text: /***************************************************************************
  
    vidhrdw.c
  
    Functions to emulate the video hardware of the machine.
  
  ***************************************************************************/
  
  #include "driver.h"
  #include "vidhrdw/generic.h"
  
  UINT8 *sbasketb_scroll;
  UINT8 *sbasketb_palettebank;
  UINT8 *sbasketb_spriteram_select;
  
  static struct tilemap *bg_tilemap;
  
  /***************************************************************************
  
    Convert the color PROMs into a more useable format.
  
    Super Basketball has three 256x4 palette PROMs (one per gun) and two 256x4
    lookup table PROMs (one for characters, one for sprites).
    I don't know for sure how the palette PROMs are connected to the RGB
    output, but it's probably the usual:
  
    bit 3 -- 220 ohm resistor  -- RED/GREEN/BLUE
          -- 470 ohm resistor  -- RED/GREEN/BLUE
          -- 1  kohm resistor  -- RED/GREEN/BLUE
    bit 0 -- 2.2kohm resistor  -- RED/GREEN/BLUE
  
  ***************************************************************************/
  PALETTE_INIT( sbasketb )
  {
  	int i;
  	#define TOTAL_COLORS(gfxn) (Machine->gfx[gfxn]->total_colors * Machine->gfx[gfxn]->color_granularity)
  	#define COLOR(gfxn,offs) (colortable[Machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])
  
  
  	for (i = 0;i < Machine->drv->total_colors;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[Machine->drv->total_colors] >> 0) & 0x01;
  		bit1 = (color_prom[Machine->drv->total_colors] >> 1) & 0x01;
  		bit2 = (color_prom[Machine->drv->total_colors] >> 2) & 0x01;
  		bit3 = (color_prom[Machine->drv->total_colors] >> 3) & 0x01;
  		g = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
  		bit0 = (color_prom[2*Machine->drv->total_colors] >> 0) & 0x01;
  		bit1 = (color_prom[2*Machine->drv->total_colors] >> 1) & 0x01;
  		bit2 = (color_prom[2*Machine->drv->total_colors] >> 2) & 0x01;
  		bit3 = (color_prom[2*Machine->drv->total_colors] >> 3) & 0x01;
  		b = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
  
  		palette_set_color(i,r,g,b);
  		color_prom++;
  	}
  
  	color_prom += 2*Machine->drv->total_colors;
  	/* color_prom now points to the beginning of the character lookup table */
  
  
  	/* characters use colors 240-255 */
  	for (i = 0;i < TOTAL_COLORS(0);i++)
  		COLOR(0,i) = (*(color_prom++) & 0x0f) + 240;
  
  	/* sprites use colors 0-256 (?) in 16 banks */
  	for (i = 0;i < TOTAL_COLORS(1)/16;i++)
  	{
  		int j;
  
  
  		for (j = 0;j < 16;j++)
  			COLOR(1,i + j * TOTAL_COLORS(1)/16) = (*color_prom & 0x0f) + 16 * j;
  
  		color_prom++;
  	}
  }
  
  WRITE_HANDLER( sbasketb_videoram_w )
  {
  	if (videoram[offset] != data)
  	{
  		videoram[offset] = data;
  		tilemap_mark_tile_dirty(bg_tilemap, offset);
  	}
  }
  
  WRITE_HANDLER( sbasketb_colorram_w )
  {
  	if (colorram[offset] != data)
  	{
  		colorram[offset] = data;
  		tilemap_mark_tile_dirty(bg_tilemap, offset);
  	}
  }
  
  WRITE_HANDLER( sbasketb_flipscreen_w )
  {
  	if (flip_screen != data)
  	{
  		flip_screen_set(data);
  		tilemap_mark_all_tiles_dirty(ALL_TILEMAPS);
  	}
  }
  
  WRITE_HANDLER( sbasketb_scroll_w )
  {
  	int col;
  
  	for (col = 6; col < 32; col++)
  	{
  		tilemap_set_scrolly(bg_tilemap, col, data);
  	}
  }
  
  static void get_bg_tile_info(int tile_index)
  {
  	int code = videoram[tile_index] + ((colorram[tile_index] & 0x20) << 3);
  	int color = colorram[tile_index] & 0x0f;
  	int flags = ((colorram[tile_index] & 0x40) ? TILE_FLIPX : 0) | ((colorram[tile_index] & 0x80) ? TILE_FLIPY : 0);
  
  	SET_TILE_INFO(0, code, color, flags)
  }
  
  VIDEO_START( sbasketb )
  {
  	bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows, 
  		TILEMAP_OPAQUE, 8, 8, 32, 32);
  
  	if ( !bg_tilemap )
  		return 1;
  
  	tilemap_set_scroll_cols(bg_tilemap, 32);
  
  	return 0;
  }
  
  static void sbasketb_draw_sprites( struct mame_bitmap *bitmap )
  {
  	int offs = (*sbasketb_spriteram_select & 0x01) * 0x100;
  	int i;
  
  	for (i = 0; i < 64; i++, offs += 4)
  	{
  		int sx = spriteram[offs + 2];
  		int sy = spriteram[offs + 3];
  
  		if (sx || sy)
  		{
  			int code  =  spriteram[offs + 0] | ((spriteram[offs + 1] & 0x20) << 3);
  			int color = (spriteram[offs + 1] & 0x0f) + 16 * *sbasketb_palettebank;
  			int flipx =  spriteram[offs + 1] & 0x40;
  			int flipy =  spriteram[offs + 1] & 0x80;
  
  			if (flip_screen)
  			{
  				sx = 240 - sx;
  				sy = 240 - sy;
  				flipx = !flipx;
  				flipy = !flipy;
  			}
  
  			drawgfx(bitmap,Machine->gfx[1],
  				code, color,
  				flipx, flipy,
  				sx, sy,
  				&Machine->visible_area,
  				TRANSPARENCY_PEN, 0);
  		}
  	}
  }
  
  VIDEO_UPDATE( sbasketb )
  {
  	tilemap_draw(bitmap, &Machine->visible_area, bg_tilemap, 0, 0);
  	sbasketb_draw_sprites(bitmap);
  }
  