/*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "driver.h" UINT8 *gundealr_bg_videoram,*gundealr_fg_videoram; static tilemap *bg_tilemap,*fg_tilemap; static int flipscreen; /*************************************************************************** Callbacks for the TileMap code ***************************************************************************/ static TILE_GET_INFO( get_bg_tile_info ) { UINT8 attr = gundealr_bg_videoram[2*tile_index+1]; SET_TILE_INFO( 0, gundealr_bg_videoram[2*tile_index] + ((attr & 0x07) << 8), (attr & 0xf0) >> 4, 0); } static TILEMAP_MAPPER( gundealr_scan ) { /* logical (col,row) -> memory offset */ return (row & 0x0f) + ((col & 0x3f) << 4) + ((row & 0x10) << 6); } static TILE_GET_INFO( get_fg_tile_info ) { UINT8 attr = gundealr_fg_videoram[2*tile_index+1]; SET_TILE_INFO( 1, gundealr_fg_videoram[2*tile_index] + ((attr & 0x03) << 8), (attr & 0xf0) >> 4, 0); } /*************************************************************************** Start the video hardware emulation. ***************************************************************************/ VIDEO_START( gundealr ) { bg_tilemap = tilemap_create(get_bg_tile_info,tilemap_scan_cols,TILEMAP_TYPE_PEN, 8, 8,32,32); fg_tilemap = tilemap_create(get_fg_tile_info,gundealr_scan, TILEMAP_TYPE_PEN,16,16,64,32); tilemap_set_transparent_pen(fg_tilemap,15); } /*************************************************************************** Memory handlers ***************************************************************************/ WRITE8_HANDLER( gundealr_bg_videoram_w ) { gundealr_bg_videoram[offset] = data; tilemap_mark_tile_dirty(bg_tilemap,offset/2); } WRITE8_HANDLER( gundealr_fg_videoram_w ) { gundealr_fg_videoram[offset] = data; tilemap_mark_tile_dirty(fg_tilemap,offset/2); } WRITE8_HANDLER( gundealr_paletteram_w ) { int r,g,b,val; paletteram[offset] = data; val = paletteram[offset & ~1]; r = (val >> 4) & 0x0f; g = (val >> 0) & 0x0f; val = paletteram[offset | 1]; b = (val >> 4) & 0x0f; /* TODO: the bottom 4 bits are used as well, but I'm not sure about the meaning */ palette_set_color_rgb(Machine,offset / 2,pal4bit(r),pal4bit(g),pal4bit(b)); } WRITE8_HANDLER( gundealr_fg_scroll_w ) { static UINT8 scroll[4]; scroll[offset] = data; tilemap_set_scrollx(fg_tilemap,0,scroll[1] | ((scroll[0] & 0x03) << 8)); tilemap_set_scrolly(fg_tilemap,0,scroll[3] | ((scroll[2] & 0x03) << 8)); } WRITE8_HANDLER( yamyam_fg_scroll_w ) { static UINT8 scroll[4]; scroll[offset] = data; tilemap_set_scrollx(fg_tilemap,0,scroll[0] | ((scroll[1] & 0x03) << 8)); tilemap_set_scrolly(fg_tilemap,0,scroll[2] | ((scroll[3] & 0x03) << 8)); } WRITE8_HANDLER( gundealr_flipscreen_w ) { flipscreen = data; tilemap_set_flip(ALL_TILEMAPS,flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0); } /*************************************************************************** Display refresh ***************************************************************************/ VIDEO_UPDATE( gundealr ) { tilemap_draw(bitmap,cliprect,bg_tilemap,0,0); tilemap_draw(bitmap,cliprect,fg_tilemap,0,0); return 0; }