/*************************************************************************** Atari Skull & Crossbones hardware ****************************************************************************/ #include "driver.h" #include "machine/atarigen.h" #include "includes/skullxbo.h" /************************************* * * Tilemap callbacks * *************************************/ static TILE_GET_INFO( get_alpha_tile_info ) { UINT16 data = atarigen_alpha[tile_index]; int code = (data ^ 0x400) & 0x7ff; int color = (data >> 11) & 0x0f; int opaque = data & 0x8000; SET_TILE_INFO(2, code, color, opaque ? TILE_FORCE_LAYER0 : 0); } static TILE_GET_INFO( get_playfield_tile_info ) { UINT16 data1 = atarigen_playfield[tile_index]; UINT16 data2 = atarigen_playfield_upper[tile_index] & 0xff; int code = data1 & 0x7fff; int color = data2 & 0x0f; SET_TILE_INFO(1, code, color, (data1 >> 15) & 1); } /************************************* * * Video system start * *************************************/ VIDEO_START( skullxbo ) { static const struct atarimo_desc modesc = { 0, /* index to which gfx system */ 2, /* 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? */ 8, /* 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 */ 0x200, /* maximum number of colors */ 0, /* transparent pen index */ {{ 0x00ff,0,0,0 }}, /* mask for the link */ {{ 0 }}, /* mask for the graphics bank */ {{ 0,0x7fff,0,0 }}, /* mask for the code index */ {{ 0 }}, /* mask for the upper code index */ {{ 0,0,0x000f,0 }}, /* mask for the color */ {{ 0,0,0xffc0,0 }}, /* mask for the X position */ {{ 0,0,0,0xff80 }}, /* mask for the Y position */ {{ 0,0,0,0x0070 }}, /* mask for the width, in tiles*/ {{ 0,0,0,0x000f }}, /* mask for the height, in tiles */ {{ 0,0x8000,0,0 }}, /* mask for the horizontal flip */ {{ 0 }}, /* mask for the vertical flip */ {{ 0,0,0x0030,0 }}, /* 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_cols, TILEMAP_TYPE_PEN, 16,8, 64,64); /* initialize the motion objects */ atarimo_init(machine, 0, &modesc); /* initialize the alphanumerics */ atarigen_alpha_tilemap = tilemap_create(get_alpha_tile_info, tilemap_scan_rows, TILEMAP_TYPE_PEN, 16,8, 64,32); tilemap_set_transparent_pen(atarigen_alpha_tilemap, 0); } /************************************* * * Video data latch * *************************************/ WRITE16_HANDLER( skullxbo_xscroll_w ) { /* combine data */ UINT16 oldscroll = *atarigen_xscroll; UINT16 newscroll = oldscroll; COMBINE_DATA(&newscroll); /* if something changed, force an update */ if (oldscroll != newscroll) video_screen_update_partial(0, video_screen_get_vpos(0)); /* adjust the actual scrolls */ tilemap_set_scrollx(atarigen_playfield_tilemap, 0, 2 * (newscroll >> 7)); atarimo_set_xscroll(0, 2 * (newscroll >> 7)); /* update the data */ *atarigen_xscroll = newscroll; } WRITE16_HANDLER( skullxbo_yscroll_w ) { /* combine data */ int scanline = video_screen_get_vpos(0); UINT16 oldscroll = *atarigen_yscroll; UINT16 newscroll = oldscroll; UINT16 effscroll; COMBINE_DATA(&newscroll); /* if something changed, force an update */ if (oldscroll != newscroll) video_screen_update_partial(0, scanline); /* adjust the effective scroll for the current scanline */ if (scanline > Machine->screen[0].visarea.max_y) scanline = 0; effscroll = (newscroll >> 7) - scanline; /* adjust the actual scrolls */ tilemap_set_scrolly(atarigen_playfield_tilemap, 0, effscroll); atarimo_set_yscroll(0, effscroll & 0x1ff); /* update the data */ *atarigen_yscroll = newscroll; } /************************************* * * Motion object bank handler * *************************************/ WRITE16_HANDLER( skullxbo_mobmsb_w ) { video_screen_update_partial(0, video_screen_get_vpos(0)); atarimo_set_bank(0, (offset >> 9) & 1); } /************************************* * * Playfield latch write handler * *************************************/ WRITE16_HANDLER( skullxbo_playfieldlatch_w ) { atarigen_set_playfield_latch(data); } /************************************* * * Periodic playfield updater * *************************************/ void skullxbo_scanline_update(int scanline) { UINT16 *base = &atarigen_alpha[(scanline / 8) * 64 + 42]; int x; /* keep in range */ if (base >= &atarigen_alpha[0x7c0]) return; /* special case: scanline 0 should re-latch the previous raw scroll */ if (scanline == 0) { int newscroll = (*atarigen_yscroll >> 7) & 0x1ff; tilemap_set_scrolly(atarigen_playfield_tilemap, 0, newscroll); atarimo_set_yscroll(0, newscroll); } /* update the current parameters */ for (x = 42; x < 64; x++) { UINT16 data = *base++; UINT16 command = data & 0x000f; /* only command I've ever seen */ if (command == 0x0d) { /* a new vscroll latches the offset into a counter; we must adjust for this */ int newscroll = ((data >> 7) - scanline) & 0x1ff; /* force a partial update with the previous scroll */ video_screen_update_partial(0, scanline - 1); /* update the new scroll */ tilemap_set_scrolly(atarigen_playfield_tilemap, 0, newscroll); atarimo_set_yscroll(0, newscroll); /* make sure we change this value so that writes to the scroll register */ /* know whether or not they are a different scroll */ *atarigen_yscroll = data; } } } /************************************* * * Main refresh * *************************************/ VIDEO_UPDATE( skullxbo ) { 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 from the GALs on the real PCB; equations follow --- O17 is an intermediate value O17=PFPIX3*PFPAL2S*PFPAL3S --- CRAM.A10 controls the high bit of the palette select; used for shadows CRAM.A10=BA11*CRAMD +!CRAMD*!LBPRI0*!LBPRI1*!O17*(LBPIX==1)*(ANPIX==0) +!CRAMD*LBPRI0*!LBPRI1*(LBPIX==1)*(ANPIX==0)*!PFPAL3S +!CRAMD*LBPRI1*(LBPIX==1)*(ANPIX==0)*!PFPAL2S*!PFPAL3S +!CRAMD*!PFPIX3*(LBPIX==1)*(ANPIX==0) --- SA and SB are the mux select lines: --- 0 = motion objects --- 1 = playfield --- 2 = alpha --- 3 = color RAM access from CPU !SA=!CRAMD*(ANPIX!=0) +!CRAMD*!LBPRI0*!LBPRI1*!O17*(LBPIX!=1)*(LBPIX!=0) +!CRAMD*LBPRI0*!LBPRI1*(LBPIX!=1)*(LBPIX!=0)*!PFPAL3S +!CRAMD*LBPRI1*(LBPIX!=1)*(LBPIX!=0)*!PFPAL2S*!PFPAL3S +!CRAMD*!PFPIX3*(LBPIX!=1)*(LBPIX!=0) !SB=!CRAMD*(ANPIX==0) +!CRAMD*LBMISC*(LBPIX!=0) */ int mopriority = mo[x] >> ATARIMO_PRIORITY_SHIFT; int mopix = mo[x] & 0x1f; int pfcolor = (pf[x] >> 4) & 0x0f; int pfpix = pf[x] & 0x0f; int o17 = ((pf[x] & 0xc8) == 0xc8); /* implement the equations */ if ((mopriority == 0 && !o17 && mopix >= 2) || (mopriority == 1 && mopix >= 2 && !(pfcolor & 0x08)) || ((mopriority & 2) && mopix >= 2 && !(pfcolor & 0x0c)) || (!(pfpix & 8) && mopix >= 2)) pf[x] = mo[x] & ATARIMO_DATA_MASK; if ((mopriority == 0 && !o17 && mopix == 1) || (mopriority == 1 && mopix == 1 && !(pfcolor & 0x08)) || ((mopriority & 2) && mopix == 1 && !(pfcolor & 0x0c)) || (!(pfpix & 8) && mopix == 1)) pf[x] |= 0x400; /* erase behind ourselves */ mo[x] = 0; } } /* add the alpha on top */ tilemap_draw(bitmap, cliprect, atarigen_alpha_tilemap, 0, 0); return 0; }