// license:BSD-3-Clause // copyright-holders:Aaron Giles /*************************************************************************** Atari Blasteroids hardware ****************************************************************************/ #include "emu.h" #include "machine/atarigen.h" #include "video/atarimo.h" #include "includes/blstroid.h" /************************************* * * Tilemap callbacks * *************************************/ TILE_GET_INFO_MEMBER(blstroid_state::get_playfield_tile_info) { uint16_t data = m_playfield_tilemap->basemem_read(tile_index); int code = data & 0x1fff; int color = (data >> 13) & 0x07; SET_TILE_INFO_MEMBER(0, code, color, 0); } /************************************* * * Video system start * *************************************/ const atari_motion_objects_config blstroid_state::s_mob_config = { 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 */ {{ 0,0x3fff,0,0 }}, /* mask for the 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" */ }; VIDEO_START_MEMBER(blstroid_state,blstroid) { m_irq_off_timer = timer_alloc(TIMER_IRQ_OFF); m_irq_on_timer = timer_alloc(TIMER_IRQ_ON); } /************************************* * * Periodic scanline updater * *************************************/ void blstroid_state::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) { switch (id) { case TIMER_IRQ_OFF: /* clear the interrupt */ scanline_int_ack_w(); break; case TIMER_IRQ_ON: /* generate the interrupt */ scanline_int_write_line(1); update_interrupts(); break; default: atarigen_state::device_timer(timer, id, param, ptr); break; } } void blstroid_state::scanline_update(screen_device &screen, int scanline) { int offset = (scanline / 8) * 64 + 40; /* check for interrupts */ if (offset < 0x1000) if (m_playfield_tilemap->basemem_read(offset) & 0x8000) { /* 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 */ int width = screen.width(); int vpos = screen.vpos(); attotime period_on = screen.time_until_pos(vpos + 7, width * 0.9); attotime period_off = screen.time_until_pos(vpos + 8, width * 0.9); m_irq_on_timer->adjust(period_on); m_irq_off_timer->adjust(period_off); } } /************************************* * * Main refresh * *************************************/ uint32_t blstroid_state::screen_update_blstroid(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) { // start drawing m_mob->draw_async(cliprect); /* draw the playfield */ m_playfield_tilemap->draw(screen, bitmap, cliprect, 0, 0); /* draw and merge the MO */ bitmap_ind16 &mobitmap = m_mob->bitmap(); for (const sparse_dirty_rect *rect = m_mob->first_dirty_rect(cliprect); rect != nullptr; rect = rect->next()) for (int y = rect->top(); y <= rect->bottom(); y++) { uint16_t *mo = &mobitmap.pix16(y); uint16_t *pf = &bitmap.pix16(y); for (int x = rect->left(); x <= rect->right(); x++) if (mo[x] != 0xffff) { /* verified via schematics priority address = HPPPMMMM */ int priaddr = ((pf[x] & 8) << 4) | (pf[x] & 0x70) | ((mo[x] & 0xf0) >> 4); if (m_priorityram[priaddr] & 1) pf[x] = mo[x]; } } return 0; }