Fixed flickering on games that do not render during every vi frame

BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64VideoProvider.cs

@@ -25,7 +25,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64
 				height > videosettings.Height ? height : videosettings.Height
 			);
 
-			core.FrameFinished += DoVideoFrame;
+			core.BeforeRender += DoVideoFrame;
 		}
 
 		public int[] GetVideoBuffer()

BizHawk.Emulation.Cores/Consoles/Nintendo/N64/NativeAPI/mupen64plusCoreApi.cs

@@ -80,7 +80,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 			M64CMD_READ_SCREEN,
 			M64CMD_RESET,
 			M64CMD_ADVANCE_FRAME,
-			M64CMD_SET_VI_CALLBACK
+			M64CMD_SET_VI_CALLBACK,
+			M64CMD_SET_RENDER_CALLBACK
 		};
 
 		public enum m64p_emu_state
@@ -255,6 +256,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
 		delegate m64p_error CoreDoCommandVICallback(m64p_command Command, int ParamInt, VICallback ParamPtr);
 		CoreDoCommandVICallback m64pCoreDoCommandVICallback;
+		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+		delegate m64p_error CoreDoCommandRenderCallback(m64p_command Command, int ParamInt, RenderCallback ParamPtr);
+		CoreDoCommandRenderCallback m64pCoreDoCommandRenderCallback;
 
 		// These are common for all four plugins
 
@@ -300,6 +304,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 		public delegate void VICallback();
 		VICallback m64pVICallback;
 
+		/// <summary>
+		/// This will be called every time before the screen is drawn
+		/// </summary>
+		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+		public delegate void RenderCallback();
+		RenderCallback m64pRenderCallback;
+
 		/// <summary>
 		/// This will be called after the emulator is setup and is ready to be used
 		/// </summary>
@@ -389,6 +400,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 			result = m64pCoreDoCommandFrameCallback(m64p_command.M64CMD_SET_FRAME_CALLBACK, 0, m64pFrameCallback);
 			m64pVICallback = new VICallback(FireVIEvent);
 			result = m64pCoreDoCommandVICallback(m64p_command.M64CMD_SET_VI_CALLBACK, 0, m64pVICallback);
+			m64pRenderCallback = new RenderCallback(FireRenderEvent);
+			result = m64pCoreDoCommandRenderCallback(m64p_command.M64CMD_SET_RENDER_CALLBACK, 0, m64pRenderCallback);
 
 			// Prepare to start the emulator in a different thread
 			m64pEmulator = new Thread(ExecuteEmulator);
@@ -436,6 +449,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 			m64pCoreDoCommandRefInt = (CoreDoCommandRefInt)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "CoreDoCommand"), typeof(CoreDoCommandRefInt));
 			m64pCoreDoCommandFrameCallback = (CoreDoCommandFrameCallback)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "CoreDoCommand"), typeof(CoreDoCommandFrameCallback));
 			m64pCoreDoCommandVICallback = (CoreDoCommandVICallback)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "CoreDoCommand"), typeof(CoreDoCommandVICallback));
+			m64pCoreDoCommandRenderCallback = (CoreDoCommandRenderCallback)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "CoreDoCommand"), typeof(CoreDoCommandRenderCallback));
 			m64pCoreAttachPlugin = (CoreAttachPlugin)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "CoreAttachPlugin"), typeof(CoreAttachPlugin));
 			m64pCoreDetachPlugin = (CoreDetachPlugin)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "CoreDetachPlugin"), typeof(CoreDetachPlugin));
 			m64pConfigOpenSection = (ConfigOpenSection)Marshal.GetDelegateForFunctionPointer(GetProcAddress(CoreDll, "ConfigOpenSection"), typeof(ConfigOpenSection));
@@ -665,6 +679,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 
 		public event Action FrameFinished;
 		public event Action VInterrupt;
+		public event Action BeforeRender;
 
 		private void FireFrameFinishedEvent()
 		{
@@ -681,6 +696,12 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 			m64pFrameComplete.Set();
 		}
 
+		private void FireRenderEvent()
+		{
+			if (BeforeRender != null)
+				BeforeRender();
+		}
+
 		private void CompletedFrameCallback()
 		{
 			m64pFrameComplete.Set();

libmupen64plus/mupen64plus-core/src/api/frontend.c

@@ -270,6 +270,9 @@ EXPORT m64p_error CALL CoreDoCommand(m64p_command Command, int ParamInt, void *P
 		case M64CMD_SET_VI_CALLBACK:
             g_VICallback = (m64p_vi_callback) ParamPtr;
             return M64ERR_SUCCESS;
+		case M64CMD_SET_RENDER_CALLBACK:
+			g_RenderCallback = (m64p_render_callback) ParamPtr;
+			return M64ERR_SUCCESS;
         case M64CMD_TAKE_NEXT_SCREENSHOT:
             if (!g_EmulatorRunning)
                 return M64ERR_INVALID_STATE;

libmupen64plus/mupen64plus-core/src/api/m64p_types.h

@@ -55,6 +55,7 @@ typedef void (*m64p_frame_callback)(unsigned int FrameIndex);
 typedef void (*m64p_input_callback)(void);
 typedef void (*m64p_audio_callback)(void);
 typedef void (*m64p_vi_callback)(void);
+typedef void (*m64p_render_callback)(void);
 
 typedef enum {
   M64TYPE_INT = 1,
@@ -156,7 +157,8 @@ typedef enum {
   M64CMD_READ_SCREEN,
   M64CMD_RESET,
   M64CMD_ADVANCE_FRAME,
-  M64CMD_SET_VI_CALLBACK
+  M64CMD_SET_VI_CALLBACK,
+  M64CMD_SET_RENDER_CALLBACK
 } m64p_command;
 
 typedef struct {

libmupen64plus/mupen64plus-core/src/main/main.c

@@ -74,6 +74,7 @@ m64p_handle g_CoreConfig = NULL;
 
 m64p_frame_callback g_FrameCallback = NULL;
 m64p_vi_callback g_VICallback = NULL;
+m64p_render_callback g_RenderCallback = NULL;
 
 int         g_MemHasBeenBSwapped = 0;   // store byte-swapped flag so we don't swap twice when re-playing game
 int         g_EmulatorRunning = 0;      // need separate boolean to tell if emulator is running, since --nogui doesn't use a thread
@@ -654,6 +655,9 @@ static void video_plugin_render_callback(int bScreenRedrawn)
         }
     }
 
+	if(g_RenderCallback != NULL)
+		g_RenderCallback();
+
     // if the OSD is enabled, then draw it now
     if (bOSD)
     {

libmupen64plus/mupen64plus-core/src/main/main.h

@@ -33,6 +33,7 @@ extern int g_EmulatorRunning;
 
 extern m64p_frame_callback g_FrameCallback;
 extern m64p_vi_callback g_VICallback;
+extern m64p_render_callback g_RenderCallback;
 
 const char* get_savestatepath(void);
 const char* get_savesrampath(void);