mame/video/snk.cpp

// license:BSD-3-Clause
// copyright-holders:Ernesto Corvi,Tim Lindquist,Carlos A. Lozano,Bryan McPhail,Jarek Parchanski,Nicola Salmoria,Tomasz Slanina,Phil Stroffolino,Acho A. Tang,Victor Trucco
// thanks-to:Marco Cassili
#include "emu.h"
#include "includes/snk.h"

/*******************************************************************************
 Shadow Handling Notes
********************************************************************************
 Shadows are handled by changing palette bank.

 Games Not Using Shadows

 those using gwar_vh_screenrefresh (gwar, bermudat, psychos, chopper1)
    (0-15 , 15 is transparent)

 Games Using Shadows

 those using tnk3_vh_screenrefresh (tnk3, athena, fitegolf) sgladiat is similar
    (0-7  , 6  is shadow, 7  is transparent) * these are using aso colour prom convert *
 those using ikari_vh_screenrefresh (ikari, victroad)
    (0-7  , 6  is shadow, 7  is transparent)
 those using tdfever_vh_screenrefresh (tdfever, fsoccer)
    (0-15 , 14 is shadow, 15 is transparent)

*******************************************************************************/


/**************************************************************************************/

void snk_state::tnk3_palette(palette_device &palette) const
{
	uint8_t const *const color_prom = memregion("proms")->base();
	constexpr int num_colors = 0x400;

	for (int i = 0; i < num_colors; i++)
	{
		int bit0, bit1, bit2, bit3;

		bit0 = BIT(color_prom[i + 2*num_colors], 3);
		bit1 = BIT(color_prom[i], 1);
		bit2 = BIT(color_prom[i], 2);
		bit3 = BIT(color_prom[i], 3);
		int const r = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;

		bit0 = BIT(color_prom[i + 2*num_colors], 2);
		bit1 = BIT(color_prom[i + num_colors], 2);
		bit2 = BIT(color_prom[i + num_colors], 3);
		bit3 = BIT(color_prom[i], 0);
		int const g = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;

		bit0 = BIT(color_prom[i + 2*num_colors], 0);
		bit1 = BIT(color_prom[i + 2*num_colors], 1);
		bit2 = BIT(color_prom[i + num_colors], 0);
		bit3 = BIT(color_prom[i + num_colors], 1);
		int const b = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;

		palette.set_pen_color(i, rgb_t(r, g, b));
	}
}

/**************************************************************************************/

TILEMAP_MAPPER_MEMBER(snk_state::marvins_tx_scan_cols)
{
	// tilemap is 36x28, the central part is from the first RAM page and the
	// extra 4 columns are from the second page
	col -= 2;
	if (col & 0x20)
		return 0x400 + row + ((col & 0x1f) << 5);
	else
		return row + (col << 5);
}

TILE_GET_INFO_MEMBER(snk_state::marvins_get_tx_tile_info)
{
	int code = m_tx_videoram[tile_index];
	int color = code >> 5;

	tileinfo.set(0,
			m_tx_tile_offset + code,
			color,
			tile_index & 0x400 ? TILE_FORCE_LAYER0 : 0);
}

TILE_GET_INFO_MEMBER(snk_state::ikari_get_tx_tile_info)
{
	int code = m_tx_videoram[tile_index];

	tileinfo.set(0,
			m_tx_tile_offset + code,
			0,
			tile_index & 0x400 ? TILE_FORCE_LAYER0 : 0);
}

TILE_GET_INFO_MEMBER(snk_state::gwar_get_tx_tile_info)
{
	int code = m_tx_videoram[tile_index];

	tileinfo.set(0,
			m_tx_tile_offset + code,
			0,
			0);
}


TILE_GET_INFO_MEMBER(snk_state::marvins_get_fg_tile_info)
{
	int code = m_fg_videoram[tile_index];

	tileinfo.set(1,
			code,
			0,
			0);
}

TILE_GET_INFO_MEMBER(snk_state::marvins_get_bg_tile_info)
{
	int code = m_bg_videoram[tile_index];

	tileinfo.set(2,
			code,
			0,
			0);
}


TILE_GET_INFO_MEMBER(snk_state::aso_get_bg_tile_info)
{
	int code = m_bg_videoram[tile_index];

	tileinfo.set(1,
			m_bg_tile_offset + code,
			0,
			0);
}

TILE_GET_INFO_MEMBER(snk_state::tnk3_get_bg_tile_info)
{
	int attr = m_bg_videoram[2*tile_index+1];
	int code = m_bg_videoram[2*tile_index] | ((attr & 0x30) << 4);
	int color = (attr & 0xf) ^ 8;

	tileinfo.set(1,
			code,
			color,
			0);
}

TILE_GET_INFO_MEMBER(snk_state::ikari_get_bg_tile_info)
{
	int attr = m_bg_videoram[2*tile_index+1];
	int code = m_bg_videoram[2*tile_index] | ((attr & 0x03) << 8);
	int color = (attr & 0x70) >> 4;

	tileinfo.set(1,
			code,
			color,
			0);
}

TILE_GET_INFO_MEMBER(snk_state::gwar_get_bg_tile_info)
{
	int attr = m_bg_videoram[2*tile_index+1];
	int code = m_bg_videoram[2*tile_index] | ((attr & 0x0f) << 8);
	int color = (attr & 0xf0) >> 4;

	if (m_is_psychos)   // psychos has a separate palette bank bit
		color &= 7;

	tileinfo.set(1,
			code,
			color,
			0);

	// bermudat, tdfever use FFFF to blank the background.
	// (still call tileinfo.set, otherwise problems might occur on boot when
	// the tile data hasn't been initialised)
	if (code >= m_gfxdecode->gfx(1)->elements())
		tileinfo.pen_data = m_empty_tile;
}


/**************************************************************************************/

VIDEO_START_MEMBER(snk_state,snk_3bpp_shadow)
{
	int i;

	if(!(m_palette->shadows_enabled()))
		fatalerror("driver should use VIDEO_HAS_SHADOWS\n");

	/* prepare shadow draw table */
	for(i = 0; i <= 5; i++) m_drawmode_table[i] = DRAWMODE_SOURCE;
	m_drawmode_table[6] = (m_palette->shadows_enabled()) ? DRAWMODE_SHADOW : DRAWMODE_SOURCE;
	m_drawmode_table[7] = DRAWMODE_NONE;

	for (i = 0x000;i < 0x400;i++)
		m_palette->shadow_table()[i] = i | 0x200;
}

VIDEO_START_MEMBER(snk_state,snk_4bpp_shadow)
{
	int i;

	if(!(m_palette->shadows_enabled()))
		fatalerror("driver should use VIDEO_HAS_SHADOWS\n");

	/* prepare shadow draw table */
	for(i = 0; i <= 13; i++) m_drawmode_table[i] = DRAWMODE_SOURCE;
	m_drawmode_table[14] = DRAWMODE_SHADOW;
	m_drawmode_table[15] = DRAWMODE_NONE;

	/* all palette entries are not affected by shadow sprites... */
	for (i = 0x000;i < 0x400;i++)
		m_palette->shadow_table()[i] = i;
	/* ... except for tilemap colors */
	for (i = 0x200;i < 0x300;i++)
		m_palette->shadow_table()[i] = i + 0x100;
}


VIDEO_START_MEMBER(snk_state,marvins)
{
	VIDEO_START_CALL_MEMBER(snk_3bpp_shadow);

	m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::marvins_get_tx_tile_info)), tilemap_mapper_delegate(*this, FUNC(snk_state::marvins_tx_scan_cols)), 8, 8, 36, 28);
	m_fg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::marvins_get_fg_tile_info)), TILEMAP_SCAN_COLS, 8, 8, 64, 32);
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::marvins_get_bg_tile_info)), TILEMAP_SCAN_COLS, 8, 8, 64, 32);

	m_tx_tilemap->set_transparent_pen(15);
	m_tx_tilemap->set_scrolldy(8, 8);

	m_fg_tilemap->set_transparent_pen(15);
	m_fg_tilemap->set_scrolldx(15,  31);
	m_fg_tilemap->set_scrolldy(8, -32);

	m_bg_tilemap->set_scrolldx(15,  31);
	m_bg_tilemap->set_scrolldy(8, -32);

	m_tx_tile_offset = 0;
}

VIDEO_START_MEMBER(snk_state,jcross)
{
	VIDEO_START_CALL_MEMBER(snk_3bpp_shadow);

	m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::marvins_get_tx_tile_info)), tilemap_mapper_delegate(*this, FUNC(snk_state::marvins_tx_scan_cols)), 8, 8, 36, 28);
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::aso_get_bg_tile_info)),     TILEMAP_SCAN_COLS, 8, 8, 64, 64);

	m_tx_tilemap->set_transparent_pen(15);
	m_tx_tilemap->set_scrolldy(8, 8);

	m_bg_tilemap->set_scrolldx(15, 24);
	m_bg_tilemap->set_scrolldy(8, -32);

	m_num_sprites = 25;
	m_yscroll_mask = 0x1ff;
	m_bg_tile_offset = 0;
	m_tx_tile_offset = 0;
}

VIDEO_START_MEMBER(snk_state,sgladiat)
{
	VIDEO_START_CALL_MEMBER(snk_3bpp_shadow);

	m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::marvins_get_tx_tile_info)), tilemap_mapper_delegate(*this, FUNC(snk_state::marvins_tx_scan_cols)), 8, 8, 36, 28);
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::aso_get_bg_tile_info)),     TILEMAP_SCAN_COLS, 8, 8, 64, 32);

	m_tx_tilemap->set_transparent_pen(15);
	m_tx_tilemap->set_scrolldy(8, 8);

	m_bg_tilemap->set_scrolldx(15, 24);
	m_bg_tilemap->set_scrolldy(8, -32);

	m_num_sprites = 25;
	m_yscroll_mask = 0x0ff;
	m_bg_tile_offset = 0;
	m_tx_tile_offset = 0;
}

VIDEO_START_MEMBER(snk_state,hal21)
{
	VIDEO_START_CALL_MEMBER(jcross);

	m_bg_tilemap->set_scrolldy(8, -32+256);

	m_num_sprites = 50;
	m_yscroll_mask = 0x1ff;
}

VIDEO_START_MEMBER(snk_state,aso)
{
	VIDEO_START_CALL_MEMBER(jcross);

	m_bg_tilemap->set_scrolldx(15+256, 24+256);

	m_num_sprites = 50;
	m_yscroll_mask = 0x1ff;
}


VIDEO_START_MEMBER(snk_state,tnk3)
{
	VIDEO_START_CALL_MEMBER(snk_3bpp_shadow);

	m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::marvins_get_tx_tile_info)), tilemap_mapper_delegate(*this, FUNC(snk_state::marvins_tx_scan_cols)), 8, 8, 36, 28);
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::tnk3_get_bg_tile_info)),    TILEMAP_SCAN_COLS, 8, 8, 64, 64);

	m_tx_tilemap->set_transparent_pen(15);
	m_tx_tilemap->set_scrolldy(8, 8);

	m_bg_tilemap->set_scrolldx(15, 24);
	m_bg_tilemap->set_scrolldy(8, -32);

	m_num_sprites = 50;
	m_yscroll_mask = 0x1ff;
	m_tx_tile_offset = 0;
}

VIDEO_START_MEMBER(snk_state,ikari)
{
	VIDEO_START_CALL_MEMBER(snk_3bpp_shadow);

	m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::ikari_get_tx_tile_info)), tilemap_mapper_delegate(*this, FUNC(snk_state::marvins_tx_scan_cols)), 8, 8, 36, 28);
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::ikari_get_bg_tile_info)), TILEMAP_SCAN_COLS, 16, 16, 32, 32);

	m_tx_tilemap->set_transparent_pen(15);
	m_tx_tilemap->set_scrolldy(8, 8);

	m_bg_tilemap->set_scrolldx(15, 24);
	m_bg_tilemap->set_scrolldy(8, -32);

	m_tx_tile_offset = 0;
}

VIDEO_START_MEMBER(snk_state,gwar)
{
	int i;

	/* prepare drawmode table */
	for(i = 0; i <= 14; i++) m_drawmode_table[i] = DRAWMODE_SOURCE;
	m_drawmode_table[15] = DRAWMODE_NONE;

	memset(m_empty_tile, 0xf, sizeof(m_empty_tile));

	m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::gwar_get_tx_tile_info)), TILEMAP_SCAN_COLS,  8,  8, 50, 32);
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(snk_state::gwar_get_bg_tile_info)), TILEMAP_SCAN_COLS, 16, 16, 32, 32);

	m_tx_tilemap->set_transparent_pen(15);

	m_bg_tilemap->set_scrolldx(16, 143);
	m_bg_tilemap->set_scrolldy(0, -32);

	m_tx_tile_offset = 0;

	m_is_psychos = 0;
}

VIDEO_START_MEMBER(snk_state,psychos)
{
	VIDEO_START_CALL_MEMBER(gwar);
	m_is_psychos = 1;
}

VIDEO_START_MEMBER(snk_state,tdfever)
{
	VIDEO_START_CALL_MEMBER(gwar);
	VIDEO_START_CALL_MEMBER(snk_4bpp_shadow);
}

/**************************************************************************************/

void snk_state::snk_tx_videoram_w(offs_t offset, uint8_t data)
{
	m_tx_videoram[offset] = data;
	m_tx_tilemap->mark_tile_dirty(offset);
}

void snk_state::marvins_fg_videoram_w(offs_t offset, uint8_t data)
{
	m_fg_videoram[offset] = data;
	m_fg_tilemap->mark_tile_dirty(offset);
}

void snk_state::marvins_bg_videoram_w(offs_t offset, uint8_t data)
{
	m_bg_videoram[offset] = data;
	m_bg_tilemap->mark_tile_dirty(offset);
}

void snk_state::snk_bg_videoram_w(offs_t offset, uint8_t data)
{
	m_bg_videoram[offset] = data;
	m_bg_tilemap->mark_tile_dirty(offset >> 1);
}


void snk_state::snk_fg_scrollx_w(uint8_t data)
{
	m_fg_scrollx = (m_fg_scrollx & ~0xff) | data;
}

void snk_state::snk_fg_scrolly_w(uint8_t data)
{
	m_fg_scrolly = (m_fg_scrolly & ~0xff) | data;
}

void snk_state::snk_bg_scrollx_w(uint8_t data)
{
	m_bg_scrollx = (m_bg_scrollx & ~0xff) | data;
}

void snk_state::snk_bg_scrolly_w(uint8_t data)
{
	m_bg_scrolly = (m_bg_scrolly & ~0xff) | data;
}

void snk_state::snk_sp16_scrollx_w(uint8_t data)
{
	m_sp16_scrollx = (m_sp16_scrollx & ~0xff) | data;
}

void snk_state::snk_sp16_scrolly_w(uint8_t data)
{
	m_sp16_scrolly = (m_sp16_scrolly & ~0xff) | data;
}

void snk_state::snk_sp32_scrollx_w(uint8_t data)
{
	m_sp32_scrollx = (m_sp32_scrollx & ~0xff) | data;
}

void snk_state::snk_sp32_scrolly_w(uint8_t data)
{
	m_sp32_scrolly = (m_sp32_scrolly & ~0xff) | data;
}

void snk_state::snk_sprite_split_point_w(uint8_t data)
{
	m_sprite_split_point = data;
}


void snk_state::marvins_palette_bank_w(uint8_t data)
{
	m_bg_tilemap->set_palette_offset(data & 0x70);
	m_fg_tilemap->set_palette_offset((data & 0x07) << 4);
}

void snk_state::marvins_flipscreen_w(uint8_t data)
{
	flip_screen_set(data & 0x80);

	// other bits unknown
}

void snk_state::sgladiat_flipscreen_w(uint8_t data)
{
	flip_screen_set(data & 0x80);

	m_bg_tilemap->set_palette_offset(((data & 0xf) ^ 8) << 4);

	// other bits unknown
}

void snk_state::hal21_flipscreen_w(uint8_t data)
{
	flip_screen_set(data & 0x80);

	m_bg_tilemap->set_palette_offset(((data & 0xf) ^ 8) << 4);
	if (m_bg_tile_offset != ((data & 0x20) << 3))
	{
		m_bg_tile_offset = (data & 0x20) << 3;
		m_bg_tilemap->mark_all_dirty();
	}

	// other bits unknown
}

void snk_state::marvins_scroll_msb_w(uint8_t data)
{
	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x04) << 6);
	m_fg_scrollx =   (m_fg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x01) << 8);
}

void snk_state::jcross_scroll_msb_w(uint8_t data)
{
	m_bg_scrolly =   (m_bg_scrolly   & 0xff) | ((data & 0x10) << 4);
	m_sp16_scrolly = (m_sp16_scrolly & 0xff) | ((data & 0x08) << 5);
	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x01) << 8);
}

void snk_state::sgladiat_scroll_msb_w(uint8_t data)
{
	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x01) << 8);
}

void snk_state::aso_videoattrs_w(uint8_t data)
{
	/*
	    video attributes:
	    X-------
	    -X------
	    --X-----    flip screen
	    ---X----    scrolly MSB (background)
	    ----X---    scrolly MSB (sprites)
	    -----X--
	    ------X-    scrollx MSB (background)
	    -------X    scrollx MSB (sprites)
	*/


	flip_screen_set(data & 0x20);

	m_bg_scrolly =   (m_bg_scrolly   & 0xff) | ((data & 0x10) << 4);
	m_sp16_scrolly = (m_sp16_scrolly & 0xff) | ((data & 0x08) << 5);
	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x01) << 8);
}

void snk_state::tnk3_videoattrs_w(uint8_t data)
{
	/*
	    video attributes:
	    X-------    flip screen
	    -X------    character bank (for text layer)
	    --X-----
	    ---X----    scrolly MSB (background)
	    ----X---    scrolly MSB (sprites)
	    -----X--
	    ------X-    scrollx MSB (background)
	    -------X    scrollx MSB (sprites)
	*/


	flip_screen_set(data & 0x80);

	if (m_tx_tile_offset != ((data & 0x40) << 2))
	{
		m_tx_tile_offset = (data & 0x40) << 2;
		m_tx_tilemap->mark_all_dirty();
	}

	m_bg_scrolly =   (m_bg_scrolly   & 0xff) | ((data & 0x10) << 4);
	m_sp16_scrolly = (m_sp16_scrolly & 0xff) | ((data & 0x08) << 5);
	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x01) << 8);
}

void snk_state::aso_bg_bank_w(uint8_t data)
{
	m_bg_tilemap->set_palette_offset(((data & 0xf) ^ 8) << 4);
	if (m_bg_tile_offset != ((data & 0x30) << 4))
	{
		m_bg_tile_offset = (data & 0x30) << 4;
		m_bg_tilemap->mark_all_dirty();
	}
}

void snk_state::ikari_bg_scroll_msb_w(uint8_t data)
{
	m_bg_scrollx = (m_bg_scrollx & 0xff) | ((data & 0x02) << 7);
	m_bg_scrolly = (m_bg_scrolly & 0xff) | ((data & 0x01) << 8);
}

void snk_state::ikari_sp_scroll_msb_w(uint8_t data)
{
	m_sp32_scrollx = (m_sp32_scrollx & 0xff) | ((data & 0x20) << 3);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x10) << 4);
	m_sp32_scrolly = (m_sp32_scrolly & 0xff) | ((data & 0x08) << 5);
	m_sp16_scrolly = (m_sp16_scrolly & 0xff) | ((data & 0x04) << 6);
}

void snk_state::ikari_unknown_video_w(uint8_t data)
{
	/* meaning of 0xc980 uncertain.
	   Normally 0x20, ikaria/ikarijp sets it to 0x31 during test mode.
	   Changing char bank is necessary to fix the display during the
	   hard flags test and the test grid.
	   Changing palette bank is necessary to fix colors in test mode. */


	if (data != 0x20 && // normal
		data != 0x31 && // ikari test
		data != 0xaa)   // victroad spurious during boot
		popmessage("attrs %02x contact MAMEDEV", data);

	m_tx_tilemap->set_palette_offset((data & 0x01) << 4);
	if (m_tx_tile_offset != ((data & 0x10) << 4))
	{
		m_tx_tile_offset = (data & 0x10) << 4;
		m_tx_tilemap->mark_all_dirty();
	}
}

void snk_state::gwar_tx_bank_w(uint8_t data)
{
	m_tx_tilemap->set_palette_offset((data & 0xf) << 4);
	if (m_tx_tile_offset != ((data & 0x30) << 4))
	{
		m_tx_tile_offset = (data & 0x30) << 4;
		m_tx_tilemap->mark_all_dirty();
	}

	if (m_is_psychos)
		m_bg_tilemap->set_palette_offset((data & 0x80));
}

void snk_state::gwar_videoattrs_w(uint8_t data)
{
	flip_screen_set(data & 0x04);

	m_sp32_scrollx = (m_sp32_scrollx & 0xff) | ((data & 0x80) << 1);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x40) << 2);
	m_sp32_scrolly = (m_sp32_scrolly & 0xff) | ((data & 0x20) << 3);
	m_sp16_scrolly = (m_sp16_scrolly & 0xff) | ((data & 0x10) << 4);
	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_bg_scrolly =   (m_bg_scrolly   & 0xff) | ((data & 0x01) << 8);
}

void snk_state::gwara_videoattrs_w(uint8_t data)
{
	flip_screen_set(data & 0x10);

	m_bg_scrollx =   (m_bg_scrollx   & 0xff) | ((data & 0x02) << 7);
	m_bg_scrolly =   (m_bg_scrolly   & 0xff) | ((data & 0x01) << 8);
}

void snk_state::gwara_sp_scroll_msb_w(uint8_t data)
{
	m_sp32_scrollx = (m_sp32_scrollx & 0xff) | ((data & 0x20) << 3);
	m_sp16_scrollx = (m_sp16_scrollx & 0xff) | ((data & 0x10) << 4);
	m_sp32_scrolly = (m_sp32_scrolly & 0xff) | ((data & 0x08) << 5);
	m_sp16_scrolly = (m_sp16_scrolly & 0xff) | ((data & 0x04) << 6);
}

void snk_state::tdfever_sp_scroll_msb_w(uint8_t data)
{
	m_sp32_scrolly = (m_sp32_scrolly & 0xff) | ((data & 0x80) << 1);
	m_sp32_scrollx = (m_sp32_scrollx & 0xff) | ((data & 0x40) << 2);
}

void snk_state::tdfever_spriteram_w(offs_t offset, uint8_t data)
{
	/*  partial updates avoid flickers in the fsoccer radar. */
	if (offset < 0x80 && m_spriteram[offset] != data)
	{
		int vpos = m_screen->vpos();

		if (vpos > 0)
			m_screen->update_partial(vpos - 1);
	}

	m_spriteram[offset] = data;
}

/**************************************************************************************/

void snk_state::marvins_draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect, const int scrollx, const int scrolly, const int from, const int to)
{
	gfx_element *gfx = m_gfxdecode->gfx(3);
	const uint8_t *source, *finish;

	source = m_spriteram + from*4;
	finish = m_spriteram + to*4;

	while( source<finish )
	{
		int attributes = source[3]; /* Y?F? CCCC */
		int tile_number = source[1];
		int sx =  scrollx + 301 - 15 - source[2] + ((attributes&0x80)?256:0);
		int sy = -scrolly - 8 + source[0];
		int color = attributes&0xf;
		int flipy = (attributes&0x20);
		int flipx = 0;

		if (flip_screen())
		{
			sx = 89 - 16 - sx;
			sy = 262 - 16 - sy;
			flipx = !flipx;
			flipy = !flipy;
		}

		sx &= 0x1ff;
		sy &= 0xff;
		if (sx > 512-16) sx -= 512;
		if (sy > 256-16) sy -= 256;

		gfx->transtable(bitmap,cliprect,
			tile_number,
			color,
			flipx, flipy,
			sx, sy,
			m_drawmode_table);

		source+=4;
	}
}


void snk_state::tnk3_draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect, const int xscroll, const int yscroll)
{
	uint8_t *spriteram = m_spriteram;
	gfx_element *gfx = m_gfxdecode->gfx(2);
	const int size = gfx->width();
	int tile_number, attributes, color, sx, sy;
	int xflip,yflip;
	int offs;

	/* jcross and sgladiat have only 25 sprites, the others 50 */

	/* jcross has 256 tiles, attribute bit 6 is unused and bit 5 is y-flip */
	/* sgladiat and tnk3 have 512 tiles, bit 6 is bank and bit 5 is y-flip */
	/* athena has 1024 tiles, bit 6 and bit 5 are bank */

	for (offs = 0; offs < m_num_sprites*4; offs += 4)
	{
		tile_number = spriteram[offs+1];
		attributes  = spriteram[offs+3];
		color = attributes & 0xf;
		sx =  xscroll + 301 - size - spriteram[offs+2];
		sy = -yscroll + 7 - size + spriteram[offs];
		sx += (attributes & 0x80) << 1;
		sy += (attributes & 0x10) << 4;
		xflip = 0;
		yflip = 0;

		if (gfx->elements() > 256)  // all except jcross
		{
			tile_number |= (attributes & 0x40) << 2;
		}

		if (gfx->elements() > 512)  // athena
		{
			tile_number |= (attributes & 0x20) << 4;
		}
		else    // all others
		{
			yflip = attributes & 0x20;
		}

		if (flip_screen())
		{
			sx = 89 - size - sx;    // this causes slight misalignment in tnk3 but is correct for athena and fitegolf
			sy = 262 - size - sy;
			xflip = !xflip;
			yflip = !yflip;
		}

		sx &= 0x1ff;
		sy &= m_yscroll_mask;    // sgladiat apparently has only 256 pixels of vertical scrolling range
		if (sx > 512-size) sx -= 512;
		if (sy > (m_yscroll_mask+1)-size) sy -= (m_yscroll_mask+1);

		gfx->transtable(bitmap,cliprect,
				tile_number,
				color,
				xflip,yflip,
				sx,sy,
				m_drawmode_table);
	}
}


void snk_state::ikari_draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect, const int start, const int xscroll, const int yscroll, const uint8_t *source, const int gfxnum )
{
	gfx_element *gfx = m_gfxdecode->gfx(gfxnum);
	const int size = gfx->width();
	int tile_number, attributes, color, sx, sy;
	int which, finish;

	finish = (start+25)*4;

	for (which = start*4; which < finish; which += 4)
	{
		tile_number = source[which+1];
		attributes  = source[which+3];
		color = attributes & 0xf;
		sx =  xscroll + 300 - size - source[which+2];
		sy = -yscroll + 7 - size + source[which];
		sx += (attributes & 0x80) << 1;
		sy += (attributes & 0x10) << 4;

		switch (size)
		{
			case 16:
				tile_number |= (attributes & 0x60) << 3;
				break;

			case 32:
				tile_number |= (attributes & 0x40) << 2;
				break;
		}

		sx &= 0x1ff;
		sy &= 0x1ff;
		if (sx > 512-size) sx -= 512;
		if (sy > 512-size) sy -= 512;

		gfx->transtable(bitmap,cliprect,
				tile_number,
				color,
				0,0,
				sx,sy,
				m_drawmode_table);
	}
}

/**************************************************************/

/*
Sprite Format
-------------
byte0: y offset
byte1: tile number
byte2: x offset
byte3: attributes

    32x32 attributes:

    76543210
    ----xxxx (color)
    ---x---- (y offset bit8)
    -xx----- (bank number)
    x------- (x offset bit8)

    16x16 attributes:

    76543210
    -----xxx (color)
    ---x---- (y offset bit8)
    -xx-x--- (bank number)
    x------- (x offset bit8)
*/
void snk_state::tdfever_draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect,   const int xscroll, const int yscroll, const uint8_t *source, const int gfxnum,
										const int hw_xflip, const int from, const int to)
{
	gfx_element *gfx = m_gfxdecode->gfx(gfxnum);
	const int size = gfx->width();
	int tile_number, attributes, sx, sy, color;
	int which;
	int flipx, flipy;

	for(which = from*4; which < to*4; which+=4)
	{
		tile_number = source[which+1];
		attributes  = source[which+3];
		color = attributes & 0x0f;
		sx = -xscroll - 9 + source[which+2];
		sy = -yscroll + 1 - size + source[which];
		sx += (attributes & 0x80) << 1;
		sy += (attributes & 0x10) << 4;

		switch (size)
		{
			case 16:
				tile_number |= ((attributes & 0x08) << 5) | ((attributes & 0x60) << 4);
				color &= 7; // attribute bit 3 is used for bank select
				if (from == 0)
					color |= 8; // low priority sprites use the other palette bank
				break;

			case 32:
				tile_number |= (attributes & 0x60) << 3;
				break;
		}

		flipx = hw_xflip;
		flipy = 0;

		if (hw_xflip)
			sx = 495 - size - sx;

		if (flip_screen())
		{
			sx = 495 - size - sx;
			sy = 258 - size - sy;
			flipx = !flipx;
			flipy = !flipy;
		}

		sx &= 0x1ff;
		sy &= 0x1ff;
		if (sx > 512-size) sx -= 512;
		if (sy > 512-size) sy -= 512;

		gfx->transtable(bitmap,cliprect,
				tile_number,
				color,
				flipx,flipy,
				sx,sy,
				m_drawmode_table);
	}
}

/**************************************************************/

uint32_t snk_state::screen_update_marvins(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_bg_scrollx);
	m_bg_tilemap->set_scrolly(0, m_bg_scrolly);
	m_fg_tilemap->set_scrollx(0, m_fg_scrollx);
	m_fg_tilemap->set_scrolly(0, m_fg_scrolly);

	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
	marvins_draw_sprites(bitmap, cliprect, m_sp16_scrollx, m_sp16_scrolly, 0, m_sprite_split_point>>2);
	m_fg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
	marvins_draw_sprites(bitmap, cliprect, m_sp16_scrollx, m_sp16_scrolly, m_sprite_split_point>>2, 25);
	m_tx_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	return 0;
}


uint32_t snk_state::screen_update_tnk3(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_bg_scrollx);
	m_bg_tilemap->set_scrolly(0, m_bg_scrolly);

	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
	tnk3_draw_sprites(bitmap, cliprect, m_sp16_scrollx, m_sp16_scrolly);
	m_tx_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	return 0;
}

uint32_t snk_state::screen_update_fitegolf2(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_bg_scrollx);
	m_bg_tilemap->set_scrolly(0, m_bg_scrolly);

	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
	tnk3_draw_sprites(bitmap, cliprect, m_sp16_scrollx+1, m_sp16_scrolly); // needs an extra offset?? neither this or fitegolf actually write to sprite offset registers tho?
	m_tx_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	return 0;
}


uint32_t snk_state::screen_update_ikari(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_bg_scrollx);
	m_bg_tilemap->set_scrolly(0, m_bg_scrolly);

	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	ikari_draw_sprites(bitmap, cliprect,  0, m_sp16_scrollx, m_sp16_scrolly, m_spriteram + 0x800, 2 );
	ikari_draw_sprites(bitmap, cliprect,  0, m_sp32_scrollx, m_sp32_scrolly, m_spriteram,         3 );
	ikari_draw_sprites(bitmap, cliprect, 25, m_sp16_scrollx, m_sp16_scrolly, m_spriteram + 0x800, 2 );

	m_tx_tilemap->draw(screen, bitmap, cliprect, 0, 0);
	return 0;
}


uint32_t snk_state::screen_update_gwar(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_bg_scrollx);
	m_bg_tilemap->set_scrolly(0, m_bg_scrolly);

	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	tdfever_draw_sprites(bitmap, cliprect, m_sp16_scrollx, m_sp16_scrolly, m_spriteram + 0x800, 2, 0, 0, m_sprite_split_point );
	tdfever_draw_sprites(bitmap, cliprect, m_sp32_scrollx, m_sp32_scrolly, m_spriteram,         3, 0, 0, 32 );
	tdfever_draw_sprites(bitmap, cliprect, m_sp16_scrollx, m_sp16_scrolly, m_spriteram + 0x800, 2, 0, m_sprite_split_point, 64 );

	m_tx_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	return 0;
}


uint32_t snk_state::screen_update_tdfever(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_bg_scrollx);
	m_bg_tilemap->set_scrolly(0, m_bg_scrolly);

	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	tdfever_draw_sprites(bitmap, cliprect, m_sp32_scrollx, m_sp32_scrolly, m_spriteram, 2, 1, 0, 32 );

	m_tx_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	return 0;
}