/*************************************************************************** Atari Blasteroids hardware ****************************************************************************/ #include "emu.h" #include "machine/atarigen.h" #include "video/atarimo.h" #include "includes/blstroid.h" /************************************* * * Tilemap callbacks * *************************************/ static TILE_GET_INFO( get_playfield_tile_info ) { blstroid_state *state = machine.driver_data(); UINT16 data = state->m_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 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 */ }; blstroid_state *state = machine.driver_data(); /* initialize the playfield */ state->m_playfield_tilemap = tilemap_create(machine, get_playfield_tile_info, tilemap_scan_rows, 16,8, 64,64); /* initialize the motion objects */ atarimo_init(machine, 0, &modesc); } /************************************* * * Periodic scanline updater * *************************************/ static TIMER_CALLBACK( irq_off ) { address_space *space = machine.device("maincpu")->memory().space(AS_PROGRAM); /* clear the interrupt */ atarigen_scanline_int_ack_w(space, 0, 0, 0xffff); } static TIMER_CALLBACK( irq_on ) { /* generate the interrupt */ atarigen_scanline_int_gen(machine.device("maincpu")); atarigen_update_interrupts(machine); } void blstroid_scanline_update(screen_device &screen, int scanline) { blstroid_state *state = screen.machine().driver_data(); int offset = (scanline / 8) * 64 + 40; /* check for interrupts */ if (offset < 0x1000) if (state->m_playfield[offset] & 0x8000) { int width, vpos; attotime period_on; attotime period_off; /* FIXME: - 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 */ width = screen.width(); vpos = screen.vpos(); period_on = screen.time_until_pos(vpos + 7, width * 0.9); period_off = screen.time_until_pos(vpos + 8, width * 0.9); screen.machine().scheduler().timer_set(period_on, FUNC(irq_on)); screen.machine().scheduler().timer_set(period_off, FUNC(irq_off)); } } /************************************* * * Main refresh * *************************************/ SCREEN_UPDATE( blstroid ) { blstroid_state *state = screen->machine().driver_data(); atarimo_rect_list rectlist; bitmap_t *mobitmap; int x, y, r; /* draw the playfield */ tilemap_draw(bitmap, cliprect, state->m_playfield_tilemap, 0, 0); /* draw and merge the MO */ mobitmap = atarimo_render(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 (state->m_priorityram[priaddr] & 1) pf[x] = mo[x]; /* erase behind ourselves */ mo[x] = 0; } } return 0; }