight()
 {
-    coord_t newSmoothedHeight = d->height + d->heightSmoothedDelta;
-    if(!de::fequal(d->heightSmoothed, newSmoothedHeight))
+    // Interpolate.
+    d->heightSmoothedDelta = d->oldHeight[0] * (1 - frameTimePos)
+                           + d->height * frameTimePos - d->height;
+
+    coord_t newHeightSmoothed = d->height + d->heightSmoothedDelta;
+    if(!de::fequal(d->heightSmoothed, newHeightSmoothed))
     {
         coord_t oldHeightSmoothed = d->heightSmoothed;
-
-        d->heightSmoothed = newSmoothedHeight;
-        d->heightSmoothedDelta = d->oldHeight[0] * (1 - frameTimePos) + d->height * frameTimePos - d->height;
-
+        d->heightSmoothed = newHeightSmoothed;
         d->notifySmoothedHeightChanged(oldHeightSmoothed);
     }
 }
 
 void Plane::resetSmoothedHeight()
 {
-    coord_t newSmoothedHeight = d->oldHeight[0] = d->oldHeight[1] = d->height;
-    if(!de::fequal(d->heightSmoothed, newSmoothedHeight))
+    // Reset interpolation.
+    d->heightSmoothedDelta = 0;
+
+    coord_t newHeightSmoothed = d->oldHeight[0] = d->oldHeight[1] = d->height;
+    if(!de::fequal(d->heightSmoothed, newHeightSmoothed))
     {
         coord_t oldHeightSmoothed = d->heightSmoothed;
-
-        d->heightSmoothed = newSmoothedHeight;
-        d->heightSmoothedDelta = 0;
-
+        d->heightSmoothed = newHeightSmoothed;
         d->notifySmoothedHeightChanged(oldHeightSmoothed);
     }
 }
 
 void Plane::updateHeightTracking()
 {
-    // $smoothplane
     d->oldHeight[0] = d->oldHeight[1];
     d->oldHeight[1] = d->height;
 
-    if(d->oldHeight[0] != d->oldHeight[1])
+    if(!de::fequal(d->oldHeight[0], d->oldHeight[1]))
     {
         if(de::abs(d->oldHeight[0] - d->oldHeight[1]) >= MAX_SMOOTH_MOVE)
         {