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

  vidhrdw.c

  Functions to emulate the video hardware of the machine.

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

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

static int palette_offset;
static struct tilemap *bg_tilemap;


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

  Callbacks for the TileMap code

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

static void holeland_get_tile_info(int tile_index)
{
	int attr = colorram[tile_index];
	int tile_number = videoram[tile_index] | ((attr & 0x03) << 8);

/*if (code_pressed(KEYCODE_Q) && (attr & 0x10)) tile_number = rand(); */
/*if (code_pressed(KEYCODE_W) && (attr & 0x20)) tile_number = rand(); */
/*if (code_pressed(KEYCODE_E) && (attr & 0x40)) tile_number = rand(); */
/*if (code_pressed(KEYCODE_R) && (attr & 0x80)) tile_number = rand(); */
	SET_TILE_INFO(
			0,
			tile_number,
			palette_offset + ((attr >> 4) & 0x0f),
			TILE_FLIPYX((attr >> 2) & 0x03) | TILE_SPLIT((attr >> 4) & 1))
}

static void crzrally_get_tile_info(int tile_index)
{
	int attr = colorram[tile_index];
	int tile_number = videoram[tile_index] | ((attr & 0x03) << 8);

	SET_TILE_INFO(
			0,
			tile_number,
			palette_offset + ((attr >> 4) & 0x0f),
			TILE_FLIPYX((attr >> 2) & 0x03) | TILE_SPLIT((attr >> 4) & 1))
}

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

  Start the video hardware emulation.

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

VIDEO_START( holeland )
{
	bg_tilemap = tilemap_create(holeland_get_tile_info,tilemap_scan_rows,TILEMAP_SPLIT,16,16,32,32);

	if (!bg_tilemap)
		return 1;

	tilemap_set_transmask(bg_tilemap,0,0xff,0x00); /* split type 0 is totally transparent in front half */
	tilemap_set_transmask(bg_tilemap,1,0x01,0xfe); /* split type 1 has pen 0? transparent in front half */
	return 0;
}

VIDEO_START( crzrally )
{
	bg_tilemap = tilemap_create(crzrally_get_tile_info,tilemap_scan_cols,TILEMAP_SPLIT,8,8,32,32);

	if (!bg_tilemap)
		return 1;

	return 0;
}

WRITE8_HANDLER( holeland_videoram_w )
{
	if( videoram[offset]!=data )
	{
		videoram[offset] = data;
		tilemap_mark_tile_dirty( bg_tilemap, offset );
	}
}

WRITE8_HANDLER( holeland_colorram_w )
{
	if( colorram[offset]!=data )
	{
		colorram[offset] = data;
		tilemap_mark_tile_dirty( bg_tilemap, offset );
	}
}

WRITE8_HANDLER( holeland_pal_offs_w )
{
	static int po[2];
	if ((data & 1) != po[offset])
	{
		po[offset] = data & 1;
		palette_offset = (po[0] + (po[1] << 1)) << 4;
		tilemap_mark_all_tiles_dirty(ALL_TILEMAPS);
	}
}

WRITE8_HANDLER( holeland_scroll_w )
{
	tilemap_set_scrollx(bg_tilemap, 0, data);
}

WRITE8_HANDLER( holeland_flipscreen_w )
{
	if (offset) flip_screen_y_set(data);
	else        flip_screen_x_set(data);
}


static void holeland_draw_sprites(struct mame_bitmap *bitmap,const struct rectangle *cliprect)
{
	int offs,code,sx,sy,color,flipx, flipy;

	/* Weird, sprites entries don't start on DWORD boundary */
	for (offs = 3;offs < spriteram_size - 1;offs += 4)
	{
		sy = 236 - spriteram[offs];
		sx = spriteram[offs+2];

		/* Bit 7 unknown */
		code = spriteram[offs+1] & 0x7f;
		color = palette_offset + (spriteram[offs+3] >> 4);

		/* Bit 0, 1 unknown */
		flipx = spriteram[offs+3] & 0x04;
		flipy = spriteram[offs+3] & 0x08;

		if (flip_screen_x)
		{
			flipx = !flipx;
			sx = 240 - sx;
		}

		if (flip_screen_y)
		{
			flipy = !flipy;
			sy = 240 - sy;
		}

		drawgfx(bitmap,Machine->gfx[1],
				code,
				color,
				flipx,flipy,
				2*sx,2*sy,
				cliprect,TRANSPARENCY_PEN,0);
	}
}

static void crzrally_draw_sprites(struct mame_bitmap *bitmap,const struct rectangle *cliprect)
{
	int offs,code,sx,sy,color,flipx, flipy;

	/* Weird, sprites entries don't start on DWORD boundary */
	for (offs = 3;offs < spriteram_size - 1;offs += 4)
	{
		sy = 236 - spriteram[offs];
		sx = spriteram[offs+2];

		code = spriteram[offs+1] + ((spriteram[offs+3] & 0x01) << 8);
		color = (spriteram[offs+3] >> 4) + ((spriteram[offs+3] & 0x01) << 4);

		/* Bit 1 unknown */
		flipx = spriteram[offs+3] & 0x04;
		flipy = spriteram[offs+3] & 0x08;

		if (flip_screen_x)
		{
			flipx = !flipx;
			sx = 240 - sx;
		}

		if (flip_screen_y)
		{
			flipy = !flipy;
			sy = 240 - sy;
		}

		drawgfx(bitmap,Machine->gfx[1],
				code,
				color,
				flipx,flipy,
				sx,sy,
				cliprect,TRANSPARENCY_PEN,0);
	}
}

VIDEO_UPDATE( holeland )
{
/*tilemap_mark_all_tiles_dirty(bg_tilemap); */
	tilemap_draw(bitmap,cliprect,bg_tilemap,TILEMAP_BACK,0);
	holeland_draw_sprites(bitmap,cliprect);
	tilemap_draw(bitmap,cliprect,bg_tilemap,TILEMAP_FRONT,0);
}

VIDEO_UPDATE( crzrally )
{
	tilemap_draw(bitmap,cliprect,bg_tilemap,0,0);
	crzrally_draw_sprites(bitmap,cliprect);
}
