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

    Karnov - Bryan McPhail, mish@tendril.co.uk

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

#include "driver.h"

static bitmap_t *bitmap_f;
UINT16 karnov_scroll[2], *karnov_pf_data;
static tilemap *fix_tilemap;
static int flipscreen;

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

  Convert the color PROMs into a more useable format.

  Karnov has two 1024x8 palette PROM.
  I don't know the exact values of the resistors between the RAM and the
  RGB output. I assumed these values (the same as Commando)

  bit 7 -- 220 ohm resistor  -- GREEN
        -- 470 ohm resistor  -- GREEN
        -- 1  kohm resistor  -- GREEN
        -- 2.2kohm resistor  -- GREEN
        -- 220 ohm resistor  -- RED
        -- 470 ohm resistor  -- RED
        -- 1  kohm resistor  -- RED
  bit 0 -- 2.2kohm resistor  -- RED

  bit 7 -- unused
        -- unused
        -- unused
        -- unused
        -- 220 ohm resistor  -- BLUE
        -- 470 ohm resistor  -- BLUE
        -- 1  kohm resistor  -- BLUE
  bit 0 -- 2.2kohm resistor  -- BLUE

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

	for (i = 0;i < machine->config->total_colors;i++)
	{
		int bit0,bit1,bit2,bit3,r,g,b;

		bit0 = (color_prom[0] >> 0) & 0x01;
		bit1 = (color_prom[0] >> 1) & 0x01;
		bit2 = (color_prom[0] >> 2) & 0x01;
		bit3 = (color_prom[0] >> 3) & 0x01;
		r = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
		bit0 = (color_prom[0] >> 4) & 0x01;
		bit1 = (color_prom[0] >> 5) & 0x01;
		bit2 = (color_prom[0] >> 6) & 0x01;
		bit3 = (color_prom[0] >> 7) & 0x01;
		g = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
		bit0 = (color_prom[machine->config->total_colors] >> 0) & 0x01;
		bit1 = (color_prom[machine->config->total_colors] >> 1) & 0x01;
		bit2 = (color_prom[machine->config->total_colors] >> 2) & 0x01;
		bit3 = (color_prom[machine->config->total_colors] >> 3) & 0x01;
		b = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;

		palette_set_color(machine,i,MAKE_RGB(r,g,b));
		color_prom++;
	}
}

void karnov_flipscreen_w(int data)
{
	flipscreen=data;
	tilemap_set_flip(ALL_TILEMAPS,flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0);
}

static void draw_background(running_machine *machine, bitmap_t *bitmap, const rectangle *cliprect)
{
	int my,mx,offs,color,tile,fx,fy;
	int scrollx=karnov_scroll[0];
	int scrolly=karnov_scroll[1];

	if (flipscreen) fx=fy=1; else fx=fy=0;

	mx=-1; my=0;
	for (offs = 0;offs < 0x400; offs ++) {
		mx++;
		if (mx==32) {mx=0; my++;}

		tile=karnov_pf_data[offs];
		color = tile >> 12;
		tile = tile&0x7ff;
		if (flipscreen)
			drawgfx(bitmap_f,machine->gfx[1],tile,
				color, fx, fy, 496-16*mx,496-16*my,
		 		0,TRANSPARENCY_NONE,0);
		else
			drawgfx(bitmap_f,machine->gfx[1],tile,
				color, fx, fy, 16*mx,16*my,
		 		0,TRANSPARENCY_NONE,0);
	}

	if (!flipscreen) {
		scrolly=-scrolly;
		scrollx=-scrollx;
	} else {
		scrolly=scrolly+256;
		scrollx=scrollx+256;
	}
	copyscrollbitmap(bitmap,bitmap_f,1,&scrollx,1,&scrolly,cliprect);
}

static void draw_sprites(running_machine *machine, bitmap_t *bitmap,const rectangle *cliprect)
{
	int offs;

	for (offs = 0;offs <0x800;offs += 4) {
		int x,y,sprite,sprite2,colour,fx,fy,extra;

	    y=buffered_spriteram16[offs];
	    if (!(y&0x8000)) continue;

	    y=y&0x1ff;
	    sprite=buffered_spriteram16[offs+3];
	    colour=sprite>>12;
	    sprite=sprite&0xfff;
	    x=buffered_spriteram16[offs+2]&0x1ff;

		fx=buffered_spriteram16[offs+1];
	    if ((fx&0x10)) extra=1; else extra=0;
		fy=fx&0x2;
		fx=fx&0x4;

		if (extra) y=y+16;

	    /* Convert the co-ords..*/
		x=(x+16)%0x200;
		y=(y+16)%0x200;
		x=256 - x;
		y=256 - y;
		if (flipscreen) {
			y=240-y;
			x=240-x;
			if (fx) fx=0; else fx=1;
			if (fy) fy=0; else fy=1;
			if (extra) y=y-16;
		}

		/* Y Flip determines order of multi-sprite */
		if (extra && fy) {
			sprite2=sprite;
			sprite++;
		}
		else sprite2=sprite+1;

		drawgfx(bitmap,machine->gfx[2],
				sprite,
				colour,fx,fy,x,y,
				cliprect,TRANSPARENCY_PEN,0);

    	/* 1 more sprite drawn underneath */
    	if (extra)
    		drawgfx(bitmap,machine->gfx[2],
				sprite2,
				colour,fx,fy,x,y+16,
				cliprect,TRANSPARENCY_PEN,0);
	}
}

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

VIDEO_UPDATE( karnov )
{
	draw_background(screen->machine,bitmap,cliprect);
	draw_sprites(screen->machine,bitmap,cliprect);
	tilemap_draw(bitmap,cliprect,fix_tilemap,0,0);
	return 0;
}

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

static TILE_GET_INFO( get_fix_tile_info )
{
	int tile=videoram16[tile_index];
	SET_TILE_INFO(
			0,
			tile&0xfff,
			tile>>14,
			0);
}

WRITE16_HANDLER( karnov_videoram_w )
{
	COMBINE_DATA(&videoram16[offset]);
	tilemap_mark_tile_dirty(fix_tilemap,offset);
}

WRITE16_HANDLER( karnov_playfield_swap_w )
{
	offset = ((offset & 0x1f) << 5) | ((offset & 0x3e0) >> 5);
	COMBINE_DATA(&karnov_pf_data[offset]);
}

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

VIDEO_START( karnov )
{
	/* Allocate bitmaps */
	bitmap_f = auto_bitmap_alloc(512,512,video_screen_get_format(machine->primary_screen));

	fix_tilemap=tilemap_create(get_fix_tile_info,tilemap_scan_rows,8,8,32,32);

	tilemap_set_transparent_pen(fix_tilemap,0);
}

VIDEO_START( wndrplnt )
{
	/* Allocate bitmaps */
	bitmap_f = auto_bitmap_alloc(512,512,video_screen_get_format(machine->primary_screen));

	fix_tilemap=tilemap_create(get_fix_tile_info,tilemap_scan_cols,8,8,32,32);

	tilemap_set_transparent_pen(fix_tilemap,0);
}

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