// license:BSD-3-Clause // copyright-holders:Jarek Parchanski /*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "emu.h" #include "includes/pingpong.h" /*************************************************************************** Convert the color PROMs into a more useable format. Ping Pong has a 32 bytes palette PROM and two 256 bytes color lookup table PROMs (one for sprites, one for characters). I don't know for sure how the palette PROM is connected to the RGB output, but it's probably the usual: bit 7 -- 220 ohm resistor -- BLUE -- 470 ohm resistor -- BLUE -- 220 ohm resistor -- GREEN -- 470 ohm resistor -- GREEN -- 1 kohm resistor -- GREEN -- 220 ohm resistor -- RED -- 470 ohm resistor -- RED bit 0 -- 1 kohm resistor -- RED ***************************************************************************/ void pingpong_state::pingpong_palette(palette_device &palette) const { const uint8_t *color_prom = memregion("proms")->base(); // create a lookup table for the palette for (int i = 0; i < 0x20; i++) { int bit0, bit1, bit2; // red component bit0 = BIT(color_prom[i], 0); bit1 = BIT(color_prom[i], 1); bit2 = BIT(color_prom[i], 2); int const r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; // green component bit0 = BIT(color_prom[i], 3); bit1 = BIT(color_prom[i], 4); bit2 = BIT(color_prom[i], 5); int const g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; // blue component bit0 = 0; bit1 = BIT(color_prom[i], 6); bit2 = BIT(color_prom[i], 7); int const b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; palette.set_indirect_color(i, rgb_t(r, g, b)); } // color_prom now points to the beginning of the lookup table color_prom += 0x20; // characters for (int i = 0; i < 0x100; i++) { uint8_t const ctabentry = (color_prom[i] & 0x0f) | 0x10; palette.set_pen_indirect(i, ctabentry); } // sprites for (int i = 0x100; i < 0x200; i++) { uint8_t const ctabentry = bitswap<8>(color_prom[i],7,6,5,4,0,1,2,3); palette.set_pen_indirect(i, ctabentry); } } WRITE8_MEMBER(pingpong_state::pingpong_videoram_w) { m_videoram[offset] = data; m_bg_tilemap->mark_tile_dirty(offset); } WRITE8_MEMBER(pingpong_state::pingpong_colorram_w) { m_colorram[offset] = data; m_bg_tilemap->mark_tile_dirty(offset); } TILE_GET_INFO_MEMBER(pingpong_state::get_bg_tile_info) { int attr = m_colorram[tile_index]; int code = m_videoram[tile_index] + ((attr & 0x20) << 3); int color = attr & 0x1f; int flags = ((attr & 0x40) ? TILE_FLIPX : 0) | ((attr & 0x80) ? TILE_FLIPY : 0); SET_TILE_INFO_MEMBER(0, code, color, flags); } void pingpong_state::video_start() { m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(pingpong_state::get_bg_tile_info)), TILEMAP_SCAN_ROWS, 8, 8, 32, 32); } void pingpong_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect ) { /* This is strange; it's unlikely that the sprites actually have a hardware */ /* clipping region, but I haven't found another way to have them masked by */ /* the characters at the top and bottom of the screen. */ const rectangle spritevisiblearea(0*8, 32*8-1, 4*8, 29*8-1); uint8_t *spriteram = m_spriteram; int offs; for (offs = m_spriteram.bytes() - 4;offs >= 0;offs -= 4) { int sx,sy,flipx,flipy,color,schar; sx = spriteram[offs + 3]; sy = 241 - spriteram[offs + 1]; flipx = spriteram[offs] & 0x40; flipy = spriteram[offs] & 0x80; color = spriteram[offs] & 0x1f; schar = spriteram[offs + 2] & 0x7f; m_gfxdecode->gfx(1)->transmask(bitmap,spritevisiblearea, schar, color, flipx,flipy, sx,sy, m_palette->transpen_mask(*m_gfxdecode->gfx(1), color, 0)); } } uint32_t pingpong_state::screen_update_pingpong(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) { m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0); draw_sprites(bitmap, cliprect); return 0; }