From 5a2aa84cec87936a8a84abb55859b6c53fc17169 Mon Sep 17 00:00:00 2001
From: DavidHaywood <28625134+DavidHaywood@users.noreply.github.com>
Date: Thu, 26 Apr 2018 22:43:20 +0100
Subject: [PATCH] rad_eu3a14 - improve rendering for rad_foot by making more
 correct use of sprite registers / bits

---
 src/mame/drivers/rad_eu3a14.cpp | 75 +++++++++++++--------------------
 1 file changed, 29 insertions(+), 46 deletions(-)

diff --git a/src/mame/drivers/rad_eu3a14.cpp b/src/mame/drivers/rad_eu3a14.cpp
index efc1021f979..fecd55fce37 100644
--- a/src/mame/drivers/rad_eu3a14.cpp
+++ b/src/mame/drivers/rad_eu3a14.cpp
@@ -76,6 +76,7 @@ public:
 		m_scrollregs(*this, "scrollregs"),
 		m_tilecfg(*this, "tilecfg"),
 		m_tilebase(*this, "tilebase"),
+		m_spritebase(*this, "spritebase"),
 		m_mainram(*this, "mainram"),
 		m_dmaparams(*this, "dmaparams"),
 		m_bank(*this, "bank"),
@@ -133,6 +134,7 @@ private:
 	required_shared_ptr<uint8_t> m_scrollregs;
 	required_shared_ptr<uint8_t> m_tilecfg;
 	required_shared_ptr<uint8_t> m_tilebase;
+	required_shared_ptr<uint8_t> m_spritebase;
 	required_shared_ptr<uint8_t> m_mainram;
 	required_shared_ptr<uint8_t> m_dmaparams;
 	required_device<address_map_bank_device> m_bank;
@@ -282,7 +284,7 @@ void radica_eu3a14_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitm
 {
 	// first 4 sprite entries seem to be garbage sprites, so we start at 0x20
 	// likely we're just interpreting them wrong and they're used for blanking things or clipping?
-	for (int i = m_spriterambase; i < m_spriterambase+0x7e0; i += 8)
+	for (int i = m_spriterambase; i < m_spriterambase + 0x7e0; i += 8)
 	{
 		/*
 		+0  e--f hhww  flip, enable, height, width
@@ -291,7 +293,7 @@ void radica_eu3a14_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitm
 		+3  pppp ----  palette
 		+4  tttt tttt  tile bits
 		+5  tttt tttt
-		+6  ---- ---- (more tile bits)
+		+6  --TT TPPP  TTT = tile bank PPP = bpp select (+more?)
 		+7  ---- ----
 
 		*/
@@ -338,62 +340,42 @@ void radica_eu3a14_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitm
 		x -= 8;
 		y -= 4;
 
-		//  int base = 0x18000;
 		int offset = ((m_mainram[i + 5] << 8) + (m_mainram[i + 4] << 0));
 		int extra = m_mainram[i + 6];
 		gfx_element *gfx;
 		gfx = m_gfxdecode->gfx(1);
 
-#if 0
-		static int test = 0x0000;
-		if (machine().input().code_pressed_once(KEYCODE_W))
-		{
-			test += 0x2000;
-			popmessage("%02x", test);
-		}
-		if (machine().input().code_pressed_once(KEYCODE_Q))
-		{
-			test -= 0x2000;
-			popmessage("%02x", test);
-		}
-#endif
+		int spritebase = (m_spritebase[1] << 8) | m_spritebase[0];
 
-		// this probably comes from somewhere else, base register
-		offset += 0x8000;
+		offset += (extra & 0xf8) << 13;
+		extra &= ~0xf8;
+		offset += spritebase << 7;
 
-		// these additions are odd, because 0x8000 should already be coming
-		// from the tile bits above
-
-		// 2bpp modes, always have bit --- --x- set?
-		if (extra == 0x02)
+		switch (extra & 0x07)
 		{
+		case 0x00: // 8bpp
+		case 0x07: // 8bpp
+			offset >>= 1;
+			gfx = m_gfxdecode->gfx(2);
+			break;
+
+		case 0x02: // 2bpp
 			offset <<= 1;
 			gfx = m_gfxdecode->gfx(0);
 			pal = 0;
+			break;
+
+		case 0x04: // 4bpp
+			break;
+
+		case 0x01: // unknowns
+		case 0x03:
+		case 0x05:
+		case 0x06:
+			pal = machine().rand();
+			break;
 		}
 
-		if (extra == 0x0a) // bits ---- x-x-
-		{
-			offset += 0x10000;
-			offset <<= 1;
-			gfx = m_gfxdecode->gfx(0);
-			pal = 0;
-		}
-
-		// 4bpp modes, always have bit --- -x-- set?
-
-		if (extra == 0x04) // bits ---- -x--
-		{
-			//
-		}
-
-		if (extra == 0x0c) // bits ---- xx--
-			offset += 0x10000;
-
-		if (extra == 0x14) // bits ---x -x--
-			offset += 0x20000;
-
-
 		offset = offset >> 1;
 
 		if (attr & 0x80)
@@ -551,7 +533,8 @@ void radica_eu3a14_state::radica_eu3a14_map(address_map &map)
 	map(0x5116, 0x5117).ram();
 	map(0x5121, 0x5124).ram().share("scrollregs");
 	map(0x5150, 0x5150).ram(); // startup
-	map(0x5151, 0x5153).ram(); // startup
+	map(0x5151, 0x5152).ram().share("spritebase");
+	map(0x5153, 0x5153).ram(); // startup
 
 	map(0x6000, 0xdfff).m(m_bank, FUNC(address_map_bank_device::amap8));