// license:BSD-3-Clause
// copyright-holders:Nicola Salmoria, Tormod Tjaberg, Mirko Buffoni,Lee Taylor, Valerio Verrando, Zsolt Vasvari
// thanks-to:Michael Strutts, Marco Cassili
/***************************************************************************
Midway 8080-based black and white hardware
****************************************************************************/
#include "emu.h"
#include "includes/mw8080bw.h"
uint32_t mw8080bw_state::screen_update_mw8080bw(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
{
uint8_t x = 0;
uint8_t y = MW8080BW_VCOUNTER_START_NO_VBLANK;
uint8_t video_data = 0;
while (1)
{
// plot the current pixel
pen_t pen = (video_data & 0x01) ? rgb_t::white() : rgb_t::black();
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, x) = pen;
// next pixel
video_data = video_data >> 1;
x = x + 1;
/* end of line? */
if (x == 0)
{
// yes, flush out the shift register
for (int i = 0; i < 4; i++)
{
pen = (video_data & 0x01) ? rgb_t::white() : rgb_t::black();
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, 256 + i) = pen;
video_data = video_data >> 1;
}
// next row, video_data is now 0, so the next line will start with 4 blank pixels
y = y + 1;
// end of screen?
if (y == 0)
break;
}
/* the video RAM is read at every 8 pixels starting with pixel 4 */
else if ((x & 0x07) == 0x04)
{
offs_t const offs = ((offs_t)y << 5) | (x >> 3);
video_data = m_main_ram[offs];
}
}
return 0;
}
/*************************************
*
* Space Encounters
*
*************************************/
/* video signals mixed via R2 open collector nand gates and 'brite' RC circuit
* when /BRITE lo, cap C23 discharge rapidly, disabling Q2, overpowering all other video signals
* when /BRITE hi, cap C23 charge through 10k res, brite voltage decrease to 0 over approx 0.4 sec
* inverted video data is fed into R2 nand gates:
* when /VIDEO lo, all gates open for max brightness
* max V = (5 - 0.7) * 470 / (470 + 100) = 3.5 V
* when /video hi, pin 5 always gnd, max = 3 V, min = 1 V
* (guess) pin 11 state controls trench color
* (guess) pin 3 low for trench side
* (guess) pin 8 low for trench floor
* thus, trench side: 1.4 or 2.2 V
* trench floor: 1.3 or 2.0 V
* trech top: 1.8 or 3 V
* scaled to 3.2 V = 255, 1.2 V = 0 (arbitrary values chosen to match video)
*/
#define SPCENCTR_TOP_TRENCH_DARK_RGB32_PEN rgb_t(0x4d, 0x4d, 0x4d)
#define SPCENCTR_TOP_TRENCH_LIGHT_RGB32_PEN rgb_t(0xe6, 0xe6, 0xe6)
#define SPCENCTR_SIDE_TRENCH_DARK_RGB32_PEN rgb_t(0x1a, 0x1a, 0x1a)
#define SPCENCTR_SIDE_TRENCH_LIGHT_RGB32_PEN rgb_t(0x80, 0x80, 0x80)
#define SPCENCTR_BOTTOM_TRENCH_DARK_RGB32_PEN rgb_t(0x0d, 0x0d, 0x0d)
#define SPCENCTR_BOTTOM_TRENCH_LIGHT_RGB32_PEN rgb_t(0x66, 0x66, 0x66)
#define SPCENCTR_BRIGHTNESS_DECAY 10
uint32_t spcenctr_state::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
{
uint8_t line_buf[256]; /* 256x1 bit RAM */
uint8_t x = 0;
uint8_t y = MW8080BW_VCOUNTER_START_NO_VBLANK;
uint8_t video_data = 0;
uint8_t draw_line = 0;
uint8_t draw_trench = 0;
uint8_t draw_floor = 0;
uint8_t width = m_trench_width;
uint8_t floor_width = width;
uint8_t center = m_trench_center;
memset(line_buf, 0, 256);
if (m_bright_control)
m_brightness = 255;
else if (m_brightness > SPCENCTR_BRIGHTNESS_DECAY)
m_brightness -= SPCENCTR_BRIGHTNESS_DECAY;
else
m_brightness = 0;
while (1)
{
// plot the current pixel
uint8_t bit = video_data & 0x01;
pen_t pen = bit ? rgb_t::white() : rgb_t::black();
if (!(width & 0x80) && draw_trench) // possibly draw trench in the background, top of trench first
{
line_buf[x] = draw_line;
if (!bit)
pen = draw_line ? SPCENCTR_TOP_TRENCH_LIGHT_RGB32_PEN : SPCENCTR_TOP_TRENCH_DARK_RGB32_PEN;
}
else if (!(floor_width & 0x80) && (draw_trench || draw_floor)) // sides of trench?
{
if (!bit)
pen = line_buf[x] ? SPCENCTR_SIDE_TRENCH_LIGHT_RGB32_PEN : SPCENCTR_SIDE_TRENCH_DARK_RGB32_PEN;
}
else if (draw_floor) // bottom of trench?
{
line_buf[x] = line_buf[x - 1];
if (!bit)
pen = line_buf[x] ? SPCENCTR_BOTTOM_TRENCH_LIGHT_RGB32_PEN : SPCENCTR_BOTTOM_TRENCH_DARK_RGB32_PEN;
}
if (m_brightness > (pen & 0xff))
pen = rgb_t(m_brightness, m_brightness, m_brightness);
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, x) = pen;
center = center + 1;
width = width + ((center & 0x80) ? -1 : 1);
floor_width = floor_width + ((center & 0x80) ? -1 : 1);
// next pixel
video_data = video_data >> 1;
x = x + 1;
if (x == 0) // end of line?
{
// yes, flush out the shift register
for (int i = 0; i < 4; i++)
{
if (video_data & 0x01)
pen = rgb_t::white();
else if(m_brightness)
pen = rgb_t(m_brightness, m_brightness, m_brightness);
else
pen = rgb_t::black();
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, 256 + i) = pen;
video_data = video_data >> 1;
}
/* update the trench control for the next line */
offs_t const offs = ((offs_t)y << 5) | 0x1f;
uint8_t const trench_control = m_main_ram[offs];
if (trench_control & 0x40)
draw_trench = 1;
if (trench_control & 0x20)
draw_trench = 0;
if (trench_control & 0x10)
draw_floor = 1;
if (trench_control & 0x08)
draw_floor = 0;
draw_line = (trench_control & 0x80) >> 7;
// add the lower 2 bits stored in the slope array to width
if (draw_trench)
width = width + (m_trench_slope[y & 0x0f] & 0x03);
// add the higher 2 bits stored in the slope array to floor width
if (draw_floor)
floor_width = floor_width + ((m_trench_slope[y & 0x0f] & 0x0c) >> 2);
// next row, video_data is now 0, so the next line will start with 4 blank pixels
y = y + 1;
// end of screen?
if (y == 0)
break;
}
else if ((x & 0x07) == 0x04) // the video RAM is read at every 8 pixels starting with pixel 4
{
offs_t const offs = ((offs_t)y << 5) | (x >> 3);
video_data = m_main_ram[offs];
}
}
return 0;
}
/*************************************
*
* Phantom II
*
*************************************/
/* the cloud generator comprises of 2 counters and a shift register:
* counter 1 is 8 bits and and clocked every pixel. It gets cleared at the end of HBLANK .
Bit 0 is used to clock the shift register, thus repeating every pixel twice.
Bits 4-7 go to address line A0-A3 of the cloud gfx prom.
* counter 2 is 12 bits starting from 0xe0b and counts up to 0xfff. It gets clocked at the
beginning of HBLANK and is never cleared.
Bits 1-7 go to address line A4-A10 of the cloud gfx prom.
*/
#define PHANTOM2_CLOUD_COUNTER_START (0x0e0b)
#define PHANTOM2_CLOUD_COUNTER_END (0x1000)
#define PHANTOM2_CLOUD_COUNTER_PERIOD (PHANTOM2_CLOUD_COUNTER_END - PHANTOM2_CLOUD_COUNTER_START)
#define PHANTOM2_RGB32_CLOUD_PEN rgb_t(0xc0, 0xc0, 0xc0)
uint32_t mw8080bw_state::screen_update_phantom2(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
{
uint8_t x = 0;
uint8_t y = MW8080BW_VCOUNTER_START_NO_VBLANK;
uint8_t video_data = 0;
uint8_t cloud_data = 0;
uint16_t cloud_counter = m_phantom2_cloud_counter;
uint8_t *cloud_region = memregion("proms")->base();
while (1)
{
int load_shift_reg;
uint8_t cloud_data_to_load = 0;
pen_t pen;
/* plot the current pixel */
uint8_t bit = video_data & 0x01;
/* if background color, cloud gfx in the background */
if ((bit == 0) && (cloud_data & 0x01))
pen = PHANTOM2_RGB32_CLOUD_PEN;
else
pen = bit ? rgb_t::white() : rgb_t::black();
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, x) = pen;
/* move to next pixel -- if ripple carry is currently set,
prepare for loading the shift register */
load_shift_reg = ((x & 0x0f) == 0x0f);
if (load_shift_reg)
{
offs_t cloud_offs = ((cloud_counter & 0xfe) << 3) | (x >> 4);
cloud_data_to_load = cloud_region[cloud_offs];
}
video_data = video_data >> 1;
x = x + 1;
/* the sift register is clocked on the falling edge of bit 0 */
if (!(x & 0x01))
{
/* load or shift? */
if (load_shift_reg)
cloud_data = cloud_data_to_load;
else
cloud_data = cloud_data >> 1;
}
/* end of line? */
if (x == 0)
{
/* yes, flush out the shift register */
int i;
for (i = 0; i < 4; i++)
{
pen = (video_data & 0x01) ? rgb_t::white() : rgb_t::black();
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, 256 + i) = pen;
video_data = video_data >> 1;
}
/* next row of clouds */
cloud_counter = cloud_counter + 1;
if (cloud_counter == PHANTOM2_CLOUD_COUNTER_END)
cloud_counter = PHANTOM2_CLOUD_COUNTER_START;
/* next row of pixels, video_data is now 0, so the next
line will start with 4 blank pixels */
y = y + 1;
/* end of screen? */
if (y == 0)
break;
}
/* the video RAM is read at every 8 pixels starting with pixel 4 */
else if ((x & 0x07) == 0x04)
{
offs_t offs = ((offs_t)y << 5) | (x >> 3);
video_data = m_main_ram[offs];
}
}
return 0;
}
WRITE_LINE_MEMBER(mw8080bw_state::screen_vblank_phantom2)
{
// falling edge
if (!state)
{
m_phantom2_cloud_counter += MW8080BW_VTOTAL;
if (m_phantom2_cloud_counter >= PHANTOM2_CLOUD_COUNTER_END)
m_phantom2_cloud_counter = PHANTOM2_CLOUD_COUNTER_START + (m_phantom2_cloud_counter - PHANTOM2_CLOUD_COUNTER_END);
}
}
/*************************************
*
* Space Invaders
*
*************************************/
// the flip screen circuit is just a couple of relays on the monitor PCB
uint32_t mw8080bw_state::screen_update_invaders(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
{
uint8_t x = 0;
uint8_t y = MW8080BW_VCOUNTER_START_NO_VBLANK;
uint8_t video_data = 0;
while (1)
{
// plot the current pixel
pen_t pen = (video_data & 0x01) ? rgb_t::white() : rgb_t::black();
if (m_flip_screen)
bitmap.pix32(MW8080BW_VBSTART - 1 - (y - MW8080BW_VCOUNTER_START_NO_VBLANK), MW8080BW_HPIXCOUNT - 1 - x) = pen;
else
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, x) = pen;
// next pixel
video_data = video_data >> 1;
x = x + 1;
// end of line?
if (x == 0)
{
// yes, flush out the shift register
for (int i = 0; i < 4; i++)
{
pen = (video_data & 0x01) ? rgb_t::white() : rgb_t::black();
if (m_flip_screen)
bitmap.pix32(MW8080BW_VBSTART - 1 - (y - MW8080BW_VCOUNTER_START_NO_VBLANK), MW8080BW_HPIXCOUNT - 1 - (256 + i)) = pen;
else
bitmap.pix32(y - MW8080BW_VCOUNTER_START_NO_VBLANK, 256 + i) = pen;
video_data = video_data >> 1;
}
// next row, video_data is now 0, so the next line will start with 4 blank pixels
y = y + 1;
// end of screen?
if (y == 0)
break;
}
else if ((x & 0x07) == 0x04) // the video RAM is read at every 8 pixels starting with pixel 4
{
offs_t const offs = (offs_t(y) << 5) | (x >> 3);
video_data = m_main_ram[offs];
}
}
return 0;
}