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

							  -= Afega 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 Layers ]
								[ Layer 0 ]		[ Layer 1 ]

		Tile Size:				16 x 16 x 4/8	8 x 8 x 4
		Layer Size (pixels):	1024 x 1024		256 x 256
		Layer Size (tiles):		64 x 64			32 x 32
		Scrolling:				Yes				No

		The layout is a bit weird. 16 consecutive tile codes define a
		vertical column. 16 columns form a page (256 x 256).
		Layer 0 is made of 4 x 4 pages. Layer 1 of just 1 page.

	[ 256 Sprites ]

		Sprites are made of 16 x 16 x 4 tiles. Size can vary from 1 to 16
		tiles both horizontally and vertically.
		Is there zooming ?

	[ Priorities ]

		The game only uses this scheme:

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

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

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

/* Variables needed by drivers: */

data16_t *afega_vram_0, *afega_scroll_0;
data16_t *afega_vram_1, *afega_scroll_1;


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


						Palette - RRRRGGGGBBBB????


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

WRITE16_HANDLER( afega_palette_w )
{
	int r,g,b;
	data = COMBINE_DATA(&paletteram16[offset]);
	b = ((data & 0x00F0) >> 0) + ((data & 0x0002) << 2);
	g = ((data & 0x0F00) >> 4) + ((data & 0x0004) << 1);
	r = ((data & 0xF000) >> 8) + ((data & 0x0008) << 0);
	palette_set_color( offset, r , g , b );
}

/* This game uses 8 bit tiles, so it ignores the color codes and just
   uses the same 256 colors for every tile */
PALETTE_INIT( grdnstrm )
{
	int color, pen;
	for( color = 0; color < 16; color++ )
		for( pen = 0; pen < 256; pen++ )
			colortable[color * 256 + pen + 256*3] = 256*0 + pen;
}


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

								Tilemaps

	Offset: 	Bits:					Value:

		2.w		fedc ---- ---- ----		Color
				---- ba98 7654 3210		Code

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

#define TILES_PER_PAGE_X	(0x10)
#define TILES_PER_PAGE_Y	(0x10)
#define PAGES_PER_TMAP_X	(0x4)
#define PAGES_PER_TMAP_Y	(0x4)

UINT32 afega_tilemap_scan_pages(UINT32 col,UINT32 row,UINT32 num_cols,UINT32 num_rows)
{
	return	(row / TILES_PER_PAGE_Y) * TILES_PER_PAGE_X * TILES_PER_PAGE_Y * PAGES_PER_TMAP_X +
			(row % TILES_PER_PAGE_Y) +

			(col / TILES_PER_PAGE_X) * TILES_PER_PAGE_X * TILES_PER_PAGE_Y +
			(col % TILES_PER_PAGE_X) * TILES_PER_PAGE_Y;
}

static struct tilemap *tilemap_0, *tilemap_1;

static void get_tile_info_0(int tile_index)
{
	data16_t code = afega_vram_0[tile_index];
	SET_TILE_INFO(
			1,
			code,
			(code & 0xf000) >> 12,
			0)
}
static void get_tile_info_1(int tile_index)
{
	data16_t code = afega_vram_1[tile_index];
	SET_TILE_INFO(
			2,
			code,
			(code & 0xf000) >> 12,
			0)
}

WRITE16_HANDLER( afega_vram_0_w )
{
	data16_t old_data	=	afega_vram_0[offset];
	data16_t new_data	=	COMBINE_DATA(&afega_vram_0[offset]);
	if (old_data != new_data)	tilemap_mark_tile_dirty(tilemap_0,offset);
}
WRITE16_HANDLER( afega_vram_1_w )
{
	data16_t old_data	=	afega_vram_1[offset];
	data16_t new_data	=	COMBINE_DATA(&afega_vram_1[offset]);
	if (old_data != new_data)	tilemap_mark_tile_dirty(tilemap_1,offset);
}


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


							Video Hardware Init


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

VIDEO_START( afega )
{
	tilemap_0 = tilemap_create(	get_tile_info_0, afega_tilemap_scan_pages,
								TILEMAP_OPAQUE,
								16,16,
								TILES_PER_PAGE_X*PAGES_PER_TMAP_X,TILES_PER_PAGE_Y*PAGES_PER_TMAP_Y);

	tilemap_1 = tilemap_create(	get_tile_info_1, tilemap_scan_cols,
								TILEMAP_TRANSPARENT,
								8,8,
								32,32);

	if ( !tilemap_0 || !tilemap_1 )
		return 1;

	tilemap_set_transparent_pen(tilemap_0,0x0);
	tilemap_set_transparent_pen(tilemap_1,0xf);
	return 0;
}


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

								Sprites Drawing

	Offset: 	Bits:					Value:

		0.w		fedc ba-- ---- ----
				---- --9- ---- ----		Flip Y?
				---- ---8 7654 3---
				---- --------- -21-		Priority?
				---- ---- ---- ---0		1 = Draw This Sprite

		2.w		fedc ba98 ---- ----
				---- ---- 7654 ----		Number Of Tiles Along Y - 1
				---- ---- ---- 3210		Number Of Tiles Along X - 1

		4.w

		6.w								Code

		8.w		fedc ba98 ---- ----
				---- ---- 7654 3210		X (Signed)

		A.w

		C.w		fedc ba98 ---- ----
				---- ---- 7654 3210		Y (Signed)

		E.w		fedc ba98 7654 ----
				---- ---- ---- 3210		Color


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

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

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

	for ( offs = 0; offs < spriteram_size/2; offs += 16/2 )
	{
		int attr, dim, code, sx, sy, color, flipx, flipy;

		int x, xnum, xstart, xend, xinc;
		int y, ynum, ystart, yend, yinc;

		attr	=		spriteram16[offs + 0x0/2];
		if (!(attr & 1))	continue;
		dim		=		spriteram16[offs + 0x2/2];
		code	=		spriteram16[offs + 0x6/2];
		sx		=		spriteram16[offs + 0x8/2];
		sy		=		spriteram16[offs + 0xc/2];
		color	=		spriteram16[offs + 0xe/2];

		flipx	=		attr & 0x000;	// ?
		flipy	=		attr & 0x000;	// ?

		xnum		=		((dim >> 0) & 0xf) + 1;
		ynum		=		((dim >> 4) & 0xf) + 1;

		sx = (sx & 0xff) - (sx & 0x100);
		sy = (sy & 0xff) - (sy & 0x100);

		if (flip_screen_x)	{	flipx = !flipx;		sx = max_x - sx - xnum * 16;	}
		if (flip_screen_y)	{	flipy = !flipy;		sy = max_y - sy - ynum * 16;	}

		if (flipx)	{ xstart = xnum-1;  xend = -1;    xinc = -1; }
		else		{ xstart = 0;       xend = xnum;  xinc = +1; }

		if (flipy)	{ ystart = ynum-1;  yend = -1;    yinc = -1; }
		else		{ ystart = 0;       yend = ynum;  yinc = +1; }

		for (y = ystart; y != yend; y += yinc)
		{
			for (x = xstart; x != xend; x += xinc)
			{
				drawgfx( bitmap,Machine->gfx[0],
								code++,
								color,
								flipx, flipy,
								sx + x * 16, sy + y * 16,
								cliprect,TRANSPARENCY_PEN,15 );
			}
		}

#ifdef MAME_DEBUG
#if 1
if (keyboard_pressed(KEYCODE_X))
{	/* Display some info on each sprite */
	struct DisplayText dt[2];	char buf[10];
	sprintf(buf, "%X",(spriteram16[offs + 0x0/2]&6)/2);
	dt[0].text = buf;	dt[0].color = UI_COLOR_NORMAL;
	dt[0].x = sy;		dt[0].y = sx;
	dt[1].text = 0;	/* terminate array */
	displaytext(Machine->scrbitmap,dt);		}
#endif
#endif
	}
}



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


								Screen Drawing


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

VIDEO_UPDATE( afega )
{
	int layers_ctrl = -1;

	/* Horizintal and vertical screen flip are hardwired to 2 dip switches */
	flip_screen_x_set(~readinputport(2) & 0x0100);
	flip_screen_y_set(~readinputport(2) & 0x0200);

	tilemap_set_scrolly(tilemap_0, 0, afega_scroll_0[0]);
	tilemap_set_scrollx(tilemap_0, 0, afega_scroll_0[1] - 0x100);

	tilemap_set_scrolly(tilemap_1, 0, afega_scroll_1[0]);
	tilemap_set_scrollx(tilemap_1, 0, afega_scroll_1[1]);

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

	if (layers_ctrl & 1)	tilemap_draw(bitmap,cliprect,tilemap_0,0,0);
	else					fillbitmap(bitmap,get_black_pen(),cliprect);

	if (layers_ctrl & 2) 	afega_draw_sprites(bitmap,cliprect);

	if (layers_ctrl & 4)	tilemap_draw(bitmap,cliprect,tilemap_1,0,0);
}

/* Same as 'afega', but no screen flip support */
VIDEO_UPDATE( bubl2000 )
{
	int layers_ctrl = -1;

/* I really would like somebody to see the schematics of 'bubl2000' for confirmation */
#if 0
	/* Horizintal and vertical screen flip are hardwired to 2 dip switches */
	flip_screen_x_set(~readinputport(2) & 0x0100);
	flip_screen_y_set(~readinputport(2) & 0x0200);
#endif

	tilemap_set_scrolly(tilemap_0, 0, afega_scroll_0[0]);
	tilemap_set_scrollx(tilemap_0, 0, afega_scroll_0[1] - 0x100);

	tilemap_set_scrolly(tilemap_1, 0, afega_scroll_1[0]);
	tilemap_set_scrollx(tilemap_1, 0, afega_scroll_1[1]);

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

	if (layers_ctrl & 1)	tilemap_draw(bitmap,cliprect,tilemap_0,0,0);
	else					fillbitmap(bitmap,get_black_pen(),cliprect);

	if (layers_ctrl & 2) 	afega_draw_sprites(bitmap,cliprect);

	if (layers_ctrl & 4)	tilemap_draw(bitmap,cliprect,tilemap_1,0,0);
}

