text: /***************************************************************************
  
      Atari Rampart hardware
  
  ****************************************************************************/
  
  #include "driver.h"
  #include "machine/atarigen.h"
  #include "rampart.h"
  
  
  
  /*************************************
   *
   *  Globals we own
   *
   *************************************/
  
  UINT16 *rampart_bitmap;
  
  
  
  /*************************************
   *
   *  Statics
   *
   *************************************/
  
  static UINT8 *pfdirty;
  static mame_bitmap *pfbitmap;
  static int xdim, ydim;
  
  
  
  /*************************************
   *
   *  Video system start
   *
   *************************************/
  
  VIDEO_START( rampart )
  {
  	static const struct atarimo_desc modesc =
  	{
  		0,					/* index to which gfx system */
  		1,					/* number of motion object banks */
  		1,					/* are the entries linked? */
  		0,					/* are the entries split? */
  		0,					/* render in reverse order? */
  		0,					/* render in swapped X/Y order? */
  		0,					/* does the neighbor bit affect the next object? */
  		8,					/* pixels per SLIP entry (0 for no-slip) */
  		0,					/* pixel offset for SLIPs */
  		0,					/* maximum number of links to visit/scanline (0=all) */
  
  		0x100,				/* base palette entry */
  		0x100,				/* maximum number of colors */
  		0,					/* transparent pen index */
  
  		{{ 0x00ff,0,0,0 }},	/* mask for the link */
  		{{ 0 }},			/* mask for the graphics bank */
  		{{ 0,0x7fff,0,0 }},	/* mask for the code index */
  		{{ 0 }},			/* mask for the upper code index */
  		{{ 0,0,0x000f,0 }},	/* mask for the color */
  		{{ 0,0,0xff80,0 }},	/* mask for the X position */
  		{{ 0,0,0,0xff80 }},	/* mask for the Y position */
  		{{ 0,0,0,0x0070 }},	/* mask for the width, in tiles*/
  		{{ 0,0,0,0x0007 }},	/* mask for the height, in tiles */
  		{{ 0,0x8000,0,0 }},	/* mask for the horizontal flip */
  		{{ 0 }},			/* mask for the vertical flip */
  		{{ 0 }},			/* mask for the priority */
  		{{ 0 }},			/* mask for the neighbor */
  		{{ 0 }},			/* mask for absolute coordinates */
  
  		{{ 0 }},			/* mask for the special value */
  		0,					/* resulting value to indicate "special" */
  		0,					/* callback routine for special entries */
  	};
  
  	/* initialize the playfield */
  	rampart_bitmap_init(machine, 43*8, 30*8);
  
  	/* initialize the motion objects */
  	atarimo_init(machine, 0, &modesc);
  
  	/* set the intial scroll offset */
  	atarimo_set_xscroll(0, -4);
  }
  
  
  
  /*************************************
   *
   *  Main refresh
   *
   *************************************/
  
  VIDEO_UPDATE( rampart )
  {
  	struct atarimo_rect_list rectlist;
  	mame_bitmap *mobitmap;
  	int x, y, r;
  
  	/* draw the playfield */
  	rampart_bitmap_render(machine, bitmap, cliprect);
  
  	/* draw and merge the MO */
  	mobitmap = atarimo_render(machine, 0, cliprect, &rectlist);
  	for (r = 0; r < rectlist.numrects; r++, rectlist.rect++)
  		for (y = rectlist.rect->min_y; y <= rectlist.rect->max_y; y++)
  		{
  			UINT16 *mo = (UINT16 *)mobitmap->base + mobitmap->rowpixels * y;
  			UINT16 *pf = (UINT16 *)bitmap->base + bitmap->rowpixels * y;
  			for (x = rectlist.rect->min_x; x <= rectlist.rect->max_x; x++)
  				if (mo[x])
  				{
  					/* not yet verified
                      */
  					pf[x] = mo[x];
  
  					/* erase behind ourselves */
  					mo[x] = 0;
  				}
  		}
  	return 0;
  }
  
  
  
  /*************************************
   *
   *  Bitmap initialization
   *
   *************************************/
  
  void rampart_bitmap_init(running_machine *machine, int _xdim, int _ydim)
  {
  	/* set the dimensions */
  	xdim = _xdim;
  	ydim = _ydim;
  
  	/* allocate dirty map */
  	pfdirty = auto_malloc(sizeof(pfdirty[0]) * ydim);
  	memset(pfdirty, 1, sizeof(pfdirty[0]) * ydim);
  
  	/* allocate playfield bitmap */
  	pfbitmap = auto_bitmap_alloc(xdim, ydim, machine->screen[0].format);
  }
  
  
  
  /*************************************
   *
   *  Bitmap RAM write handler
   *
   *************************************/
  
  WRITE16_HANDLER( rampart_bitmap_w )
  {
  	int oldword = rampart_bitmap[offset];
  	int newword = oldword;
  	int x, y;
  
  	COMBINE_DATA(&newword);
  	if (oldword != newword)
  	{
  		rampart_bitmap[offset] = newword;
  
  		/* track color usage */
  		x = offset % 256;
  		y = offset / 256;
  		if (x < xdim && y < ydim)
  			pfdirty[y] = 1;
  	}
  }
  
  
  
  /*************************************
   *
   *  Bitmap rendering
   *
   *************************************/
  
  void rampart_bitmap_render(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect)
  {
  	int x, y;
  
  	/* update any dirty scanlines */
  	for (y = 0; y < ydim; y++)
  		if (pfdirty[y])
  		{
  			const UINT16 *src = &rampart_bitmap[256 * y];
  			UINT8 scanline[512];
  			UINT8 *dst = scanline;
  
  			/* regenerate the line */
  			for (x = 0; x < xdim / 2; x++)
  			{
  				int bits = *src++;
  				*dst++ = bits >> 8;
  				*dst++ = bits;
  			}
  			pfdirty[y] = 0;
  
  			/* draw it */
  			draw_scanline8(pfbitmap, 0, y, xdim, scanline, machine->pens, -1);
  		}
  
  	/* copy the cached bitmap */
  	copybitmap(bitmap, pfbitmap, 0, 0, 0, 0, cliprect, TRANSPARENCY_NONE, 0);
  }
  