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

    Atari Cloak & Dagger hardware

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

#include "driver.h"
#include "cloak.h"

static mame_bitmap *tmpbitmap2;
static UINT8 x,y,bmap;
static UINT8 *tmpvideoram,*tmpvideoram2;

static tilemap *bg_tilemap;

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

  CLOAK & DAGGER uses RAM to dynamically
  create the palette. The resolution is 9 bit (3 bits per gun). The palette
  contains 64 entries, but it is accessed through a memory windows 128 bytes
  long: writing to the first 64 bytes sets the msb of the red component to 0,
  while writing to the last 64 bytes sets it to 1.

  Colors 0-15  Character mapped graphics
  Colors 16-31 Bitmapped graphics (maybe 8 colors per bitmap?)
  Colors 32-47 Sprites
  Colors 48-63 not used

  These are the exact resistor values from the schematics:

  bit 8 -- diode |< -- pullup 1 kohm -- 2.2 kohm resistor -- pulldown 100 pf -- RED
        -- diode |< -- pullup 1 kohm -- 4.7 kohm resistor -- pulldown 100 pf -- RED
        -- diode |< -- pullup 1 kohm -- 10  kohm resistor -- pulldown 100 pf -- RED
        -- diode |< -- pullup 1 kohm -- 2.2 kohm resistor -- pulldown 100 pf -- GREEN
        -- diode |< -- pullup 1 kohm -- 4.7 kohm resistor -- pulldown 100 pf -- GREEN
        -- diode |< -- pullup 1 kohm -- 10  kohm resistor -- pulldown 100 pf -- GREEN
        -- diode |< -- pullup 1 kohm -- 2.2 kohm resistor -- pulldown 100 pf -- BLUE
        -- diode |< -- pullup 1 kohm -- 4.7 kohm resistor -- pulldown 100 pf -- BLUE
  bit 0 -- diode |< -- pullup 1 kohm -- 10  kohm resistor -- pulldown 100 pf -- BLUE

***************************************************************************/
WRITE8_HANDLER( cloak_paletteram_w )
{
	int r,g,b;
	int bit0,bit1,bit2;

	/* a write to offset 64-127 means to set the msb of the red component */
	int color = data | ((offset & 0x40) << 2);

	r = (~color & 0x1c0) >> 6;
	g = (~color & 0x038) >> 3;
	b = (~color & 0x007);

	// the following is WRONG! fix it

	bit0 = (r >> 0) & 0x01;
	bit1 = (r >> 1) & 0x01;
	bit2 = (r >> 2) & 0x01;
	r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
	bit0 = (g >> 0) & 0x01;
	bit1 = (g >> 1) & 0x01;
	bit2 = (g >> 2) & 0x01;
	g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
	bit0 = (b >> 0) & 0x01;
	bit1 = (b >> 1) & 0x01;
	bit2 = (b >> 2) & 0x01;
	b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;

	palette_set_color(Machine,offset & 0x3f,r,g,b);
}

WRITE8_HANDLER( cloak_clearbmp_w )
{
	bmap = data & 0x01;

	if (data & 0x02)	/* clear */
	{
		if (bmap)
		{
			fillbitmap(tmpbitmap, Machine->pens[16], &Machine->screen[0].visarea);
			memset(tmpvideoram, 0, 256*256);
		}
		else
		{
			fillbitmap(tmpbitmap2, Machine->pens[16], &Machine->screen[0].visarea);
			memset(tmpvideoram2, 0, 256*256);
		}
	}
}

static void adjust_xy(int offset)
{
	switch(offset)
	{
		case 0x00:  x--; y++; break;
		case 0x01:       y--; break;
		case 0x02:  x--;      break;
		case 0x04:  x++; y++; break;
		case 0x05:  	 y++; break;
		case 0x06:  x++;      break;
	}
}

READ8_HANDLER( graph_processor_r )
{
	int ret;

	if (bmap)
	{
		ret = tmpvideoram2[y * 256 + x];
	}
 	else
	{
		ret = tmpvideoram[y * 256 + x];
	}

	adjust_xy(offset);

	return ret;
}

WRITE8_HANDLER( graph_processor_w )
{
	int color;

	switch (offset)
	{
		case 0x03: x = data; break;
		case 0x07: y = data; break;
		default:
			color = data & 0x07;

			if (bmap)
			{
				plot_pixel(tmpbitmap, (x-6)&0xff, y, Machine->pens[16 + color]);
				tmpvideoram[y*256+x] = color;
			}
			else
			{
				plot_pixel(tmpbitmap2, (x-6)&0xff, y, Machine->pens[16 + color]);
				tmpvideoram2[y*256+x] = color;
			}

			adjust_xy(offset);
			break;
		}
}

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

WRITE8_HANDLER( cloak_flipscreen_w )
{
	flip_screen_set(data & 0x80);
}

static void get_bg_tile_info(int tile_index)
{
	int code = videoram[tile_index];

	SET_TILE_INFO(0, code, 0, 0)
}

static void refresh_bitmaps(void)
{
	int lx,ly;

	for (ly = 0; ly < 256; ly++)
	{
		for (lx = 0; lx < 256; lx++)
		{
			plot_pixel(tmpbitmap,  (lx-6)&0xff, ly, Machine->pens[16 + tmpvideoram[ly*256+lx]]);
			plot_pixel(tmpbitmap2, (lx-6)&0xff, ly, Machine->pens[16 + tmpvideoram2[ly*256+lx]]);
		}
	}
}

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

	tmpbitmap = auto_bitmap_alloc(machine->screen[0].width,machine->screen[0].height,machine->screen[0].format);
	tmpbitmap2 = auto_bitmap_alloc(machine->screen[0].width,machine->screen[0].height,machine->screen[0].format);

	tmpvideoram = auto_malloc(256*256);
	tmpvideoram2 = auto_malloc(256*256);

	state_save_register_global(x);
	state_save_register_global(y);
	state_save_register_global(bmap);
	state_save_register_global_pointer(tmpvideoram, 256*256);
	state_save_register_global_pointer(tmpvideoram2, 256*256);
	state_save_register_func_postload(refresh_bitmaps);

	return 0;
}

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

	for (offs = (spriteram_size / 4) - 1; offs >= 0; offs--)
	{
		int code = spriteram[offs + 64] & 0x7f;
		int flipx = spriteram[offs + 64] & 0x80;
		int flipy = 0;
		int sx = spriteram[offs + 192];
		int sy = 240 - spriteram[offs];

		if (flip_screen)
		{
			sx -= 9;
			sy = 240 - sy;
			flipx = !flipx;
			flipy = !flipy;
		}

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

VIDEO_UPDATE( cloak )
{
	tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0);
	copybitmap(bitmap, (bmap ? tmpbitmap2 : tmpbitmap),flip_screen,flip_screen,0,0,cliprect,TRANSPARENCY_COLOR,16);
	cloak_draw_sprites(bitmap, cliprect);
	return 0;
}
