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

                          -= ESD 16 Bit Games =-

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


Note:   if MAME_DEBUG is defined, pressing Z with:

        Q / W           Shows Layer 0 / 1
        A               Shows Sprites

        Keys can be used together!


    [ 2 Scrolling Layers ]

        Tile Size:              8 x 8 x 8
        Color Codes:            1 per Layer (banked for Layer 0)
        Layer Size (tiles) :    128 x 64
        Layer Size (pixels):    1024 x 512

    [ 256 Sprites ]

        Sprites are made of 16 x 16 x 5 tiles. Size can vary from 1 to
        8 tiles vertically, while their width is always 1 tile.

    [ Priorities ]

        The game only uses this scheme:

        Back -> Front:  Layer 0, Layer 1, Sprites

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

#include "driver.h"

/* Variables needed by drivers: */

UINT16 *esd16_vram_0, *esd16_scroll_0;
UINT16 *esd16_vram_1, *esd16_scroll_1;
UINT16 *head_layersize;
static int esd16_tilemap0_color = 0;

/* Functions defined in video: */

WRITE16_HANDLER( esd16_vram_0_w );
WRITE16_HANDLER( esd16_vram_1_w );
WRITE16_HANDLER( esd16_tilemap0_color_w );

VIDEO_START( esd16 );
VIDEO_UPDATE( esd16 );


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

                                    Tilemaps

    Offset:     Bits:                   Value:

        0.w                             Code

    Color code:  layer 0 (backmost) can bank at every 256 colors,
                 layer 1 uses the first 256.

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

tilemap *esdtilemap_0, *esdtilemap_1, *esdtilemap_1_16x16;

static void get_tile_info_0(int tile_index)
{
	UINT16 code = esd16_vram_0[tile_index];
	SET_TILE_INFO(
			1,
			code,
			esd16_tilemap0_color,
			0)
}

static void get_tile_info_1(int tile_index)
{
	UINT16 code = esd16_vram_1[tile_index];
	SET_TILE_INFO(
			1,
			code,
			0,
			0)
}

static void get_tile_info_1_16x16(int tile_index)
{
	UINT16 code = esd16_vram_1[tile_index];
	SET_TILE_INFO(
			2,
			code,
			0,
			0)
}

WRITE16_HANDLER( esd16_vram_0_w )
{
	UINT16 old_data	=	esd16_vram_0[offset];
	UINT16 new_data	=	COMBINE_DATA(&esd16_vram_0[offset]);
	if (old_data != new_data)	tilemap_mark_tile_dirty(esdtilemap_0,offset);
}

WRITE16_HANDLER( esd16_vram_1_w )
{
	UINT16 old_data	=	esd16_vram_1[offset];
	UINT16 new_data	=	COMBINE_DATA(&esd16_vram_1[offset]);
	if (old_data != new_data)
	{
		tilemap_mark_tile_dirty(esdtilemap_1,offset);
		tilemap_mark_tile_dirty(esdtilemap_1_16x16,offset);
	}
}

WRITE16_HANDLER( esd16_tilemap0_color_w )
{
	esd16_tilemap0_color = data & 3;
	tilemap_mark_all_tiles_dirty(esdtilemap_0);

	flip_screen_set(data & 0x80);
}


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


                            Video Hardware Init


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


VIDEO_START( esd16 )
{
	esdtilemap_0 = tilemap_create(	get_tile_info_0, tilemap_scan_rows,
								TILEMAP_OPAQUE,			8,8,	0x80,0x40);

	esdtilemap_1 = tilemap_create(	get_tile_info_1, tilemap_scan_rows,
								TILEMAP_TRANSPARENT,	8,8,	0x80,0x40);

	/* hedpanic changes tilemap 1 to 16x16 at various times */
	esdtilemap_1_16x16 = tilemap_create(	get_tile_info_1_16x16, tilemap_scan_rows,
								TILEMAP_TRANSPARENT,	16,16,	0x40,0x40);

	tilemap_set_scrolldx(esdtilemap_0, -0x60 + 2, -0x60     );
	tilemap_set_scrolldx(esdtilemap_1, -0x60    , -0x60 + 2 );
	tilemap_set_scrolldx(esdtilemap_1_16x16, -0x60    , -0x60 + 2 );

	tilemap_set_transparent_pen(esdtilemap_0,0x00);
	tilemap_set_transparent_pen(esdtilemap_1,0x00);
	tilemap_set_transparent_pen(esdtilemap_1_16x16,0x00);

	return 0;
}




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

                                Sprites Drawing

    Offset:     Bits:                   Value:

        0.w     fedc b--- ---- ----
                ---- -a9- ---- ----     Y Size: (1 << N) Tiles
                ---- ---8 7654 3210     Y (Signed, Bottom-Up)

        2.w                             Code

        4.w     f--- ---- ---- ----     Sprite priority
                -ed- ---- ---- ----
                ---c ---- ---- ----     Color?
                ---- ba9- ---- ----     Color
                ---- ---8 7654 3210     X (Signed)

        6.w     fedc ba9- ---- ----
                ---- ---8 ---- ----     ? 1 (Display Sprite?)
                ---- ---- 7654 3210

- To Do: Flip X&Y ? They seem unused.

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

static void esd16_draw_sprites(mame_bitmap *bitmap, const rectangle *cliprect)
{
	int offs;

	int max_x		=	Machine->screen[0].width;
	int max_y		=	Machine->screen[0].height;

	for ( offs = spriteram_size/2 - 8/2; offs >= 0 ; offs -= 8/2 )
	{
		int y, starty, endy, incy;

		int	sy		=	spriteram16[ offs + 0 ];
		int	code	=	spriteram16[ offs + 1 ];
		int	sx		=	spriteram16[ offs + 2 ];
		int	attr	=	spriteram16[ offs + 3 ];

		int dimy	=	1 << ((sy >> 9) & 3);

		int	flipx	=	attr & 0x0000;
		int	flipy	=	attr & 0x0000;

		int color	=	(sx >> 9) & 0xf;

		int pri_mask;

		if(sx & 0x8000)
			pri_mask = 0xfffe; // under "tilemap 1"
		else
			pri_mask = 0; // above everything

		sx	=	sx & 0x1ff;
		if (sx >= 0x180)	sx -= 0x200;

		sy	 =	0x100 - ((sy & 0xff)  - (sy & 0x100));
		sy	-=	dimy*16;

		if (flip_screen)
		{	flipx = !flipx;		sx = max_x - sx -    1 * 16 + 2;	// small offset
			flipy = !flipy;		sy = max_y - sy - dimy * 16;	}

		if (flipy)	{	starty = sy+(dimy-1)*16;	endy = sy-16;		incy = -16;	}
		else		{	starty = sy;				endy = sy+dimy*16;	incy = +16;	}

		for (y = starty ; y != endy ; y += incy)
		{
			pdrawgfx(	bitmap, Machine->gfx[0],
						code++,
						color,
						flipx, flipy,
						sx, y,
						cliprect, TRANSPARENCY_PEN, 0, pri_mask	);
		}
	}
}

/* note, check if i can re-merge this with the other or if its really different */
static void hedpanic_draw_sprites(mame_bitmap *bitmap, const rectangle *cliprect)
{
	int offs;

	int max_x		=	Machine->screen[0].width;
	int max_y		=	Machine->screen[0].height;

	for ( offs = spriteram_size/2 - 8/2; offs >= 0 ; offs -= 8/2 )
	{
		int y, starty, endy, incy;

		int	sy		=	spriteram16[ offs + 0 ];
		int	code	=	spriteram16[ offs + 1 ];
		int	sx		=	spriteram16[ offs + 2 ];
//      int attr    =   spriteram16[ offs + 3 ];

		int dimy	=	1 << ((sy >> 9) & 3);

		int	flipx	=	spriteram16[ offs + 0 ] & 0x2000;
		int	flipy	=	sy & 0x0000;

		int color	=	(sx >> 9) & 0xf;

		int pri_mask;

		if(sx & 0x8000)
			pri_mask = 0xfffe; // under "tilemap 1"
		else
			pri_mask = 0; // above everything

		sx	=	sx & 0x1ff;
		if (sx >= 0x180)	sx -= 0x200;

		sy &= 0x1ff;

		sx -= 24;

		sy = 0x1ff-sy;

		if (flip_screen)
		{	flipx = !flipx;		sx = max_x - sx -    1 * 16 + 2;	// small offset
			flipy = !flipy;		sy = max_y - sy - dimy * 16;	}

		if (flipy)	{	starty = sy+(dimy-1)*16;	endy = sy-16;		incy = -16;	}
		else		{	starty = sy-dimy*16;				endy = sy;	incy = +16;	}

		for (y = starty ; y != endy ; y += incy)
		{
			pdrawgfx(	bitmap, Machine->gfx[0],
						code++,
						color,
						flipx, flipy,
						sx, y,
						cliprect, TRANSPARENCY_PEN, 0, pri_mask	);
		}
	}
}



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


                                Screen Drawing


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

VIDEO_UPDATE( esd16 )
{
	int layers_ctrl = -1;

	fillbitmap(priority_bitmap,0,cliprect);

	tilemap_set_scrollx(esdtilemap_0, 0, esd16_scroll_0[0]);
	tilemap_set_scrolly(esdtilemap_0, 0, esd16_scroll_0[1]);

	tilemap_set_scrollx(esdtilemap_1, 0, esd16_scroll_1[0]);
	tilemap_set_scrolly(esdtilemap_1, 0, esd16_scroll_1[1]);

#ifdef MAME_DEBUG
if ( code_pressed(KEYCODE_Z) )
{	int msk = 0;
	if (code_pressed(KEYCODE_Q))	msk |= 1;
	if (code_pressed(KEYCODE_W))	msk |= 2;
	if (code_pressed(KEYCODE_A))	msk |= 4;
	if (msk != 0) layers_ctrl &= msk;	}
#endif

	if (layers_ctrl & 1)	tilemap_draw(bitmap,cliprect,esdtilemap_0,0,0);
	else					fillbitmap(bitmap,machine->pens[0],cliprect);

	if (layers_ctrl & 2)	tilemap_draw(bitmap,cliprect,esdtilemap_1,0,1);

	if (layers_ctrl & 4)	esd16_draw_sprites(bitmap,cliprect);
	return 0;
}


VIDEO_UPDATE( hedpanic )
{
	int layers_ctrl = -1;

	fillbitmap(priority_bitmap,0,cliprect);

	tilemap_set_scrollx(esdtilemap_0, 0, esd16_scroll_0[0]);
	tilemap_set_scrolly(esdtilemap_0, 0, esd16_scroll_0[1]);

#ifdef MAME_DEBUG
if ( code_pressed(KEYCODE_Z) )
{	int msk = 0;
	if (code_pressed(KEYCODE_Q))	msk |= 1;
	if (code_pressed(KEYCODE_W))	msk |= 2;
	if (code_pressed(KEYCODE_A))	msk |= 4;
	if (msk != 0) layers_ctrl &= msk;	}
#endif

	if (layers_ctrl & 1)	tilemap_draw(bitmap,cliprect,esdtilemap_0,0,0);
	else					fillbitmap(bitmap,machine->pens[0],cliprect);

	if (layers_ctrl & 2)
	{
		if (head_layersize[0]&0x0002)
		{
			tilemap_set_scrollx(esdtilemap_1_16x16, 0, esd16_scroll_1[0]);
			tilemap_set_scrolly(esdtilemap_1_16x16, 0, esd16_scroll_1[1]);
			tilemap_draw(bitmap,cliprect,esdtilemap_1_16x16,0,1);
		}
		else
		{
			tilemap_set_scrollx(esdtilemap_1, 0, esd16_scroll_1[0]);
			tilemap_set_scrolly(esdtilemap_1, 0, esd16_scroll_1[1]);
			tilemap_draw(bitmap,cliprect,esdtilemap_1,0,1);
		}

	}

	if (layers_ctrl & 4)	hedpanic_draw_sprites(bitmap,cliprect);


//  popmessage("%04x %04x %04x %04x %04x",head_unknown1[0],head_layersize[0],head_unknown3[0],head_unknown4[0],head_unknown5[0]);
	return 0;
}
