
/* based on driver from vidhrdw/metro.c by Luca Elia */
/* modified by Eisuke Watanabe */

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

							  -= Metro Games =-

					driver by	Luca Elia (l.elia@tin.it)


Note:	if MAME_DEBUG is defined, pressing Z with:

				Q		Shows Layer 0
				W		Shows Layer 1
				E		Shows Layer 2
				A		Shows Sprites

		Keys can be used together!


							[ 3 Scrolling Layers ]

		There is memory for a huge layer, but the actual tilemap
		is a smaller window (of fixed size) carved from anywhere
		inside that layer.

		Tile Size:				  	8 x 8 x 4
		(later games can switch to  8 x 8 x 8, 16 x 16 x 4/8 at run time)

		Big Layer Size:			2048 x 2048 (8x8 tiles) or 4096 x 4096 (16x16 tiles)

		Tilemap Window Size:	512 x 256 (8x8 tiles) or 1024 x 512 (16x16 tiles)

		The tile codes in memory do not map directly to tiles. They
		are indexes into a table (with 0x200 entries) that defines
		a virtual set of tiles for the 3 layers. Each entry in that
		table adds 16 tiles to the set of available tiles, and decides
		their color code.

		Tile code with their msbit set are different as they mean:
		draw a tile filled with a single color (0-1ff)


							[ 512 Zooming Sprites ]

		The sprites are NOT tile based: the "tile" size can vary from
		8 to 64 (independently for width and height) with an 8 pixel
		granularity. The "tile" address is a multiple of 8x8 pixels.

		Each sprite can be shrinked to ~1/4 or enlarged to ~32x following
		an exponential curve of sizes (with one zoom value for both width
		and height)

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

#include "driver.h"
#include "vidhrdw/generic.h"

#define RASTER_LINES 262
#define FIRST_VISIBLE_LINE 0
#define LAST_VISIBLE_LINE 223

/* Variables that driver has access to: */

data16_t *hyprduel_videoregs;
data16_t *hyprduel_screenctrl;
data16_t *hyprduel_tiletable;
size_t hyprduel_tiletable_size;
data16_t *hyprduel_vram_0,*hyprduel_vram_1,*hyprduel_vram_2;
data16_t *hyprduel_window;

data16_t hyprduel_scrollx[3][RASTER_LINES+1];
data16_t hyprduel_scrolly[3][RASTER_LINES+1];

static data16_t *hypr_tiletable_old;


/***************************************************************************
							Palette GGGGGRRRRRBBBBBx
***************************************************************************/

WRITE16_HANDLER( hyprduel_paletteram_w )
{
	int r,g,b;

	data = COMBINE_DATA(&paletteram16[offset]);

	b = (data >>  1) & 0x1f;
	r = (data >>  6) & 0x1f;
	g = (data >> 11) & 0x1f;

	/* We need the ^0xff because we had to invert the pens in the gfx */
	palette_set_color(offset^0xff,(r << 3) | (r >> 2),(g << 3) | (g >> 2),(b << 3) | (b >> 2));
}


/***************************************************************************
						Tilemaps: Tiles Set & Window

	Each entry in the Tiles Set RAM uses 2 words to specify a starting
	tile code and a color code. This adds 16 consecutive tiles with
	that color code to the set of available tiles.

		Offset:		Bits:					Value:

		0.w			fedc ---- ---- ----
					---- ba98 7654 ----		Color Code
					---- ---- ---- 3210		Code High Bits

		2.w									Code Low Bits
***************************************************************************/


/***************************************************************************
							Tilemaps: Rendering
***************************************************************************/

static struct tilemap *tilemap[3];
static UINT8 *empty_tiles;

/* A 2048 x 2048 virtual tilemap */

#define BIG_NX		(0x100)
#define BIG_NY		(0x100)

/* A smaller 512 x 256 window defines the actual tilemap */

#define WIN_NX		(0x40)
#define WIN_NY		(0x20)
//#define WIN_NX		(0x40+1)
//#define WIN_NY		(0x20+1)


/* 8x8x4 tiles only */
INLINE void get_tile_info(int tile_index,int layer,data16_t *vram)
{
	data16_t code;
	int      table_index;
	UINT32   tile;

	/* The actual tile index depends on the window */
	tile_index	=	((tile_index / WIN_NX + hyprduel_window[layer * 2 + 0] / 8) % BIG_NY) * BIG_NX +
					((tile_index % WIN_NX + hyprduel_window[layer * 2 + 1] / 8) % BIG_NX);

	/* Fetch the code */
	code			=	vram[ tile_index ];

	/* Use it as an index into the tiles set table */
	table_index		=	( (code & 0x1ff0) >> 4 ) * 2;
	tile			=	(hyprduel_tiletable[table_index + 0] << 16 ) +
						 hyprduel_tiletable[table_index + 1];

	if (code & 0x8000) /* Special: draw a tile of a single color (i.e. not from the gfx ROMs) */
	{
		int _code = code & 0x000f;
		tile_info.tile_number = _code;
		tile_info.pen_data = empty_tiles + _code*16*16;
		tile_info.pal_data = &Machine->remapped_colortable[(((code & 0x0ff0) ^ 0x0f0) + 0x1000)];
		tile_info.pen_usage = 0;
		tile_info.flags = 0;
	}
	else
		SET_TILE_INFO(
				0,
				(tile & 0xfffff) + (code & 0xf),
				(((tile & 0x0ff00000) >> 20) ^ 0x0f) + 0x100,
				TILE_FLIPXY((code & 0x6000) >> 13))
}


/* 8x8x4 or 8x8x8 tiles. It's the tile's color that decides: if its low 4
   bits are high ($f,$1f,$2f etc) the tile is 8bpp, otherwise it's 4bpp */
INLINE void get_tile_info_8bit(int tile_index,int layer,data16_t *vram)
{
	data16_t code;
	int      table_index;
	UINT32   tile;

	/* The actual tile index depends on the window */
	tile_index	=	((tile_index / WIN_NX + hyprduel_window[layer * 2 + 0] / 8) % BIG_NY) * BIG_NX +
					((tile_index % WIN_NX + hyprduel_window[layer * 2 + 1] / 8) % BIG_NX);

	/* Fetch the code */
	code			=	vram[ tile_index ];

	/* Use it as an index into the tiles set table */
	table_index		=	( (code & 0x1ff0) >> 4 ) * 2;
	tile			=	(hyprduel_tiletable[table_index + 0] << 16 ) +
						 hyprduel_tiletable[table_index + 1];

	if (code & 0x8000) /* Special: draw a tile of a single color (i.e. not from the gfx ROMs) */
	{
		int _code = code & 0x000f;
		tile_info.tile_number = _code;
		tile_info.pen_data = empty_tiles + _code*16*16;
		tile_info.pal_data = &Machine->remapped_colortable[(((code & 0x0ff0) ^ 0x0f0) + 0x1000)];
		tile_info.pen_usage = 0;
		tile_info.flags = 0;
	}
	else if ((tile & 0x00f00000)==0x00f00000)	/* draw tile as 8bpp */
		SET_TILE_INFO(
				1,
				(tile & 0xfffff) + 2*(code & 0xf),
				((tile & 0x0f000000) >> 24) + 0x10,
				TILE_FLIPXY((code & 0x6000) >> 13))
	else
		SET_TILE_INFO(
				0,
				(tile & 0xfffff) + (code & 0xf),
				(((tile & 0x0ff00000) >> 20) ^ 0x0f) + 0x100,
				TILE_FLIPXY((code & 0x6000) >> 13))
}

/* 16x16x4 or 16x16x8 tiles. It's the tile's color that decides: if its low 4
   bits are high ($f,$1f,$2f etc) the tile is 8bpp, otherwise it's 4bpp */
INLINE void get_tile_info_16x16_8bit(int tile_index,int layer,data16_t *vram)
{
	data16_t code;
	int      table_index;
	UINT32   tile;

	/* The actual tile index depends on the window */
	tile_index	=	((tile_index / WIN_NX + hyprduel_window[layer * 2 + 0] / 8) % BIG_NY) * BIG_NX +
					((tile_index % WIN_NX + hyprduel_window[layer * 2 + 1] / 8) % BIG_NX);

	/* Fetch the code */
	code			=	vram[ tile_index ];

	/* Use it as an index into the tiles set table */
	table_index		=	( (code & 0x1ff0) >> 4 ) * 2;
	tile			=	(hyprduel_tiletable[table_index + 0] << 16 ) +
						 hyprduel_tiletable[table_index + 1];

	if (code & 0x8000) /* Special: draw a tile of a single color (i.e. not from the gfx ROMs) */
	{
		int _code = code & 0x000f;
		tile_info.tile_number = _code;
		tile_info.pen_data = empty_tiles + _code*16*16;
		tile_info.pal_data = &Machine->remapped_colortable[(((code & 0x0ff0) ^ 0x0f0) + 0x1000)];
		tile_info.pen_usage = 0;
		tile_info.flags = 0;
	}
	else if ((tile & 0x00f00000)==0x00f00000)	/* draw tile as 8bpp */
		SET_TILE_INFO(
				3,
				(tile & 0xfffff) + 8*(code & 0xf),
				((tile & 0x0f000000) >> 24) + 0x10,
				TILE_FLIPXY((code & 0x6000) >> 13))
	else
		SET_TILE_INFO(
				2,
				(tile & 0xfffff) + 4*(code & 0xf),
				(((tile & 0x0ff00000) >> 20) ^ 0x0f) + 0x100,
				TILE_FLIPXY((code & 0x6000) >> 13))
}


INLINE void hyprduel_vram_w(offs_t offset,data16_t data,data16_t mem_mask,int layer,data16_t *vram)
{
	data16_t olddata = vram[offset];
	data16_t newdata = COMBINE_DATA(&vram[offset]);
	if ( newdata != olddata )
	{
		/* Account for the window */
		int col		=	(offset % BIG_NX) - ((hyprduel_window[layer * 2 + 1] / 8) % BIG_NX);
		int row		=	(offset / BIG_NX) - ((hyprduel_window[layer * 2 + 0] / 8) % BIG_NY);
		if (col < -(BIG_NX-WIN_NX))	col += (BIG_NX-WIN_NX) + WIN_NX;
		if (row < -(BIG_NY-WIN_NY))	row += (BIG_NY-WIN_NY) + WIN_NY;
		if	( (col >= 0) && (col < WIN_NX) &&
			  (row >= 0) && (row < WIN_NY) )
		{
			tilemap_mark_tile_dirty(tilemap[layer], row * WIN_NX + col );
		}
	}
}



static void get_tile_info_0_8bit(int tile_index) { get_tile_info_8bit(tile_index,0,hyprduel_vram_0); }
static void get_tile_info_1_8bit(int tile_index) { get_tile_info_8bit(tile_index,1,hyprduel_vram_1); }
static void get_tile_info_2_8bit(int tile_index) { get_tile_info_8bit(tile_index,2,hyprduel_vram_2); }

WRITE16_HANDLER( hyprduel_vram_0_w ) { hyprduel_vram_w(offset,data,mem_mask,0,hyprduel_vram_0); }
WRITE16_HANDLER( hyprduel_vram_1_w ) { hyprduel_vram_w(offset,data,mem_mask,1,hyprduel_vram_1); }
WRITE16_HANDLER( hyprduel_vram_2_w ) { hyprduel_vram_w(offset,data,mem_mask,2,hyprduel_vram_2); }


/* Dirty the relevant tilemap when its window changes */
WRITE16_HANDLER( hyprduel_window_w )
{
	data16_t olddata = hyprduel_window[offset];
	data16_t newdata = COMBINE_DATA( &hyprduel_window[offset] );
	if ( newdata != olddata )
	{
		offset /= 2;
		tilemap_mark_all_tiles_dirty(tilemap[offset]);
	}
}


/***************************************************************************
							Video Init Routines
***************************************************************************/

/*
 Sprites are not tile based, so we decode their graphics at runtime.

 We can't do it at startup because drawgfx requires the tiles to be
 pre-rotated to support vertical games, and that, in turn, requires
 the tile's sizes to be known at startup - which we don't!
*/

int hyprduel_sprite_xoffs, hyprduel_sprite_yoffs;


static void alloc_empty_tiles(void)
{
	int code,i;

	empty_tiles = auto_malloc(16*16*16);
	if (!empty_tiles) return;

	for (code = 0;code < 0x10;code++)
		for (i = 0;i < 16*16;i++)
			empty_tiles[16*16*code + i] = code ^ 0x0f;
}

VIDEO_START( hyprduel_14220 )
{
	alloc_empty_tiles();
	hypr_tiletable_old = auto_malloc(hyprduel_tiletable_size);

	tilemap[0] = tilemap_create(get_tile_info_0_8bit,tilemap_scan_rows,TILEMAP_TRANSPARENT,8,8,WIN_NX,WIN_NY);
	tilemap[1] = tilemap_create(get_tile_info_1_8bit,tilemap_scan_rows,TILEMAP_TRANSPARENT,8,8,WIN_NX,WIN_NY);
	tilemap[2] = tilemap_create(get_tile_info_2_8bit,tilemap_scan_rows,TILEMAP_TRANSPARENT,8,8,WIN_NX,WIN_NY);

	if (!tilemap[0] || !tilemap[1] || !tilemap[2] || !empty_tiles || !hypr_tiletable_old)
		return 1;

	tilemap_set_transparent_pen(tilemap[0],0);
	tilemap_set_transparent_pen(tilemap[1],0);
	tilemap_set_transparent_pen(tilemap[2],0);

	tilemap_set_scrolldx(tilemap[0], 0, 0);
	tilemap_set_scrolldx(tilemap[1], 0, 0);
	tilemap_set_scrolldx(tilemap[2], 0, 0);

	return 0;
}

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

								Video Registers


		Offset:		Bits:					Value:

		0.w									Number Of Sprites To Draw
		2.w			fedc ba-- ---- ----		?
					---- --98 ---- ----		Sprites Priority
					---- ---- 7654 3210		?
		4.w									Sprites Y Offset
		6.w									Sprites X Offset
		8.w									Sprites Color Codes Start

		-

		10.w		fedc ba98 76-- ----
					---- ---- --54 ----		Layer 2 Priority (3 backmost, 0 frontmost)
					---- ---- ---- 32--		Layer 1 Priority
					---- ---- ---- --10		Layer 0 Priority

		12.w								Backround Color

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



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

								Sprites Drawing


		Offset:		Bits:					Value:

		0.w			fedc b--- ---- ----		Priority (0 = Max)
					---- -a98 7654 3210		X

		2.w			fedc ba-- ---- ----		Zoom (Both X & Y)
					---- --98 7654 3210		Y

		4.w			f--- ---- ---- ----		Flip X
					-e-- ---- ---- ----		Flip Y
					--dc b--- ---- ----		Size X *
					---- -a98 ---- ----		Size Y *
					---- ---- 7654 ----		Color
					---- ---- ---- 3210		Code High Bits **

		6.w									Code Low Bits  **

*  8 pixel increments
** 8x8 pixel increments
***************************************************************************/

/* Draw sprites of a given priority */

static void hypr_draw_sprites(struct mame_bitmap *bitmap, const struct rectangle *cliprect, int pri)
{
	const int region		=	REGION_GFX1;

	unsigned char *base_gfx	=	memory_region(region);
	unsigned char *gfx_max	=	base_gfx + memory_region_length(region);

	int max_x				=	Machine->drv->screen_width;
	int max_y				=	Machine->drv->screen_height;

	int max_sprites			=	spriteram_size / 8;
	int sprites				=	hyprduel_videoregs[0x00/2] % max_sprites;

	data16_t *src			=	spriteram16 + (sprites - 1) * (8/2);
	data16_t *end			=	spriteram16;

	int color_start			=	((hyprduel_videoregs[0x08/2] & 0xf) << 4 ) + 0x100;

	pri = (~pri & 0x1f) << (16-5);

	for ( ; src >= end; src -= 8/2 )
	{
		int x,y, attr,code,color,flipx,flipy, zoom, curr_pri,width,height;
		unsigned char *gfxdata;

		/* Exponential zoom table extracted from daitoride */
		const int zoomtable[0x40] =
		{	0xAAC,0x800,0x668,0x554,0x494,0x400,0x390,0x334,
			0x2E8,0x2AC,0x278,0x248,0x224,0x200,0x1E0,0x1C8,
			0x1B0,0x198,0x188,0x174,0x164,0x154,0x148,0x13C,
			0x130,0x124,0x11C,0x110,0x108,0x100,0x0F8,0x0F0,
			0x0EC,0x0E4,0x0DC,0x0D8,0x0D4,0x0CC,0x0C8,0x0C4,
			0x0C0,0x0BC,0x0B8,0x0B4,0x0B0,0x0AC,0x0A8,0x0A4,
			0x0A0,0x09C,0x098,0x094,0x090,0x08C,0x088,0x080,
			0x078,0x070,0x068,0x060,0x058,0x050,0x048,0x040	};

		x					=	src[ 0 ];
		curr_pri			=	x & 0xf800;
		if ( (curr_pri == 0xf800) || (curr_pri != pri) )	continue;
		y					=	src[ 1 ];
		attr				=	src[ 2 ];
		code				=	src[ 3 ];

		flipx				=	attr & 0x8000;
		flipy				=	attr & 0x4000;
		color				=   (attr & 0xf0) >> 4;

		zoom				=	zoomtable[(y & 0xfc00) >> 10] << (16-8);

		x					=	(x & 0x07ff) - hyprduel_sprite_xoffs -1;
		y					=	(y & 0x03ff) - hyprduel_sprite_yoffs +2;

		width				= (( (attr >> 11) & 0x7 ) + 1 ) * 8;
		height				= (( (attr >>  8) & 0x7 ) + 1 ) * 8;

		gfxdata		=	base_gfx + (8*8*4/8) * (((attr & 0x000f) << 16) + code);

		if (flip_screen)
		{
			flipx = !flipx;		x = max_x - x - width;
			flipy = !flipy;		y = max_y - y - height;
		}

		if (color == 0xf)	/* 8bpp */
		{
			/* prepare GfxElement on the fly */
			struct GfxElement gfx;
			gfx.width = width;
			gfx.height = height;
			gfx.total_elements = 1;
			gfx.color_granularity = 256;
			gfx.colortable = Machine->remapped_colortable;
			gfx.total_colors = 0x20;
			gfx.pen_usage = NULL;
			gfx.gfxdata = gfxdata;
			gfx.line_modulo = width;
			gfx.char_modulo = 0;	/* doesn't matter */
			gfx.flags = 0;

			/* Bounds checking */
			if ( (gfxdata + width * height - 1) >= gfx_max )
				continue;

			drawgfxzoom(	bitmap,&gfx,
							0,
							color_start >> 4,
							flipx, flipy,
							x, y,
							cliprect, TRANSPARENCY_PEN, 0,
							zoom, zoom	);
		}
		else
		{
			/* prepare GfxElement on the fly */
			struct GfxElement gfx;
			gfx.width = width;
			gfx.height = height;
			gfx.total_elements = 1;
			gfx.color_granularity = 16;
			gfx.colortable = Machine->remapped_colortable;
			gfx.total_colors = 0x200;
			gfx.pen_usage = NULL;
			gfx.gfxdata = gfxdata;
			gfx.line_modulo = width/2;
			gfx.char_modulo = 0;	/* doesn't matter */
			gfx.flags = GFX_PACKED;

			/* Bounds checking */
			if ( (gfxdata + width/2 * height - 1) >= gfx_max )
				continue;

			drawgfxzoom(	bitmap,&gfx,
							0,
							(color ^ 0x0f) + color_start,
							flipx, flipy,
							x, y,
							cliprect, TRANSPARENCY_PEN, 0,
							zoom, zoom	);
		}
#if 0
{	/* Display priority + zoom on each sprite */
	struct DisplayText dt[2];	char buf[80];
	sprintf(buf, "%02X %02X",((src[ 0 ] & 0xf800) >> 11)^0x1f,((src[ 1 ] & 0xfc00) >> 10) );
    dt[0].text = buf;	dt[0].color = UI_COLOR_NORMAL;
    dt[0].x = x;    dt[0].y = y;    dt[1].text = 0; /* terminate array */
	displaytext(Machine->scrbitmap,dt);		}
#endif
	}
}


/***************************************************************************
								Screen Drawing
***************************************************************************/

/* Draw all the layers that match the given priority */
static void draw_layers(struct mame_bitmap *bitmap, const struct rectangle *cliprect, int pri, int layers_ctrl)
{
	data16_t layers_pri = hyprduel_videoregs[0x10/2];
	int layer;
	int offs;
	struct rectangle clip;

	clip.min_x = 0;
	clip.max_x = 319;

	/* Draw all the layers with priority == pri */
	for (layer = 2; layer >= 0; layer--)	// tilemap[2] below?
	{
		if ( pri == ((layers_pri >> (layer*2)) & 3) )
		{
			/* Scroll and Window values */
			data16_t wx = hyprduel_window[layer * 2 + 1];
			data16_t wy = hyprduel_window[layer * 2 + 0];
			wx = wx - (wx & 7);
			wy = wy - (wy & 7);

			if (layers_ctrl & (1<<layer))
			{
				for (offs = cliprect->min_y; offs <= cliprect->max_y; offs++)
				{
					clip.min_y = offs;
					clip.max_y = offs;

					tilemap_set_scrollx(tilemap[layer], 0, hyprduel_scrollx[layer][offs+RASTER_LINES-(LAST_VISIBLE_LINE+1)] - wx);
					tilemap_set_scrolly(tilemap[layer], 0, hyprduel_scrolly[layer][offs+RASTER_LINES-(LAST_VISIBLE_LINE+1)] - wy);
					tilemap_draw(bitmap,&clip,tilemap[layer], 0, 0);
				}
			}
		}
	}
}


/* Dirty tilemaps when the tiles set changes */
static void dirty_tiles(int layer,data16_t *vram,data8_t *dirtyindex)
{
	int col,row;

	for (row = 0;row < WIN_NY;row++)
	{
		for (col = 0;col < WIN_NX;col++)
		{
			int offset = (col + hyprduel_window[layer * 2 + 1] / 8) % BIG_NX +
						((row + hyprduel_window[layer * 2 + 0] / 8) % BIG_NY) * BIG_NX;
			data16_t code = vram[offset];

			if (!(code & 0x8000) && dirtyindex[(code & 0x1ff0) >> 4])
				tilemap_mark_tile_dirty(tilemap[layer], row * WIN_NX + col );
		}
	}
}


VIDEO_UPDATE( hyprduel )
{
	int i,pri,sprites_pri,layers_ctrl = -1;
	data8_t *dirtyindex;
	data16_t screenctrl = *hyprduel_screenctrl;

	dirtyindex = malloc(hyprduel_tiletable_size/4);
	if (dirtyindex)
	{
		int dirty = 0;

		memset(dirtyindex,0,hyprduel_tiletable_size/4);
		for (i = 0;i < hyprduel_tiletable_size/4;i++)
		{
			UINT32 tile_new = (hyprduel_tiletable[2*i + 0] << 16 ) + hyprduel_tiletable[2*i + 1];
			UINT32 tile_old = (hypr_tiletable_old[2*i + 0] << 16 ) + hypr_tiletable_old[2*i + 1];

			if ((tile_new ^ tile_old) & 0x0fffffff)
			{
				dirtyindex[i] = 1;
				dirty = 1;
			}
		}
		memcpy(hypr_tiletable_old,hyprduel_tiletable,hyprduel_tiletable_size);

		if (dirty)
		{
			dirty_tiles(0,hyprduel_vram_0,dirtyindex);
			dirty_tiles(1,hyprduel_vram_1,dirtyindex);
			dirty_tiles(2,hyprduel_vram_2,dirtyindex);
		}
		free(dirtyindex);
	}

	hyprduel_sprite_xoffs	=	hyprduel_videoregs[0x06/2] - Machine->drv->screen_width  / 2;
	hyprduel_sprite_yoffs	=	hyprduel_videoregs[0x04/2] - Machine->drv->screen_height / 2;

	/* The background color is selected by a register */
	fillbitmap(bitmap,Machine->pens[((hyprduel_videoregs[0x12/2] & 0x0fff) ^ 0x0ff) + 0x1000],cliprect);

	/*	Screen Control Register:

		f--- ---- ---- ----		?
		-edc b--- ---- ----
		---- -a98 ---- ----		? Leds
		---- ---- 7--- ----		16x16 Tiles (Layer 2)
		---- ---- -6-- ----		16x16 Tiles (Layer 1)
		---- ---- --5- ----		16x16 Tiles (Layer 0)
		---- ---- ---4 32--
		---- ---- ---- --1-		? Blank Screen
		---- ---- ---- ---0		Flip  Screen	*/
	if (screenctrl & 2)	return;
	flip_screen_set(screenctrl & 1);

	/* If the game supports 16x16 tiles, make sure that the
	   16x16 and 8x8 tilemaps of a given layer are not simultaneously
	   enabled! */

	/* Sprites priority wrt layers: 3..0 (low..high) */
	sprites_pri	=	(hyprduel_videoregs[0x02/2] & 0x0300) >> 8;

	for (pri = 3; pri >=0; pri--)
	{
		draw_layers(bitmap,cliprect,pri,layers_ctrl);

		if ((layers_ctrl & 8) && (sprites_pri == pri))
			for (i = 0; i < 0x20; i++)
				hypr_draw_sprites(bitmap,cliprect, i);
	}
}
