added option to disable emulation shading in pause mode via command line (resolves #755)

docs/index.html

@@ -2730,6 +2730,10 @@
         indicating serious errors override this setting, and are always
         shown.</td>
     </tr>
+    <tr>
+      <td><pre>-pauseshade &lt;1|0&gt;</pre></td>
+      <td>Enable or disable emulation shading in pause mode.</td>
+    </tr>
 
     <tr>
       <td><pre>-audio.enabled &lt;1|0&gt;</pre></td>

src/emucore/FrameBuffer.cxx

@@ -343,14 +343,16 @@ void FrameBuffer::update(UpdateMode mode)
     case EventHandlerState::PAUSE:
     {
       // Show a pause message immediately and then every 7 seconds
+      bool shade = myOSystem.settings().getBool("pauseshade");
+
       if(myPausedCount-- <= 0)
       {
         myPausedCount = uInt32(7 * myOSystem.frameRate());
         showTextMessage("Paused", MessagePosition::MiddleCenter);
-        myTIASurface->render(true);
+        myTIASurface->render(shade);
       }
       if(rerender)
-        myTIASurface->render(true);
+        myTIASurface->render(shade);
       break;  // EventHandlerState::PAUSE
     }
 

src/emucore/Settings.cxx

@@ -47,6 +47,7 @@ Settings::Settings()
   setPermanent("windowedpos", Common::Point(50, 50));
   setPermanent("display", 0);
   setPermanent("uimessages", "true");
+  setPermanent("pauseshade", "true");
   // TIA specific options
   setPermanent("tia.inter", "false");
   setPermanent("tia.zoom", "3");
@@ -446,6 +447,7 @@ void Settings::usage() const
     << "  -speed        <number>       Run emulation at the given speed\n"
     << "  -turbo        <1|0>          Enable 'Turbo' mode for maximum emulation speed\n"
     << "  -uimessages   <1|0>          Show onscreen UI messages for different events\n"
+    << "  -pauseshade   <1|0>          Enable emulation shading in pause mode\n"
     << endl
   #ifdef SOUND_SUPPORT
     << "  -audio.enabled            <1|0>      Enable audio\n"