From 9903683f5702cd56c0a098bc222f6e01c4e4bb38 Mon Sep 17 00:00:00 2001
From: angelosa <lordkale4@gmail.com>
Date: Sun, 15 Sep 2024 17:27:28 +0200
Subject: funtech/supracan.cpp: add overscan mode

---
 hash/supracan.xml             |  8 ++++----
 src/mame/funtech/supracan.cpp | 14 +++++++++++---
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/hash/supracan.xml b/hash/supracan.xml
index 433d1c7944a..93672bda29f 100644
--- a/hash/supracan.xml
+++ b/hash/supracan.xml
@@ -83,7 +83,7 @@ Broken [video] during intro, uses bitmap mode with ROZ layer
 		</part>
 	</software>
 
-    <!-- NOTE: supported=no for broken sound -->
+	<!-- NOTE: supported=no for broken sound -->
 	<software name="staiwbbl" supported="no">
 		<description>Super Taiwanese Baseball League ~ Chao Ji Zhong Hua Zhi Bang Lian Meng</description>
 		<year>1995</year>
@@ -192,9 +192,9 @@ few [video] missing/glitched tiles in gameplay, likely related to above.
 		<notes><![CDATA[
 Erratic gameplay speed, controls [irq 3] as FRC
 [sound] BGM plays random tune on title (verify, two video refs plays different BGMs there wtf?)
-[video] use layer 1 as clipping effect (sprites goes under it)
-[video] character select has misaligned sprites
-[video] billiard cue sprite cut off left side (should wraparound)
+[video] title screen doesn't cliprect properly against white
+[video] title screen has priority issues with overlapping overlays (layer 1 + ROZ)
+[video] garbage sprites in 1p vs. com gameplay, [DMA]s with invalid dest pointers.
 [sound] main menu selection channel 14 keeps repeating (1f 15 0b dd)
 ]]></notes>
 		<info name="serial" value="F010" />
diff --git a/src/mame/funtech/supracan.cpp b/src/mame/funtech/supracan.cpp
index 0090357d112..14142b4e257 100644
--- a/src/mame/funtech/supracan.cpp
+++ b/src/mame/funtech/supracan.cpp
@@ -2060,16 +2060,24 @@ void supracan_state::video_w(offs_t offset, uint16_t data, uint16_t mem_mask)
 		{
 			LOGMASKED(LOG_VIDEO, "video_flags = %04x\n", data);
 
-			const int h320_mode = BIT(data, 8);
+			if (data & 0xc00)
+				popmessage("Interlace enable %04x", data & 0xc00);
 
 			// TODO: verify if this support midframe switching
-			if (h320_mode != BIT(m_video_flags, 8))
+			if ((data & 0x300) != (m_video_flags & 0x300))
 			{
 				rectangle visarea = m_screen->visible_area();
+				const int h320_mode = BIT(data, 8);
+				// enabled by sangofgt (224 + 16 borders), magipool wants (240)
+				const int overscan_mode = BIT(data, 9);
+
 				const int htotal = h320_mode ? 455 : 342;
 				const int divider = h320_mode ? 8 : 10;
 
-				visarea.set(0, (h320_mode ? 320 : 256) - 1, 8, 232 - 1);
+				const int vdisplay_start = overscan_mode ? 8 : 0;
+				const int vdisplay_end = overscan_mode ? 232 : 240;
+
+				visarea.set(0, (h320_mode ? 320 : 256) - 1, vdisplay_start, vdisplay_end - 1);
 				m_screen->configure(htotal, 262, visarea, attotime::from_ticks(htotal * 262, U13_CLOCK / divider).as_attoseconds());
 				//m_screen->reset_origin(0, 0);
 			}
-- 
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