text: // license:BSD-3-Clause
  // copyright-holders:Aaron Giles
  /*************************************************************************
  
      BattleToads
  
      Video hardware emulation
  
  **************************************************************************/
  
  #include "emu.h"
  #include "includes/btoads.h"
  
  
  #define BT_DEBUG 0
  
  
  
  /*************************************
   *
   *  Video system start
   *
   *************************************/
  
  void btoads_state::video_start()
  {
  	/* initialize the swapped pointers */
  	m_vram_fg_draw = m_vram_fg0;
  	m_vram_fg_display = m_vram_fg1;
  
  	save_item(NAME(m_xscroll0));
  	save_item(NAME(m_xscroll1));
  	save_item(NAME(m_yscroll0));
  	save_item(NAME(m_yscroll1));
  	save_item(NAME(m_screen_control));
  
  	save_item(NAME(m_sprite_source_offs));
  	save_item(NAME(m_sprite_dest_offs));
  	save_item(NAME(m_misc_control));
  }
  
  
  
  /*************************************
   *
   *  Control registers
   *
   *************************************/
  
  WRITE16_MEMBER( btoads_state::misc_control_w )
  {
  	COMBINE_DATA(&m_misc_control);
  
  	/* bit 3 controls sound reset line */
  	m_audiocpu->set_input_line(INPUT_LINE_RESET, (m_misc_control & 8) ? CLEAR_LINE : ASSERT_LINE);
  }
  
  
  WRITE16_MEMBER( btoads_state::display_control_w )
  {
  	if (ACCESSING_BITS_8_15)
  	{
  		/* allow multiple changes during display */
  		int scanline = m_screen->vpos();
  		if (scanline > 0)
  			m_screen->update_partial(scanline - 1);
  
  		/* bit 15 controls which page is rendered and which page is displayed */
  		if (data & 0x8000)
  		{
  			m_vram_fg_draw = m_vram_fg1;
  			m_vram_fg_display = m_vram_fg0;
  		}
  		else
  		{
  			m_vram_fg_draw = m_vram_fg0;
  			m_vram_fg_display = m_vram_fg1;
  		}
  
  		/* stash the remaining data for later */
  		m_screen_control = data >> 8;
  	}
  }
  
  
  
  /*************************************
   *
   *  Scroll registers
   *
   *************************************/
  
  WRITE16_MEMBER( btoads_state::scroll0_w )
  {
  	/* allow multiple changes during display */
  //  m_screen->update_now();
  	m_screen->update_partial(m_screen->vpos());
  
  	/* upper bits are Y scroll, lower bits are X scroll */
  	if (ACCESSING_BITS_8_15)
  		m_yscroll0 = data >> 8;
  	if (ACCESSING_BITS_0_7)
  		m_xscroll0 = data & 0xff;
  }
  
  
  WRITE16_MEMBER( btoads_state::scroll1_w )
  {
  	/* allow multiple changes during display */
  //  m_screen->update_now();
  	m_screen->update_partial(m_screen->vpos());
  
  	/* upper bits are Y scroll, lower bits are X scroll */
  	if (ACCESSING_BITS_8_15)
  		m_yscroll1 = data >> 8;
  	if (ACCESSING_BITS_0_7)
  		m_xscroll1 = data & 0xff;
  }
  
  
  
  /*************************************
   *
   *  Palette RAM
   *
   *************************************/
  
  WRITE16_MEMBER( btoads_state::paletteram_w )
  {
  	m_tlc34076->write(space, offset/2, data);
  }
  
  
  READ16_MEMBER( btoads_state::paletteram_r )
  {
  	return m_tlc34076->read(space, offset/2);
  }
  
  
  
  /*************************************
   *
   *  Background video RAM
   *
   *************************************/
  
  WRITE16_MEMBER( btoads_state::vram_bg0_w )
  {
  	COMBINE_DATA(&m_vram_bg0[offset & 0x3fcff]);
  }
  
  
  WRITE16_MEMBER( btoads_state::vram_bg1_w )
  {
  	COMBINE_DATA(&m_vram_bg1[offset & 0x3fcff]);
  }
  
  
  READ16_MEMBER( btoads_state::vram_bg0_r )
  {
  	return m_vram_bg0[offset & 0x3fcff];
  }
  
  
  READ16_MEMBER( btoads_state::vram_bg1_r )
  {
  	return m_vram_bg1[offset & 0x3fcff];
  }
  
  
  
  /*************************************
   *
   *  Foreground video RAM
   *
   *************************************/
  
  WRITE16_MEMBER( btoads_state::vram_fg_display_w )
  {
  	if (ACCESSING_BITS_0_7)
  		m_vram_fg_display[offset] = data;
  }
  
  
  WRITE16_MEMBER( btoads_state::vram_fg_draw_w )
  {
  	if (ACCESSING_BITS_0_7)
  		m_vram_fg_draw[offset] = data;
  }
  
  
  READ16_MEMBER( btoads_state::vram_fg_display_r )
  {
  	return m_vram_fg_display[offset];
  }
  
  
  READ16_MEMBER( btoads_state::vram_fg_draw_r )
  {
  	return m_vram_fg_draw[offset];
  }
  
  
  
  /*************************************
   *
   *  Sprite rendering
   *
   *************************************/
  
  void btoads_state::render_sprite_row(uint16_t *sprite_source, uint32_t address)
  {
  	int flipxor = ((*m_sprite_control >> 10) & 1) ? 0xffff : 0x0000;
  	int width = (~*m_sprite_control & 0x1ff) + 2;
  	int color = (~*m_sprite_control >> 8) & 0xf0;
  	int srcoffs = m_sprite_source_offs << 8;
  	int srcend = srcoffs + (width << 8);
  	int srcstep = 0x100 - m_sprite_scale[0];
  	int dststep = 0x100 - m_sprite_scale[8];
  	int dstoffs = m_sprite_dest_offs << 8;
  
  	/* non-shadow case */
  	if (!(m_misc_control & 0x10))
  	{
  		for ( ; srcoffs < srcend; srcoffs += srcstep, dstoffs += dststep)
  		{
  			uint16_t src = sprite_source[(srcoffs >> 10) & 0x1ff];
  			if (src)
  			{
  				src = (src >> (((srcoffs ^ flipxor) >> 6) & 0x0c)) & 0x0f;
  				if (src)
  					m_sprite_dest_base[(dstoffs >> 8) & 0x1ff] = src | color;
  			}
  		}
  	}
  
  	/* shadow case */
  	else
  	{
  		for ( ; srcoffs < srcend; srcoffs += srcstep, dstoffs += dststep)
  		{
  			uint16_t src = sprite_source[(srcoffs >> 10) & 0x1ff];
  			if (src)
  			{
  				src = (src >> (((srcoffs ^ flipxor) >> 6) & 0x0c)) & 0x0f;
  				if (src)
  					m_sprite_dest_base[(dstoffs >> 8) & 0x1ff] = color;
  			}
  		}
  	}
  
  	m_sprite_source_offs += width;
  	m_sprite_dest_offs = dstoffs >> 8;
  }
  
  
  
  /*************************************
   *
   *  Shift register read/write
   *
   *************************************/
  
  TMS340X0_TO_SHIFTREG_CB_MEMBER(btoads_state::to_shiftreg)
  {
  	address &= ~0x40000000;
  
  	/* reads from this first region are usual shift register reads */
  	if (address >= 0xa0000000 && address <= 0xa3ffffff)
  		memcpy(shiftreg, &m_vram_fg_display[(address & 0x3fffff) >> 4], 0x200);
  
  	/* reads from this region set the sprite destination address */
  	else if (address >= 0xa4000000 && address <= 0xa7ffffff)
  	{
  		m_sprite_dest_base = &m_vram_fg_draw[(address & 0x3fc000) >> 4];
  		m_sprite_dest_offs = (address & 0x003fff) >> 5;
  	}
  
  	/* reads from this region set the sprite source address */
  	else if (address >= 0xa8000000 && address <= 0xabffffff)
  	{
  		memcpy(shiftreg, &m_vram_fg_data[(address & 0x7fc000) >> 4], 0x400);
  		m_sprite_source_offs = (address & 0x003fff) >> 3;
  	}
  
  	else
  		logerror("%s:btoads_to_shiftreg(%08X)\n", machine().describe_context(), address);
  }
  
  
  TMS340X0_FROM_SHIFTREG_CB_MEMBER(btoads_state::from_shiftreg)
  {
  	address &= ~0x40000000;
  
  	/* writes to this first region are usual shift register writes */
  	if (address >= 0xa0000000 && address <= 0xa3ffffff)
  		memcpy(&m_vram_fg_display[(address & 0x3fc000) >> 4], shiftreg, 0x200);
  
  	/* writes to this region are ignored for our purposes */
  	else if (address >= 0xa4000000 && address <= 0xa7ffffff)
  		;
  
  	/* writes to this region copy standard data */
  	else if (address >= 0xa8000000 && address <= 0xabffffff)
  		memcpy(&m_vram_fg_data[(address & 0x7fc000) >> 4], shiftreg, 0x400);
  
  	/* writes to this region render the current sprite data */
  	else if (address >= 0xac000000 && address <= 0xafffffff)
  		render_sprite_row(shiftreg, address);
  
  	else
  		logerror("%s:btoads_from_shiftreg(%08X)\n", machine().describe_context(), address);
  }
  
  
  
  /*************************************
   *
   *  Main refresh
   *
   *************************************/
  
  TMS340X0_SCANLINE_RGB32_CB_MEMBER(btoads_state::scanline_update)
  {
  	uint32_t fulladdr = ((params->rowaddr << 16) | params->coladdr) >> 4;
  	uint16_t *bg0_base = &m_vram_bg0[(fulladdr + (m_yscroll0 << 10)) & 0x3fc00];
  	uint16_t *bg1_base = &m_vram_bg1[(fulladdr + (m_yscroll1 << 10)) & 0x3fc00];
  	uint8_t *spr_base = &m_vram_fg_display[fulladdr & 0x3fc00];
  	uint32_t *dst = &bitmap.pix32(scanline);
  	const rgb_t *pens = m_tlc34076->get_pens();
  	int coladdr = fulladdr & 0x3ff;
  	int x;
  
  	/* for each scanline, switch off the render mode */
  	switch (m_screen_control & 3)
  	{
  		/* mode 0: used in ship level, snake boss, title screen (free play) */
  		/* priority is:
  		    1. Sprite pixels with high bit clear
  		    2. BG1 pixels with the high bit set
  		    3. Sprites
  		    4. BG1
  		    5. BG0
  		*/
  		case 0:
  			for (x = params->heblnk; x < params->hsblnk; x += 2, coladdr++)
  			{
  				uint8_t sprpix = spr_base[coladdr & 0xff];
  
  				if (sprpix && !(sprpix & 0x80))
  				{
  					dst[x + 0] = pens[sprpix];
  					dst[x + 1] = pens[sprpix];
  				}
  				else
  				{
  					uint16_t bg0pix = bg0_base[(coladdr + m_xscroll0) & 0xff];
  					uint16_t bg1pix = bg1_base[(coladdr + m_xscroll1) & 0xff];
  					uint8_t sprpix = spr_base[coladdr & 0xff];
  
  					if (bg1pix & 0x80)
  						dst[x + 0] = pens[bg1pix & 0xff];
  					else if (sprpix)
  						dst[x + 0] = pens[sprpix];
  					else if (bg1pix & 0xff)
  						dst[x + 0] = pens[bg1pix & 0xff];
  					else
  						dst[x + 0] = pens[bg0pix & 0xff];
  
  					if (bg1pix & 0x8000)
  						dst[x + 1] = pens[bg1pix >> 8];
  					else if (sprpix)
  						dst[x + 1] = pens[sprpix];
  					else if (bg1pix >> 8)
  						dst[x + 1] = pens[bg1pix >> 8];
  					else
  						dst[x + 1] = pens[bg0pix >> 8];
  				}
  			}
  			break;
  
  		/* mode 1: used in snow level, title screen (free play), top part of rolling ball level */
  		/* priority is:
  		    1. Sprite pixels with high bit clear
  		    2. BG0
  		    3. BG1 pixels with high bit set
  		    4. Sprites
  		    5. BG1
  		*/
  		case 1:
  			for (x = params->heblnk; x < params->hsblnk; x += 2, coladdr++)
  			{
  				uint8_t sprpix = spr_base[coladdr & 0xff];
  
  				if (sprpix && !(sprpix & 0x80))
  				{
  					dst[x + 0] = pens[sprpix];
  					dst[x + 1] = pens[sprpix];
  				}
  				else
  				{
  					uint16_t bg0pix = bg0_base[(coladdr + m_xscroll0) & 0xff];
  					uint16_t bg1pix = bg1_base[(coladdr + m_xscroll1) & 0xff];
  
  					if (bg0pix & 0xff)
  						dst[x + 0] = pens[bg0pix & 0xff];
  					else if (bg1pix & 0x80)
  						dst[x + 0] = pens[bg1pix & 0xff];
  					else if (sprpix)
  						dst[x + 0] = pens[sprpix];
  					else
  						dst[x + 0] = pens[bg1pix & 0xff];
  
  					if (bg0pix >> 8)
  						dst[x + 1] = pens[bg0pix >> 8];
  					else if (bg1pix & 0x8000)
  						dst[x + 1] = pens[bg1pix >> 8];
  					else if (sprpix)
  						dst[x + 1] = pens[sprpix];
  					else
  						dst[x + 1] = pens[bg1pix >> 8];
  				}
  			}
  			break;
  
  		/* mode 2: used in EOA screen, jetpack level, first level, high score screen */
  		/* priority is:
  		    1. Sprites
  		    2. BG1
  		    3. BG0
  		*/
  		case 2:
  			for (x = params->heblnk; x < params->hsblnk; x += 2, coladdr++)
  			{
  				uint8_t sprpix = spr_base[coladdr & 0xff];
  
  				if (sprpix)
  				{
  					dst[x + 0] = pens[sprpix];
  					dst[x + 1] = pens[sprpix];
  				}
  				else
  				{
  					uint16_t bg0pix = bg0_base[(coladdr + m_xscroll0) & 0xff];
  					uint16_t bg1pix = bg1_base[(coladdr + m_xscroll1) & 0xff];
  
  					if (bg1pix & 0xff)
  						dst[x + 0] = pens[bg1pix & 0xff];
  					else
  						dst[x + 0] = pens[bg0pix & 0xff];
  
  					if (bg1pix >> 8)
  						dst[x + 1] = pens[bg1pix >> 8];
  					else
  						dst[x + 1] = pens[bg0pix >> 8];
  				}
  			}
  			break;
  
  		/* mode 3: used in toilet level, toad intros, bottom of rolling ball level */
  		/* priority is:
  		    1. BG1 pixels with the high bit set
  		    2. Sprite pixels with the high bit set
  		    3. BG1
  		    4. Sprites
  		    5. BG0
  		*/
  		case 3:
  			for (x = params->heblnk; x < params->hsblnk; x += 2, coladdr++)
  			{
  				uint16_t bg0pix = bg0_base[(coladdr + m_xscroll0) & 0xff];
  				uint16_t bg1pix = bg1_base[(coladdr + m_xscroll1) & 0xff];
  				uint8_t sprpix = spr_base[coladdr & 0xff];
  
  				if (bg1pix & 0x80)
  					dst[x + 0] = pens[bg1pix & 0xff];
  				else if (sprpix & 0x80)
  					dst[x + 0] = pens[sprpix];
  				else if (bg1pix & 0xff)
  					dst[x + 0] = pens[bg1pix & 0xff];
  				else if (sprpix)
  					dst[x + 0] = pens[sprpix];
  				else
  					dst[x + 0] = pens[bg0pix & 0xff];
  
  				if (bg1pix & 0x8000)
  					dst[x + 1] = pens[bg1pix >> 8];
  				else if (sprpix & 0x80)
  					dst[x + 1] = pens[sprpix];
  				else if (bg1pix >> 8)
  					dst[x + 1] = pens[bg1pix >> 8];
  				else if (sprpix)
  					dst[x + 1] = pens[sprpix];
  				else
  					dst[x + 1] = pens[bg0pix >> 8];
  			}
  			break;
  	}
  
  	/* debugging - dump the screen contents to a file */
  #if BT_DEBUG
  	popmessage("screen_control = %02X", m_screen_control & 0x7f);
  
  	if (machine().input().code_pressed(KEYCODE_X))
  	{
  		char name[10];
  		FILE *f;
  		int i;
  
  		while (machine().input().code_pressed(KEYCODE_X)) ;
  
  		sprintf(name, "disp%d.log", m_xcount++);
  		f = fopen(name, "w");
  		fprintf(f, "screen_control = %04X\n\n", m_screen_control << 8);
  
  		for (i = 0; i < 3; i++)
  		{
  			uint16_t *base = (i == 0) ? (uint16_t *)m_vram_fg_display : (i == 1) ? m_vram_bg0 : m_vram_bg1;
  			int xscr = (i == 0) ? 0 : (i == 1) ? m_xscroll0 : m_xscroll1;
  			int yscr = (i == 0) ? 0 : (i == 1) ? m_yscroll0 : m_yscroll1;
  			int y;
  
  			for (y = 0; y < 224; y++)
  			{
  				uint32_t offs = ((y + yscr) & 0xff) * TOWORD(0x4000);
  				for (x = 0; x < 256; x++)
  				{
  					uint16_t pix = base[offs + ((x + xscr) & 0xff)];
  					fprintf(f, "%02X%02X", pix & 0xff, pix >> 8);
  					if (x % 16 == 15) fprintf(f, " ");
  				}
  				fprintf(f, "\n");
  			}
  			fprintf(f, "\n\n");
  		}
  		fclose(f);
  	}
  
  	logerror("---VBLANK---\n");
  #endif
  }
  