fine tuning on interval factor and state compression

rewind now displayed immediately (instead of "Paused")
two initial rewinds in continuous rewind mode fixed
Horizon widget disabled when Uncompressed size == Buffer size
fixed minimum Interval

docs/index.html

@@ -3107,9 +3107,12 @@
             <td>
               Defines the horizon of the rewind buffer. A large horizon allows
               going back further in time. To reach the horizon, save states
-              will be compressed. This means that more and more intermediate
+              will be compressed (*). This means that more and more intermediate
               states will be removed and the interval between save states
-              becomes larger the further they are back in time.
+              becomes larger the further they are back in time. The very first
+              save state will not be removed.<br>
+              (*) Compresion only works if 'Uncompressed size' is smaller than
+              'Buffer size'.
             </td>
             <td>-plr.rewind.horizon<br>-dev.rewind.horizon</td>
           </tr>

src/common/RewindManager.cxx

@@ -36,6 +36,8 @@ RewindManager::RewindManager(OSystem& system, StateManager& statemgr)
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void RewindManager::setup()
 {
+  myLastContinuousAdd = false;
+
   string prefix = myOSystem.settings().getBool("dev.settings") ? "dev." : "plr.";
 
   mySize = myOSystem.settings().getInt(prefix + "rewind.size");
@@ -55,20 +57,22 @@ void RewindManager::setup()
       myHorizon = HORIZON_CYCLES[i];
 
   // calc interval growth factor
+  // this factor defines the backward horizon
   const double MAX_FACTOR = 1E8;
   double minFactor = 0, maxFactor = MAX_FACTOR;
+  myFactor = 1;
 
-  while(true)
+  while(myUncompressed < mySize)
   {
     double interval = myInterval;
-    double cycleSum = interval * myUncompressed;
+    double cycleSum = interval * (myUncompressed + 1);
     // calculate nextCycles factor
     myFactor = (minFactor + maxFactor) / 2;
     // horizon not reachable?
     if(myFactor == MAX_FACTOR)
       break;
-    // sum up interval cycles
-    for(uInt32 i = myUncompressed; i < mySize; ++i)
+    // sum up interval cycles (first and last state are not compressed)
+    for(uInt32 i = myUncompressed + 1; i < mySize - 1; ++i)
     {
       interval *= myFactor;
       cycleSum += interval;
@@ -119,6 +123,7 @@ bool RewindManager::addState(const string& message, bool continuous)
     state.cycles = myOSystem.console().tia().cycles();
     //state.count = count++;
 //cerr << "add " << state.count << endl;
+    myLastContinuousAdd = continuous;
     return true;
   }
   return false;
@@ -129,15 +134,17 @@ bool RewindManager::rewindState()
 {
   if(!atFirst())
   {
-    RewindState& lastState = myStateList.current();
-
+    if (!myLastContinuousAdd)
     // Set internal current iterator to previous state (back in time),
     // since we will now processed this state
-    myStateList.moveToPrevious();
+      myStateList.moveToPrevious();
+    myLastContinuousAdd = false;
+
+    //RewindState& lastState = myStateList.current();
 
     RewindState& state = myStateList.current();
     Serializer& s = state.data;
-    string message = getMessage(state, lastState);
+    string message = getMessage(state);
 //cerr << "rewind " << state.count << endl;
 
     s.rewind();  // rewind Serializer internal buffers
@@ -163,7 +170,7 @@ bool RewindManager::unwindState()
 
     RewindState& state = myStateList.current();
     Serializer& s = state.data;
-    string message = getMessage(state, state);
+    string message = getMessage(state);
 //cerr << "unwind " << state.count << endl;
 
     s.rewind();  // rewind Serializer internal buffers
@@ -182,8 +189,8 @@ bool RewindManager::unwindState()
 void RewindManager::compressStates()
 {
   uInt64 currentCycles = myOSystem.console().tia().cycles();
-  double expectedCycles = myInterval * (1*0 + myFactor);
-  double maxError = 0;
+  double expectedCycles = myInterval * myFactor * (1 + myFactor);
+  double maxError = 1;
   uInt32 removeIdx = 0;
   uInt32 idx = myStateList.size() - 2;
 
@@ -223,17 +230,18 @@ void RewindManager::compressStates()
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-string RewindManager::getMessage(RewindState& state, RewindState& lastState)
+string RewindManager::getMessage(RewindState& state)
 {
   Int64 diff = myOSystem.console().tia().cycles() - state.cycles;
   stringstream message;
 
   message << (diff >= 0 ? "Rewind" : "Unwind") << " " << getUnitString(diff);
 
-  // add optional message (TODO: when smart removal works, we have to do something smart with this part too)
-  if(!lastState.message.empty())
-    message << " (" << lastState.message << ")";
   message << " [" << myStateList.currentIdx() << "/" << myStateList.size() << "]";
+  // add optional message
+  if(!state.message.empty())
+    message << " (" << state.message << ")";
+
   return message.str();
 }
 

src/common/RewindManager.hxx

@@ -144,6 +144,7 @@ class RewindManager
     uInt32 myInterval;
     uInt64 myHorizon;
     double myFactor;
+    bool   myLastContinuousAdd;
 
     struct RewindState {
       Serializer data;
@@ -168,7 +169,7 @@ class RewindManager
 
     void compressStates();
 
-    string getMessage(RewindState& state, RewindState& lastState);
+    string getMessage(RewindState& state);
 
   private:
     // Following constructors and assignment operators not supported

src/common/StateManager.cxx

@@ -161,7 +161,7 @@ void StateManager::update()
   switch(myActiveMode)
   {
     case Mode::Rewind:
-      myRewindManager->addState("1 frame", true);
+      myRewindManager->addState("continuous rewind", true);
       break;
 
 #if 0

src/emucore/EventHandler.cxx

@@ -299,13 +299,15 @@ void EventHandler::handleKeyEvent(StellaKey key, StellaMod mod, bool state)
       switch(key)
       {
         case KBDK_LEFT:  // Alt-left rewinds states
-          if(myOSystem.state().rewindState() && myState != S_PAUSE)
-            setEventState(S_PAUSE);
+          myOSystem.frameBuffer().resetPauseDelay();
+          setEventState(S_PAUSE);
+          myOSystem.state().rewindState();
           break;
 
         case KBDK_RIGHT:  // Alt-right unwinds states
-          if(myOSystem.state().unwindState() && myState != S_PAUSE)
-            setEventState(S_PAUSE);
+          myOSystem.frameBuffer().resetPauseDelay();
+          setEventState(S_PAUSE);
+          myOSystem.state().unwindState();
           break;
 
         default:

src/emucore/FrameBuffer.cxx

@@ -301,7 +301,7 @@ void FrameBuffer::update()
       // Show a pause message immediately and then every 7 seconds
       if (myPausedCount-- <= 0)
       {
-        myPausedCount = uInt32(7 * myOSystem.frameRate());
+        resetPauseDelay();
         showMessage("Paused", kMiddleCenter);
       }
       break;  // S_PAUSE
@@ -471,6 +471,12 @@ inline void FrameBuffer::drawMessage()
     myMsg.enabled = false;
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void FrameBuffer::resetPauseDelay()
+{
+  myPausedCount = uInt32(7 * myOSystem.frameRate());
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 shared_ptr<FBSurface> FrameBuffer::allocateSurface(int w, int h, const uInt32* data)
 {

src/emucore/FrameBuffer.hxx

@@ -144,6 +144,11 @@ class FrameBuffer
     */
     void enableMessages(bool enable);
 
+    /**
+      Reset 'Paused' display delay counter
+    */
+    void resetPauseDelay();
+
     /**
       Allocate a new surface.  The FrameBuffer class takes all responsibility
       for freeing this surface (ie, other classes must not delete it directly).

src/emucore/Settings.cxx

@@ -329,11 +329,11 @@ void Settings::validate()
   i = getInt("dev.rewind.uncompressed");
   if(i < 0 || i > size) setInternal("dev.rewind.uncompressed", size);
 
-  i = getInt("dev.rewind.interval");
+  /*i = getInt("dev.rewind.interval");
   if(i < 0 || i > 5) setInternal("dev.rewind.interval", 0);
 
   i = getInt("dev.rewind.horizon");
-  if(i < 0 || i > 6) setInternal("dev.rewind.horizon", 1);
+  if(i < 0 || i > 6) setInternal("dev.rewind.horizon", 1);*/
 
   i = getInt("plr.tv.jitter_recovery");
   if(i < 1 || i > 20) setInternal("plr.tv.jitter_recovery", "10");

src/gui/DeveloperDialog.cxx

@@ -999,6 +999,7 @@ void DeveloperDialog::handleSize()
     myUncompressedWidget->setValue(size);
   myStateIntervalWidget->setSelectedIndex(interval);
   myStateHorizonWidget->setSelectedIndex(i);
+  myStateHorizonWidget->setEnabled(size > uncompressed);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -1011,6 +1012,7 @@ void DeveloperDialog::handleUncompressed()
 
   if(size < uncompressed)
     myStateSizeWidget->setValue(uncompressed);
+  myStateHorizonWidget->setEnabled(size > uncompressed);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -