From e938fa4a9d832cffd69003fbb7f0d43a49c554f0 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Wed, 25 Mar 2015 18:12:04 +0100
Subject: [PATCH] Implement extrapolation mode in ControllerFunction (Bug
 #1871)

---
 components/nifosg/controller.cpp | 59 ++++++++++++++++++--------------
 components/nifosg/controller.hpp | 15 ++++----
 components/nifosg/nifloader.cpp  |  4 +--
 3 files changed, 44 insertions(+), 34 deletions(-)

diff --git a/components/nifosg/controller.cpp b/components/nifosg/controller.cpp
index a31263d8b..6aa920553 100644
--- a/components/nifosg/controller.cpp
+++ b/components/nifosg/controller.cpp
@@ -18,50 +18,59 @@
 namespace NifOsg
 {
 
-ControllerFunction::ControllerFunction(const Nif::Controller *ctrl, bool deltaInput)
-    : mDeltaInput(deltaInput)
-    , mFrequency(ctrl->frequency)
+ControllerFunction::ControllerFunction(const Nif::Controller *ctrl)
+    : mFrequency(ctrl->frequency)
     , mPhase(ctrl->phase)
     , mStartTime(ctrl->timeStart)
     , mStopTime(ctrl->timeStop)
-    , mDeltaCount(0.f)
+    , mExtrapolationMode(static_cast<ExtrapolationMode>((ctrl->flags&0x6) >> 1))
 {
-    if(mDeltaInput)
-        mDeltaCount = mPhase;
 }
 
 float ControllerFunction::calculate(float value)
 {
-    if(mDeltaInput)
+    float time = mFrequency * value + mPhase;
+    if (time >= mStartTime && time <= mStopTime)
+        return time;
+    switch (mExtrapolationMode)
     {
-        if (mStopTime - mStartTime == 0.f)
-            return 0.f;
-
-        mDeltaCount += value*mFrequency;
-        if(mDeltaCount < mStartTime)
-            mDeltaCount = mStopTime - std::fmod(mStartTime - mDeltaCount,
-                                                mStopTime - mStartTime);
-        mDeltaCount = std::fmod(mDeltaCount - mStartTime,
-                                mStopTime - mStartTime) + mStartTime;
-        return mDeltaCount;
+    case Cycle:
+    {
+        float delta = mStopTime - mStartTime;
+        if ( delta <= 0 )
+            return mStartTime;
+        float cycles = ( time - mStartTime ) / delta;
+        float remainder = ( cycles - std::floor( cycles ) ) * delta;
+        return mStartTime + remainder;
     }
+    case Reverse:
+    {
+        float delta = mStopTime - mStartTime;
+        if ( delta <= 0 )
+            return mStartTime;
+
+        float cycles = ( time - mStartTime ) / delta;
+        float remainder = ( cycles - std::floor( cycles ) ) * delta;
 
-    value = std::min(mStopTime, std::max(mStartTime, value+mPhase));
-    return value;
+        // Even number of cycles?
+        if ( ( static_cast<int>(std::fabs( std::floor( cycles ) )) % 2 ) == 0 )
+            return mStartTime + remainder;
+
+        return mStopTime - remainder;
+    }
+    case Constant:
+    default:
+        return std::min(mStopTime, std::max(mStartTime, time));
+    }
 }
 
 FrameTimeSource::FrameTimeSource()
-    : mLastTime(0.0)
 {
 }
 
 float FrameTimeSource::getValue(osg::NodeVisitor *nv)
 {
-    // TODO: dt could be computed globally instead of once per instance
-    double time = nv->getFrameStamp()->getReferenceTime();
-    float dt = static_cast<float>(time - mLastTime);
-    mLastTime = time;
-    return dt;
+    return nv->getFrameStamp()->getReferenceTime();
 }
 
 KeyframeController::KeyframeController()
diff --git a/components/nifosg/controller.hpp b/components/nifosg/controller.hpp
index c6ef74d2a..7579735ca 100644
--- a/components/nifosg/controller.hpp
+++ b/components/nifosg/controller.hpp
@@ -81,17 +81,20 @@ namespace NifOsg
         float mFrequency;
         float mPhase;
         float mStartTime;
-        bool mDeltaInput;
-        float mDeltaCount;
-    public:
         float mStopTime;
+        enum ExtrapolationMode
+        {
+            Cycle = 0,
+            Reverse = 1,
+            Constant = 2
+        };
+        ExtrapolationMode mExtrapolationMode;
 
     public:
-        ControllerFunction(const Nif::Controller *ctrl, bool deltaInput);
+        ControllerFunction(const Nif::Controller *ctrl);
 
         float calculate(float value);
     };
-    typedef ControllerFunction DefaultFunction;
 
     class ControllerSource
     {
@@ -104,8 +107,6 @@ namespace NifOsg
     public:
         FrameTimeSource();
         virtual float getValue(osg::NodeVisitor* nv);
-    private:
-        double mLastTime;
     };
 
     class Controller
diff --git a/components/nifosg/nifloader.cpp b/components/nifosg/nifloader.cpp
index a15ad7416..17a669312 100644
--- a/components/nifosg/nifloader.cpp
+++ b/components/nifosg/nifloader.cpp
@@ -302,7 +302,7 @@ namespace
                 const Nif::NiKeyframeController* keyframectrl = found->second;
 
                 osg::ref_ptr<NifOsg::SourcedKeyframeController> callback(new NifOsg::SourcedKeyframeController(keyframectrl->data.getPtr(), mSourceIndex));
-                callback->mFunction = boost::shared_ptr<NifOsg::ControllerFunction>(new NifOsg::ControllerFunction(keyframectrl, false));
+                callback->mFunction = boost::shared_ptr<NifOsg::ControllerFunction>(new NifOsg::ControllerFunction(keyframectrl));
 
                 // Insert in front of the callback list, to make sure UpdateBone is last.
                 // The order of SourcedKeyframeControllers doesn't matter since only one of them should be enabled at a time.
@@ -490,7 +490,7 @@ namespace NifOsg
             //if (autoPlay)
                 toSetup->mSource = boost::shared_ptr<ControllerSource>(new FrameTimeSource);
 
-            toSetup->mFunction = boost::shared_ptr<ControllerFunction>(new ControllerFunction(ctrl, 1 /*autoPlay*/));
+            toSetup->mFunction = boost::shared_ptr<ControllerFunction>(new ControllerFunction(ctrl));
         }
 
         osg::ref_ptr<osg::Node> handleNode(const Nif::Node* nifNode, bool createSkeleton,