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/***************************************************************************
Atari Drag Race video emulation
***************************************************************************/
#include "driver.h"
#include "includes/dragrace.h"
UINT8* dragrace_playfield_ram;
UINT8* dragrace_position_ram;
static tilemap* bg_tilemap;
static TILE_GET_INFO( get_tile_info )
{
UINT8 code = dragrace_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(((code & 0xA0) == 0x80) ? 1 : 0, num, col, 0);
}
VIDEO_START( dragrace )
{
bg_tilemap = tilemap_create(
get_tile_info, tilemap_scan_rows, TILEMAP_TYPE_PEN, 16, 16, 16, 16);
}
VIDEO_UPDATE( dragrace )
{
int y;
tilemap_mark_all_tiles_dirty(bg_tilemap);
for (y = 0; y < 256; y += 4)
{
rectangle rect = *cliprect;
int xl = dragrace_position_ram[y + 0] & 15;
int xh = dragrace_position_ram[y + 1] & 15;
int yl = dragrace_position_ram[y + 2] & 15;
int yh = dragrace_position_ram[y + 3] & 15;
tilemap_set_scrollx(bg_tilemap, 0, 16 * xh + xl - 8);
tilemap_set_scrolly(bg_tilemap, 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;
tilemap_draw(bitmap, &rect, bg_tilemap, 0, 0);
}
return 0;
}
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