// license:GPL-2.0+ // copyright-holders:Juergen Buchmueller /*************************************************************/ /* */ /* Lazer Command video handler */ /* */ /*************************************************************/ #include "emu.h" #include "includes/lazercmd.h" /* scale a markers vertical position */ /* the following table shows how the markers */ /* vertical position worked in hardware */ /* marker_y lines marker_y lines */ /* 0 0 + 1 8 10 + 11 */ /* 1 2 + 3 9 12 + 13 */ /* 2 4 + 5 10 14 + 15 */ /* 3 6 + 7 11 16 + 17 */ /* 4 8 + 9 12 18 + 19 */ int lazercmd_state::vert_scale(int data) { return ((data & 0x07) << 1) + ((data & 0xf8) >> 3) * VERT_CHR; } /* plot a bitmap marker */ /* hardware has 2 marker sizes 2x2 and 4x2 selected by jumper */ /* meadows lanes normaly use 2x2 pixels and lazer command uses either */ void lazercmd_state::plot_pattern( bitmap_ind16 &bitmap, int x, int y ) { int size = 2; if (ioport("DSW")->read() & 0x40) { size = 4; } for (int ybit = 0; ybit < 2; ybit++) { if (y + ybit < 0 || y + ybit >= VERT_RES * VERT_CHR) return; for (int xbit = 0; xbit < size; xbit++) { if (x + xbit < 0 || x + xbit >= HORZ_RES * HORZ_CHR) continue; bitmap.pix(y + ybit, x + xbit) = 4; } } } uint32_t lazercmd_state::screen_update_lazercmd(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) { int i, x, y; int video_inverted = (ioport("DSW")->read() ^ m_attract) & 0x20; /* The first row of characters are invisible */ for (i = 0; i < (VERT_RES - 1) * HORZ_RES; i++) { int sx, sy; sx = i % HORZ_RES; sy = i / HORZ_RES; sx *= HORZ_CHR; sy *= VERT_CHR; m_gfxdecode->gfx(0)->opaque(bitmap,cliprect, m_videoram[i], video_inverted ? 1 : 0, 0,0, sx,sy); } x = m_marker_x - 1; /* normal video lags marker by 1 pixel */ y = vert_scale(m_marker_y) - VERT_CHR; /* first line used as scratch pad */ plot_pattern(bitmap, x, y); return 0; }