/*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "emu.h" #include "includes/gng.h" /*************************************************************************** Callbacks for the TileMap code ***************************************************************************/ static TILE_GET_INFO( get_fg_tile_info ) { gng_state *state = machine.driver_data(); UINT8 attr = state->m_fgvideoram[tile_index + 0x400]; SET_TILE_INFO( 0, state->m_fgvideoram[tile_index] + ((attr & 0xc0) << 2), attr & 0x0f, TILE_FLIPYX((attr & 0x30) >> 4)); } static TILE_GET_INFO( get_bg_tile_info ) { gng_state *state = machine.driver_data(); UINT8 attr = state->m_bgvideoram[tile_index + 0x400]; SET_TILE_INFO( 1, state->m_bgvideoram[tile_index] + ((attr & 0xc0) << 2), attr & 0x07, TILE_FLIPYX((attr & 0x30) >> 4)); tileinfo->group = (attr & 0x08) >> 3; } /*************************************************************************** Start the video hardware emulation. ***************************************************************************/ VIDEO_START( gng ) { gng_state *state = machine.driver_data(); state->m_fg_tilemap = tilemap_create(machine, get_fg_tile_info, tilemap_scan_rows, 8, 8, 32, 32); state->m_bg_tilemap = tilemap_create(machine, get_bg_tile_info, tilemap_scan_cols, 16, 16, 32, 32); tilemap_set_transparent_pen(state->m_fg_tilemap, 3); tilemap_set_transmask(state->m_bg_tilemap, 0, 0xff, 0x00); /* split type 0 is totally transparent in front half */ tilemap_set_transmask(state->m_bg_tilemap, 1, 0x41, 0xbe); /* split type 1 has pens 0 and 6 transparent in front half */ } /*************************************************************************** Memory handlers ***************************************************************************/ WRITE8_HANDLER( gng_fgvideoram_w ) { gng_state *state = space->machine().driver_data(); state->m_fgvideoram[offset] = data; tilemap_mark_tile_dirty(state->m_fg_tilemap, offset & 0x3ff); } WRITE8_HANDLER( gng_bgvideoram_w ) { gng_state *state = space->machine().driver_data(); state->m_bgvideoram[offset] = data; tilemap_mark_tile_dirty(state->m_bg_tilemap, offset & 0x3ff); } WRITE8_HANDLER( gng_bgscrollx_w ) { gng_state *state = space->machine().driver_data(); state->m_scrollx[offset] = data; tilemap_set_scrollx(state->m_bg_tilemap, 0, state->m_scrollx[0] + 256 * state->m_scrollx[1]); } WRITE8_HANDLER( gng_bgscrolly_w ) { gng_state *state = space->machine().driver_data(); state->m_scrolly[offset] = data; tilemap_set_scrolly(state->m_bg_tilemap, 0, state->m_scrolly[0] + 256 * state->m_scrolly[1]); } WRITE8_HANDLER( gng_flipscreen_w ) { flip_screen_set(space->machine(), ~data & 1); } /*************************************************************************** Display refresh ***************************************************************************/ static void draw_sprites( running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect ) { UINT8 *buffered_spriteram = machine.generic.buffered_spriteram.u8; const gfx_element *gfx = machine.gfx[2]; int offs; for (offs = machine.generic.spriteram_size - 4; offs >= 0; offs -= 4) { UINT8 attributes = buffered_spriteram[offs + 1]; int sx = buffered_spriteram[offs + 3] - 0x100 * (attributes & 0x01); int sy = buffered_spriteram[offs + 2]; int flipx = attributes & 0x04; int flipy = attributes & 0x08; if (flip_screen_get(machine)) { sx = 240 - sx; sy = 240 - sy; flipx = !flipx; flipy = !flipy; } drawgfx_transpen(bitmap,cliprect,gfx, buffered_spriteram[offs] + ((attributes << 2) & 0x300), (attributes >> 4) & 3, flipx,flipy, sx,sy,15); } } SCREEN_UPDATE( gng ) { gng_state *state = screen->machine().driver_data(); tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, TILEMAP_DRAW_LAYER1, 0); draw_sprites(screen->machine(), bitmap, cliprect); tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, TILEMAP_DRAW_LAYER0, 0); tilemap_draw(bitmap, cliprect, state->m_fg_tilemap, 0, 0); return 0; } SCREEN_EOF( gng ) { address_space *space = machine.device("maincpu")->memory().space(AS_PROGRAM); buffer_spriteram_w(space, 0, 0); }