/*************************************************************************** Atari Drag Race video emulation ***************************************************************************/ #include "emu.h" #include "includes/dragrace.h" static TILE_GET_INFO( get_tile_info ) { dragrace_state *state = machine.driver_data(); UINT8 code = state->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(((code & 0xA0) == 0x80) ? 1 : 0, num, col, 0); } VIDEO_START( dragrace ) { dragrace_state *state = machine.driver_data(); state->m_bg_tilemap = tilemap_create(machine, get_tile_info, tilemap_scan_rows, 16, 16, 16, 16); } SCREEN_UPDATE( dragrace ) { dragrace_state *state = screen->machine().driver_data(); int y; tilemap_mark_all_tiles_dirty(state->m_bg_tilemap); for (y = 0; y < 256; y += 4) { rectangle rect = *cliprect; int xl = state->m_position_ram[y + 0] & 15; int xh = state->m_position_ram[y + 1] & 15; int yl = state->m_position_ram[y + 2] & 15; int yh = state->m_position_ram[y + 3] & 15; tilemap_set_scrollx(state->m_bg_tilemap, 0, 16 * xh + xl - 8); tilemap_set_scrolly(state->m_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, state->m_bg_tilemap, 0, 0); } return 0; }