/*************************************************************************** video.c Functions to emulate the video hardware of the machine. ***************************************************************************/ #include "driver.h" #include "arabian.h" /* Constants */ #define BITMAP_WIDTH 256 #define BITMAP_HEIGHT 256 /* Local variables */ static UINT8 *main_bitmap; static UINT8 *converted_gfx; /* Globals */ UINT8 arabian_video_control; UINT8 arabian_flip_screen; /************************************* * * Color PROM conversion * *************************************/ PALETTE_INIT( arabian ) { int i; /* there are effectively 6 bits of color: 2 red, 2 green, 2 blue */ for (i = 0; i < 64; i++) { palette_set_color_rgb(machine, i, ((i >> 5) & 1) * (153*192/255) + ((i >> 4) & 1) * (102*192/255) + ((i & 0x30) ? 63 : 0), ((i >> 3) & 1) * (156*192/255) + ((i >> 2) & 1) * (99*192/255) + ((i & 0x0c) ? 63 : 0), ((i >> 1) & 1) * 192 + ((i >> 0) & 1) * 63); } /* there are 13 color table bits */ for (i = 0; i < (1 << 13); i++) { int ena = (i >> 12) & 1; int enb = (i >> 11) & 1; int abhf = (~i >> 10) & 1; int aghf = (~i >> 9) & 1; int arhf = (~i >> 8) & 1; int az = (i >> 7) & 1; int ar = (i >> 6) & 1; int ag = (i >> 5) & 1; int ab = (i >> 4) & 1; int bz = (i >> 3) & 1; int br = (i >> 2) & 1; int bg = (i >> 1) & 1; int bb = (i >> 0) & 1; int planea = (az | ar | ag | ab) & ena; /*------------------------------------------------------------------------- red derivation: ROUT.1200 = !IC192.11 = !(!(!IC117.11 | !IC118.12)) = !IC117.11 | !IC118.12 = !(IC99.8 ^ IC119.6) | !(!(!BLNK & IC119.11 & BR)) = !((!ARHF & !BLNK & AR & AZ) ^ !(AR & !BLNK)) | (!BLNK & IC119.11 & BR) = !BLNK & (!((!ARHF & AR & AZ) ^ !AR) | (IC119.11 & BR)) = !BLNK & ((!(!ARHF & AR & AZ) ^ AR) | (BR & !(AZ | AR | AG | AB))) ROUT.1800 = !IC192.3 = !(!(!IC119.6 | !IC118.12)) = !IC119.6 | !IC118.12 = !(!(AR & !BLNK) | !(!(!BLNK & IC119.11 & BZ))) = (AR & !BLNK) | (!BLNK & IC119.11 & BZ) = !BLNK & (AR | (BZ & !(AZ | AR | AG | AB))) RENA = IC116.6 = !IC192.11 | !IC192.3 = ROUT.1200 | ROUT.1800 red.hi = planea ? ar : bz; red.lo = planea ? ((!arhf & az) ? 0 : ar) : br; red.base = (red.hi | red.lo) -------------------------------------------------------------------------*/ int rhi = planea ? ar : enb ? bz : 0; int rlo = planea ? ((!arhf & az) ? 0 : ar) : enb ? br : 0; /*------------------------------------------------------------------------- green derivation: GOUT.750 = !IC192.8 = !(!(!IC119.8 | !IC120.8)) = !IC119.8 | !IC120.8 = !(!(AG & !BLNK)) | !(!(!BLNK & IC119.11 & BB)) = (AG & !BLNK) | (!BLNK & IC119.11 & BB) = !BLNK & (AG | (IC119.11 & BB)) = !BLNK & (AG | (BB & !(AZ | AR | AG | AB))) GOUT.1200 = !IC192.6 = !(!(!IC117.3 | !IC118.6)) = !IC117.3 | !IC118.6 = !(IC99.6 ^ IC119.8) | !(!(!BLNK & IC119.11 & BG)) = !((!AGHF & !BLNK & AG & AZ) ^ !(AG & !BLNK)) | (!BLNK & IC119.11 & BG) = !BLNK & (!((!AGHF & AG & AZ) ^ !AG) | (IC119.11 & BG)) = !BLNK & ((!(!AGHF & AG & AZ) ^ AG) | (BG & !(AZ | AR | AG | AB))) GENA = IC116.8 = !IC192.8 | !IC192.6 = GOUT.750 | GOUT.1200 grn.hi = planea ? ag : bb; grn.lo = planea ? ((!aghf & az) ? 0 : ag) : bg; grn.base = (grn.hi | grn.lo) -------------------------------------------------------------------------*/ int ghi = planea ? ag : enb ? bb : 0; int glo = planea ? ((!aghf & az) ? 0 : ag) : enb ? bg : 0; /*------------------------------------------------------------------------- blue derivation: BOUT.1200 = !IC117.6 = !IC119.3 = !(!(AB & !BLNK)) = !BLNK & AB BENA = !IC117.8 = !(IC189.6 ^ IC119.3) = !((!ABHF & !BLNK & AB & AZ) ^ !(AB & !BLNK)) = (!(!ABHF & !BLNK & AB & AZ) ^ (AB & !BLNK)) = !BLNK & (!(!ABHF & AB & AZ) ^ AB) blu.hi = ab; blu.base = ((!abhf & az) ? 0 : ab); -------------------------------------------------------------------------*/ int bhi = ab; int bbase = (!abhf & az) ? 0 : ab; *colortable++ = (rhi << 5) | (rlo << 4) | (ghi << 3) | (glo << 2) | (bhi << 1) | bbase; } } /************************************* * * Video startup * *************************************/ VIDEO_START( arabian ) { UINT8 *gfxbase = memory_region(REGION_GFX1); int offs; /* allocate a common bitmap to use for both planes */ /* plane A (top plane with motion objects) is in the upper 4 bits */ /* plane B (bottom plane with playfield) is in the lower 4 bits */ main_bitmap = auto_malloc(BITMAP_WIDTH * BITMAP_HEIGHT); /* allocate memory for the converted graphics data */ converted_gfx = auto_malloc(0x8000 * 2); /*-------------------------------------------------- transform graphics data into more usable format which is coded like this: byte adr+0x4000 byte adr DCBA DCBA DCBA DCBA D-bits of pixel 4 C-bits of pixel 3 B-bits of pixel 2 A-bits of pixel 1 after conversion : byte adr+0x4000 byte adr DDDD CCCC BBBB AAAA --------------------------------------------------*/ for (offs = 0; offs < 0x4000; offs++) { int v1 = gfxbase[offs + 0x0000]; int v2 = gfxbase[offs + 0x4000]; int p1, p2, p3, p4; p1 = (v1 & 0x01) | ((v1 & 0x10) >> 3) | ((v2 & 0x01) << 2) | ((v2 & 0x10) >> 1); v1 >>= 1; v2 >>= 1; p2 = (v1 & 0x01) | ((v1 & 0x10) >> 3) | ((v2 & 0x01) << 2) | ((v2 & 0x10) >> 1); v1 >>= 1; v2 >>= 1; p3 = (v1 & 0x01) | ((v1 & 0x10) >> 3) | ((v2 & 0x01) << 2) | ((v2 & 0x10) >> 1); v1 >>= 1; v2 >>= 1; p4 = (v1 & 0x01) | ((v1 & 0x10) >> 3) | ((v2 & 0x01) << 2) | ((v2 & 0x10) >> 1); converted_gfx[offs * 4 + 3] = p1; converted_gfx[offs * 4 + 2] = p2; converted_gfx[offs * 4 + 1] = p3; converted_gfx[offs * 4 + 0] = p4; } } /************************************* * * DMA blitter simulation * *************************************/ static void blit_area(UINT8 plane, UINT16 src, UINT8 x, UINT8 y, UINT8 sx, UINT8 sy) { UINT8 *srcdata = &converted_gfx[src * 4]; int i,j; /* loop over X, then Y */ for (i = 0; i <= sx; i++, x += 4) for (j = 0; j <= sy; j++) { UINT8 p1 = *srcdata++; UINT8 p2 = *srcdata++; UINT8 p3 = *srcdata++; UINT8 p4 = *srcdata++; UINT8 *base; /* get a pointer to the bitmap */ base = &main_bitmap[((y + j) & 0xff) * BITMAP_WIDTH + (x & 0xff)]; /* bit 0 means write to upper plane (upper 4 bits of our bitmap) */ if (plane & 0x01) { if (p4 != 8) base[0] = (base[0] & ~0xf0) | (p4 << 4); if (p3 != 8) base[1] = (base[1] & ~0xf0) | (p3 << 4); if (p2 != 8) base[2] = (base[2] & ~0xf0) | (p2 << 4); if (p1 != 8) base[3] = (base[3] & ~0xf0) | (p1 << 4); } /* bit 2 means write to lower plane (lower 4 bits of our bitmap) */ if (plane & 0x04) { if (p4 != 8) base[0] = (base[0] & ~0x0f) | p4; if (p3 != 8) base[1] = (base[1] & ~0x0f) | p3; if (p2 != 8) base[2] = (base[2] & ~0x0f) | p2; if (p1 != 8) base[3] = (base[3] & ~0x0f) | p1; } } } /************************************* * * DMA blitter parameters * *************************************/ WRITE8_HANDLER( arabian_blitter_w ) { /* write the data */ offset &= 7; spriteram[offset] = data; /* watch for a write to offset 6 -- that triggers the blit */ if ((offset & 0x07) == 6) { /* extract the data */ int plane = spriteram[offset - 6]; int src = spriteram[offset - 5] | (spriteram[offset - 4] << 8); int x = spriteram[offset - 2] << 2; int y = spriteram[offset - 3]; int sx = spriteram[offset - 0]; int sy = spriteram[offset - 1]; /* blit it */ blit_area(plane, src, x, y, sx, sy); } } /************************************* * * VRAM direct I/O * *************************************/ WRITE8_HANDLER( arabian_videoram_w ) { UINT8 *base; UINT8 x, y; /* determine X/Y and mark the area dirty */ x = (offset >> 8) << 2; y = offset & 0xff; /* get a pointer to the pixels */ base = &main_bitmap[y * BITMAP_WIDTH + x]; /* the data is written as 4 2-bit values, as follows: bit 7 = pixel 3, upper bit bit 6 = pixel 2, upper bit bit 5 = pixel 1, upper bit bit 4 = pixel 0, upper bit bit 3 = pixel 3, lower bit bit 2 = pixel 2, lower bit bit 1 = pixel 1, lower bit bit 0 = pixel 0, lower bit */ /* enable writes to AZ/AR */ if (spriteram[0] & 0x08) { base[0] = (base[0] & ~0x03) | ((data & 0x10) >> 3) | ((data & 0x01) >> 0); base[1] = (base[1] & ~0x03) | ((data & 0x20) >> 4) | ((data & 0x02) >> 1); base[2] = (base[2] & ~0x03) | ((data & 0x40) >> 5) | ((data & 0x04) >> 2); base[3] = (base[3] & ~0x03) | ((data & 0x80) >> 6) | ((data & 0x08) >> 3); } /* enable writes to AG/AB */ if (spriteram[0] & 0x04) { base[0] = (base[0] & ~0x0c) | ((data & 0x10) >> 1) | ((data & 0x01) << 2); base[1] = (base[1] & ~0x0c) | ((data & 0x20) >> 2) | ((data & 0x02) << 1); base[2] = (base[2] & ~0x0c) | ((data & 0x40) >> 3) | ((data & 0x04) << 0); base[3] = (base[3] & ~0x0c) | ((data & 0x80) >> 4) | ((data & 0x08) >> 1); } /* enable writes to BZ/BR */ if (spriteram[0] & 0x02) { base[0] = (base[0] & ~0x30) | ((data & 0x10) << 1) | ((data & 0x01) << 4); base[1] = (base[1] & ~0x30) | ((data & 0x20) << 0) | ((data & 0x02) << 3); base[2] = (base[2] & ~0x30) | ((data & 0x40) >> 1) | ((data & 0x04) << 2); base[3] = (base[3] & ~0x30) | ((data & 0x80) >> 2) | ((data & 0x08) << 1); } /* enable writes to BG/BB */ if (spriteram[0] & 0x01) { base[0] = (base[0] & ~0xc0) | ((data & 0x10) << 3) | ((data & 0x01) << 6); base[1] = (base[1] & ~0xc0) | ((data & 0x20) << 2) | ((data & 0x02) << 5); base[2] = (base[2] & ~0xc0) | ((data & 0x40) << 1) | ((data & 0x04) << 4); base[3] = (base[3] & ~0xc0) | ((data & 0x80) << 0) | ((data & 0x08) << 3); } } /************************************* * * Core video refresh * *************************************/ VIDEO_UPDATE( arabian ) { const pen_t *colortable = &machine->remapped_colortable[(arabian_video_control >> 3) << 8]; int y; /* render the screen from the bitmap */ for (y = 0; y < BITMAP_HEIGHT; y++) { /* non-flipped case */ if (!arabian_flip_screen) draw_scanline8(bitmap, 0, y, BITMAP_WIDTH, &main_bitmap[y * BITMAP_WIDTH], colortable, -1); /* flipped case */ else { UINT8 scanline[BITMAP_WIDTH]; int x; for (x = 0; x < BITMAP_WIDTH; x++) scanline[BITMAP_WIDTH - 1 - x] = main_bitmap[y * BITMAP_WIDTH + x]; draw_scanline8(bitmap, 0, BITMAP_HEIGHT - 1 - y, BITMAP_WIDTH, scanline, colortable, -1); } } return 0; }