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

Atari Canyon Bomber video emulation

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

#include "emu.h"
#include "includes/canyon.h"


WRITE8_MEMBER(canyon_state::canyon_videoram_w)
{
	m_videoram[offset] = data;
	m_bg_tilemap->mark_tile_dirty(offset);
}


TILE_GET_INFO_MEMBER(canyon_state::get_bg_tile_info)
{
	UINT8 code = m_videoram[tile_index];

	SET_TILE_INFO_MEMBER(0, code & 0x3f, code >> 7, 0);
}


void canyon_state::video_start()
{
	m_bg_tilemap = &machine().tilemap().create(tilemap_get_info_delegate(FUNC(canyon_state::get_bg_tile_info),this), TILEMAP_SCAN_ROWS, 8, 8, 32, 32);
}


void canyon_state::draw_sprites( bitmap_ind16 &bitmap, const rectangle &cliprect )
{
	int i;

	for (i = 0; i < 2; i++)
	{
		int x = m_videoram[0x3d0 + 2 * i + 0x1];
		int y = m_videoram[0x3d0 + 2 * i + 0x8];
		int c = m_videoram[0x3d0 + 2 * i + 0x9];

		drawgfx_transpen(bitmap, cliprect,
			machine().gfx[1],
			c >> 3,
			i,
			!(c & 0x80), 0,
			224 - x,
			240 - y, 0);
	}
}


void canyon_state::draw_bombs( bitmap_ind16 &bitmap, const rectangle &cliprect )
{
	int i;

	for (i = 0; i < 2; i++)
	{
		int sx = 254 - m_videoram[0x3d0 + 2 * i + 0x5];
		int sy = 246 - m_videoram[0x3d0 + 2 * i + 0xc];

		rectangle rect(sx, sx + 1, sy, sy + 1);
		rect &= cliprect;

		bitmap.fill(1 + 2 * i, rect);
	}
}


UINT32 canyon_state::screen_update_canyon(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
	m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);

	draw_sprites(bitmap, cliprect);

	draw_bombs(bitmap, cliprect);

	/* watchdog is disabled during service mode */
	machine().watchdog_enable(!(ioport("IN2")->read() & 0x10));

	return 0;
}
