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

  vidhrdw.c

  Functions to emulate the video hardware of the machine.

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

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

UINT8 *zodiack_videoram2;
UINT8 *zodiack_attributesram;
UINT8 *zodiack_bulletsram;
size_t zodiack_bulletsram_size;

extern int percuss_hardware;

static struct tilemap *bg_tilemap, *fg_tilemap;

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

WRITE8_HANDLER( zodiack_videoram2_w )
{
	if (zodiack_videoram2[offset] != data)
	{
		zodiack_videoram2[offset] = data;
		tilemap_mark_tile_dirty(bg_tilemap, offset);
	}
}

WRITE8_HANDLER( zodiack_attributes_w )
{
	if ((offset & 1) && zodiack_attributesram[offset] != data)
	{
		int i;

		for (i = offset / 2;i < videoram_size; i += 32)
		{
			tilemap_mark_tile_dirty(bg_tilemap, i);
			tilemap_mark_tile_dirty(fg_tilemap, i);
		}
	}

	zodiack_attributesram[offset] = data;
}

WRITE8_HANDLER( zodiack_flipscreen_w )
{
	if (flip_screen != (~data & 0x01))
	{
		flip_screen_set(~data & 0x01);
		tilemap_mark_all_tiles_dirty(ALL_TILEMAPS);
	}
}

PALETTE_INIT( zodiack )
{
	int i;

	#define TOTAL_COLORS(gfxn) (Machine->gfx[gfxn]->total_colors * Machine->gfx[gfxn]->color_granularity)
	#define COLOR(gfxn,offs) (colortable[Machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])

	/* first, the character/sprite palette */
	for (i = 0;i < Machine->drv->total_colors-1; i++)
	{
		int bit0,bit1,bit2,r,g,b;

		/* red component */

		bit0 = (*color_prom >> 0) & 0x01;
		bit1 = (*color_prom >> 1) & 0x01;
		bit2 = (*color_prom >> 2) & 0x01;

		r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		/* green component */

		bit0 = (*color_prom >> 3) & 0x01;
		bit1 = (*color_prom >> 4) & 0x01;
		bit2 = (*color_prom >> 5) & 0x01;

		g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		/* blue component */

		bit0 = 0;
		bit1 = (*color_prom >> 6) & 0x01;
		bit2 = (*color_prom >> 7) & 0x01;

		b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

		palette_set_color(i,r,g,b);

		color_prom++;
	}

	/* white for bullets */

	palette_set_color(Machine->drv->total_colors-1,0xff,0xff,0xff);

	for (i = 0;i < TOTAL_COLORS(0);i+=2)
	{
		COLOR(0,i  ) = (32 + (i / 2));
		COLOR(0,i+1) = (40 + (i / 2));
	}

	for (i = 0;i < TOTAL_COLORS(3);i++)
	{
		if ((i & 3) == 0)  COLOR(3,i) = 0;
	}

	/* bullet */
	COLOR(2, 0) = 0;
	COLOR(2, 1) = 48;
}

static void get_bg_tile_info(int tile_index)
{
	int code = zodiack_videoram2[tile_index];
	int color = (zodiack_attributesram[2 * (tile_index % 32) + 1] >> 4) & 0x07;

	SET_TILE_INFO(0, code, color, 0)
}

static void get_fg_tile_info(int tile_index)
{
	int code = videoram[tile_index];
	int color = zodiack_attributesram[2 * (tile_index % 32) + 1] & 0x07;

	SET_TILE_INFO(3, code, color, 0)
}

VIDEO_START( zodiack )
{
	bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows,
		TILEMAP_OPAQUE, 8, 8, 32, 32);

	if ( !bg_tilemap )
		return 1;

	fg_tilemap = tilemap_create(get_fg_tile_info, tilemap_scan_rows,
		TILEMAP_TRANSPARENT, 8, 8, 32, 32);

	if ( !fg_tilemap )
		return 1;

	tilemap_set_transparent_pen(fg_tilemap, 0);
	tilemap_set_scroll_cols(fg_tilemap, 32);

	flip_screen = 0;

	return 0;
}

static void zodiack_draw_bullets( struct mame_bitmap *bitmap )
{
	int offs;

	for (offs = 0; offs < zodiack_bulletsram_size; offs += 4)
	{
		int x, y;

		x = zodiack_bulletsram[offs + 3] + Machine->drv->gfxdecodeinfo[2].gfxlayout->width;
		y = 255 - zodiack_bulletsram[offs + 1];

		if (flip_screen && percuss_hardware)
		{
			y = 255 - y;
		}

		drawgfx(
			bitmap,
			Machine->gfx[2],
			0,	/* this is just a dot, generated by the hardware */
			0,
			0,0,
			x,y,
			&Machine->visible_area,TRANSPARENCY_PEN,0);
	}
}

static void zodiack_draw_sprites( struct mame_bitmap *bitmap )
{
	int offs;

	for (offs = spriteram_size - 4; offs >= 0; offs -= 4)
	{
		int flipx, flipy, sx, sy, spritecode;

		sx = 240 - spriteram[offs + 3];
		sy = 240 - spriteram[offs];
		flipx = !(spriteram[offs + 1] & 0x40);
		flipy = spriteram[offs + 1] & 0x80;
		spritecode = spriteram[offs + 1] & 0x3f;

		if (flip_screen && percuss_hardware)
		{
			sy = 240 - sy;
			flipy = !flipy;
		}

		drawgfx(bitmap, Machine->gfx[1],
			spritecode,
			spriteram[offs + 2] & 0x07,
			flipx, flipy,
			sx, sy,
			/*flip_screen[0] ? &spritevisibleareaflipx : &spritevisiblearea,TRANSPARENCY_PEN,0); */
			/*&spritevisiblearea,TRANSPARENCY_PEN,0); */
			&Machine->visible_area, TRANSPARENCY_PEN, 0);
	}
}

VIDEO_UPDATE( zodiack )
{
	int i;

	for (i = 0; i < 32; i++)
	{
		tilemap_set_scrolly(fg_tilemap, i, zodiack_attributesram[i * 2]);
	}

	tilemap_draw(bitmap, &Machine->visible_area, bg_tilemap, 0, 0);
	tilemap_draw(bitmap, &Machine->visible_area, fg_tilemap, 0, 0);
	zodiack_draw_bullets(bitmap);
	zodiack_draw_sprites(bitmap);
}
