/*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "driver.h" UINT8 *ironhors_scroll; static int palettebank, charbank, spriterambank; static tilemap *bg_tilemap; /*************************************************************************** Convert the color PROMs into a more useable format. Iron Horse 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 ***************************************************************************/ PALETTE_INIT( ironhors ) { int i; #define TOTAL_COLORS(gfxn) (machine->gfx[gfxn]->total_colors * machine->gfx[gfxn]->color_granularity) #define COLOR(gfxn,offs) (colortable[machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs]) for (i = 0;i < machine->drv->total_colors;i++) { int bit0,bit1,bit2,bit3,r,g,b; bit0 = (color_prom[0] >> 0) & 0x01; bit1 = (color_prom[0] >> 1) & 0x01; bit2 = (color_prom[0] >> 2) & 0x01; bit3 = (color_prom[0] >> 3) & 0x01; r = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3; bit0 = (color_prom[machine->drv->total_colors] >> 0) & 0x01; bit1 = (color_prom[machine->drv->total_colors] >> 1) & 0x01; bit2 = (color_prom[machine->drv->total_colors] >> 2) & 0x01; bit3 = (color_prom[machine->drv->total_colors] >> 3) & 0x01; g = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3; bit0 = (color_prom[2*machine->drv->total_colors] >> 0) & 0x01; bit1 = (color_prom[2*machine->drv->total_colors] >> 1) & 0x01; bit2 = (color_prom[2*machine->drv->total_colors] >> 2) & 0x01; bit3 = (color_prom[2*machine->drv->total_colors] >> 3) & 0x01; b = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3; palette_set_color(machine,i,MAKE_RGB(r,g,b)); color_prom++; } color_prom += 2*machine->drv->total_colors; /* color_prom now points to the beginning of the character lookup table */ /* there are eight 32 colors palette banks; sprites use colors 0-15 and */ /* characters 16-31 of each bank. */ for (i = 0;i < TOTAL_COLORS(0)/8;i++) { int j; for (j = 0;j < 8;j++) COLOR(0,i + j * TOTAL_COLORS(0)/8) = (*color_prom & 0x0f) + 32 * j + 16; color_prom++; } for (i = 0;i < TOTAL_COLORS(1)/8;i++) { int j; for (j = 0;j < 8;j++) COLOR(1,i + j * TOTAL_COLORS(1)/8) = (*color_prom & 0x0f) + 32 * j; color_prom++; } } WRITE8_HANDLER( ironhors_videoram_w ) { videoram[offset] = data; tilemap_mark_tile_dirty(bg_tilemap, offset); } WRITE8_HANDLER( ironhors_colorram_w ) { colorram[offset] = data; tilemap_mark_tile_dirty(bg_tilemap, offset); } WRITE8_HANDLER( ironhors_charbank_w ) { if (charbank != (data & 0x03)) { charbank = data & 0x03; tilemap_mark_all_tiles_dirty(ALL_TILEMAPS); } spriterambank = data & 0x08; /* other bits unknown */ } WRITE8_HANDLER( ironhors_palettebank_w ) { if (palettebank != (data & 0x07)) { palettebank = data & 0x07; tilemap_mark_all_tiles_dirty(ALL_TILEMAPS); } coin_counter_w(0, data & 0x10); coin_counter_w(1, data & 0x20); /* bit 6 unknown - set after game over */ if (data & 0x88) popmessage("ironhors_palettebank_w %02x",data); } WRITE8_HANDLER( ironhors_flipscreen_w ) { if (flip_screen != (~data & 0x08)) { flip_screen_set(~data & 0x08); tilemap_mark_all_tiles_dirty(ALL_TILEMAPS); } /* other bits are used too, but unknown */ } static TILE_GET_INFO( get_bg_tile_info ) { int code = videoram[tile_index] + ((colorram[tile_index] & 0x40) << 2) + ((colorram[tile_index] & 0x20) << 4) + (charbank << 10); int color = (colorram[tile_index] & 0x0f) + 16 * palettebank; int flags = ((colorram[tile_index] & 0x10) ? TILE_FLIPX : 0) | ((colorram[tile_index] & 0x20) ? TILE_FLIPY : 0); SET_TILE_INFO(0, code, color, flags); } VIDEO_START( ironhors ) { bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows, TILEMAP_TYPE_PEN, 8, 8, 32, 32); tilemap_set_scroll_rows(bg_tilemap, 32); } static void draw_sprites(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect) { int offs; UINT8 *sr; if (spriterambank != 0) sr = spriteram; else sr = spriteram_2; for (offs = 0;offs < spriteram_size;offs += 5) { int sx = sr[offs+3]; int sy = sr[offs+2]; int flipx = sr[offs+4] & 0x20; int flipy = sr[offs+4] & 0x40; int code = (sr[offs] << 2) + ((sr[offs+1] & 0x03) << 10) + ((sr[offs+1] & 0x0c) >> 2); int color = ((sr[offs+1] & 0xf0)>>4) + 16 * palettebank; // int mod = flip_screen ? -8 : 8; if (flip_screen) { sx = 240 - sx; sy = 240 - sy; flipx = !flipx; flipy = !flipy; } switch (sr[offs+4] & 0x0c) { case 0x00: /* 16x16 */ drawgfx(bitmap,machine->gfx[1], code/4, color, flipx,flipy, sx,sy, cliprect,TRANSPARENCY_PEN,0); break; case 0x04: /* 16x8 */ { if (flip_screen) sy += 8; // this fixes the train wheels' position drawgfx(bitmap,machine->gfx[2], code & ~1, color, flipx,flipy, flipx?sx+8:sx,sy, cliprect,TRANSPARENCY_PEN,0); drawgfx(bitmap,machine->gfx[2], code | 1, color, flipx,flipy, flipx?sx:sx+8,sy, cliprect,TRANSPARENCY_PEN,0); } break; case 0x08: /* 8x16 */ { drawgfx(bitmap,machine->gfx[2], code & ~2, color, flipx,flipy, sx,flipy?sy+8:sy, cliprect,TRANSPARENCY_PEN,0); drawgfx(bitmap,machine->gfx[2], code | 2, color, flipx,flipy, sx,flipy?sy:sy+8, cliprect,TRANSPARENCY_PEN,0); } break; case 0x0c: /* 8x8 */ { drawgfx(bitmap,machine->gfx[2], code, color, flipx,flipy, sx,sy, cliprect,TRANSPARENCY_PEN,0); } break; } } } VIDEO_UPDATE( ironhors ) { int row; for (row = 0; row < 32; row++) tilemap_set_scrollx(bg_tilemap, row, ironhors_scroll[row]); tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0); draw_sprites(machine, bitmap, cliprect); return 0; }