// license:BSD-3-Clause
// copyright-holders:Allard van der Bas
/***************************************************************************
shaolins.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "video/resnet.h"
#include "includes/shaolins.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Shao-lin's Road 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_MEMBER(shaolins_state, shaolins)
{
const uint8_t *color_prom = memregion("proms")->base();
static const int resistances[4] = { 2200, 1000, 470, 220 };
double rweights[4], gweights[4], bweights[4];
int i;
/* compute the color output resistor weights */
compute_resistor_weights(0, 255, -1.0,
4, resistances, rweights, 470, 0,
4, resistances, gweights, 470, 0,
4, resistances, bweights, 470, 0);
/* create a lookup table for the palette */
for (i = 0; i < 0x100; i++)
{
int bit0, bit1, bit2, bit3;
int r, g, b;
/* red component */
bit0 = (color_prom[i + 0x000] >> 0) & 0x01;
bit1 = (color_prom[i + 0x000] >> 1) & 0x01;
bit2 = (color_prom[i + 0x000] >> 2) & 0x01;
bit3 = (color_prom[i + 0x000] >> 3) & 0x01;
r = combine_4_weights(rweights, bit0, bit1, bit2, bit3);
/* green component */
bit0 = (color_prom[i + 0x100] >> 0) & 0x01;
bit1 = (color_prom[i + 0x100] >> 1) & 0x01;
bit2 = (color_prom[i + 0x100] >> 2) & 0x01;
bit3 = (color_prom[i + 0x100] >> 3) & 0x01;
g = combine_4_weights(gweights, bit0, bit1, bit2, bit3);
/* blue component */
bit0 = (color_prom[i + 0x200] >> 0) & 0x01;
bit1 = (color_prom[i + 0x200] >> 1) & 0x01;
bit2 = (color_prom[i + 0x200] >> 2) & 0x01;
bit3 = (color_prom[i + 0x200] >> 3) & 0x01;
b = combine_4_weights(bweights, bit0, bit1, bit2, bit3);
palette.set_indirect_color(i, rgb_t(r, g, b));
}
/* color_prom now points to the beginning of the lookup table,*/
color_prom += 0x300;
/* characters use colors 0x10-0x1f of each 0x20 color bank,
while sprites use colors 0-0x0f */
for (i = 0; i < 0x200; i++)
{
int j;
for (j = 0; j < 8; j++)
{
uint8_t ctabentry = (j << 5) | ((~i & 0x100) >> 4) | (color_prom[i] & 0x0f);
palette.set_pen_indirect(((i & 0x100) << 3) | (j << 8) | (i & 0xff), ctabentry);
}
}
}
WRITE8_MEMBER(shaolins_state::videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE8_MEMBER(shaolins_state::colorram_w)
{
m_colorram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE8_MEMBER(shaolins_state::palettebank_w)
{
if (m_palettebank != (data & 0x07))
{
m_palettebank = data & 0x07;
machine().tilemap().mark_all_dirty();
}
}
WRITE8_MEMBER(shaolins_state::scroll_w)
{
for (int col = 4; col < 32; col++)
m_bg_tilemap->set_scrolly(col, data + 1);
}
WRITE8_MEMBER(shaolins_state::nmi_w)
{
m_nmi_enable = data;
if (flip_screen() != (data & 0x01))
{
flip_screen_set(data & 0x01);
machine().tilemap().mark_all_dirty();
}
}
TILE_GET_INFO_MEMBER(shaolins_state::get_bg_tile_info)
{
int attr = m_colorram[tile_index];
int code = m_videoram[tile_index] + ((attr & 0x40) << 2);
int color = (attr & 0x0f) + 16 * m_palettebank;
int flags = (attr & 0x20) ? TILE_FLIPY : 0;
SET_TILE_INFO_MEMBER(0, code, color, flags);
}
void shaolins_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(shaolins_state::get_bg_tile_info),this), TILEMAP_SCAN_ROWS,
8, 8, 32, 32);
m_bg_tilemap->set_scroll_cols(32);
save_item(NAME(m_palettebank));
save_item(NAME(m_nmi_enable));
}
void shaolins_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect)
{
for (int offs = m_spriteram.bytes() - 32; offs >= 0; offs -= 32 ) /* max 24 sprites */
{
if (m_spriteram[offs] && m_spriteram[offs + 6]) /* stop rogue sprites on high score screen */
{
int code = m_spriteram[offs + 8];
int color = (m_spriteram[offs + 9] & 0x0f) | (m_palettebank << 4);
int flipx = !(m_spriteram[offs + 9] & 0x40);
int flipy = m_spriteram[offs + 9] & 0x80;
int sx = 240 - m_spriteram[offs + 6];
int sy = 248 - m_spriteram[offs + 4];
if (flip_screen())
{
sx = 240 - sx;
sy = 248 - sy;
flipx = !flipx;
flipy = !flipy;
}
m_gfxdecode->gfx(1)->transmask(bitmap,cliprect,
code, color,
flipx, flipy,
sx, sy,
m_palette->transpen_mask(*m_gfxdecode->gfx(1), color, m_palettebank << 5));
}
}
}
uint32_t shaolins_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_sprites(bitmap, cliprect);
return 0;
}