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

  vidhrdw.c

  Functions to emulate the video hardware of the machine.

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

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


static int gfx_bank, palette_bank;
static int grid_on;
static const UINT8 *color_codes;

static struct tilemap *bg_tilemap;

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

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

  Convert the color PROMs into a more useable format.

  Donkey Kong has two 256x4 palette PROMs and one 256x4 PROM which contains
  the color codes to use for characters on a per row/column basis (groups of
  of 4 characters in the same column - actually row, since the display is
  rotated)
  The palette PROMs are connected to the RGB output this way:

  bit 3 -- 220 ohm resistor -- inverter  -- RED
        -- 470 ohm resistor -- inverter  -- RED
        -- 1  kohm resistor -- inverter  -- RED
  bit 0 -- 220 ohm resistor -- inverter  -- GREEN
  bit 3 -- 470 ohm resistor -- inverter  -- GREEN
        -- 1  kohm resistor -- inverter  -- GREEN
        -- 220 ohm resistor -- inverter  -- BLUE
  bit 0 -- 470 ohm resistor -- inverter  -- BLUE

***************************************************************************/
PALETTE_INIT( dkong )
{
	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])


	for (i = 0;i < 256;i++)
	{
		int bit0,bit1,bit2,r,g,b;


		/* red component */
		bit0 = (color_prom[256] >> 1) & 1;
		bit1 = (color_prom[256] >> 2) & 1;
		bit2 = (color_prom[256] >> 3) & 1;
		r = 255 - (0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2);
		/* green component */
		bit0 = (color_prom[0] >> 2) & 1;
		bit1 = (color_prom[0] >> 3) & 1;
		bit2 = (color_prom[256] >> 0) & 1;
		g = 255 - (0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2);
		/* blue component */
		bit0 = (color_prom[0] >> 0) & 1;
		bit1 = (color_prom[0] >> 1) & 1;
		b = 255 - (0x55 * bit0 + 0xaa * bit1);

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

	color_prom += 256;
	/* color_prom now points to the beginning of the character color codes */
	color_codes = color_prom;	/* we'll need it later */
}

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

  Convert the color PROMs into a more useable format.

  Donkey Kong 3 has two 512x8 palette PROMs and one 256x4 PROM which contains
  the color codes to use for characters on a per row/column basis (groups of
  of 4 characters in the same column - actually row, since the display is
  rotated)
  Interstingly, bytes 0-255 of the palette PROMs contain an inverted palette,
  as other Nintendo games like Donkey Kong, while bytes 256-511 contain a non
  inverted palette. This was probably done to allow connection to both the
  special Nintendo and a standard monitor.
  I don't know the exact values of the resistors between the PROMs and the
  RGB output, but they are probably the usual:

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

  bit 3 -- 220 ohm resistor -- inverter  -- BLUE
        -- 470 ohm resistor -- inverter  -- BLUE
        -- 1  kohm resistor -- inverter  -- BLUE
  bit 0 -- 2.2kohm resistor -- inverter  -- BLUE

***************************************************************************/
PALETTE_INIT( dkong3 )
{
	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])


	for (i = 0;i < 256;i++)
	{
		int bit0,bit1,bit2,bit3,r,g,b;


		/* red component */
		bit0 = (color_prom[0] >> 4) & 0x01;
		bit1 = (color_prom[0] >> 5) & 0x01;
		bit2 = (color_prom[0] >> 6) & 0x01;
		bit3 = (color_prom[0] >> 7) & 0x01;
		r = 255 - (0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3);
		/* green component */
		bit0 = (color_prom[0] >> 0) & 0x01;
		bit1 = (color_prom[0] >> 1) & 0x01;
		bit2 = (color_prom[0] >> 2) & 0x01;
		bit3 = (color_prom[0] >> 3) & 0x01;
		g = 255 - (0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3);
		/* blue component */
		bit0 = (color_prom[256] >> 0) & 0x01;
		bit1 = (color_prom[256] >> 1) & 0x01;
		bit2 = (color_prom[256] >> 2) & 0x01;
		bit3 = (color_prom[256] >> 3) & 0x01;
		b = 255 - (0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3);

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

	color_prom += 256;
	/* color_prom now points to the beginning of the character color codes */
	color_codes = color_prom;	/* we'll need it later */
}

static void get_bg_tile_info(int tile_index)
{
	int code = videoram[tile_index] + 256 * gfx_bank;
	int color = (color_codes[tile_index % 32 + 32 * (tile_index / 32 / 4)] & 0x0f) + 0x10 * palette_bank;

	SET_TILE_INFO(0, code, color, 0)
}

VIDEO_START( dkong )
{
	gfx_bank = 0;
	palette_bank = 0;

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

	if ( !bg_tilemap )
		return 1;

	return 0;
}


WRITE_HANDLER( dkongjr_gfxbank_w )
{
	if (gfx_bank != (data & 0x01))
	{
		gfx_bank = data & 0x01;
		tilemap_mark_all_tiles_dirty(bg_tilemap);
	}
}

WRITE_HANDLER( dkong3_gfxbank_w )
{
	if (gfx_bank != (~data & 0x01))
	{
		gfx_bank = ~data & 0x01;
		tilemap_mark_all_tiles_dirty(bg_tilemap);
	}
}

WRITE_HANDLER( dkong_palettebank_w )
{
	int newbank;

	newbank = palette_bank;

	if (data & 1)
		newbank |= 1 << offset;
	else
		newbank &= ~(1 << offset);

	if (palette_bank != newbank)
	{
		palette_bank = newbank;
		tilemap_mark_all_tiles_dirty(bg_tilemap);
	}
}

WRITE_HANDLER( radarscp_grid_enable_w )
{
	grid_on = data & 0x01;
}

WRITE_HANDLER( radarscp_grid_color_w )
{
	int r,g,b;

	r = ((~data >> 0) & 0x01) * 0xff;
	g = ((~data >> 1) & 0x01) * 0xff;
	b = ((~data >> 2) & 0x01) * 0xff;
/*	palette_set_color(257,r,g,b);*/
	palette_set_color(257,0x00,0x00,0xff);
}

WRITE_HANDLER( dkong_flipscreen_w )
{
	flip_screen_set(~data & 0x01);
}

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

  Draw the game screen in the given mame_bitmap.
  Do NOT call osd_update_display() from this function, it will be called by
  the main emulation engine.

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

static void draw_sprites(struct mame_bitmap *bitmap, unsigned int mask_bank, unsigned int shift_bits)
{
	int offs;

	/* Draw the sprites. */
	for (offs = 0;offs < spriteram_size;offs += 4)
	{
		if (spriteram[offs])
		{
			/* spriteram[offs + 2] & 0x40 is used by Donkey Kong 3 only */
			/* spriteram[offs + 2] & 0x30 don't seem to be used (they are */
			/* probably not part of the color code, since Mario Bros, which */
			/* has similar hardware, uses a memory mapped port to change */
			/* palette bank, so it's limited to 16 color codes) */

			int x,y;

			x = spriteram[offs + 3] - 8;
			y = 240 - spriteram[offs] + 7;

			if (flip_screen)
			{
				x = 240 - x;
				y = 240 - y;

				drawgfx(bitmap,Machine->gfx[1],
						(spriteram[offs + 1] & 0x7f) + ((spriteram[offs + 2] & mask_bank) << shift_bits),
						(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
						!(spriteram[offs + 2] & 0x80),!(spriteram[offs + 1] & 0x80),
						x,y,
						&Machine->visible_area,TRANSPARENCY_PEN,0);

				/* draw with wrap around - this fixes the 'beheading' bug */
				drawgfx(bitmap,Machine->gfx[1],
						(spriteram[offs + 1] & 0x7f) + ((spriteram[offs + 2] & mask_bank) << shift_bits),
						(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
						(spriteram[offs + 2] & 0x80),(spriteram[offs + 1] & 0x80),
						x-256,y,
						&Machine->visible_area,TRANSPARENCY_PEN,0);
			}
			else
			{
				drawgfx(bitmap,Machine->gfx[1],
						(spriteram[offs + 1] & 0x7f) + ((spriteram[offs + 2] & mask_bank) << shift_bits),
						(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
						(spriteram[offs + 2] & 0x80),(spriteram[offs + 1] & 0x80),
						x,y,
						&Machine->visible_area,TRANSPARENCY_PEN,0);

				/* draw with wrap around - this fixes the 'beheading' bug */
				drawgfx(bitmap,Machine->gfx[1],
						(spriteram[offs + 1] & 0x7f) + ((spriteram[offs + 2] & mask_bank) << shift_bits),
						(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
						(spriteram[offs + 2] & 0x80),(spriteram[offs + 1] & 0x80),
						x+256,y,
						&Machine->visible_area,TRANSPARENCY_PEN,0);
			}
		}
	}
}

static void draw_grid(struct mame_bitmap *bitmap)
{
	const UINT8 *table = memory_region(REGION_GFX3);
	int x,y,counter;

	counter = flip_screen ? 0x000 : 0x400;

	x = Machine->visible_area.min_x;
	y = Machine->visible_area.min_y;
	while (y <= Machine->visible_area.max_y)
	{
		x = 4 * (table[counter] & 0x7f);
		if (x >= Machine->visible_area.min_x &&
				x <= Machine->visible_area.max_x)
		{
			if (table[counter] & 0x80)	/* star */
			{
				if (rand() & 1)	/* noise coming from sound board */
					plot_pixel(bitmap,x,y,Machine->pens[256]);
			}
			else if (grid_on)			/* radar */
				plot_pixel(bitmap,x,y,Machine->pens[257]);
		}

		counter++;

		if (x >= 4 * (table[counter] & 0x7f))
			y++;
	}
}

VIDEO_UPDATE( radarscp )
{
	palette_set_color(256,0xff,0x00,0x00);	/* stars */

	tilemap_draw(bitmap, &Machine->visible_area, bg_tilemap, 0, 0);
	draw_grid(bitmap);
	draw_sprites(bitmap, 0x40, 1);
}

VIDEO_UPDATE( dkong )
{
	tilemap_draw(bitmap, &Machine->visible_area, bg_tilemap, 0, 0);
	draw_sprites(bitmap, 0x40, 1);
}

VIDEO_UPDATE( pestplce )
{
	int offs;

	tilemap_draw(bitmap, &Machine->visible_area, bg_tilemap, 0, 0);

	/* Draw the sprites. */
	for (offs = 0;offs < spriteram_size;offs += 4)
	{
		if (spriteram[offs])
		{
			drawgfx(bitmap,Machine->gfx[1],
					spriteram[offs + 2],
					(spriteram[offs + 1] & 0x0f) + 16 * palette_bank,
					spriteram[offs + 1] & 0x80,spriteram[offs + 1] & 0x40,
					spriteram[offs + 3] - 8,240 - spriteram[offs] + 8,
					&Machine->visible_area,TRANSPARENCY_PEN,0);
		}
	}
}

VIDEO_UPDATE( spclforc )
{
	tilemap_draw(bitmap, &Machine->visible_area, bg_tilemap, 0, 0);

	/* it uses spriteram[offs + 2] & 0x10 for sprite bank */
	draw_sprites(bitmap, 0x10, 3);
}
