Ystart is sleeping with the fishes.

.gitignore

@@ -30,5 +30,4 @@ src/windows/Stella.vcxproj.user
 src/**/*.psess
 src/**/*.vspx
 src/**/**.pdb
-
+Stella.xcscheme
-

src/debugger/gui/TiaOutputWidget.cxx

@@ -120,7 +120,7 @@ void TiaOutputWidget::handleMouseDown(int x, int y, MouseButton b, int clickCoun
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void TiaOutputWidget::handleCommand(CommandSender* sender, int cmd, int data, int id)
 {
-  uInt32 ystart = instance().console().tia().ystart();
+  uInt32 startLine = instance().console().tia().startLine();
 
   switch(cmd)
   {
@@ -131,7 +131,7 @@ void TiaOutputWidget::handleCommand(CommandSender* sender, int cmd, int data, in
       if(rmb == "scanline")
       {
         ostringstream command;
-        int lines = myClickY + ystart - instance().console().tia().scanlines();
+        int lines = myClickY + startLine - instance().console().tia().scanlines();
 
         if(lines < 0)
           lines += instance().console().tia().scanlinesLastFrame();
@@ -145,7 +145,7 @@ void TiaOutputWidget::handleCommand(CommandSender* sender, int cmd, int data, in
       else if(rmb == "bp")
       {
         ostringstream command;
-        int scanline = myClickY + ystart;
+        int scanline = myClickY + startLine;
         command << "breakif _scan==#" << scanline;
         string message = instance().debugger().parser().run(command.str());
         instance().frameBuffer().showMessage(message);

src/debugger/gui/TiaZoomWidget.cxx

@@ -249,13 +249,13 @@ void TiaZoomWidget::handleCommand(CommandSender* sender, int cmd, int data, int
   {
     case ContextMenu::kItemSelectedCmd:
     {
-      uInt32 ystart = instance().console().tia().ystart();
+      uInt32 startLine = instance().console().tia().startLine();
       const string& rmb = myMenu->getSelectedTag().toString();
 
       if(rmb == "scanline")
       {
         ostringstream command;
-        int lines = myClickY / myZoomLevel + myOffY + ystart - instance().console().tia().scanlines();
+        int lines = myClickY / myZoomLevel + myOffY + startLine - instance().console().tia().scanlines();
 
         if (lines < 0)
           lines += instance().console().tia().scanlinesLastFrame();
@@ -269,7 +269,7 @@ void TiaZoomWidget::handleCommand(CommandSender* sender, int cmd, int data, int
       else if(rmb == "bp")
       {
         ostringstream command;
-        int scanline = myClickY / myZoomLevel + myOffY + ystart;
+        int scanline = myClickY / myZoomLevel + myOffY + startLine;
         command << "breakif _scan==#" << scanline;
         string message = instance().debugger().parser().run(command.str());
         instance().frameBuffer().showMessage(message);

src/emucore/Console.cxx

@@ -60,7 +60,6 @@
 #include "AudioSettings.hxx"
 #include "frame-manager/FrameManager.hxx"
 #include "frame-manager/FrameLayoutDetector.hxx"
-#include "frame-manager/YStartDetector.hxx"
 
 #ifdef CHEATCODE_SUPPORT
   #include "CheatManager.hxx"
@@ -71,10 +70,6 @@
 
 #include "Console.hxx"
 
-namespace {
-  constexpr uInt8 YSTART_EXTRA = 2;
-}
-
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Console::Console(OSystem& osystem, unique_ptr<Cartridge>& cart,
                  const Properties& props, AudioSettings& audioSettings)
@@ -84,8 +79,6 @@ Console::Console(OSystem& osystem, unique_ptr<Cartridge>& cart,
     myCart(std::move(cart)),
     myDisplayFormat(""),  // Unknown TV format @ start
     myCurrentFormat(0),   // Unknown format @ start,
-    myAutodetectedYstart(0),
-    myYStartAutodetected(false),
     myFormatAutodetected(false),
     myUserPaletteDefined(false),
     myConsoleTiming(ConsoleTiming::ntsc),
@@ -151,10 +144,6 @@ Console::Console(OSystem& osystem, unique_ptr<Cartridge>& cart,
     }
   }
 
-  if (atoi(myProperties.get(PropType::Display_VCenter).c_str()) == 0) {
-    autodetectYStart();
-  }
-
   myConsoleInfo.DisplayFormat = myDisplayFormat + autodetected;
 
   // Set up the correct properties used when toggling format
@@ -265,49 +254,6 @@ void Console::redetectFrameLayout()
   save(s);
 
   autodetectFrameLayout(false);
-  if (myYStartAutodetected) autodetectYStart();
-
-  load(s);
-  initializeAudio();
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void Console::autodetectYStart(bool reset)
-{
-  // We turn off the SuperCharger progress bars, otherwise the SC BIOS
-  // will take over 250 frames!
-  // The 'fastscbios' option must be changed before the system is reset
-  bool fastscbios = myOSystem.settings().getBool("fastscbios");
-  myOSystem.settings().setValue("fastscbios", true);
-
-  YStartDetector ystartDetector;
-  ystartDetector.setLayout(myDisplayFormat == "PAL" ? FrameLayout::pal : FrameLayout::ntsc);
-  myTIA->setFrameManager(&ystartDetector);
-
-  if (reset) {
-    mySystem->reset(true);
-    myRiot->update();
-  }
-
-  for (int i = 0; i < 80; i++) myTIA->update();
-
-  myTIA->setFrameManager(myFrameManager.get());
-
-  myAutodetectedYstart = ystartDetector.detectedYStart() - YSTART_EXTRA;
-
-  // Don't forget to reset the SC progress bars again
-  myOSystem.settings().setValue("fastscbios", fastscbios);
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void Console::redetectYStart()
-{
-  Serializer s;
-
-  myOSystem.sound().close();
-  save(s);
-
-  autodetectYStart(false);
 
   load(s);
   initializeAudio();
@@ -696,75 +642,57 @@ void Console::fry() const
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Console::changeVerticalCenter(int direction)
 {
-  uInt32 ystart = myTIA->ystart();
+  Int32 vcenter = myTIA->vcenter();
 
-  if(direction == +1)       // increase YStart
+  if(direction == +1)       // increase vcenter
   {
-    if(ystart >= TIAConstants::maxYStart)
+    if(vcenter >= TIAConstants::maxVcenter)
     {
       myOSystem.frameBuffer().showMessage("V-Center at minimum");
       return;
     }
 
-    ++ystart;
+    ++vcenter;
-    myYStartAutodetected = false;
   }
-  else if(direction == -1)  // decrease YStart
+  else if(direction == -1)  // decrease vcenter
   {
-    if (ystart <= TIAConstants::minYStart)
+    if (vcenter <= TIAConstants::minVcenter)
     {
       myOSystem.frameBuffer().showMessage("V-Center at maximum");
       return;
     }
 
-    --ystart;
+    --vcenter;
-    myYStartAutodetected = false;
   }
   else
     return;
 
   ostringstream ss;
-  ss << ystart;
+  ss << vcenter;
 
   myProperties.set(PropType::Display_VCenter, ss.str());
-  if (ystart != myTIA->ystart()) myTIA->setYStart(ystart);
+  if (vcenter != myTIA->vcenter()) myTIA->setVcenter(vcenter);
 
-  // use vertical center instead of y-start for display
-  int vCenter = TIAConstants::defaultYStart - ystart;
   ss.str("");
-  ss << "V-Center " << vCenter;
+  ss << "V-Center " << vcenter;
 
   myOSystem.frameBuffer().showMessage(ss.str());
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void Console::updateYStart(uInt32 ystart)
+void Console::updateVcenter(Int32 vcenter)
 {
-  if (ystart > TIAConstants::maxYStart) return;
+  if (vcenter > TIAConstants::maxVcenter | vcenter < TIAConstants::minVcenter) return;
 
-  if (ystart == 0) {
+  if (vcenter != myTIA->vcenter()) myTIA->setVcenter(vcenter);
-    if (myYStartAutodetected) return;
-
-    redetectYStart();
-    myYStartAutodetected = true;
-    ystart = myAutodetectedYstart;
-  } else
-    myYStartAutodetected = false;
-
-  if (ystart != myTIA->ystart()) myTIA->setYStart(ystart);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Console::setTIAProperties()
 {
-  // FIXME - ystart is probably disappearing soon, or at least autodetection is
+  Int32 vcenter = BSPF::clamp(
-  uInt32 ystart = atoi(myProperties.get(PropType::Display_VCenter).c_str());
+    static_cast<Int32>(atoi(myProperties.get(PropType::Display_VCenter).c_str())), TIAConstants::minVcenter, TIAConstants::maxVcenter
-  if(ystart != 0)
+  );
-    ystart = BSPF::clamp(ystart, 0u, TIAConstants::maxYStart);
-  else {
-    ystart = myAutodetectedYstart;
-    myYStartAutodetected = true;
-  }
 
   if(myDisplayFormat == "NTSC" || myDisplayFormat == "PAL60" ||
      myDisplayFormat == "SECAM60")
@@ -778,7 +706,7 @@ void Console::setTIAProperties()
     myTIA->setLayout(FrameLayout::pal);
   }
 
-  myTIA->setYStart(ystart);
+  myTIA->setVcenter(vcenter);
 
   myEmulationTiming.updateFrameLayout(myTIA->frameLayout());
   myEmulationTiming.updateConsoleTiming(myConsoleTiming);

src/emucore/Console.hxx

@@ -306,9 +306,9 @@ class Console : public Serializable, public ConsoleIO
     void toggleJitter() const;
 
     /**
-     * Update yatart and run autodetection if necessary.
+     * Update vcenter
      */
-    void updateYStart(uInt32 ystart);
+    void updateVcenter(Int32 vcenter);
 
   private:
     /**
@@ -316,23 +316,13 @@ class Console : public Serializable, public ConsoleIO
      */
     void autodetectFrameLayout(bool reset = true);
 
-    /**
-     * Dryrun the emulation and detect ystart (the first visible scanline).
-     */
-    void autodetectYStart(bool reset = true);
-
     /**
      * Rerun frame layout autodetection
      */
     void redetectFrameLayout();
 
     /**
-     * Rerun ystart autodetection.
+      Sets various properties of the TIA (vcenter, Height, etc) based on
-     */
-    void redetectYStart();
-
-    /**
-      Sets various properties of the TIA (YStart, Height, etc) based on
       the current display format.
     */
     void setTIAProperties();
@@ -411,12 +401,6 @@ class Console : public Serializable, public ConsoleIO
     // Display format currently in use
     uInt32 myCurrentFormat;
 
-    // Autodetected ystart.
-    uInt32 myAutodetectedYstart;
-
-    // Is ystart currently autodetected?
-    bool myYStartAutodetected;
-
     // Is the TV format autodetected?
     bool myFormatAutodetected;
 

src/emucore/OSystem.cxx

@@ -587,7 +587,7 @@ unique_ptr<Console> OSystem::openConsole(const FilesystemNode& romfile, string&
     CMDLINE_PROPS_UPDATE("rd", PropType::Console_RightDiff);
     CMDLINE_PROPS_UPDATE("tv", PropType::Console_TVType);
     CMDLINE_PROPS_UPDATE("format", PropType::Display_Format);
-    CMDLINE_PROPS_UPDATE("ystart", PropType::Display_VCenter); // TODO (SA): change option
+    CMDLINE_PROPS_UPDATE("vcenter", PropType::Display_VCenter); // TODO (SA): change option
     CMDLINE_PROPS_UPDATE("pp", PropType::Display_Phosphor);
     CMDLINE_PROPS_UPDATE("ppblend", PropType::Display_PPBlend);
 

src/emucore/ProfilingRunner.cxx

@@ -29,7 +29,6 @@
 #include "TIA.hxx"
 #include "ConsoleTiming.hxx"
 #include "FrameManager.hxx"
-#include "YStartDetector.hxx"
 #include "FrameLayoutDetector.hxx"
 #include "EmulationTiming.hxx"
 #include "ConsoleTiming.hxx"
@@ -159,20 +158,9 @@ bool ProfilingRunner::runOne(const ProfilingRun run)
 
   (cout << endl).flush();
 
-  YStartDetector ystartDetector;
-  tia.setFrameManager(&ystartDetector);
-  system.reset();
-
-  (cout << "detecting ystart... ").flush();
-  for (int i = 0; i < 80; i++) tia.update();
-
-  uInt32 yStart = ystartDetector.detectedYStart();
-  (cout << yStart << endl).flush();
-
   FrameManager frameManager;
   tia.setFrameManager(&frameManager);
   tia.setLayout(frameLayout);
-  tia.setYStart(yStart);
 
   system.reset();
 

src/emucore/Settings.cxx

@@ -553,7 +553,7 @@ void Settings::usage() const
     << "   -bc          <arg>          Same as using both -lc and -rc\n"
     << "   -cp          <arg>          Sets the 'Controller.SwapPaddles' property\n"
     << "   -format      <arg>          Sets the 'Display.Format' property\n"
-    << "   -ystart      <arg>          Sets the 'Display.YStart' property\n"
+    << "   -vcenter     <arg>          Sets the 'Display.vcenter' property\n"
     << "   -pp          <arg>          Sets the 'Display.Phosphor' property\n"
     << "   -ppblend     <arg>          Sets the 'Display.PPBlend' property\n"
     << endl

src/emucore/tia/TIA.hxx

@@ -249,12 +249,13 @@ class TIA : public Device
     */
     uInt32 width() const  { return TIAConstants::H_PIXEL; }
     uInt32 height() const { return myFrameManager->height(); }
-    uInt32 ystart() const { return myFrameManager->ystart(); }
+    Int32 vcenter() const { return myFrameManager->vcenter(); }
+    uInt32 startLine() const { return myFrameManager->startLine(); }
 
     /**
-      Changes the current YStart property.
+      Changes the current vcenter property.
     */
-    void setYStart(uInt32 ystart) { myFrameManager->setYstart(ystart); }
+    void setVcenter(Int32 vcenter) { myFrameManager->setVcenter(vcenter); }
 
     void setLayout(FrameLayout layout) { myFrameManager->setLayout(layout); }
     FrameLayout frameLayout() const { return myFrameManager->layout(); }

src/emucore/tia/TIAConstants.hxx

@@ -24,9 +24,8 @@ namespace TIAConstants {
 
   static constexpr uInt32 frameBufferWidth = 160;
   static constexpr uInt32 frameBufferHeight = 320;
-  static constexpr uInt32 defaultYStart = 34; // TODO: PAL-50 might need a different value here
+  static constexpr Int32 maxVcenter = 20; // limit to reasonable values
-  static constexpr uInt32 minYStart = defaultYStart - 15; // limit to reasonable values
+  static constexpr Int32 minVcenter = -20; // limit to reasonable values
-  static constexpr uInt32 maxYStart = defaultYStart + 15; // limit to reasonable values
   static constexpr uInt32 viewableWidth = 320;
   static constexpr uInt32 viewableHeight = 240;
   static constexpr uInt32 initialGarbageFrames = 10;

src/emucore/tia/frame-manager/AbstractFrameManager.hxx

@@ -22,6 +22,7 @@
 
 #include "Serializable.hxx"
 #include "FrameLayout.hxx"
+#include "bspf.hxx"
 
 class AbstractFrameManager : public Serializable
 {
@@ -160,14 +161,19 @@ class AbstractFrameManager : public Serializable
     virtual uInt32 scanlines() const { return 0; }
 
     /**
-     * Configure the ystart value.
+     * Configure the vcenter value.
      */
-    virtual void setYstart(uInt32 ystart) {}
+    virtual void setVcenter(Int32 vcenter) {}
 
     /**
-     * The configured ystart value.
+     * The configured vcenter value.
      */
-    virtual uInt32 ystart() const { return 0; }
+    virtual Int32 vcenter() const { return 0; }
+
+    /**
+     * The corresponding start line.
+     */
+    virtual uInt32 startLine() const { return 0; }
 
     /**
      * Set the frame layout. This may be a noop (on the autodetection manager).

src/emucore/tia/frame-manager/FrameManager.cxx

@@ -31,7 +31,9 @@ enum Metrics: uInt32 {
   vsync                         = 3,
   maxLinesVsync                 = 50,
   visibleOverscan               = 20,
-  initialGarbageFrames          = TIAConstants::initialGarbageFrames
+  initialGarbageFrames          = TIAConstants::initialGarbageFrames,
+  ystartNTSC                    = 34,
+  ystartPAL                     = 39
 };
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -46,9 +48,11 @@ FrameManager::FrameManager()
     myFrameLines(0),
     myHeight(0),
     myYStart(0),
+    myVcenter(0),
     myJitterEnabled(false)
 {
   reset();
+  updateYStart();
   onLayoutChange();
 }
 
@@ -98,7 +102,7 @@ void FrameManager::onNextLine()
     case State::frame:
       if (myLineInState >= myHeight)
       {
-        myLastY = ystart() + myY;  // Last line drawn in this frame
+        myLastY = myYStart + myY;  // Last line drawn in this frame
         setState(State::waitForVsyncStart);
       }
       break;
@@ -121,10 +125,10 @@ Int32 FrameManager::missingScanlines() const
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void FrameManager::setYstart(uInt32 ystart)
+void FrameManager::setVcenter(Int32 vcenter)
 {
-  myYStart = ystart;
+  myVcenter = vcenter;
-  myJitterEmulation.setYStart(ystart);
+  updateYStart();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -241,3 +245,9 @@ bool FrameManager::onLoad(Serializer& in)
 
   return true;
 }
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void FrameManager::updateYStart() {
+  myYStart = (layout() == FrameLayout::ntsc ? Metrics::ystartNTSC : Metrics::ystartPAL) - myVcenter;
+  myJitterEmulation.setYStart(myYStart);
+}

src/emucore/tia/frame-manager/FrameManager.hxx

@@ -44,9 +44,11 @@ class FrameManager: public AbstractFrameManager {
 
     Int32 missingScanlines() const override;
 
-    void setYstart(uInt32 ystart) override;
+    void setVcenter(Int32 vcenter) override;
 
-    uInt32 ystart() const override { return myYStart; }
+    Int32 vcenter() const override { return myVcenter; }
+
+    uInt32 startLine() const override { return myYStart; }
 
     void setLayout(FrameLayout mode) override { layout(mode); }
 
@@ -77,6 +79,8 @@ class FrameManager: public AbstractFrameManager {
 
     void updateIsRendering();
 
+    void updateYStart();
+
   private:
 
     State myState;
@@ -90,6 +94,7 @@ class FrameManager: public AbstractFrameManager {
     uInt32 myFrameLines;
     uInt32 myHeight;
     uInt32 myYStart;
+    Int32 myVcenter;
 
     bool myJitterEnabled;
 

src/emucore/tia/frame-manager/YStartDetector.cxx

@@ -1,230 +0,0 @@
-//============================================================================
-//
-//   SSSS    tt          lll  lll
-//  SS  SS   tt           ll   ll
-//  SS     tttttt  eeee   ll   ll   aaaa
-//   SSSS    tt   ee  ee  ll   ll      aa
-//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
-//  SS  SS   tt   ee      ll   ll  aa  aa
-//   SSSS     ttt  eeeee llll llll  aaaaa
-//
-// Copyright (c) 1995-2019 by Bradford W. Mott, Stephen Anthony
-// and the Stella Team
-//
-// See the file "License.txt" for information on usage and redistribution of
-// this file, and for a DISCLAIMER OF ALL WARRANTIES.
-//============================================================================
-
-#include "YStartDetector.hxx"
-#include "TIAConstants.hxx"
-
-/**
- * Misc. numeric constants used in the algorithm.
- */
-enum Metrics: uInt32 {
-  // ideal world frame sizes
-  frameLinesNTSC            = 262,
-  frameLinesPAL             = 312,
-
-  // the ideal vblank zone
-  vblankNTSC                = 37,
-  vblankPAL                 = 45,
-
-  // number of scanlines to wait for vsync to start (exceeding after the ideal frame size) and stop
-  waitForVsync              = 50,
-
-  // max lines underscan
-  maxUnderscan              = 10,
-
-  // max lines deviations from detected ystart before we switch back to floating
-  maxVblankViolations       = 2,
-
-  // switch to fixed mode after this number of stable frames (+1)
-  minStableVblankFrames     = 1,
-
-  // no transitions to fixed mode will happend during those
-  initialGarbageFrames      = TIAConstants::initialGarbageFrames
-};
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-YStartDetector::YStartDetector()
-  : myState(State::waitForVsyncStart),
-    myVblankMode(VblankMode::floating),
-    myLinesWaitingForVsyncToStart(0),
-    myCurrentVblankLines(0),
-    myLastVblankLines(0),
-    myVblankViolations(0),
-    myStableVblankFrames(0),
-    myVblankViolated(false)
-{
-  reset();
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-uInt32 YStartDetector::detectedYStart() const
-{
-  return myLastVblankLines;
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void YStartDetector::onReset()
-{
-  myState = State::waitForVsyncStart;
-  myVblankMode = VblankMode::floating;
-  myLinesWaitingForVsyncToStart = 0;
-  myCurrentVblankLines = 0;
-  myLastVblankLines = 0;
-  myVblankViolations = 0;
-  myStableVblankFrames = 0;
-  myVblankViolated = false;
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void YStartDetector::onSetVsync()
-{
-  if (myVsync)
-    setState(State::waitForVsyncEnd);
-  else
-    setState(State::waitForFrameStart);
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void YStartDetector::onNextLine()
-{
-  const uInt32 frameLines = layout() == FrameLayout::ntsc ? Metrics::frameLinesNTSC : Metrics::frameLinesPAL;
-
-  switch (myState) {
-    case State::waitForVsyncStart:
-      // We start counting the number of "lines spent while waiting for vsync start" from
-      // the "ideal" frame size (corrected by the three scanlines spent in vsync).
-      if (myCurrentFrameTotalLines > frameLines - 3 || myTotalFrames == 0)
-        ++myLinesWaitingForVsyncToStart;
-
-      if (myLinesWaitingForVsyncToStart > Metrics::waitForVsync) setState(State::waitForVsyncEnd);
-
-      break;
-
-    case State::waitForVsyncEnd:
-      if (++myLinesWaitingForVsyncToStart > Metrics::waitForVsync) setState(State::waitForFrameStart);
-
-      break;
-
-    case State::waitForFrameStart:
-      if (shouldTransitionToFrame()) setState(State::waitForVsyncStart);
-      else ++myCurrentVblankLines;
-
-      break;
-
-    default:
-      throw runtime_error("cannot happen");
-  }
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-bool YStartDetector::shouldTransitionToFrame()
-{
-  uInt32 vblankLines = layout() == FrameLayout::pal ? Metrics::vblankPAL : Metrics::vblankNTSC;
-
-  // Are we free to transition as per vblank cycle?
-  bool shouldTransition = myCurrentVblankLines + 1 >= (myVblank ? vblankLines : vblankLines - Metrics::maxUnderscan);
-
-  // Do we **actually** transition? This depends on what mode we are in.
-  bool transition = false;
-
-  switch (myVblankMode) {
-    // Floating mode: we still are looking for a stable frame start
-    case VblankMode::floating:
-
-      // Are we free to transition?
-      if (shouldTransition) {
-        // Is this same scanline in which the transition ocurred last frame?
-        if (myTotalFrames > Metrics::initialGarbageFrames && myCurrentVblankLines == myLastVblankLines)
-          // Yes? -> Increase the number of stable frames
-          ++myStableVblankFrames;
-        else
-          // No? -> Frame start shifted again, set the number of consecutive stable frames to zero
-          myStableVblankFrames = 0;
-
-        // Save the transition point for checking on it next frame
-        myLastVblankLines = myCurrentVblankLines;
-
-        // In floating mode, we transition whenever we can.
-        transition = true;
-      }
-
-      // Transition to locked mode if we saw enough stable frames in a row.
-      if (myStableVblankFrames >= Metrics::minStableVblankFrames) {
-        myVblankMode = VblankMode::locked;
-        myVblankViolations = 0;
-      }
-
-      break;
-
-    // Locked mode: always transition at the same point, but check whether this is actually the
-    // detected transition point and revert state if applicable
-    case VblankMode::locked:
-
-      // Have we reached the transition point?
-      if (myCurrentVblankLines == myLastVblankLines) {
-
-        // Are we free to transition per the algorithm and didn't observe an violation before?
-        // (aka did the algorithm tell us to transition before reaching the actual line)
-        if (shouldTransition && !myVblankViolated)
-          // Reset the number of irregular frames (if any)
-          myVblankViolations = 0;
-        else {
-          // Record a violation if it wasn't recorded before
-          if (!myVblankViolated) ++myVblankViolations;
-          myVblankViolated = true;
-        }
-
-        // transition
-        transition = true;
-      // The algorithm tells us to transition although we haven't reached the trip line before
-      } else if (shouldTransition) {
-        // Record a violation if it wasn't recorded before
-        if (!myVblankViolated) ++myVblankViolations;
-        myVblankViolated = true;
-      }
-
-      // Revert to floating mode if there were too many irregular frames in a row
-      if (myVblankViolations > Metrics::maxVblankViolations) {
-        myVblankMode = VblankMode::floating;
-        myStableVblankFrames = 0;
-      }
-
-      break;
-
-    default:
-      throw runtime_error("cannot happen");
-  }
-
-    return transition;
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void YStartDetector::setState(State state)
-{
-  if (state == myState) return;
-
-  myState = state;
-  myLinesWaitingForVsyncToStart = 0;
-
-  switch (state) {
-    case State::waitForVsyncEnd:
-      break;
-
-    case State::waitForVsyncStart:
-      notifyFrameComplete();
-      notifyFrameStart();
-      break;
-
-    case State::waitForFrameStart:
-      myVblankViolated = false;
-      myCurrentVblankLines = 0;
-      break;
-
-    default:
-      throw new runtime_error("cannot happen");
-  }
-}

src/emucore/tia/frame-manager/YStartDetector.hxx

@@ -1,155 +0,0 @@
-//============================================================================
-//
-//   SSSS    tt          lll  lll
-//  SS  SS   tt           ll   ll
-//  SS     tttttt  eeee   ll   ll   aaaa
-//   SSSS    tt   ee  ee  ll   ll      aa
-//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
-//  SS  SS   tt   ee      ll   ll  aa  aa
-//   SSSS     ttt  eeeee llll llll  aaaaa
-//
-// Copyright (c) 1995-2019 by Bradford W. Mott, Stephen Anthony
-// and the Stella Team
-//
-// See the file "License.txt" for information on usage and redistribution of
-// this file, and for a DISCLAIMER OF ALL WARRANTIES.
-//============================================================================
-
-#ifndef TIA_YSTART_DETECTOR
-#define TIA_YSTART_DETECTOR
-
-#include "AbstractFrameManager.hxx"
-
-/**
- * This frame manager detects ystart from the first line with vblank = off.
- */
-
-class YStartDetector: public AbstractFrameManager {
-
-  public:
-
-    YStartDetector();
-
-  public:
-
-    /**
-     * Getter for the detected ystart value
-     */
-    uInt32 detectedYStart() const;
-
-    /**
-     * We require frame layout to be set from outside.
-     */
-    void setLayout(FrameLayout layout) override { this->layout(layout); }
-
-  protected:
-
-    /**
-     * We need to track vsync changes.
-     */
-    void onSetVsync() override;
-
-    /**
-     * Reset hook.
-     */
-    void onReset() override;
-
-    /**
-     * The workhorse.
-     */
-    void onNextLine() override;
-
-  private:
-
-    /**
-     * Our various states.
-     */
-    enum class State {
-      // Wait for vsync on
-      waitForVsyncStart,
-
-      // Wait for vsync off
-      waitForVsyncEnd,
-
-      // Wait for the visible frame to start
-      waitForFrameStart
-    };
-
-    /**
-     * Have we settled on a frame start?
-     */
-    enum class VblankMode {
-      // We have settled on a frame start and have some hysteresis before we return to floating
-      locked,
-
-      // We are actively looking for the frame to start
-      floating
-    };
-
-  private:
-
-    /**
-     * Side effects for state transitions.
-     */
-    void setState(State state);
-
-    /**
-     * Perform detection and decide whether the frame starts now.
-     */
-    bool shouldTransitionToFrame();
-
-  private:
-
-    /**
-     * State.
-     */
-    State myState;
-
-    /**
-     * locked / floating
-     */
-    VblankMode myVblankMode;
-
-    /**
-     * Counts the scanlines that we wait for vsync to start.
-     */
-    uInt32 myLinesWaitingForVsyncToStart;
-
-    /**
-     * The number of lines we are currently waiting for the frame to start (and vblank to end).
-     */
-    uInt32 myCurrentVblankLines;
-
-    /**
-     * The number of vblank lines on the last frame.
-     */
-    uInt32 myLastVblankLines;
-
-    /**
-     * Count "vblank violations" in fixed mode (the number of consecutive frames where ystart
-     * differs from the previously detected value). Once a trip point is reached, we transition
-     * back to floating mode.
-     */
-    uInt32 myVblankViolations;
-
-    /**
-     * The number of frames in floating mode with stable ystart. Once a trip point is reacted,
-     * we transition to fixed mode
-     */
-    uInt32 myStableVblankFrames;
-
-    /**
-     * Tracks deviations from the determined ystart value during a fixed mode frame in order to
-     * avoid double counting.
-     */
-    bool myVblankViolated;
-
-  private:
-
-    YStartDetector(const YStartDetector&) = delete;
-    YStartDetector(YStartDetector&&) = delete;
-    YStartDetector& operator=(const YStartDetector&) = delete;
-    YStartDetector& operator=(YStartDetector&&) = delete;
-};
-
-#endif // TIA_YSTART_DETECTOR

src/emucore/tia/frame-manager/module.mk

@@ -4,7 +4,6 @@ MODULE_OBJS := \
 	src/emucore/tia/frame-manager/FrameManager.o \
 	src/emucore/tia/frame-manager/AbstractFrameManager.o \
 	src/emucore/tia/frame-manager/FrameLayoutDetector.o \
-	src/emucore/tia/frame-manager/YStartDetector.o \
 	src/emucore/tia/frame-manager/JitterEmulation.o
 
 MODULE_DIRS += \

src/gui/GameInfoDialog.cxx

@@ -138,9 +138,9 @@ GameInfoDialog::GameInfoDialog(
   t = new StaticTextWidget(myTab, font, HBORDER, ypos + 1, "V-Center ");
   myVCenter = new SliderWidget(myTab, font, t->getRight() + 2, ypos,
                               "", 0, kVCenterChanged, 7 * fontWidth, "px");
-// TODO (SA):check relationship of ystart and vcenter
+
-  myVCenter->setMinValue(TIAConstants::minYStart - TIAConstants::defaultYStart);
+  myVCenter->setMinValue(TIAConstants::minVcenter);
-  myVCenter->setMaxValue(TIAConstants::maxYStart - TIAConstants::defaultYStart);
+  myVCenter->setMaxValue(TIAConstants::maxVcenter);
   myVCenter->setTickmarkIntervals(4);
   wid.push_back(myVCenter);
 
@@ -458,20 +458,10 @@ void GameInfoDialog::loadEmulationProperties(const Properties& props)
   myPPBlend->setValue(atoi(blend.c_str()));
 
   // set vertical center
-  int vCenter = atoi(props.get(PropType::Display_VCenter).c_str());
+  Int32 vcenter = atoi(props.get(PropType::Display_VCenter).c_str());
-  if (vCenter)
+  myVCenter->setValueLabel(vcenter);
-  {
+  myVCenter->setValue(vcenter);
-    // convert y-start into v-center
+  myVCenter->setValueUnit(vcenter ? "px" : "");
-    // TODO (SA): fix this
-    vCenter = TIAConstants::defaultYStart - vCenter;
-    myVCenter->setValueLabel(vCenter);
-  }
-  else
-  {
-    myVCenter->setValueLabel("default");
-  }
-  myVCenter->setValue(vCenter);
-  myVCenter->setValueUnit(vCenter ? "px" : "");
 
   mySound->setState(props.get(PropType::Cart_Sound) == "STEREO");
   // if stereo is always enabled, disable game specific stereo setting
@@ -548,11 +538,9 @@ void GameInfoDialog::saveConfig()
   myGameProperties.set(PropType::Display_Phosphor, myPhosphor->getState() ? "YES" : "NO");
   myGameProperties.set(PropType::Display_PPBlend, myPPBlend->getValueLabel() == "Off" ? "0" :
                        myPPBlend->getValueLabel());
-  int vCenter = myVCenter->getValue();
+  Int32 vcenter = myVCenter->getValue();
-  if (vCenter)
+
-    // convert v-center into y-start TODO (SA): fix this
+  myGameProperties.set(PropType::Display_VCenter, std::to_string(vcenter));
-    vCenter = TIAConstants::defaultYStart - vCenter;
-  myGameProperties.set(PropType::Display_VCenter, std::to_string(vCenter));
   myGameProperties.set(PropType::Cart_Sound, mySound->getState() ? "STEREO" : "MONO");
 
   // Console properties
@@ -595,7 +583,7 @@ void GameInfoDialog::saveConfig()
     // update 'Emulation' tab settings immediately
     instance().console().setFormat(myFormat->getSelected());
     instance().frameBuffer().tiaSurface().enablePhosphor(myPhosphor->getState(), myPPBlend->getValue());
-    instance().console().updateYStart(vCenter);
+    instance().console().updateVcenter(vcenter);
     instance().console().initializeAudio();
 
     // update 'Console' tab settings immediately