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// license:BSD-3-Clause
// copyright-holders:Stefan Jokisch
/***************************************************************************
Atari Drag Race video emulation
***************************************************************************/
#include "emu.h"
#include "includes/dragrace.h"
TILE_GET_INFO_MEMBER(dragrace_state::get_tile_info)
{
uint8_t code = m_playfield_ram[tile_index];
int num = 0;
int col = 0;
num = code & 0x1f;
if ((code & 0xc0) == 0x40)
num |= 0x20;
switch (code & 0xA0)
{
case 0x00:
col = 0;
break;
case 0x20:
col = 1;
break;
case 0x80:
col = (code & 0x40) ? 1 : 0;
break;
case 0xA0:
col = (code & 0x40) ? 3 : 2;
break;
}
SET_TILE_INFO_MEMBER(((code & 0xA0) == 0x80) ? 1 : 0, num, col, 0);
}
void dragrace_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(dragrace_state::get_tile_info),this), TILEMAP_SCAN_ROWS, 16, 16, 16, 16);
}
uint32_t dragrace_state::screen_update_dragrace(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->mark_all_dirty();
for (int y = 0; y < 256; y += 4)
{
rectangle rect = cliprect;
int xl = m_position_ram[y + 0] & 15;
int xh = m_position_ram[y + 1] & 15;
int yl = m_position_ram[y + 2] & 15;
int yh = m_position_ram[y + 3] & 15;
m_bg_tilemap->set_scrollx(0, 16 * xh + xl - 8);
m_bg_tilemap->set_scrolly(0, 16 * yh + yl);
if (rect.min_y < y + 0) rect.min_y = y + 0;
if (rect.max_y > y + 3) rect.max_y = y + 3;
m_bg_tilemap->draw(screen, bitmap, rect, 0, 0);
}
return 0;
}
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