From 8e0a5e6cb4f9a7ecc90d1cef192cd1dfbb612ade Mon Sep 17 00:00:00 2001
From: dinkc64 <12570148+dinkc64@users.noreply.github.com>
Date: Mon, 5 May 2014 06:52:59 +0000
Subject: [PATCH] Fix for the graphical glitches on the volcano level in
 Caveman Ninja

---
 src/burn/drv/dataeast/d_cninja.cpp | 3 +++
 src/burn/drv/dataeast/deco16ic.cpp | 7 ++++++-
 src/burn/drv/dataeast/deco16ic.h   | 1 +
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/burn/drv/dataeast/d_cninja.cpp b/src/burn/drv/dataeast/d_cninja.cpp
index f2de8c61b..6cf182a60 100644
--- a/src/burn/drv/dataeast/d_cninja.cpp
+++ b/src/burn/drv/dataeast/d_cninja.cpp
@@ -1185,6 +1185,8 @@ static INT32 CninjaInit()
 	deco16SoundInit(DrvHucROM, DrvHucRAM, 8055000, 1, DrvYM2151WritePort, 0.45, 1006875, 0.75, 2013750, 0.60);
 	BurnYM2203SetAllRoutes(0, 0.60, BURN_SND_ROUTE_BOTH);
 
+	deco16ic_cninja_scrolly = 1;
+
 	GenericTilesInit();
 
 	DrvDoReset();
@@ -1751,6 +1753,7 @@ static INT32 DrvExit()
 	BurnFree (AllMem);
 
 	MSM6295ROM = NULL;
+	deco16ic_cninja_scrolly = 0;
 
 	return 0;
 }
diff --git a/src/burn/drv/dataeast/deco16ic.cpp b/src/burn/drv/dataeast/deco16ic.cpp
index ed1339470..9dcb243b7 100644
--- a/src/burn/drv/dataeast/deco16ic.cpp
+++ b/src/burn/drv/dataeast/deco16ic.cpp
@@ -53,6 +53,7 @@ UINT8 *deco16_prio_map;
 UINT8 *deco16_sprite_prio_map; // boogwing
 
 INT32 deco16_vblank;
+UINT16 deco16ic_cninja_scrolly = 0; // use different indexing of scroll_y for Caveman Ninja
 
 void deco16ProtScan();
 void deco16ProtReset();
@@ -270,7 +271,11 @@ void deco16_draw_layer(INT32 tmap, UINT16 *dest, INT32 flags)
 
 		for (INT32 x = 0; x < nScreenWidth + size; x+=size)
 		{
-			INT32 yoff = deco16_scroll_y[tmap][x] & hmask;
+			INT32 yoff;
+			if (deco16ic_cninja_scrolly)
+				yoff = deco16_scroll_y[tmap][x + deco16_scroll_x[tmap][y]] & hmask;
+			else
+				yoff = deco16_scroll_y[tmap][x] & hmask;
 
 			INT32 yy = (y + yoff) & hmask;
 			INT32 xx = (x + xoff) & wmask;
diff --git a/src/burn/drv/dataeast/deco16ic.h b/src/burn/drv/dataeast/deco16ic.h
index af86b3108..a33dc23dd 100644
--- a/src/burn/drv/dataeast/deco16ic.h
+++ b/src/burn/drv/dataeast/deco16ic.h
@@ -6,6 +6,7 @@ extern UINT8 *deco16_pf_ram[4];
 extern UINT8 *deco16_pf_rowscroll[4];
 
 extern UINT16 deco16_priority;
+extern UINT16 deco16ic_cninja_scrolly; // use different indexing of scroll_y for Caveman Ninja
 
 void deco16_set_bank_callback(INT32 tmap, INT32 (*callback)(const INT32 bank));
 void deco16_set_color_base(INT32 tmap, INT32 base);