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

    Video emulation for Astro Invader, Space Intruder et al

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

#include "driver.h"

static int spaceint_color;
static int astinvad_adjust;
static int astinvad_flash;


void astinvad_set_flash(int data)
{
	astinvad_flash = data;
}


WRITE8_HANDLER( spaceint_color_w )
{
	spaceint_color = data & 15;
}


static void plot_byte(int x, int y, int data, int col)
{
	int i;

	for (i = 0; i < 8; i++)
	{
		if (flip_screen)
		{
			plot_pixel(tmpbitmap, 255 - (x + i), 255 - y, (data & 1) ? col : 0);
		}
		else
		{
			plot_pixel(tmpbitmap, x + i, y, (data & 1) ? col : 0);
		}

		data >>= 1;
	}
}


static void spaceint_refresh(int offset)
{
	int n = ((offset >> 5) & 0xf0) | colorram[offset];

	//
	//  This is almost certainly wrong.
	//

	int col = memory_region(REGION_PROMS)[n];

	plot_byte(8 * (offset / 256), 255 - offset % 256, videoram[offset], col & 7);
}


static void astinvad_refresh(int offset)
{
	int n = ((offset >> 3) & ~0x1f) | (offset & 0x1f);

	int col;

	if (!flip_screen)
	{
		col = memory_region(REGION_PROMS)[(~n + astinvad_adjust) & 0x3ff];
	}
	else
	{
		col = memory_region(REGION_PROMS)[n] >> 4;
	}

	plot_byte(8 * (offset % 32), offset / 32, videoram[offset], col & 7);
}


WRITE8_HANDLER( spaceint_videoram_w )
{
	videoram[offset] = data;
	colorram[offset] = spaceint_color;

	spaceint_refresh(offset);
}


WRITE8_HANDLER( astinvad_videoram_w )
{
	videoram[offset] = data;

	astinvad_refresh(offset);
}


VIDEO_START( astinvad )
{
	astinvad_adjust = 0x80;

	return video_start_generic_bitmapped();
}


VIDEO_START( spcking2 )
{
	astinvad_adjust = 0;

	return video_start_generic_bitmapped();
}


VIDEO_START( spaceint )
{
	colorram = auto_malloc(0x2000);
	memset(colorram, 0, 0x2000);

	return video_start_generic_bitmapped();
}


VIDEO_UPDATE( spaceint )
{
	if (get_vh_global_attribute_changed())
	{
		int offset;

		for (offset = 0; offset < videoram_size; offset++)
		{
			spaceint_refresh(offset);
		}
	}

	copybitmap(bitmap, tmpbitmap, 0, 0, 0, 0, cliprect, TRANSPARENCY_NONE, 0);
}


VIDEO_UPDATE( astinvad )
{
	if (astinvad_flash)
	{
		fillbitmap(bitmap, 1, cliprect);
	}
	else
	{
		if (get_vh_global_attribute_changed())
		{
			int offset;

			for (offset = 0; offset < videoram_size; offset++)
			{
				astinvad_refresh(offset);
			}
		}

		copybitmap(bitmap, tmpbitmap, 0, 0, 0, 0, cliprect, TRANSPARENCY_NONE, 0);
	}
}
