// license:BSD-3-Clause
// copyright-holders:Nicola Salmoria
/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/seicross.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Seicross has two 32x8 palette PROMs, connected to the RGB output this way:
bit 7 -- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
bit 0 -- 1 kohm resistor -- RED
***************************************************************************/
PALETTE_INIT_MEMBER(seicross_state, seicross)
{
const uint8_t *color_prom = memregion("proms")->base();
int i;
for (i = 0;i < palette.entries();i++)
{
int bit0,bit1,bit2,r,g,b;
/* red component */
bit0 = (color_prom[i] >> 0) & 0x01;
bit1 = (color_prom[i] >> 1) & 0x01;
bit2 = (color_prom[i] >> 2) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[i] >> 3) & 0x01;
bit1 = (color_prom[i] >> 4) & 0x01;
bit2 = (color_prom[i] >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[i] >> 6) & 0x01;
bit1 = (color_prom[i] >> 7) & 0x01;
b = 0x4f * bit0 + 0xa8 * bit1;
palette.set_pen_color(i,rgb_t(r,g,b));
}
}
WRITE8_MEMBER(seicross_state::videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE8_MEMBER(seicross_state::colorram_w)
{
/* bit 5 of the address is not used for color memory. There is just */
/* 512k of memory; every two consecutive rows share the same memory */
/* region. */
offset &= 0xffdf;
m_colorram[offset] = data;
m_colorram[offset + 0x20] = data;
m_bg_tilemap->mark_tile_dirty(offset);
m_bg_tilemap->mark_tile_dirty(offset + 0x20);
}
TILE_GET_INFO_MEMBER(seicross_state::get_bg_tile_info)
{
int code = m_videoram[tile_index] + ((m_colorram[tile_index] & 0x10) << 4);
int color = m_colorram[tile_index] & 0x0f;
int flags = ((m_colorram[tile_index] & 0x40) ? TILE_FLIPX : 0) | ((m_colorram[tile_index] & 0x80) ? TILE_FLIPY : 0);
SET_TILE_INFO_MEMBER(0, code, color, flags);
}
void seicross_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(
*m_gfxdecode, tilemap_get_info_delegate(FUNC(seicross_state::get_bg_tile_info),this), TILEMAP_SCAN_ROWS,
8, 8, 32, 32);
m_bg_tilemap->set_scroll_cols(32);
}
void seicross_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect )
{
int offs;
for (offs = m_spriteram.bytes() - 4; offs >= 0; offs -= 4)
{
int x = m_spriteram[offs + 3];
m_gfxdecode->gfx(1)->transpen(bitmap,cliprect,
(m_spriteram[offs] & 0x3f) + ((m_spriteram[offs + 1] & 0x10) << 2) + 128,
m_spriteram[offs + 1] & 0x0f,
m_spriteram[offs] & 0x40,m_spriteram[offs] & 0x80,
x,240-m_spriteram[offs + 2],0);
if(x>0xf0)
m_gfxdecode->gfx(1)->transpen(bitmap,cliprect,
(m_spriteram[offs] & 0x3f) + ((m_spriteram[offs + 1] & 0x10) << 2) + 128,
m_spriteram[offs + 1] & 0x0f,
m_spriteram[offs] & 0x40,m_spriteram[offs] & 0x80,
x-256,240-m_spriteram[offs + 2],0);
}
for (offs = m_spriteram2.bytes() - 4; offs >= 0; offs -= 4)
{
int x = m_spriteram2[offs + 3];
m_gfxdecode->gfx(1)->transpen(bitmap,cliprect,
(m_spriteram2[offs] & 0x3f) + ((m_spriteram2[offs + 1] & 0x10) << 2),
m_spriteram2[offs + 1] & 0x0f,
m_spriteram2[offs] & 0x40,m_spriteram2[offs] & 0x80,
x,240-m_spriteram2[offs + 2],0);
if(x>0xf0)
m_gfxdecode->gfx(1)->transpen(bitmap,cliprect,
(m_spriteram2[offs] & 0x3f) + ((m_spriteram2[offs + 1] & 0x10) << 2),
m_spriteram2[offs + 1] & 0x0f,
m_spriteram2[offs] & 0x40,m_spriteram2[offs] & 0x80,
x-256,240-m_spriteram2[offs + 2],0);
}
}
uint32_t seicross_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
int col;
for (col = 0; col < 32; col++)
m_bg_tilemap->set_scrolly(col, m_row_scroll[col]);
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_sprites(bitmap, cliprect);
return 0;
}