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

  Capcom Vulgus hardware

  Functions to emulate the video hardware of the machine.

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

#include "emu.h"
#include "includes/vulgus.h"


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

  Convert the color PROMs into a more useable format.

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

PALETTE_INIT_MEMBER(vulgus_state, vulgus)
{
	const UINT8 *color_prom = memregion("proms")->base();
	int i;

	for (i = 0;i < 256;i++)
	{
		int bit0,bit1,bit2,bit3,r,g,b;

		bit0 = (color_prom[0] >> 0) & 0x01;
		bit1 = (color_prom[0] >> 1) & 0x01;
		bit2 = (color_prom[0] >> 2) & 0x01;
		bit3 = (color_prom[0] >> 3) & 0x01;
		r = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
		bit0 = (color_prom[256] >> 0) & 0x01;
		bit1 = (color_prom[256] >> 1) & 0x01;
		bit2 = (color_prom[256] >> 2) & 0x01;
		bit3 = (color_prom[256] >> 3) & 0x01;
		g = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
		bit0 = (color_prom[2*256] >> 0) & 0x01;
		bit1 = (color_prom[2*256] >> 1) & 0x01;
		bit2 = (color_prom[2*256] >> 2) & 0x01;
		bit3 = (color_prom[2*256] >> 3) & 0x01;
		b = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;

		palette.set_indirect_color(i,rgb_t(r,g,b));
		color_prom++;
	}

	color_prom += 2*256;
	/* color_prom now points to the beginning of the lookup table */


	/* characters use colors 32-47 (?) */
	for (i = 0;i < m_gfxdecode->gfx(0)->colors() * m_gfxdecode->gfx(0)->granularity();i++)
		palette.set_pen_indirect(m_gfxdecode->gfx(0)->colorbase() + i, 32 + *color_prom++);

	/* sprites use colors 16-31 */
	for (i = 0;i < m_gfxdecode->gfx(2)->colors() * m_gfxdecode->gfx(2)->granularity();i++)
		palette.set_pen_indirect(m_gfxdecode->gfx(2)->colorbase() + i, 16 + *color_prom++);

	/* background tiles use colors 0-15, 64-79, 128-143, 192-207 in four banks */
	for (i = 0;i < m_gfxdecode->gfx(1)->colors() * m_gfxdecode->gfx(1)->granularity() / 4;i++)
	{
		palette.set_pen_indirect(m_gfxdecode->gfx(1)->colorbase() + 0*32*8 + i, *color_prom);
		palette.set_pen_indirect(m_gfxdecode->gfx(1)->colorbase() + 1*32*8 + i, *color_prom + 64);
		palette.set_pen_indirect(m_gfxdecode->gfx(1)->colorbase() + 2*32*8 + i, *color_prom + 128);
		palette.set_pen_indirect(m_gfxdecode->gfx(1)->colorbase() + 3*32*8 + i, *color_prom + 192);
		color_prom++;
	}
}


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

  Callbacks for the TileMap code

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

TILE_GET_INFO_MEMBER(vulgus_state::get_fg_tile_info)
{
	int code, color;

	code = m_fgvideoram[tile_index];
	color = m_fgvideoram[tile_index + 0x400];
	SET_TILE_INFO_MEMBER(0,
			code + ((color & 0x80) << 1),
			color & 0x3f,
			0);
	tileinfo.group = color & 0x3f;
}

TILE_GET_INFO_MEMBER(vulgus_state::get_bg_tile_info)
{
	int code, color;

	code = m_bgvideoram[tile_index];
	color = m_bgvideoram[tile_index + 0x400];
	SET_TILE_INFO_MEMBER(1,
			code + ((color & 0x80) << 1),
			(color & 0x1f) + (0x20 * m_palette_bank),
			TILE_FLIPYX((color & 0x60) >> 5));
}


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

  Start the video hardware emulation.

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

void vulgus_state::video_start()
{
	m_fg_tilemap = &machine().tilemap().create(m_gfxdecode, tilemap_get_info_delegate(FUNC(vulgus_state::get_fg_tile_info),this),TILEMAP_SCAN_ROWS, 8, 8,32,32);
	m_bg_tilemap = &machine().tilemap().create(m_gfxdecode, tilemap_get_info_delegate(FUNC(vulgus_state::get_bg_tile_info),this),TILEMAP_SCAN_COLS,16,16,32,32);

	m_fg_tilemap->configure_groups(*m_gfxdecode->gfx(0), 47);
}


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

  Memory handlers

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

WRITE8_MEMBER(vulgus_state::vulgus_fgvideoram_w)
{
	m_fgvideoram[offset] = data;
	m_fg_tilemap->mark_tile_dirty(offset & 0x3ff);
}

WRITE8_MEMBER(vulgus_state::vulgus_bgvideoram_w)
{
	m_bgvideoram[offset] = data;
	m_bg_tilemap->mark_tile_dirty(offset & 0x3ff);
}


WRITE8_MEMBER(vulgus_state::vulgus_c804_w)
{
	/* bits 0 and 1 are coin counters */
	coin_counter_w(machine(), 0, data & 0x01);
	coin_counter_w(machine(), 1, data & 0x02);

	/* bit 7 flips screen */
	flip_screen_set(data & 0x80);
}


WRITE8_MEMBER(vulgus_state::vulgus_palette_bank_w)
{
	if (m_palette_bank != (data & 3))
	{
		m_palette_bank = data & 3;
		m_bg_tilemap->mark_all_dirty();
	}
}


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

  Display refresh

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

void vulgus_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	gfx_element *gfx = m_gfxdecode->gfx(2);

	for (int offs = m_spriteram.bytes() - 4; offs >= 0; offs -= 4)
	{
		int code = m_spriteram[offs];
		int color = m_spriteram[offs + 1] & 0x0f;
		int sy = m_spriteram[offs + 2];
		int sx = m_spriteram[offs + 3];
		bool flip = flip_screen() ? true : false;
		int dir = 1;

		if (sy == 0)
			continue;

		if (flip)
		{
			sx = 240 - sx;
			sy = 240 - sy;
			dir = -1;
		}

		// draw sprite rows (16*16, 16*32, or 16*64)
		int row = (m_spriteram[offs + 1] & 0xc0) >> 6;
		if (row == 2) row = 3;

		for (; row >= 0; row--)
			gfx->transpen(bitmap, cliprect, code + row, color, flip, flip, sx, sy + 16 * row * dir, 15);
	}
}

UINT32 vulgus_state::screen_update_vulgus(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->set_scrollx(0, m_scroll_low[1] + 256 * m_scroll_high[1]);
	m_bg_tilemap->set_scrolly(0, m_scroll_low[0] + 256 * m_scroll_high[0]);

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

	return 0;
}
