diff --git a/src/jsapi.c b/src/jsapi.c
index 768c4dc..879689c 100644
--- a/src/jsapi.c
+++ b/src/jsapi.c
@@ -828,3 +828,8 @@ void callJavascriptScanline(tic_mem* memory, s32 row)
 	}
 	else duk_pop(duk);
 }
+
+void callJavascriptOverlap(tic_mem* memory)
+{
+	
+}
\ No newline at end of file
diff --git a/src/luaapi.c b/src/luaapi.c
index 2dd9168..eb7f77a 100644
--- a/src/luaapi.c
+++ b/src/luaapi.c
@@ -1245,4 +1245,9 @@ void callLuaScanline(tic_mem* memory, s32 row)
 		}
 		else lua_pop(lua, 1);
 	}
-}
\ No newline at end of file
+}
+
+void callLuaOverlap(tic_mem* memory)
+{
+	
+}
diff --git a/src/machine.h b/src/machine.h
index 39d7f4f..bf08dc3 100644
--- a/src/machine.h
+++ b/src/machine.h
@@ -46,8 +46,6 @@ typedef struct
 	s32 duration;
 } Channel;
 
-typedef void(ScanlineFunc)(tic_mem* memory, s32 row);
-
 typedef struct
 {
 	s32 l;
@@ -84,7 +82,8 @@ typedef struct
 		Channel channels[TIC_SOUND_CHANNELS];
 	} music;
 
-	ScanlineFunc* scanline;
+	tic_scanline scanline;
+	tic_overlap overlap;
 	bool initialized;
 } MachineState;
 
@@ -134,3 +133,6 @@ void callJavascriptTick(tic_machine* machine);
 
 void callLuaScanline(tic_mem* memory, s32 row);
 void callJavascriptScanline(tic_mem* memory, s32 row);
+
+void callLuaOverlap(tic_mem* memory);
+void callJavascriptOverlap(tic_mem* memory);
diff --git a/src/studio.c b/src/studio.c
index 456e410..6c41ce3 100644
--- a/src/studio.c
+++ b/src/studio.c
@@ -1452,7 +1452,7 @@ static void setCoverImage()
 
 		if(pixels)
 		{
-			tic->api.blit(tic, pixels, tic->api.scanline);
+			tic->api.blit(tic, pixels, tic->api.scanline, tic->api.overlap);
 
 			u32* buffer = SDL_malloc(TIC80_WIDTH * TIC80_HEIGHT * sizeof(u32));
 
@@ -1932,11 +1932,13 @@ static void blitTexture()
 	SDL_LockTexture(studio.texture, NULL, &pixels, &pitch);
 
 	tic_scanline scanline = NULL;
+	tic_overlap overlap = NULL;
 
 	switch(studio.mode)
 	{
 	case TIC_RUN_MODE:
 		scanline = tic->api.scanline;
+		overlap = tic->api.overlap;
 		break;
 	case TIC_SPRITE_MODE:
 		scanline = studio.sprite.scanline;
@@ -1948,7 +1950,7 @@ static void blitTexture()
 		break;
 	}
 
-	tic->api.blit(tic, pixels, scanline);
+	tic->api.blit(tic, pixels, scanline, overlap);
 
 	recordFrame(pixels);
 
diff --git a/src/tic.c b/src/tic.c
index c66f29d..d57afca 100644
--- a/src/tic.c
+++ b/src/tic.c
@@ -430,6 +430,7 @@ static void api_reset(tic_mem* memory)
 	tic_machine* machine = (tic_machine*)memory;
 	machine->state.initialized = false;
 	machine->state.scanline = NULL;
+	machine->state.overlap = NULL;
 
 	updateSaveid(memory);
 }
@@ -1428,6 +1429,7 @@ static void api_tick(tic_mem* memory, tic_tick_data* data)
 			if(done)
 			{
 				machine->state.scanline = memory->script == tic_script_js ? callJavascriptScanline : callLuaScanline;
+				machine->state.overlap = memory->script == tic_script_js ? callJavascriptOverlap : callLuaOverlap;
 				machine->state.initialized = true;				
 			}
 			else return;
@@ -1447,6 +1449,14 @@ static void api_scanline(tic_mem* memory, s32 row)
 		machine->state.scanline(memory, row);
 }
 
+static void api_overlap(tic_mem* memory)
+{
+	tic_machine* machine = (tic_machine*)memory;
+
+	if(machine->state.initialized)
+		machine->state.overlap(memory);
+}
+
 static double api_time(tic_mem* memory)
 {
 	tic_machine* machine = (tic_machine*)memory;
@@ -1645,7 +1655,7 @@ static u32* paletteBlit(tic_mem* tic)
 	return pal;
 }
 
-static void api_blit(tic_mem* tic, u32* out, tic_scanline scanline)
+static void api_blit(tic_mem* tic, u32* out, tic_scanline scanline, tic_overlap overlap)
 {
 	const u32* pal = paletteBlit(tic);
 
@@ -1721,6 +1731,11 @@ static void api_blit(tic_mem* tic, u32* out, tic_scanline scanline)
 	}
 
 	memset4(&out[(TIC80_FULLHEIGHT-Bottom) * TIC80_FULLWIDTH], pal[tic->ram.vram.vars.border], TIC80_FULLWIDTH*Bottom);
+
+	if(overlap)
+	{
+		overlap(tic);
+	}
 }
 
 static void initApi(tic_api* api)
@@ -1757,6 +1772,7 @@ static void initApi(tic_api* api)
 	INIT_API(time);
 	INIT_API(tick);
 	INIT_API(scanline);
+	INIT_API(overlap);
 	INIT_API(reset);
 	INIT_API(pause);
 	INIT_API(resume);
diff --git a/src/tic80.c b/src/tic80.c
index 11c1799..2f0fde1 100644
--- a/src/tic80.c
+++ b/src/tic80.c
@@ -121,7 +121,7 @@ TIC80_API void tic80_tick(tic80* tic, tic80_input input)
 	tic80->memory->api.tick(tic80->memory, &tic80->tickData);
 	tic80->memory->api.tick_end(tic80->memory);
 
-	tic80->memory->api.blit(tic80->memory, tic->screen, tic80->memory->api.scanline);
+	tic80->memory->api.blit(tic80->memory, tic->screen, tic80->memory->api.scanline, tic80->memory->api.overlap);
 
 	TickCounter++;
 }
diff --git a/src/ticapi.h b/src/ticapi.h
index 674885c..1e98282 100644
--- a/src/ticapi.h
+++ b/src/ticapi.h
@@ -63,6 +63,7 @@ typedef struct
 
 typedef struct tic_mem tic_mem;
 typedef void(*tic_scanline)(tic_mem* memory, s32 row);
+typedef void(*tic_overlap)(tic_mem* memory);
 
 typedef struct
 {
@@ -96,6 +97,7 @@ typedef struct
 	double (*time)				(tic_mem* memory);
 	void (*tick)				(tic_mem* memory, tic_tick_data* data);
 	void (*scanline)			(tic_mem* memory, s32 row);
+	void (*overlap)				(tic_mem* memory);
 	void (*reset)				(tic_mem* memory);
 	void (*pause)				(tic_mem* memory);
 	void (*resume)				(tic_mem* memory);
@@ -107,7 +109,7 @@ typedef struct
 
 	void (*tick_start)			(tic_mem* memory, const tic_sound* src);
 	void (*tick_end)			(tic_mem* memory);
-	void (*blit)				(tic_mem* tic, u32* out, tic_scanline scanline);
+	void (*blit)				(tic_mem* tic, u32* out, tic_scanline scanline, tic_overlap overlap);
 
 	tic_script_lang (*get_script)(tic_mem* memory);
 } tic_api;