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// license:BSD-3-Clause
// copyright-holders:Nicola Salmoria
/***************************************************************************

 Pang Video Hardware

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

#include "emu.h"
#include "sound/okim6295.h"
#include "includes/mitchell.h"

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

  Callbacks for the TileMap code

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

TILE_GET_INFO_MEMBER(mitchell_state::get_tile_info)
{
	uint8_t attr = m_colorram[tile_index];
	int code = m_videoram[2 * tile_index] + (m_videoram[2 * tile_index + 1] << 8);
	SET_TILE_INFO_MEMBER(0,
			code,
			attr & 0x7f,
			(attr & 0x80) ? TILE_FLIPX : 0);
}



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

  Start the video hardware emulation.

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

VIDEO_START_MEMBER(mitchell_state,pang)
{
	m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(mitchell_state::get_tile_info)), TILEMAP_SCAN_ROWS, 8, 8, 64, 32);
	m_bg_tilemap->set_transparent_pen(15);

	/* OBJ RAM */
	m_objram.resize(m_videoram.bytes());

	/* Palette RAM */
	m_paletteram.resize(2 * m_palette->entries());
	m_palette->basemem().set(m_paletteram, ENDIANNESS_LITTLE, 2);

	save_item(NAME(m_objram));
	save_item(NAME(m_paletteram));
}



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

  Memory handlers

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

/***************************************************************************
  OBJ / CHAR RAM HANDLERS (BANK 0 = CHAR, BANK 1=OBJ)
***************************************************************************/

WRITE8_MEMBER(mitchell_state::pang_video_bank_w)
{
	/* Bank handler (sets base pointers for video write) (doesn't apply to mgakuen) */
	m_video_bank = data;
}

WRITE8_MEMBER(mitchell_state::mstworld_video_bank_w)
{
	/* Monsters World seems to freak out if more bits are used.. */
	m_video_bank = data & 1;
}


WRITE8_MEMBER(mitchell_state::mgakuen_videoram_w)
{
	m_videoram[offset] = data;
	m_bg_tilemap->mark_tile_dirty(offset / 2);
}

READ8_MEMBER(mitchell_state::mgakuen_videoram_r)
{
	return m_videoram[offset];
}

WRITE8_MEMBER(mitchell_state::mgakuen_objram_w)
{
	m_objram[offset] = data;
}

READ8_MEMBER(mitchell_state::mgakuen_objram_r)
{
	return m_objram[offset];
}

WRITE8_MEMBER(mitchell_state::pang_videoram_w)
{
	if (m_video_bank)
		mgakuen_objram_w(space, offset, data);
	else
		mgakuen_videoram_w(space, offset, data);
}

READ8_MEMBER(mitchell_state::pang_videoram_r)
{
	if (m_video_bank)
		return mgakuen_objram_r(space, offset);
	else
		return mgakuen_videoram_r(space, offset);
}

/***************************************************************************
  COLOUR RAM
****************************************************************************/

WRITE8_MEMBER(mitchell_state::pang_colorram_w)
{
	m_colorram[offset] = data;
	m_bg_tilemap->mark_tile_dirty(offset);
}

READ8_MEMBER(mitchell_state::pang_colorram_r)
{
	return m_colorram[offset];
}

/***************************************************************************
  PALETTE HANDLERS (COLOURS: BANK 0 = 0x00-0x3f BANK 1=0x40-0xff)
****************************************************************************/

WRITE8_MEMBER(mitchell_state::pang_gfxctrl_w)
{
logerror("PC %04x: pang_gfxctrl_w %02x\n",m_maincpu->pc(),data);
{
#if 0
	char baf[40];
	sprintf(baf,"%02x",data);
	popmessage(baf);
#endif
}

	/* bit 0 is unknown (used, maybe back color enable?) */

	/* bit 1 is coin counter */
	machine().bookkeeping().coin_counter_w(0, data & 2);

	/* bit 2 is flip screen */
	if (m_flipscreen != (data & 0x04))
	{
		m_flipscreen = data & 0x04;
		machine().tilemap().set_flip_all(m_flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0);
	}

	/* bit 3 is unknown (used, e.g. marukin pulses it on the title screen) */

	/* bit 4 selects OKI M6295 bank */
	if (m_oki != nullptr)
		m_oki->set_rom_bank((data >> 4) & 1);

	/* bit 5 is palette RAM bank selector (doesn't apply to mgakuen) */
	m_paletteram_bank = data & 0x20;

	/* bits 6 and 7 are unknown, used in several places. At first I thought */
	/* they were bg and sprites enable, but this screws up spang (screen flickers */
	/* every time you pop a bubble). However, not using them as enable bits screws */
	/* up marukin - you can see partially built up screens during attract mode. */
}

WRITE8_MEMBER(mitchell_state::pangbl_gfxctrl_w)
{
logerror("PC %04x: pang_gfxctrl_w %02x\n",m_maincpu->pc(),data);
{
#if 0
	char baf[40];
	sprintf(baf,"%02x",data);
	popmessage(baf);
#endif
}

	/* bit 0 is unknown (used, maybe back color enable?) */

	/* bit 1 is coin counter */
	machine().bookkeeping().coin_counter_w(0, data & 2);

	/* bit 2 is flip screen */
	if (m_flipscreen != (data & 0x04))
	{
		m_flipscreen = data & 0x04;
		machine().tilemap().set_flip_all(m_flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0);
	}

	/* bit 3 is unknown (used, e.g. marukin pulses it on the title screen) */

	/* bit 4 selects OKI M6295 bank, nop'ed here */

	/* bit 5 is palette RAM bank selector (doesn't apply to mgakuen) */
	m_paletteram_bank = data & 0x20;

	/* bits 6 and 7 are unknown, used in several places. At first I thought */
	/* they were bg and sprites enable, but this screws up spang (screen flickers */
	/* every time you pop a bubble). However, not using them as enable bits screws */
	/* up marukin - you can see partially built up screens during attract mode. */
}

WRITE8_MEMBER(mitchell_state::mstworld_gfxctrl_w)
{
logerror("PC %04x: pang_gfxctrl_w %02x\n",m_maincpu->pc(),data);
{
	char baf[40];
	sprintf(baf,"%02x",data);
//  popmessage(baf);
}

	/* bit 0 is unknown (used, maybe back color enable?) */

	/* bit 1 is coin counter */
	machine().bookkeeping().coin_counter_w(0, data & 2);

	/* bit 2 is flip screen */
	if (m_flipscreen != (data & 0x04))
	{
		m_flipscreen = data & 0x04;
		machine().tilemap().set_flip_all(m_flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0);
	}

	/* bit 3 is unknown (used, e.g. marukin pulses it on the title screen) */

	/* bit 4 here does not select OKI M6295 bank: mstworld has its own z80 + sound banking */

	/* bit 5 is palette RAM bank selector (doesn't apply to mgakuen) */
	m_paletteram_bank = data & 0x20;

	/* bits 6 and 7 are unknown, used in several places. At first I thought */
	/* they were bg and sprites enable, but this screws up spang (screen flickers */
	/* every time you pop a bubble). However, not using them as enable bits screws */
	/* up marukin - you can see partially built up screens during attract mode. */
}

WRITE8_MEMBER(mitchell_state::pang_paletteram_w)
{
	m_palette->write8(offset + (m_paletteram_bank ? 0x800 : 0x000), data);
}

READ8_MEMBER(mitchell_state::pang_paletteram_r)
{
	return m_paletteram[offset + (m_paletteram_bank ? 0x800 : 0x000)];
}



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

  Display refresh

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

void mitchell_state::draw_sprites( bitmap_ind16 &bitmap, const rectangle &cliprect )
{
	int offs, sx, sy;

	/* the last entry is not a sprite, we skip it otherwise spang shows a bubble */
	/* moving diagonally across the screen */
	for (offs = 0x1000 - 0x40; offs >= 0; offs -= 0x20)
	{
		int code = m_objram[offs];
		int attr = m_objram[offs + 1];
		int color = attr & 0x0f;
		sx = m_objram[offs + 3] + ((attr & 0x10) << 4);
		sy = ((m_objram[offs + 2] + 8) & 0xff) - 8;
		code += (attr & 0xe0) << 3;
		if (m_flipscreen)
		{
			sx = 496 - sx;
			sy = 240 - sy;
		}
		m_gfxdecode->gfx(1)->transpen(bitmap,cliprect,
					code,
					color,
					m_flipscreen, m_flipscreen,
					sx,sy,15);
	}
}

uint32_t mitchell_state::screen_update_pang(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	bitmap.fill(0, cliprect);
	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
	draw_sprites(bitmap, cliprect);
	return 0;
}