// license:BSD-3-Clause
// copyright-holders:Angelo Salese, Pierpaolo Prazzoli
/*****************************************************************************************
Speed Attack video hardware emulation
*****************************************************************************************/
#include "emu.h"
#include "includes/speedatk.h"
PALETTE_INIT_MEMBER(speedatk_state, speedatk)
{
const uint8_t *color_prom = memregion("proms")->base();
int i;
/* create a lookup table for the palette */
for (i = 0; i < 0x10; i++)
{
int bit0, bit1, bit2;
int 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 = 0;
bit1 = (color_prom[i] >> 6) & 0x01;
bit2 = (color_prom[i] >> 7) & 0x01;
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 += 0x20;
for (i = 0; i < 0x100; i++)
{
uint8_t ctabentry = color_prom[i] & 0x0f;
palette.set_pen_indirect(i, ctabentry);
}
}
void speedatk_state::video_start()
{
save_item(NAME(m_crtc_vreg));
save_item(NAME(m_crtc_index));
save_item(NAME(m_flip_scr));
}
WRITE8_MEMBER(speedatk_state::m6845_w)
{
if(offset == 0)
{
m_crtc_index = data;
m_crtc->address_w(space,0,data);
}
else
{
m_crtc_vreg[m_crtc_index] = data;
m_crtc->register_w(space,0,data);
}
}
uint32_t speedatk_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
int x,y;
int count;
uint16_t tile;
uint8_t color, region;
bitmap.fill(0, cliprect);
count = (m_crtc_vreg[0x0c]<<8)|(m_crtc_vreg[0x0d] & 0xff);
if(m_flip_scr) { count = 0x3ff - count; }
for(y=0;y<m_crtc_vreg[6];y++)
{
for(x=0;x<m_crtc_vreg[1];x++)
{
tile = m_videoram[count] + ((m_colorram[count] & 0xe0) << 3);
color = m_colorram[count] & 0x1f;
region = (m_colorram[count] & 0x10) >> 4;
m_gfxdecode->gfx(region)->opaque(bitmap,cliprect,tile,color,m_flip_scr,m_flip_scr,x*8,y*8);
count = (m_flip_scr) ? count-1 : count+1;
count&=0x3ff;
}
}
return 0;
}