/*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "emu.h" #include "includes/pingpong.h" /* 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. */ static const rectangle spritevisiblearea = { 0*8, 32*8-1, 4*8, 29*8-1 }; /*************************************************************************** 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 ***************************************************************************/ PALETTE_INIT( pingpong ) { int i; /* allocate the colortable */ machine.colortable = colortable_alloc(machine, 0x20); /* create a lookup table for the palette */ for (i = 0; i < 0x20; i++) { int bit0, bit1, bit2; int r, g, b; /* red component */ bit0 = (color_prom[i] >> 0) & 0x01; bit1 = (color_prom[i] >> 1) & 0x01; bit2 = (color_prom[i] >> 2) & 0x01; r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; /* green component */ bit0 = (color_prom[i] >> 3) & 0x01; bit1 = (color_prom[i] >> 4) & 0x01; bit2 = (color_prom[i] >> 5) & 0x01; g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; /* blue component */ bit0 = 0; bit1 = (color_prom[i] >> 6) & 0x01; bit2 = (color_prom[i] >> 7) & 0x01; b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b)); } /* color_prom now points to the beginning of the lookup table */ color_prom += 0x20; /* characters */ for (i = 0; i < 0x100; i++) { UINT8 ctabentry = (color_prom[i] & 0x0f) | 0x10; colortable_entry_set_value(machine.colortable, i, ctabentry); } /* sprites */ for (i = 0x100; i < 0x200; i++) { UINT8 ctabentry = BITSWAP8(color_prom[i],7,6,5,4,0,1,2,3); colortable_entry_set_value(machine.colortable, i, ctabentry); } } WRITE8_HANDLER( pingpong_videoram_w ) { pingpong_state *state = space->machine().driver_data(); state->m_videoram[offset] = data; tilemap_mark_tile_dirty(state->m_bg_tilemap, offset); } WRITE8_HANDLER( pingpong_colorram_w ) { pingpong_state *state = space->machine().driver_data(); state->m_colorram[offset] = data; tilemap_mark_tile_dirty(state->m_bg_tilemap, offset); } static TILE_GET_INFO( get_bg_tile_info ) { pingpong_state *state = machine.driver_data(); int attr = state->m_colorram[tile_index]; int code = state->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(0, code, color, flags); } VIDEO_START( pingpong ) { pingpong_state *state = machine.driver_data(); state->m_bg_tilemap = tilemap_create(machine, get_bg_tile_info, tilemap_scan_rows, 8, 8, 32, 32); } static void draw_sprites(running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect ) { pingpong_state *state = machine.driver_data(); UINT8 *spriteram = state->m_spriteram; int offs; for (offs = state->m_spriteram_size - 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; drawgfx_transmask(bitmap,&spritevisiblearea,machine.gfx[1], schar, color, flipx,flipy, sx,sy, colortable_get_transpen_mask(machine.colortable, machine.gfx[1], color, 0)); } } SCREEN_UPDATE( pingpong ) { pingpong_state *state = screen->machine().driver_data(); tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, 0, 0); draw_sprites(screen->machine(), bitmap, cliprect); return 0; }