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

  video.c

  Functions to emulate the video hardware of the machine.

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

#include "driver.h"

static tilemap *bg_tilemap;

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

  Convert the color PROMs. (from video/pengo.c)

***************************************************************************/
PALETTE_INIT( mrjong )
{
	int i;

	/* allocate the colortable */
	machine->colortable = colortable_alloc(machine, 0x10);

	/* create a lookup table for the palette */
	for (i = 0; i < 0x10; i++)
	{
		int bit0, bit1, bit2;
		int r, g, b;

		/* red component */
		bit0 = (color_prom[i] >> 0) & 0x01;
		bit1 = (color_prom[i] >> 1) & 0x01;
		bit2 = (color_prom[i] >> 2) & 0x01;
		r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		/* green component */
		bit0 = (color_prom[i] >> 3) & 0x01;
		bit1 = (color_prom[i] >> 4) & 0x01;
		bit2 = (color_prom[i] >> 5) & 0x01;
		g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		/* blue component */
		bit0 = 0;
		bit1 = (color_prom[i] >> 6) & 0x01;
		bit2 = (color_prom[i] >> 7) & 0x01;
		b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		colortable_palette_set_color(machine->colortable, i, MAKE_RGB(r, g, b));
	}

	/* color_prom now points to the beginning of the lookup table */
	color_prom += 0x20;

	/* characters/sprites */
	for (i = 0; i < 0x80; i++)
	{
		UINT8 ctabentry = color_prom[i] & 0x0f;
		colortable_entry_set_value(machine->colortable, i, ctabentry);
	}
}


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

  Display control parameter.

***************************************************************************/
WRITE8_HANDLER( mrjong_videoram_w )
{
	videoram[offset] = data;
	tilemap_mark_tile_dirty(bg_tilemap, offset);
}

WRITE8_HANDLER( mrjong_colorram_w )
{
	colorram[offset] = data;
	tilemap_mark_tile_dirty(bg_tilemap, offset);
}

WRITE8_HANDLER( mrjong_flipscreen_w )
{
	if (flip_screen_get(space->machine) != (data & 0x01))
	{
		flip_screen_set(space->machine, data & 0x01);
		tilemap_mark_all_tiles_dirty_all(space->machine);
	}
}

static TILE_GET_INFO( get_bg_tile_info )
{
	int code = videoram[tile_index] | ((colorram[tile_index] & 0x20) << 3);
	int color = colorram[tile_index] & 0x1f;
	int flags = ((colorram[tile_index] & 0x40) ? TILE_FLIPX : 0) | ((colorram[tile_index] & 0x80) ? TILE_FLIPY : 0);

	SET_TILE_INFO(0, code, color, flags);
}

VIDEO_START( mrjong )
{
	bg_tilemap = tilemap_create(machine, get_bg_tile_info, tilemap_scan_rows_flip_xy, 8, 8, 32, 32);
}

/*
Note: First 0x40 entries in the videoram are actually spriteram
*/
static void draw_sprites(running_machine *machine, bitmap_t *bitmap, const rectangle *cliprect)
{
	int offs;

	for (offs = (0x40 - 4); offs >= 0; offs -= 4)
	{
		int sprt;
		int color;
		int sx, sy;
		int flipx, flipy;

		sprt = (((videoram[offs + 1] >> 2) & 0x3f) | ((videoram[offs + 3] & 0x20) << 1));
		flipx = (videoram[offs + 1] & 0x01) >> 0;
		flipy = (videoram[offs + 1] & 0x02) >> 1;
		color = (videoram[offs + 3] & 0x1f);

		sx = 224 - videoram[offs + 2];
		sy = videoram[offs + 0];
		if (flip_screen_get(machine))
		{
			sx = 208 - sx;
			sy = 240 - sy;
			flipx = !flipx;
			flipy = !flipy;
		}

		drawgfx_transpen(bitmap, cliprect, machine->gfx[1],
				sprt,
				color,
				flipx, flipy,
				sx, sy, 0);
	}
}

VIDEO_UPDATE( mrjong )
{
	tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0);
	draw_sprites(screen->machine, bitmap, cliprect);
	return 0;
}
