/*************************************************************************** Atari Blasteroids hardware ****************************************************************************/ #include "driver.h" #include "machine/atarigen.h" #include "blstroid.h" /************************************* * * Globals we own * *************************************/ UINT16 *blstroid_priorityram; /************************************* * * Tilemap callbacks * *************************************/ static TILE_GET_INFO( get_playfield_tile_info ) { UINT16 data = atarigen_playfield[tile_index]; int code = data & 0x1fff; int color = (data >> 13) & 0x07; SET_TILE_INFO(0, code, color, 0); } /************************************* * * Video system start * *************************************/ VIDEO_START( blstroid ) { static const struct atarimo_desc modesc = { 1, /* index to which gfx system */ 1, /* number of motion object banks */ 1, /* are the entries linked? */ 0, /* are the entries split? */ 0, /* render in reverse order? */ 0, /* render in swapped X/Y order? */ 0, /* does the neighbor bit affect the next object? */ 0, /* pixels per SLIP entry (0 for no-slip) */ 0, /* pixel offset for SLIPs */ 0, /* maximum number of links to visit/scanline (0=all) */ 0x000, /* base palette entry */ 0x100, /* maximum number of colors */ 0, /* transparent pen index */ {{ 0,0,0x0ff8,0 }}, /* mask for the link */ {{ 0 }}, /* mask for the graphics bank */ {{ 0,0x3fff,0,0 }}, /* mask for the code index */ {{ 0 }}, /* mask for the upper code index */ {{ 0,0,0,0x000f }}, /* mask for the color */ {{ 0,0,0,0xffc0 }}, /* mask for the X position */ {{ 0xff80,0,0,0 }}, /* mask for the Y position */ {{ 0 }}, /* mask for the width, in tiles*/ {{ 0x000f,0,0,0 }}, /* mask for the height, in tiles */ {{ 0,0x8000,0,0 }}, /* mask for the horizontal flip */ {{ 0,0x4000,0,0 }}, /* mask for the vertical flip */ {{ 0 }}, /* mask for the priority */ {{ 0 }}, /* mask for the neighbor */ {{ 0 }}, /* mask for absolute coordinates */ {{ 0 }}, /* mask for the special value */ 0, /* resulting value to indicate "special" */ 0 /* callback routine for special entries */ }; /* initialize the playfield */ atarigen_playfield_tilemap = tilemap_create(get_playfield_tile_info, tilemap_scan_rows, TILEMAP_TYPE_PEN, 16,8, 64,64); /* initialize the motion objects */ atarimo_init(machine, 0, &modesc); } /************************************* * * Periodic scanline updater * *************************************/ static TIMER_CALLBACK( irq_off ) { /* clear the interrupt */ atarigen_scanline_int_ack_w(0, 0, 0); } static TIMER_CALLBACK( irq_on ) { /* generate the interrupt */ atarigen_scanline_int_gen(); atarigen_update_interrupts(); } void blstroid_scanline_update(running_machine *machine, int scrnum, int scanline) { int offset = (scanline / 8) * 64 + 40; /* check for interrupts */ if (offset < 0x1000) if (atarigen_playfield[offset] & 0x8000) { attotime period_on; attotime period_off; /* fix me - the only thing this IRQ does it tweak the starting MO link */ /* unfortunately, it does it too early for the given MOs! */ /* perhaps it is not actually hooked up on the real PCB... */ return; /* set a timer to turn the interrupt on at HBLANK of the 7th scanline */ /* and another to turn it off one scanline later */ period_on = video_screen_get_time_until_pos(scrnum, video_screen_get_vpos(scrnum) + 7, machine->screen[scrnum].width * 0.9); period_off = video_screen_get_time_until_pos(scrnum, video_screen_get_vpos(scrnum) + 8, machine->screen[scrnum].width * 0.9); timer_set(period_on, 0, irq_on); timer_set(period_off, 0, irq_off); } } /************************************* * * Main refresh * *************************************/ VIDEO_UPDATE( blstroid ) { struct atarimo_rect_list rectlist; mame_bitmap *mobitmap; int x, y, r; /* draw the playfield */ tilemap_draw(bitmap, cliprect, atarigen_playfield_tilemap, 0, 0); /* draw and merge the MO */ mobitmap = atarimo_render(machine, 0, cliprect, &rectlist); for (r = 0; r < rectlist.numrects; r++, rectlist.rect++) for (y = rectlist.rect->min_y; y <= rectlist.rect->max_y; y++) { UINT16 *mo = (UINT16 *)mobitmap->base + mobitmap->rowpixels * y; UINT16 *pf = (UINT16 *)bitmap->base + bitmap->rowpixels * y; for (x = rectlist.rect->min_x; x <= rectlist.rect->max_x; x++) if (mo[x]) { /* verified via schematics priority address = HPPPMMMM */ int priaddr = ((pf[x] & 8) << 4) | (pf[x] & 0x70) | ((mo[x] & 0xf0) >> 4); if (blstroid_priorityram[priaddr] & 1) pf[x] = mo[x]; /* erase behind ourselves */ mo[x] = 0; } } return 0; }