text: #include "driver.h"
  #include "video/konamiic.h"
  
  
  static int layer_colorbase[3],sprite_colorbase,bg_colorbase;
  static int layerpri[3];
  
  
  /***************************************************************************
  
    Callbacks for the K052109
  
  ***************************************************************************/
  
  static void tile_callback(int layer,int bank,int *code,int *color,int *flags,int *priority)
  {
  	*code |= ((*color & 0x03) << 8) | ((*color & 0x10) << 6) | ((*color & 0x0c) << 9) | (bank << 13);
  	*color = layer_colorbase[layer] + ((*color & 0xe0) >> 5);
  }
  
  /***************************************************************************
  
    Callbacks for the K053245
  
  ***************************************************************************/
  
  static void sprite_callback(int *code,int *color,int *priority_mask)
  {
  	int pri = 0x20 | ((*color & 0x60) >> 2);
  	if (pri <= layerpri[2])								*priority_mask = 0;
  	else if (pri > layerpri[2] && pri <= layerpri[1])	*priority_mask = 0xf0;
  	else if (pri > layerpri[1] && pri <= layerpri[0])	*priority_mask = 0xf0|0xcc;
  	else 												*priority_mask = 0xf0|0xcc|0xaa;
  
  	*color = sprite_colorbase + (*color & 0x1f);
  }
  
  
  /***************************************************************************
  
      Start the video hardware emulation.
  
  ***************************************************************************/
  
  VIDEO_START( parodius )
  {
  	K053251_vh_start();
  	K052109_vh_start(machine,REGION_GFX1,NORMAL_PLANE_ORDER,tile_callback);
  	K053245_vh_start(machine,0,REGION_GFX2,NORMAL_PLANE_ORDER,sprite_callback);
  }
  
  /* useful function to sort the three tile layers by priority order */
  static void sortlayers(int *layer,int *pri)
  {
  #define SWAP(a,b) \
  	if (pri[a] < pri[b]) \
  	{ \
  		int t; \
  		t = pri[a]; pri[a] = pri[b]; pri[b] = t; \
  		t = layer[a]; layer[a] = layer[b]; layer[b] = t; \
  	}
  
  	SWAP(0,1)
  	SWAP(0,2)
  	SWAP(1,2)
  }
  
  VIDEO_UPDATE( parodius )
  {
  	int layer[3];
  
  
  	bg_colorbase       = K053251_get_palette_index(K053251_CI0);
  	sprite_colorbase   = K053251_get_palette_index(K053251_CI1);
  	layer_colorbase[0] = K053251_get_palette_index(K053251_CI2);
  	layer_colorbase[1] = K053251_get_palette_index(K053251_CI4);
  	layer_colorbase[2] = K053251_get_palette_index(K053251_CI3);
  
  	K052109_tilemap_update();
  
  	layer[0] = 0;
  	layerpri[0] = K053251_get_priority(K053251_CI2);
  	layer[1] = 1;
  	layerpri[1] = K053251_get_priority(K053251_CI4);
  	layer[2] = 2;
  	layerpri[2] = K053251_get_priority(K053251_CI3);
  
  	sortlayers(layer,layerpri);
  
  	fillbitmap(priority_bitmap,0,cliprect);
  	fillbitmap(bitmap,machine->pens[16 * bg_colorbase],cliprect);
  	tilemap_draw(bitmap,cliprect,K052109_tilemap[layer[0]],0,1);
  	tilemap_draw(bitmap,cliprect,K052109_tilemap[layer[1]],0,2);
  	tilemap_draw(bitmap,cliprect,K052109_tilemap[layer[2]],0,4);
  
  	K053245_sprites_draw(0,bitmap,cliprect);
  	return 0;
  }
  