Radica 6502: some hacks to improve the video, (#3074)

* Radica 6502: some hacks to improve the video, lack of test cases / makes these tricky to figure out properly

* at least these aren't *my* bugs.. (nw)

src/mame/drivers/radicasi.cpp

@@ -128,6 +128,7 @@
 
 
 	Flaws (NOT emulation bugs, happen on hardware):
+	--
 
 	In QIX the sprites lag behind the line drawing, so you see the line infront of your player until you stop moving
 	
@@ -137,6 +138,19 @@
 
 	Colony 7 has a typo in the instructions
 
+	The fake 'colour band' effect does not apply to the thruster (and several other elements) in Lunar Rescue
+
+	Enemies in Phoenix are rendered above the score panel
+
+	The 200pt right facing bird on the Phoenix score table is corrupt
+
+	Uncertain (to check)
+
+	Space Invaders seems to be using a darker than expected palette, there are lighter colours in the palette but
+	they don't seem to be used.  It's difficult to judge from hardware videos, although it definitely isn't as
+	white as the menu, so this might also be a non-bug.
+
+
 */
 
 #include "emu.h"
@@ -306,6 +320,8 @@ private:
 	void handle_sound_1_w(int which, int offset, uint8_t data);
 	uint8_t handle_sound_1_r(int which, int offset);
 
+	bool get_tile_data(int base, int drawpri, int& tile, int &attr, int &unk2);
+	void draw_tilemaps(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect, int drawpri);
 	void draw_sprites(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
 };
 
@@ -325,14 +341,15 @@ void radica_6502_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitmap
 
 	/*
 		Sprites
-		AA yy xx ?? XX YY aa bb
+		AA yy xx cc XX YY aa bb
 
 		yy = y position
 		xx = x position
 		XX = texture x start
 		YY = texture y start
-		aa = same as final param on tiles?
+		aa = same as unk2 on tiles
 		bb = sometimes set in invaders
+		cc = same as attr on tiles (colour / priority?)
 
 		AA = attributes
 		e--- fFsS
@@ -349,23 +366,60 @@ void radica_6502_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitmap
 		uint8_t x = m_spriteram[i + 2];
 		uint8_t y = m_spriteram[i + 1];
 
+		/*
+		   Space Invaders draws the player base with this specific y value before the start of each life
+		   and expects it to NOT wrap around.  There are no high priority tiles or anything else to hide
+		   and it doesn't appear on real hardware.
+
+		   it's possible sprites don't wrap around at all (but then you couldn't have smooth entry at the
+		   top of the screen - there are no extra y co-ordinate bits.  However there would have been easier
+		   ways to hide this tho as there are a bunch of unseen lines at the bottom of the screen anyway!
+
+		   needs further investigation.
+		*/
+		if (y==255)
+			continue;
+
 		uint8_t tex_x = m_spriteram[i + 4];
 		uint8_t tex_y = m_spriteram[i + 5];
 
-		uint8_t attrs = m_spriteram[i + 0];
+		uint8_t flags = m_spriteram[i + 0];
+		uint8_t attr = m_spriteram[i + 3];
+		uint8_t unk2 = m_spriteram[i + 6];
 
-		if (!(attrs & 0x80))
+
+		//int priority = attr & 0x0f;
+		int colour = attr & 0xf0;
+
+		// ? game select has this set to 0xff, but clearly doesn't want the palette to change!
+		// while in Space Invaders this has to be palette for the UFO to be red.
+		if (colour & 0x80)
+			colour = 0;
+
+		int transpen = 0;
+
+		 /* HACK - how is this calculated
+		   phoenix and the game select need it like this
+		   it isn't a simple case of unk2 being transpen either because Qix has some elements set to 0x07
+		   where the transpen needs to be 0x00 and Space Invaders has it set to 0x04
+		   it could be a global register rather than something in the spritelist?
+		*/
+		if ((attr == 0xff) && (unk2 == 0xff))
+			transpen = 0xff;
+
+
+		if (!(flags & 0x80))
 			continue;
 
 		int sizex = 8;
 		int sizey = 8;
 
-		if (attrs & 0x01)
+		if (flags & 0x01)
 		{
 			sizex = 16;
 		}
 
-		if (attrs & 0x02)
+		if (flags & 0x02)
 		{
 			sizey = 16;
 		}
@@ -375,8 +429,8 @@ void radica_6502_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitmap
 		for (int yy = 0; yy < sizey; yy++)
 		{
 			uint16_t* row;
-				
+
-			if (attrs & 0x08) // guess flipy
+			if (flags & 0x08) // guess flipy
 			{
 				row = &bitmap.pix16((y + (sizey - 1 - yy)) & 0xff);
 			}
@@ -387,20 +441,20 @@ void radica_6502_state::draw_sprites(screen_device &screen, bitmap_ind16 &bitmap
 
 			for (int xx = 0; xx < sizex; xx++)
 			{
-				int realaddr = base + ((tex_x+xx)&0xff);
+				int realaddr = base + ((tex_x + xx) & 0xff);
-				realaddr += ((tex_y+yy)&0xff) * 256;
+				realaddr += ((tex_y + yy) & 0xff) * 256;
 
 				uint8_t pix = fullbankspace.read_byte(realaddr);
 
-				if (pix)
+				if (pix != transpen)
 				{
-					if (attrs & 0x04) // flipx
+					if (flags & 0x04) // flipx
 					{
-						row[(x + (sizex - 1 - xx)) & 0xff] = pix;// + attr;
+						row[(x + (sizex - 1 - xx)) & 0xff] = (pix + ((colour & 0x70) << 1)) & 0xff;
 					}
 					else
 					{
-						row[(x + xx) & 0xff] = pix;// + attr;
+						row[(x + xx) & 0xff] = (pix + ((colour & 0x70) << 1)) & 0xff;
 					}
 				}
 			}
@@ -418,6 +472,160 @@ double hue2rgb(double p, double q, double t)
 	return p;
 }
 
+// a hacky mess for now
+bool radica_6502_state::get_tile_data(int base, int drawpri, int& tile, int &attr, int &unk2)
+{
+	tile = m_vram[base * 4] + (m_vram[(base * 4) + 1] << 8);
+	
+	// these seem to be the basically the same as attr/unk2 in the sprites, which also make
+	// very little sense.
+	attr = m_vram[(base * 4) + 2];
+	unk2 = m_vram[(base * 4) + 3];
+
+	/* hack for phoenix title screens.. the have attr set to 0x3f which change the colour bank in ways we don't want
+	   and also by our interpretation of 0x0f bits sets the tiles to priority over sprites (although in this case
+	   that might tbe ok, because it looks like the sprites also have that set */
+	if (unk2 == 0x07)
+		attr = 0;
+
+	int priority = attr & 0x0f;
+
+	// likely wrong
+	if ((drawpri == 0 && priority == 0x0f) || (drawpri == 1 && priority != 0x0f))
+		return false;
+
+	return true;
+}
+void radica_6502_state::draw_tilemaps(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect, int drawpri)
+{
+	/* this doesn't handle 8x8 4bpp, haven't seen it used
+	   nor is there support for horizontal scrolling etc.
+	   for the same reasons
+	*/
+
+	int scroll = (m_bg_scroll[1] << 8) | m_bg_scroll[0];
+	address_space& fullbankspace = m_bank->space(AS_PROGRAM);
+
+	if (m_5027_data & 0x40) // 16x16 tiles
+	{
+		int startrow = (scroll >> 4) & 0x1f;
+
+		for (int y = 0; y < 16; y++)
+		{
+			for (int x = 0; x < 16; x++)
+			{
+				int realstartrow = (startrow + y);
+
+				if (realstartrow >= 28)
+					realstartrow -= 28;
+
+				int base = (((realstartrow + y) & 0x1f) * 8) + x;
+				
+				int tile,attr,unk2;
+
+				if (!get_tile_data(base, drawpri, tile,attr,unk2))
+					continue;
+
+				int colour = attr & 0xf0;
+		
+				if (m_5027_data & 0x20) // 4bpp mode
+				{
+					tile = (tile & 0xf) + ((tile & ~0xf) * 16);
+					tile += ((m_tile_gfxbase_lo_data | m_tile_gfxbase_hi_data << 8) << 5);
+				}
+				else
+				{
+					tile = (tile & 0xf) + ((tile & ~0xf) * 16);
+					tile <<= 1;
+
+					tile += ((m_tile_gfxbase_lo_data | m_tile_gfxbase_hi_data << 8) << 5);
+				}
+
+				for (int i = 0; i < 16; i++)
+				{
+					int drawline = (y * 16) + i;
+					drawline -= scroll & 0xf;
+
+					if ((drawline >= 0) && (drawline < 256))
+					{
+						uint16_t* row = &bitmap.pix16(drawline);
+
+						if (m_5027_data & 0x20) // 4bpp
+						{
+							for (int xx = 0; xx < 16; xx += 2)
+							{
+								int realaddr = ((tile + i * 16) << 3) + (xx >> 1);
+								uint8_t pix = fullbankspace.read_byte(realaddr);
+								row[x * 16 + xx + 0] = ((pix & 0xf0) >> 4) + colour;
+								row[x * 16 + xx + 1] = ((pix & 0x0f) >> 0) + colour;
+							}
+						}
+						else // 8bpp
+						{
+							for (int xx = 0; xx < 16; xx++)
+							{
+								int realaddr = ((tile + i * 32) << 3) + xx;
+								uint8_t pix = fullbankspace.read_byte(realaddr);
+								row[x * 16 + xx] = (pix + ((colour & 0x70) << 1)) & 0xff;
+							}
+						}
+
+					}
+				}
+			}
+		}
+	}
+	else // 8x8 tiles
+	{
+		// Phoenix scrolling actually skips a pixel, jumping from 0x001 to 0x1bf, scroll 0x000 isn't used, maybe it has other meanings?
+
+		int startrow = (scroll >> 3) & 0x3f;
+
+		for (int y = 0; y < 32; y++)
+		{
+			for (int x = 0; x < 32; x++)
+			{
+				int realstartrow = (startrow + y);
+
+				if (realstartrow >= 56)
+					realstartrow -= 56;
+
+				int base = (((realstartrow) & 0x3f) * 32) + x;
+				
+				int tile,attr,unk2;
+
+				if (!get_tile_data(base, drawpri, tile,attr,unk2))
+					continue;
+
+				int colour = attr & 0xf0;
+
+				tile = (tile & 0x1f) + ((tile & ~0x1f) * 8);
+				tile += ((m_tile_gfxbase_lo_data | m_tile_gfxbase_hi_data << 8) << 5);
+
+				for (int i = 0; i < 8; i++)
+				{
+					int drawline = (y * 8) + i;
+					drawline -= scroll & 0x7;
+
+					if ((drawline >= 0) && (drawline < 256))
+					{
+						uint16_t* row = &bitmap.pix16(drawline);
+
+						for (int xx = 0; xx < 8; xx++)
+						{
+							int realaddr = ((tile + i * 32) << 3) + xx;
+							uint8_t pix = fullbankspace.read_byte(realaddr);
+							row[x * 8 + xx] = (pix + ((colour & 0x70) << 1)) & 0xff;
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+
+
 uint32_t radica_6502_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
 {
 	bitmap.fill(0, cliprect);
@@ -457,119 +665,10 @@ uint32_t radica_6502_state::screen_update(screen_device &screen, bitmap_ind16 &b
 		m_palette->set_pen_color(index, r_real, g_real, b_real);
 	}	
 
-	// Tilemaps
-
-	int scroll = (m_bg_scroll[1] << 8) | m_bg_scroll[0];
-	address_space& fullbankspace = m_bank->space(AS_PROGRAM);
-
-	if (m_5027_data & 0x40) // 16x16 tiles
-	{
-		int startrow = (scroll >> 4) & 0x1f;
-
-		for (int y = 0; y < 16; y++)
-		{
-			for (int x = 0; x < 16; x++)
-			{
-				int realstartrow = (startrow + y);
-
-				if (realstartrow >= 28)
-					realstartrow -= 28;
-
-				int base = (((realstartrow + y)&0x1f)*8)+x;
-				int tile = m_vram[base * 4] + (m_vram[(base * 4)+1] << 8);
-				int attr = m_vram[(base * 4)+ 2];
-
-				if (m_5027_data & 0x20) // 4bpp mode
-				{
-					tile = (tile & 0xf) + ((tile & ~0xf) * 16);
-					tile += ((m_tile_gfxbase_lo_data | m_tile_gfxbase_hi_data << 8) << 5);
-				}
-				else
-				{
-					tile = (tile & 0xf) + ((tile & ~0xf) * 16);
-					tile <<= 1;
-
-					tile += ((m_tile_gfxbase_lo_data | m_tile_gfxbase_hi_data << 8) << 5);
-				}
-
-				for (int i = 0; i < 16; i++)
-				{
-					int drawline = (y * 16) + i;
-					drawline -= scroll & 0xf;
-
-					if ((drawline >= 0) && (drawline < 256))
-					{
-						uint16_t* row = &bitmap.pix16(drawline);
-
-						if (m_5027_data & 0x20) // 4bpp
-						{
-							for (int xx = 0; xx < 16; xx += 2)
-							{
-								int realaddr = ((tile + i * 16) << 3) + (xx >> 1);
-								uint8_t pix = fullbankspace.read_byte(realaddr);
-								row[x * 16 + xx + 0] = ((pix & 0xf0) >> 4) + attr;
-								row[x * 16 + xx + 1] = ((pix & 0x0f) >> 0) + attr;
-							}
-						}
-						else // 8bpp
-						{
-							for (int xx = 0; xx < 16; xx++)
-							{
-								int realaddr = ((tile + i * 32) << 3) + xx;
-								uint8_t pix = fullbankspace.read_byte(realaddr);
-								row[x * 16 + xx] = pix;// + attr;
-							}
-						}
-
-					}
-				}
-			}
-		}
-	}
-	else // 8x8 tiles
-	{
-		// Phoenix scrolling actually skips a pixel, jumping from 0x001 to 0x1bf, scroll 0x000 isn't used, maybe it has other meanings?
-
-		int startrow = (scroll >> 3) & 0x3f;
-
-		for (int y = 0; y < 32; y++)
-		{
-			for (int x = 0; x < 32; x++)
-			{
-				int realstartrow = (startrow + y);
-
-				if (realstartrow >= 56)
-					realstartrow -= 56;
-
-				int base = (((realstartrow)&0x3f)*32)+x;
-				int tile = m_vram[base * 4] + (m_vram[(base * 4)+1] << 8);
-				//int attr = m_vram[(base * 4)+ 2];
-
-				tile = (tile & 0x1f) + ((tile & ~0x1f) * 8);
-				tile += ((m_tile_gfxbase_lo_data | m_tile_gfxbase_hi_data << 8) << 5);
-
-				for (int i = 0; i < 8; i++)
-				{
-					int drawline = (y * 8) + i;
-					drawline -= scroll & 0x7;
-					
-					if ((drawline >= 0) && (drawline < 256))
-					{
-						uint16_t* row = &bitmap.pix16(drawline);
-
-						for (int xx = 0; xx < 8; xx++)
-						{
-							int realaddr = ((tile + i * 32) << 3) + xx;
-							uint8_t pix = fullbankspace.read_byte(realaddr);
-							row[x * 8 + xx] = pix;// + attr;
-						}
-					}
-				}
-			}
-		}
-	}
 
+	draw_tilemaps(screen,bitmap,cliprect,0);
 	draw_sprites(screen,bitmap,cliprect);
+	draw_tilemaps(screen,bitmap,cliprect,1);
 
 	return 0;
 }
@@ -1327,7 +1426,7 @@ static MACHINE_CONFIG_START( radicasi )
 	MCFG_SCREEN_VISIBLE_AREA(0*8, 32*8-1, 0*8, 28*8-1)
 	MCFG_SCREEN_PALETTE("palette")
 
-	MCFG_PALETTE_ADD("palette", 1024)
+	MCFG_PALETTE_ADD("palette", 256)
 
 	MCFG_GFXDECODE_ADD("gfxdecode", "palette", radicasi_fake)