// license:BSD-3-Clause
// copyright-holders:Ernesto Corvi, Juergen Buchmueller, Alex Pasadyn, Aaron Giles, Nicola Salmoria
#include "emu.h"
#include "includes/polepos.h"
/* modified vertical position built from three nibbles (12 bit)
* of ROMs 136014-142, 136014-143, 136014-144
* The value RVP (road vertical position, lower 12 bits) is added
* to this value and the upper 10 bits of the result are used to
* address the playfield video memory (AB0 - AB9).
*/
/***************************************************************************
Convert the color PROMs.
Pole Position has three 256x4 palette PROMs (one per gun)
and a lot ;-) of 256x4 lookup table PROMs.
The palette PROMs are connected to the RGB output this way:
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_MEMBER(polepos_state,polepos)
{
const uint8_t *color_prom = memregion("proms")->base();
int i, j;
/*******************************************************
* Color PROMs
* Sheet 15B: middle, 136014-137,138,139
* Inputs: MUX0 ... MUX3, ALPHA/BACK, SPRITE/BACK, 128V, COMPBLANK
*
* Note that we only decode the lower 128 colors because
* the upper 128 are all black and used during the
* horizontal and vertical blanking periods.
* The purpose of the 128V input is to use a different palette for the
* background and for the road; it is irrelevant for alpha and
* sprites because their palette is the same in both halves.
* Anyway, we emulate that to a certain extent, using different
* colortables for the two halves of the screen. We don't support the
* palette change in the middle of a sprite, however.
* Also, note that priority encoding is done is such a way that alpha
* will use palette bank 2 or 3 depending on whether there is a sprite
* below the pixel or not. That would be tricky to emulate, and it's
* not needed because of course the two banks are the same.
*******************************************************/
for (i = 0; i < 128; i++)
{
int bit0,bit1,bit2,bit3,r,g,b;
/* Sheet 15B: 136014-0137 red component */
bit0 = (color_prom[0x000 + i] >> 0) & 1;
bit1 = (color_prom[0x000 + i] >> 1) & 1;
bit2 = (color_prom[0x000 + i] >> 2) & 1;
bit3 = (color_prom[0x000 + i] >> 3) & 1;
r = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
/* Sheet 15B: 136014-0138 green component */
bit0 = (color_prom[0x100 + i] >> 0) & 1;
bit1 = (color_prom[0x100 + i] >> 1) & 1;
bit2 = (color_prom[0x100 + i] >> 2) & 1;
bit3 = (color_prom[0x100 + i] >> 3) & 1;
g = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
/* Sheet 15B: 136014-0139 blue component */
bit0 = (color_prom[0x200 + i] >> 0) & 1;
bit1 = (color_prom[0x200 + i] >> 1) & 1;
bit2 = (color_prom[0x200 + i] >> 2) & 1;
bit3 = (color_prom[0x200 + i] >> 3) & 1;
b = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
palette.set_indirect_color(i,rgb_t(r,g,b));
}
/*******************************************************
* Alpha colors (colors 0x000-0x1ff)
* Sheet 15B: top left, 136014-140
* Inputs: SHFT0, SHFT1 and CHA8* ... CHA13*
*******************************************************/
for (i = 0; i < 64*4; i++)
{
int color = color_prom[0x300 + i];
palette.set_pen_indirect(0x0000 + i, (color != 15) ? (0x020 + color) : 0x2f);
palette.set_pen_indirect(0x0100 + i, (color != 15) ? (0x060 + color) : 0x2f);
}
/*******************************************************
* Background colors (colors 0x200-0x2ff)
* Sheet 13A: left, 136014-141
* Inputs: SHFT2, SHFT3 and CHA8 ... CHA13
* The background is only in the top half of the screen
*******************************************************/
for (i = 0; i < 64*4; i++)
{
int color = color_prom[0x400 + i];
palette.set_pen_indirect(0x0200 + i, 0x000 + color);
}
/*******************************************************
* Sprite colors (colors 0x300-0xaff)
* Sheet 14B: right, 136014-146
* Inputs: CUSTOM0 ... CUSTOM3 and DATA0 ... DATA5
*******************************************************/
for (i = 0; i < 64*16; i++)
{
int color = color_prom[0xc00 + i];
palette.set_pen_indirect(0x0300 + i, (color != 15) ? (0x010 + color) : 0x1f);
palette.set_pen_indirect(0x0700 + i, (color != 15) ? (0x050 + color) : 0x1f);
}
/*******************************************************
* Road colors (colors 0xb00-0x0eff)
* Sheet 13A: bottom left, 136014-145
* Inputs: R1 ... R6 and CHA0 ... CHA3
* The road is only in the bottom half of the screen
*******************************************************/
for (i = 0; i < 64*16; i++)
{
int color = color_prom[0x800 + i];
palette.set_pen_indirect(0x0b00 + i, 0x040 + color);
}
/* 136014-142, 136014-143, 136014-144 Vertical position modifiers */
for (i = 0; i < 256; i++)
{
j = color_prom[0x500 + i] + (color_prom[0x600 + i] << 4) + (color_prom[0x700 + i] << 8);
m_vertical_position_modifier[i] = j;
}
}
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
TILE_GET_INFO_MEMBER(polepos_state::bg_get_tile_info)
{
uint16_t word = m_view16_memory[tile_index];
int code = (word & 0xff) | ((word & 0x4000) >> 6);
int color = (word & 0x3f00) >> 8;
SET_TILE_INFO_MEMBER(1,
code,
color,
0);
}
TILE_GET_INFO_MEMBER(polepos_state::tx_get_tile_info)
{
uint16_t word = m_alpha16_memory[tile_index];
int code = (word & 0xff) | ((word & 0x4000) >> 6);
int color = (word & 0x3f00) >> 8;
/* I assume the purpose of CHACL is to allow the Z80 to control
the display (therefore using only the bottom 8 bits of tilemap RAM)
in case the Z8002 is not working. */
if (m_chacl == 0)
{
code &= 0xff;
color = 0;
}
/* 128V input to the palette PROM */
if (tile_index >= 32*16) color |= 0x40;
SET_TILE_INFO_MEMBER(0,
code,
color,
0);
tileinfo.group = color;
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
VIDEO_START_MEMBER(polepos_state,polepos)
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(polepos_state::bg_get_tile_info),this),TILEMAP_SCAN_COLS,8,8,64,16);
m_tx_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(polepos_state::tx_get_tile_info),this),TILEMAP_SCAN_ROWS,8,8,32,32);
m_tx_tilemap->configure_groups(*m_gfxdecode->gfx(0), 0x2f);
}
/***************************************************************************
Sprite memory
***************************************************************************/
READ16_MEMBER(polepos_state::polepos_sprite16_r)
{
return m_sprite16_memory[offset];
}
WRITE16_MEMBER(polepos_state::polepos_sprite16_w)
{
COMBINE_DATA(&m_sprite16_memory[offset]);
}
READ8_MEMBER(polepos_state::polepos_sprite_r)
{
return m_sprite16_memory[offset] & 0xff;
}
WRITE8_MEMBER(polepos_state::polepos_sprite_w)
{
m_sprite16_memory[offset] = (m_sprite16_memory[offset] & 0xff00) | data;
}
/***************************************************************************
Road memory
***************************************************************************/
READ16_MEMBER(polepos_state::polepos_road16_r)
{
return m_road16_memory[offset];
}
WRITE16_MEMBER(polepos_state::polepos_road16_w)
{
COMBINE_DATA(&m_road16_memory[offset]);
}
READ8_MEMBER(polepos_state::polepos_road_r)
{
return m_road16_memory[offset] & 0xff;
}
WRITE8_MEMBER(polepos_state::polepos_road_w)
{
m_road16_memory[offset] = (m_road16_memory[offset] & 0xff00) | data;
}
WRITE16_MEMBER(polepos_state::polepos_road16_vscroll_w)
{
COMBINE_DATA(&m_road16_vscroll);
}
/***************************************************************************
View memory
***************************************************************************/
READ16_MEMBER(polepos_state::polepos_view16_r)
{
return m_view16_memory[offset];
}
WRITE16_MEMBER(polepos_state::polepos_view16_w)
{
COMBINE_DATA(&m_view16_memory[offset]);
if (offset < 0x400)
m_bg_tilemap->mark_tile_dirty(offset);
}
READ8_MEMBER(polepos_state::polepos_view_r)
{
return m_view16_memory[offset] & 0xff;
}
WRITE8_MEMBER(polepos_state::polepos_view_w)
{
m_view16_memory[offset] = (m_view16_memory[offset] & 0xff00) | data;
if (offset < 0x400)
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE16_MEMBER(polepos_state::polepos_view16_hscroll_w)
{
COMBINE_DATA(&m_scroll);
m_bg_tilemap->set_scrollx(0,m_scroll);
}
WRITE_LINE_MEMBER(polepos_state::chacl_w)
{
m_chacl = state;
m_tx_tilemap->mark_all_dirty();
}
/***************************************************************************
Alpha memory
***************************************************************************/
READ16_MEMBER(polepos_state::polepos_alpha16_r)
{
return m_alpha16_memory[offset];
}
WRITE16_MEMBER(polepos_state::polepos_alpha16_w)
{
COMBINE_DATA(&m_alpha16_memory[offset]);
m_tx_tilemap->mark_tile_dirty(offset);
}
READ8_MEMBER(polepos_state::polepos_alpha_r)
{
return m_alpha16_memory[offset] & 0xff;
}
WRITE8_MEMBER(polepos_state::polepos_alpha_w)
{
m_alpha16_memory[offset] = (m_alpha16_memory[offset] & 0xff00) | data;
m_tx_tilemap->mark_tile_dirty(offset);
}
/***************************************************************************
Display refresh
***************************************************************************/
void polepos_state::draw_road(bitmap_ind16 &bitmap)
{
const uint8_t *road_control = memregion("gfx5")->base();
const uint8_t *road_bits1 = road_control + 0x2000;
const uint8_t *road_bits2 = road_control + 0x4000;
int x, y, i;
/* loop over the lower half of the screen */
for (y = 128; y < 256; y++)
{
int xoffs, yoffs, xscroll, roadpal;
uint16_t scanline[256 + 8];
uint16_t *dest = scanline;
pen_t pen_base;
/* first add the vertical position modifier and the vertical scroll */
yoffs = ((m_vertical_position_modifier[y] + m_road16_vscroll) >> 3) & 0x1ff;
/* then use that as a lookup into the road memory */
roadpal = m_road16_memory[yoffs] & 15;
/* this becomes the palette base for the scanline */
pen_base = 0x0b00 + (roadpal << 6);
/* now fetch the horizontal scroll offset for this scanline */
xoffs = m_road16_memory[0x380 + (y & 0x7f)] & 0x3ff;
/* the road is drawn in 8-pixel chunks, so round downward and adjust the base */
/* note that we assume there is at least 8 pixels of slop on the left/right */
xscroll = xoffs & 7;
xoffs &= ~7;
/* loop over 8-pixel chunks */
for (x = 0; x < 256 / 8 + 1; x++, xoffs += 8)
{
/* if the 0x200 bit of the xoffset is set, a special pin on the custom */
/* chip is set and the /CE and /OE for the road chips is disabled */
if (xoffs & 0x200)
{
/* in this case, it looks like we just fill with 0 */
for (i = 0; i < 8; i++)
*dest++ = pen_base | 0;
}
/* otherwise, we clock in the bits and compute the road value */
else
{
/* the road ROM offset comes from the current scanline and the X offset */
int romoffs = ((y & 0x07f) << 6) + ((xoffs & 0x1f8) >> 3);
/* fetch the current data from the road ROMs */
int control = road_control[romoffs];
int bits1 = road_bits1[romoffs];
int bits2 = road_bits2[(romoffs & 0xfff) | ((romoffs & 0x1000) >> 1)];
/* extract the road value and the carry-in bit */
int roadval = control & 0x3f;
int carin = control >> 7;
/* draw this 8-pixel chunk */
for (i = 8; i > 0; i--)
{
int bits = BIT(bits1,i) + (BIT(bits2,i) << 1);
if (!carin && bits) bits++;
*dest++ = pen_base | (roadval & 0x3f);
roadval += bits;
}
}
}
/* draw the scanline */
draw_scanline16(bitmap, 0, y, 256, &scanline[xscroll], nullptr);
}
}
void polepos_state::zoom_sprite(bitmap_ind16 &bitmap,int big,
uint32_t code,uint32_t color,int flipx,int sx,int sy,
int sizex,int sizey)
{
gfx_element *gfx = m_gfxdecode->gfx(big ? 3 : 2);
const uint8_t *gfxdata = gfx->get_data(code % gfx->elements());
uint8_t *scaling_rom = memregion("gfx6")->base();
uint32_t transmask = m_palette->transpen_mask(*gfx, color, 0x1f);
int coloroffs = gfx->colorbase() + color * gfx->granularity();
int x,y;
if (flipx) flipx = big ? 0x1f : 0x0f;
for (y = 0;y <= sizey;y++)
{
int yy = (sy + y) & 0x1ff;
/* the following should be a reasonable reproduction of how the real hardware works */
if (yy >= 0x10 && yy < 0xf0)
{
int dy = scaling_rom[(y << 6) + sizey] & 0x1f;
int xx = sx & 0x3ff;
int siz = 0;
int offs = 0;
const uint8_t *src;
if (!big) dy >>= 1;
src = gfxdata + dy * gfx->rowbytes();
for (x = (big ? 0x40 : 0x20);x > 0;x--)
{
if (xx < 0x100)
{
int pen = src[offs/2 ^ flipx];
if (!((transmask >> pen) & 1))
bitmap.pix16(yy, xx) = pen + coloroffs;
}
offs++;
siz = siz+1+sizex;
if (siz & 0x40)
{
siz &= 0x3f;
xx = (xx+1) & 0x3ff;
}
}
}
}
}
void polepos_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect )
{
uint16_t *posmem = &m_sprite16_memory[0x380];
uint16_t *sizmem = &m_sprite16_memory[0x780];
int i;
for (i = 0; i < 64; i++, posmem += 2, sizmem += 2)
{
int sx = (posmem[1] & 0x3ff) - 0x40 + 4;
int sy = 512 - (posmem[0] & 0x1ff) + 1; // sprites are buffered and delayed by one scanline
int sizex = (sizmem[1] & 0x3f00) >> 8;
int sizey = (sizmem[0] & 0x3f00) >> 8;
int code = sizmem[0] & 0x7f;
int flipx = sizmem[0] & 0x80;
int color = sizmem[1] & 0x3f;
/* 128V input to the palette PROM */
if (sy >= 128) color |= 0x40;
zoom_sprite(bitmap, (sizmem[0] & 0x8000) ? 1 : 0,
code,
color,
flipx,
sx, sy,
sizex,sizey);
}
}
uint32_t polepos_state::screen_update_polepos(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
rectangle clip = cliprect;
clip.max_y = 127;
m_bg_tilemap->draw(screen, bitmap, clip, 0,0);
draw_road(bitmap);
draw_sprites(bitmap,cliprect);
m_tx_tilemap->draw(screen, bitmap, cliprect, 0,0);
return 0;
}