// license:BSD-3-Clause // copyright-holders:Allard van der Bas /*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "emu.h" #include "video/resnet.h" #include "includes/mikie.h" /*************************************************************************** Convert the color PROMs into a more useable format. Mikie has three 256x4 palette PROMs (one per gun) and two 256x4 lookup table PROMs (one for characters, one for sprites). I don't know for sure how the palette PROMs are connected to the RGB output, but it's probably the usual: bit 3 -- 220 ohm resistor -- RED/GREEN/BLUE -- 470 ohm resistor -- RED/GREEN/BLUE -- 1 kohm resistor -- RED/GREEN/BLUE bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE ***************************************************************************/ void mikie_state::mikie_palette(palette_device &palette) const { uint8_t const *color_prom = memregion("proms")->base(); static constexpr int resistances[4] = { 2200, 1000, 470, 220 }; // compute the color output resistor weights double rweights[4], gweights[4], bweights[4]; compute_resistor_weights(0, 255, -1.0, 4, resistances, rweights, 470, 0, 4, resistances, gweights, 470, 0, 4, resistances, bweights, 470, 0); // create a lookup table for the palette for (int i = 0; i < 0x100; i++) { int bit0, bit1, bit2, bit3; // red component bit0 = BIT(color_prom[i + 0x000], 0); bit1 = BIT(color_prom[i + 0x000], 1); bit2 = BIT(color_prom[i + 0x000], 2); bit3 = BIT(color_prom[i + 0x000], 3); int const r = combine_weights(rweights, bit0, bit1, bit2, bit3); // green component bit0 = BIT(color_prom[i + 0x100], 0); bit1 = BIT(color_prom[i + 0x100], 1); bit2 = BIT(color_prom[i + 0x100], 2); bit3 = BIT(color_prom[i + 0x100], 3); int const g = combine_weights(gweights, bit0, bit1, bit2, bit3); // blue component bit0 = BIT(color_prom[i + 0x200], 0); bit1 = BIT(color_prom[i + 0x200], 1); bit2 = BIT(color_prom[i + 0x200], 2); bit3 = BIT(color_prom[i + 0x200], 3); int const b = combine_weights(bweights, bit0, bit1, bit2, bit3); palette.set_indirect_color(i, rgb_t(r, g, b)); } // color_prom now points to the beginning of the lookup table, color_prom += 0x300; // characters use colors 0x10-0x1f of each 0x20 color bank, while sprites use colors 0-0x0f for (int i = 0; i < 0x200; i++) { for (int j = 0; j < 8; j++) { uint8_t const ctabentry = (j << 5) | ((~i & 0x100) >> 4) | (color_prom[i] & 0x0f); m_palette->set_pen_indirect(((i & 0x100) << 3) | (j << 8) | (i & 0xff), ctabentry); } } } WRITE8_MEMBER(mikie_state::mikie_videoram_w) { m_videoram[offset] = data; m_bg_tilemap->mark_tile_dirty(offset); } WRITE8_MEMBER(mikie_state::mikie_colorram_w) { m_colorram[offset] = data; m_bg_tilemap->mark_tile_dirty(offset); } WRITE8_MEMBER(mikie_state::mikie_palettebank_w) { if (m_palettebank != (data & 0x07)) { m_palettebank = data & 0x07; machine().tilemap().mark_all_dirty(); } } WRITE_LINE_MEMBER(mikie_state::flipscreen_w) { flip_screen_set(state); machine().tilemap().mark_all_dirty(); } TILE_GET_INFO_MEMBER(mikie_state::get_bg_tile_info) { int code = m_videoram[tile_index] + ((m_colorram[tile_index] & 0x20) << 3); int color = (m_colorram[tile_index] & 0x0f) + 16 * m_palettebank; int flags = ((m_colorram[tile_index] & 0x40) ? TILE_FLIPX : 0) | ((m_colorram[tile_index] & 0x80) ? TILE_FLIPY : 0); if (m_colorram[tile_index] & 0x10) tileinfo.category = 1; else tileinfo.category = 0; SET_TILE_INFO_MEMBER(0, code, color, flags); } void mikie_state::video_start() { m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(mikie_state::get_bg_tile_info)), TILEMAP_SCAN_ROWS, 8, 8, 32, 32); } void mikie_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect) { uint8_t *spriteram = m_spriteram; int offs; for (offs = 0; offs < m_spriteram.bytes(); offs += 4) { int gfxbank = (spriteram[offs + 2] & 0x40) ? 2 : 1; int code = (spriteram[offs + 2] & 0x3f) + ((spriteram[offs + 2] & 0x80) >> 1) + ((spriteram[offs] & 0x40) << 1); int color = (spriteram[offs] & 0x0f) + 16 * m_palettebank; int sx = spriteram[offs + 3]; int sy = 244 - spriteram[offs + 1]; int flipx = ~spriteram[offs] & 0x10; int flipy = spriteram[offs] & 0x20; if (flip_screen()) { sy = 242 - sy; flipy = !flipy; } m_gfxdecode->gfx(gfxbank)->transpen(bitmap,cliprect, code, color, flipx,flipy, sx,sy, 0); } } uint32_t mikie_state::screen_update_mikie(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) { m_bg_tilemap->draw(screen, bitmap, cliprect, TILEMAP_DRAW_CATEGORY(0), 0); draw_sprites(bitmap, cliprect); m_bg_tilemap->draw(screen, bitmap, cliprect, TILEMAP_DRAW_CATEGORY(1), 0); return 0; }