Lua unpause and invisible seek support

Assets/Lua/GBA/SonicAdvance_CamHack.lua

@@ -6,6 +6,8 @@ local addr_offY = 0x5B98
 local addr_camX = 0x59D0
 local addr_camY = 0x59D2
 
+event.onexit(function() client.invisibleemulation(false) end)
+
 while true do
 	client.invisibleemulation(true)
 	local memorystate = memorysavestate.savecorestate()
@@ -21,12 +23,11 @@ while true do
 	mainmemory.write_u16_le(addr_camX, Xval)
 	mainmemory.write_u16_le(addr_camY, Yval)
 
-	client.seekframe(emu.framecount()+1)
+	emu.frameadvance()
 	client.invisibleemulation(false)
-	client.seekframe(emu.framecount()+1)
+	emu.frameadvance()
 	client.invisibleemulation(true)
 	memorysavestate.loadcorestate(memorystate)
 	memorysavestate.removestate(memorystate)
---	client.invisibleemulation(false)
 	emu.frameadvance()
 end

Assets/Lua/seek.lua

@@ -0,0 +1,26 @@
+-- Seek forward to a given frame.
+-- This will unpause emulation, and restore the users' desired pause state when seeking is completed.
+-- Note that this may interfere with TAStudio's seeking behavior.
+local function force_seek_frame(frame)
+	local pause = client.unpause()
+	while emu.framecount() < frame do
+		-- The user may pause mid-seek, perhaps even by accident.
+		-- In this case, we will unpause but remember that the user wants to pause at the end.
+		if client.ispaused() then
+			pause = true
+			client.unpause()
+		end
+		-- Yield, not frameadvance. With frameadvance we cannot detect pauses, since frameadvance would not return.
+		-- This is true even if we have just called client.unpause.
+		emu.yield()
+	end
+
+	if pause then client.pause() end
+end
+
+-- Seek but without touching the pause state. Function will not return if the given frame is never reached due to the user manaully pausing/rewinding.
+local function seek_frame(frame)
+	while emu.framecount() < frame do
+		emu.frameadvance()
+	end
+end

src/BizHawk.Client.Common/Api/Classes/EmuClientApi.cs

@@ -228,7 +228,7 @@ public void SpeedMode(int percent)
 
 		public Point TransformPoint(Point point) => _displayManager.TransformPoint(point);
 
-		public void Unpause() => _mainForm.UnpauseEmulator();
+		public bool Unpause() => _mainForm.UnpauseEmulator();
 
 		public void UnpauseAv() => _mainForm.PauseAvi = false;
 

src/BizHawk.Client.Common/Api/Interfaces/IEmuClientApi.cs

@@ -154,7 +154,10 @@ public interface IEmuClientApi : IDisposable, IExternalApi
 
 		Point TransformPoint(Point point);
 
-		void Unpause();
+		/// <returns>True if <see cref="Pause"/> should be called if you want to restore the previous pause state.
+		/// <br/>Note that this is not the same as checking <see cref="IsPaused"/> before unpausing.
+		/// If the user was holding frame advance, emulation will have already been unpaused and releasing frame advance will not pause.</returns>
+		bool Unpause();
 
 		void UnpauseAv();
 

src/BizHawk.Client.Common/IMainFormForApi.cs

@@ -128,7 +128,7 @@ public interface IMainFormForApi
 		void ToggleSound();
 
 		/// <remarks>only referenced from <see cref="EmuClientApi"/></remarks>
-		void UnpauseEmulator();
+		bool UnpauseEmulator();
 
 		/// <remarks>only referenced from <see cref="EmuClientApi"/></remarks>
 		event BeforeQuickLoadEventHandler QuicksaveLoad;

src/BizHawk.Client.Common/lua/CommonLibs/ClientLuaLibrary.cs

@@ -95,7 +95,14 @@ public string GetLuaEngine()
 			=> "NLua+Lua";
 
 		[LuaMethodExample("client.invisibleemulation( true );")]
-		[LuaMethod("invisibleemulation", "Enters/exits turbo mode and disables/enables most emulator updates.")]
+		[LuaMethod(
+			name: "invisibleemulation",
+			description: "Disables/enables invisible emulation, starting on the next frame. During invisible emulation:"
+				+ " (1) All rendering and sound is disabled, including A/V capture."
+				+ " (2) Emulation runs at maximum speed with turbo enabled, regardless of pause state."
+				+ " (3) Frame rate is not calculated."
+				+ " (4) With one additional frame of delay, state capture for rewind+TAStudio is disabled."
+			)]
 		public void InvisibleEmulation(bool invisible)
 			=> APIs.EmuClient.InvisibleEmulation(invisible);
 
@@ -304,8 +311,8 @@ public LuaTable TransformPoint(int x, int y) {
 		}
 
 		[LuaMethodExample("client.unpause( );")]
-		[LuaMethod("unpause", "Unpauses the emulator")]
-		public void Unpause()
+		[LuaMethod("unpause", "Unpauses the emulator. Returns True if client.pause should be called if you want to restore the previous pause state. Note that this is not the same as checking client.ispaused before unpausing. If the user was holding frame advance, emulation will have already been unpaused and releasing frame advance will not pause.")]
+		public bool Unpause()
 			=> APIs.EmuClient.Unpause();
 
 		[LuaMethodExample("client.unpause_av( );")]

src/BizHawk.Client.EmuHawk/IMainFormForTools.cs

@@ -85,7 +85,7 @@ public interface IMainFormForTools : IDialogController
 		void TogglePause();
 
 		/// <remarks>referenced by 3 or more tools</remarks>
-		void UnpauseEmulator();
+		bool UnpauseEmulator();
 
 		/// <remarks>only referenced from <see cref="BasicBot"/></remarks>
 		void Unthrottle();

src/BizHawk.Client.EmuHawk/MainForm.cs

@@ -1002,8 +1002,12 @@ public int ProgramRunLoop()
 				Tools.GeneralUpdateActiveExtTools();
 
 				StepRunLoop_Core();
-				Render();
-				StepRunLoop_Throttle();
+
+				if (!_invisibleEmulation)
+				{
+					Render();
+					StepRunLoop_Throttle();
+				}
 
 				// HACK: RAIntegration might peek at memory during messages
 				// we need this to allow memory access here, otherwise it will deadlock
@@ -1076,20 +1080,44 @@ protected override void Dispose(bool disposing)
 		private bool _emulatorPaused;
 		public bool EmulatorPaused
 		{
-			get => _emulatorPaused;
+			get => _emulatorPaused && !_unpauseByFrameAdvance;
 
 			private set
 			{
 				_didMenuPause = false; // overwritten where relevant
 				if (_emulatorPaused == value) return;
-				if (_emulatorPaused && !value) // Unpausing
-				{
-					InitializeFpsData();
-				}
-
-				if (value != _emulatorPaused) Tools.OnPauseToggle(value);
 				_emulatorPaused = value;
+
+				OnPauseToggle(value);
+			}
+		}
+
+		private bool _unpauseByFrameAdvance;
+
+		/// <summary>
+		/// Avoids using EmulatorPaused to handle frame advance, thus allowing Lua to unpause during a frame advance.
+		/// </summary>
+		private bool UnpauseByFrameAdvance
+		{
+			get => _unpauseByFrameAdvance;
+			set
+			{
+				if (_unpauseByFrameAdvance == value) return;
+				_unpauseByFrameAdvance = value;
+
+				OnPauseToggle(!value);
+			}
+		}
+
+		private void OnPauseToggle(bool newPauseState)
+		{
+			if (!newPauseState) // Unpausing
+			{
+				InitializeFpsData();
 			}
+
+			Tools.OnPauseToggle(newPauseState);
+			SetPauseStatusBarIcon();
 		}
 
 		public bool BlockFrameAdvance { get; set; }
@@ -1121,7 +1149,11 @@ private set
 		/// <item><description><see cref="ClientLuaLibrary.InvisibleEmulation(bool)"/></description></item>
 		/// </list>
 		/// </summary>
-		public bool InvisibleEmulation { get; set; }
+		public bool InvisibleEmulation { get => _invisibleUpdate; set => _invisibleEmulateNextFrame = value; }
+
+		private bool _invisibleEmulateNextFrame;
+		private bool _invisibleEmulation;
+		private bool _invisibleUpdate;
 
 		private long MouseWheelTracker;
 
@@ -1146,7 +1178,7 @@ private set
 
 		public bool IsSeeking => PauseOnFrame.HasValue;
 		private bool IsTurboSeeking => PauseOnFrame.HasValue && Config.TurboSeek;
-		public bool IsTurboing => InputManager.ClientControls["Turbo"] || IsTurboSeeking || InvisibleEmulation;
+		public bool IsTurboing => InputManager.ClientControls["Turbo"] || IsTurboSeeking || _invisibleUpdate;
 		public bool IsFastForwarding => InputManager.ClientControls["Fast Forward"] || IsTurboing;
 		public bool IsRewinding { get; private set; }
 
@@ -1341,13 +1373,13 @@ public bool RebootCore()
 		public void PauseEmulator()
 		{
 			EmulatorPaused = true;
-			SetPauseStatusBarIcon();
 		}
 
-		public void UnpauseEmulator()
+		public bool UnpauseEmulator()
 		{
+			bool ret = _emulatorPaused;
 			EmulatorPaused = false;
-			SetPauseStatusBarIcon();
+			return ret;
 		}
 
 		public void TogglePause()
@@ -2930,32 +2962,33 @@ private void StepRunLoop_Core(bool force = false)
 					// handle the initial trigger of a frame advance
 					runFrame = true;
 					_frameAdvanceTimestamp = currentTimestamp;
+					// Pausing is inconsistent with the behavior of TAStudio while seeking, but it's always been this way so.
 					PauseEmulator();
 				}
 				else if (frameProgressTimeElapsed)
 				{
 					runFrame = true;
 					_runloopFrameProgress = true;
-					UnpauseEmulator();
+					UnpauseByFrameAdvance = true;
 				}
 			}
 			else
 			{
 				if (_runloopFrameAdvance)
 				{
 					// handle release of frame advance
-					PauseEmulator();
+					UnpauseByFrameAdvance = false;
 				}
 				_runloopFrameProgress = false;
 			}
 
 			_runloopFrameAdvance = frameAdvance;
 
+			bool unpaused = !EmulatorPaused || _invisibleEmulation;
 #if BIZHAWKBUILD_SUPERHAWK
-			if (!EmulatorPaused && (!Config.SuperHawkThrottle || InputManager.ClientControls.AnyInputHeld))
-#else
-			if (!EmulatorPaused)
+			unpaused = unpaused && (!Config.SuperHawkThrottle || InputManager.ClientControls.AnyInputHeld);
 #endif
+			if (unpaused)
 			{
 				runFrame = true;
 			}
@@ -2969,15 +3002,20 @@ private void StepRunLoop_Core(bool force = false)
 			// BlockFrameAdvance (true when input it being editted in TAStudio) supercedes all other frame advance conditions
 			if ((runFrame || force) && !BlockFrameAdvance)
 			{
+				_invisibleEmulation = _invisibleEmulateNextFrame;
+
 				var isFastForwarding = IsFastForwarding;
 				var isFastForwardingOrRewinding = isFastForwarding || isRewinding || Config.Unthrottled;
 
-				if (isFastForwardingOrRewinding != _lastFastForwardingOrRewinding)
+				if (!_invisibleEmulation)
 				{
-					InitializeFpsData();
-				}
+					if (isFastForwardingOrRewinding != _lastFastForwardingOrRewinding)
+					{
+						InitializeFpsData();
+					}
 
-				_lastFastForwardingOrRewinding = isFastForwardingOrRewinding;
+					_lastFastForwardingOrRewinding = isFastForwardingOrRewinding;
+				}
 
 				// client input-related duties
 				OSD.ClearGuiText();
@@ -2997,13 +3035,13 @@ private void StepRunLoop_Core(bool force = false)
 					Tools.UpdateToolsBefore();
 				}
 
-				if (!InvisibleEmulation)
+				if (!_invisibleEmulation)
 				{
 					CaptureRewind(isRewinding);
 				}
 
 				// Set volume, if enabled
-				if (Config.SoundEnabledNormal && !InvisibleEmulation)
+				if (Config.SoundEnabledNormal && !_invisibleEmulation)
 				{
 					atten = Config.SoundVolume / 100.0f;
 
@@ -3030,7 +3068,7 @@ private void StepRunLoop_Core(bool force = false)
 
 				RA?.OnFrameAdvance();
 
-				if (Config.AutosaveSaveRAM)
+				if (Config.AutosaveSaveRAM && !_invisibleEmulation)
 				{
 					AutoFlushSaveRamIn--;
 					if (AutoFlushSaveRamIn <= 0)
@@ -3048,10 +3086,10 @@ private void StepRunLoop_Core(bool force = false)
 				}
 
 				bool atTurboSeekEnd = IsTurboSeeking && Emulator.Frame == PauseOnFrame.Value - 1;
-				bool render = !InvisibleEmulation && (!_throttle.skipNextFrame || _currAviWriter?.UsesVideo is true || atTurboSeekEnd);
+				bool render = !_invisibleEmulation && (!_throttle.skipNextFrame || _currAviWriter?.UsesVideo is true || atTurboSeekEnd);
 				bool newFrame = Emulator.FrameAdvance(InputManager.ControllerOutput, render, renderSound);
 
-				MovieSession.HandleFrameAfter(ToolBypassingMovieEndAction is not null);
+				if (!_invisibleUpdate) MovieSession.HandleFrameAfter(ToolBypassingMovieEndAction is not null);
 
 				if (returnToRecording)
 				{
@@ -3088,13 +3126,14 @@ private void StepRunLoop_Core(bool force = false)
 						UpdateToolsAfter();
 					}
 				}
+				_invisibleUpdate = _invisibleEmulation;
 
-				if (!PauseAvi && newFrame && !InvisibleEmulation)
+				if (!PauseAvi && newFrame && !_invisibleEmulation)
 				{
 					AvFrameAdvance();
 				}
 
-				if (newFrame)
+				if (newFrame && !_invisibleEmulation)
 				{
 					_framesSinceLastFpsUpdate++;
 
@@ -4375,6 +4414,8 @@ private bool Rewind(ref bool runFrame, long currentTimestamp, out bool returnToR
 
 			returnToRecording = false;
 
+			if (_invisibleEmulation) return false;
+
 			if (ToolControllingRewind is { } rewindTool)
 			{
 				if (InputManager.ClientControls["Rewind"] || PressRewind)

src/BizHawk.Client.EmuHawk/RetroAchievements/RAIntegration.cs

@@ -137,7 +137,7 @@ public RAIntegration(
 				clientVer: $"{VersionInfo.MainVersion}{(VersionInfo.DeveloperBuild ? "-dev" : string.Empty)}");
 
 			_isActive = () => !Emu.IsNull();
-			_unpause = _mainForm.UnpauseEmulator;
+			_unpause = () => _ = _mainForm.UnpauseEmulator();
 			_pause = _mainForm.PauseEmulator;
 			_rebuildMenu = RebuildMenu;
 			_estimateTitle = buffer =>

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.IToolForm.cs

@@ -71,7 +71,7 @@ protected override void GeneralUpdate()
 
 		protected override void UpdateAfter()
 		{
-			if (!IsHandleCreated || IsDisposed || CurrentTasMovie == null)
+			if (!IsHandleCreated || IsDisposed || CurrentTasMovie == null || MainForm.InvisibleEmulation)
 			{
 				return;
 			}
@@ -109,6 +109,8 @@ protected override void UpdateAfter()
 
 		protected override void FastUpdateAfter()
 		{
+			if (MainForm.InvisibleEmulation) return;
+
 			if (_seekingTo != -1 && Emulator.Frame >= _seekingTo)
 			{
 				bool smga = _shouldMoveGreenArrow;