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

                      -= Fantasy Land / Galaxy Gunners =-

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

    This game has sprites only:

    tiles are 16 x 16 x 6. There are $400 sprites, each one is allotted
    8 bytes of memory (but only 5 are used) :

    Offset:     Bits:           Value:

        0                       X (low bits)

        1       7--- ----       X (high bit)
                -6-- ----       Y (high bit)
                --5- ----       Flip X
                ---4 ----       Flip Y
                ---- 32--
                ---- --10       Color

        2                       Code (high bits)

        3                       Code (low bits)

        4                       Y (low bits)

    Then follows a table with 1 byte per sprite: the index of a x,y
    and code offset that sprite will use, from a table with 256 entries:

        0                       Y offset (low bits)

        1       7654 321-       Code offset
                ---- ---0       Y offset (high bit)

        2                       X offset (low bits)

        3                       X offset (high bit)

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

#include "vidhrdw/generic.h"

static void fantland_draw_sprites(struct mame_bitmap *bitmap,const struct rectangle *cliprect)
{
	data8_t	*ram	=	spriteram,		// spriteram start
			*end	=	ram + 0x2000,	// spriteram end
			*ram2	=	ram + 0x2000;	// table of indexes into the table of offsets

	for ( ; ram < end; ram += 8,ram2 ++)
	{
		int attr,code,color, x,y,xoffs,yoffs,flipx,flipy, idx;

		attr	=	ram[1];

		x		=	ram[0];
		code	=	ram[3] + (ram[2] << 8);
		y		=	ram[4];

		color	=	(attr & 0x03);
		flipy	=	(attr & 0x10);
		flipx	=	(attr & 0x20);

		y		+=	(attr & 0x40) << 2;
		x		+=	(attr & 0x80) << 1;

		/* Index in the table of offsets */
		idx		=	ram2[0] * 4;

		/* Fetch the offsets */
		yoffs	=	spriteram_2[idx + 0] + (spriteram_2[idx + 1] << 8);
		xoffs	=	spriteram_2[idx + 2] + (spriteram_2[idx + 3] << 8);

		y		+=	yoffs;
		x		+=	xoffs;
		code	+=	yoffs >> 9;

		y		=	(y & 0xff) - (y & 0x100);
		x		=	(x & 0x1ff);

		if (x >= 0x180)		x -= 0x200;

		drawgfx(bitmap,Machine->gfx[0], code,color, flipx,flipy, x,y, &Machine->visible_area,TRANSPARENCY_PEN,0);
	}
}

VIDEO_UPDATE( fantland )
{
	fillbitmap(bitmap,Machine->pens[0],cliprect);
	fantland_draw_sprites(bitmap,cliprect);
}

