// license:BSD-3-Clause
// copyright-holders:Lee Taylor
// thanks-to:John Clegg,Tomasz Slanina
/***************************************************************************
video.c
Traverse USA
L Taylor
J Clegg
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/travrusa.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Traverse USA has one 256x8 character palette PROM (some versions have two
256x4), one 32x8 sprite palette PROM, and one 256x4 sprite color lookup
table PROM.
I don't know for sure how the palette PROMs are connected to the RGB
output, but it's probably something like this; note that RED and BLUE
are swapped wrt the usual configuration.
bit 7 -- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
bit 0 -- 1 kohm resistor -- BLUE
***************************************************************************/
void travrusa_state::travrusa_palette(palette_device &palette) const
{
const uint8_t *color_prom = memregion("proms")->base();
// create a lookup table for the palette
for (int i = 0; i < 0x80; i++)
{
int bit0, bit1, bit2;
// red component
bit0 = 0;
bit1 = BIT(color_prom[i], 6);
bit2 = BIT(color_prom[i], 7);
int const r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// green component
bit0 = BIT(color_prom[i], 3);
bit1 = BIT(color_prom[i], 4);
bit2 = BIT(color_prom[i], 5);
int const g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// blue component
bit0 = BIT(color_prom[i], 0);
bit1 = BIT(color_prom[i], 1);
bit2 = BIT(color_prom[i], 2);
int const b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette.set_indirect_color(i, rgb_t(r, g, b));
}
for (int i = 0x80; i < 0x90; i++)
{
int bit0, bit1, bit2;
// red component
bit0 = 0;
bit1 = BIT(color_prom[(i - 0x80) + 0x200], 6);
bit2 = BIT(color_prom[(i - 0x80) + 0x200], 7);
int const r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// green component
bit0 = BIT(color_prom[(i - 0x80) + 0x200], 3);
bit1 = BIT(color_prom[(i - 0x80) + 0x200], 4);
bit2 = BIT(color_prom[(i - 0x80) + 0x200], 5);
int const g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// blue component
bit0 = BIT(color_prom[(i - 0x80) + 0x200], 0);
bit1 = BIT(color_prom[(i - 0x80) + 0x200], 1);
bit2 = BIT(color_prom[(i - 0x80) + 0x200], 2);
int const b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette.set_indirect_color(i, rgb_t(r, g, b));
}
// color_prom now points to the beginning of the lookup table
color_prom += 0x220;
// characters
for (int i = 0; i < 0x80; i++)
palette.set_pen_indirect(i, i);
// sprites
for (int i = 0x80; i < 0x100; i++)
{
uint8_t const ctabentry = (color_prom[i - 0x80] & 0x0f) | 0x80;
palette.set_pen_indirect(i, ctabentry);
}
}
void travrusa_state::shtrider_palette(palette_device &palette) const
{
const uint8_t *color_prom = memregion("proms")->base();
// create a lookup table for the palette
for (int i = 0; i < 0x80; i++)
{
int bit0, bit1, bit2;
// red component
bit0 = 0;
bit1 = BIT(color_prom[i + 0x000], 2);
bit2 = BIT(color_prom[i + 0x000], 3);
int const r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// green component
bit0 = BIT(color_prom[i + 0x100], 3);
bit1 = BIT(color_prom[i + 0x000], 0);
bit2 = BIT(color_prom[i + 0x000], 1);
int const g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// blue component
bit0 = BIT(color_prom[i + 0x100], 0);
bit1 = BIT(color_prom[i + 0x100], 1);
bit2 = BIT(color_prom[i + 0x100], 2);
int const b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette.set_indirect_color(i, rgb_t(r, g, b));
}
for (int i = 0x80; i < 0x90; i++)
{
int bit0, bit1, bit2;
// red component
bit0 = 0;
bit1 = BIT(color_prom[(i - 0x80) + 0x200], 6);
bit2 = BIT(color_prom[(i - 0x80) + 0x200], 7);
int const r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// green component
bit0 = BIT(color_prom[(i - 0x80) + 0x200], 3);
bit1 = BIT(color_prom[(i - 0x80) + 0x200], 4);
bit2 = BIT(color_prom[(i - 0x80) + 0x200], 5);
int const g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
// blue component
bit0 = BIT(color_prom[(i - 0x80) + 0x200], 0);
bit1 = BIT(color_prom[(i - 0x80) + 0x200], 1);
bit2 = BIT(color_prom[(i - 0x80) + 0x200], 2);
int const b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette.set_indirect_color(i, rgb_t(r, g, b));
}
// color_prom now points to the beginning of the lookup table
color_prom += 0x220;
// characters
for (int i = 0; i < 0x80; i++)
palette.set_pen_indirect(i, i);
// sprites
for (int i = 0x80; i < 0x100; i++)
{
uint8_t const ctabentry = (color_prom[i - 0x80] & 0x0f) | 0x80;
palette.set_pen_indirect(i, ctabentry);
}
}
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
TILE_GET_INFO_MEMBER(travrusa_state::get_tile_info)
{
uint8_t attr = m_videoram[2 * tile_index + 1];
int flags = TILE_FLIPXY((attr & 0x30) >> 4);
tileinfo.group = ((attr & 0x0f) == 0x0f) ? 1 : 0; /* tunnels */
SET_TILE_INFO_MEMBER(0,
m_videoram[2 * tile_index] + ((attr & 0xc0) << 2),
attr & 0x0f,
flags);
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
void travrusa_state::video_start()
{
save_item(NAME(m_scrollx));
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(travrusa_state::get_tile_info)), TILEMAP_SCAN_ROWS, 8, 8, 64, 32);
m_bg_tilemap->set_transmask(0, 0xff, 0x00); /* split type 0 is totally transparent in front half */
m_bg_tilemap->set_transmask(1, 0x3f, 0xc0); /* split type 1 has pens 6 and 7 opaque - tunnels */
m_bg_tilemap->set_scroll_rows(4);
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE8_MEMBER(travrusa_state::travrusa_videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset / 2);
}
void travrusa_state::set_scroll( )
{
int i;
for (i = 0; i <= 2; i++)
m_bg_tilemap->set_scrollx(i, m_scrollx[0] + 256 * m_scrollx[1]);
m_bg_tilemap->set_scrollx(3, 0);
}
WRITE8_MEMBER(travrusa_state::travrusa_scroll_x_low_w)
{
m_scrollx[0] = data;
set_scroll();
}
WRITE8_MEMBER(travrusa_state::travrusa_scroll_x_high_w)
{
m_scrollx[1] = data;
set_scroll();
}
WRITE8_MEMBER(travrusa_state::travrusa_flipscreen_w)
{
/* screen flip is handled both by software and hardware */
data ^= ~ioport("DSW2")->read() & 1;
flip_screen_set(data & 1);
machine().bookkeeping().coin_counter_w(0, data & 0x02);
machine().bookkeeping().coin_counter_w(1, data & 0x20);
}
/***************************************************************************
Display refresh
***************************************************************************/
void travrusa_state::draw_sprites(bitmap_ind16 &bitmap,const rectangle &cliprect)
{
int offs;
const rectangle spritevisiblearea(1*8, 31*8-1, 0*8, 24*8-1);
const rectangle spritevisibleareaflip(1*8, 31*8-1, 8*8, 32*8-1);
rectangle clip = cliprect;
if (flip_screen())
clip &= spritevisibleareaflip;
else
clip &= spritevisiblearea;
for (offs = m_spriteram.bytes() - 4; offs >= 0; offs -= 4)
{
int sx = ((m_spriteram[offs + 3] + 8) & 0xff) - 8;
int sy = 240 - m_spriteram[offs];
int code = m_spriteram[offs + 2];
int attr = m_spriteram[offs + 1];
int flipx = attr & 0x40;
int flipy = attr & 0x80;
if (flip_screen())
{
sx = 240 - sx;
sy = 240 - sy;
flipx = !flipx;
flipy = !flipy;
}
m_gfxdecode->gfx(1)->transpen(bitmap,clip,
code,
attr & 0x0f,
flipx, flipy,
sx, sy, 0);
}
}
uint32_t travrusa_state::screen_update_travrusa(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, TILEMAP_DRAW_LAYER1, 0);
draw_sprites(bitmap,cliprect);
m_bg_tilemap->draw(screen, bitmap, cliprect, TILEMAP_DRAW_LAYER0, 0);
return 0;
}