/***************************************************************************
Midway 8080-based black and white hardware
****************************************************************************/
#include "emu.h"
#include "includes/mw8080bw.h"
SCREEN_UPDATE( mw8080bw )
{
mw8080bw_state *state = screen->machine().driver_data<mw8080bw_state>();
UINT8 x = 0;
UINT8 y = MW8080BW_VCOUNTER_START_NO_VBLANK;
UINT8 video_data = 0;
while (1)
{
/* plot the current pixel */
pen_t pen = (video_data & 0x01) ? RGB_WHITE : RGB_BLACK;
*BITMAP_ADDR32(bitmap, 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 */
int i;
for (i = 0; i < 4; i++)
{
pen = (video_data & 0x01) ? RGB_WHITE : RGB_BLACK;
*BITMAP_ADDR32(bitmap, 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 offs = ((offs_t)y << 5) | (x >> 3);
video_data = state->m_main_ram[offs];
}
}
return 0;
}
/*************************************
*
* Space Encounters
*
*************************************/
#define PHANTOM2_BOTTOM_TRENCH_DARK_RGB32_PEN RGB_BLACK
#define PHANTOM2_BOTTOM_TRENCH_LIGHT_RGB32_PEN MAKE_RGB(0x5a, 0x5a, 0x5a)
#define PHANTOM2_TOP_TRENCH_DARK_RGB32_PEN RGB_BLACK
#define PHANTOM2_TOP_TRENCH_LIGHT_RGB32_PEN RGB_WHITE
#define PHANTOM2_SIDE_TRENCH_DARK_RGB32_PEN RGB_BLACK
#define PHANTOM2_SIDE_TRENCH_LIGHT_RGB32_PEN MAKE_RGB(0x72, 0x72, 0x72)
SCREEN_UPDATE( spcenctr )
{
mw8080bw_state *state = screen->machine().driver_data<mw8080bw_state>();
UINT8 line_buf[256]; /* 256x1 bit RAM */
UINT8 x = 0;
UINT8 y = MW8080BW_VCOUNTER_START_NO_VBLANK;
UINT8 video_data = 0;
UINT8 draw_line = 0;
UINT8 draw_trench = 0;
UINT8 draw_floor = 0;
UINT8 width = state->m_spcenctr_trench_width;
UINT8 floor_width = width;
UINT8 center = state->m_spcenctr_trench_center;
memset(line_buf, 0, 256);
while (1)
{
/* plot the current pixel */
UINT8 bit = video_data & 0x01;
pen_t pen = bit ? RGB_WHITE : RGB_BLACK;
/* possibly draw trench in the background, top of trench first */
if (!(width & 0x80) && draw_trench)
{
line_buf[x] = draw_line;
if (!bit)
pen = draw_line ? PHANTOM2_TOP_TRENCH_LIGHT_RGB32_PEN : PHANTOM2_TOP_TRENCH_DARK_RGB32_PEN;
}
/* sides of trench? */
else if (!(floor_width & 0x80) && (draw_trench || draw_floor))
{
if (!bit)
pen = line_buf[x] ? PHANTOM2_SIDE_TRENCH_LIGHT_RGB32_PEN : PHANTOM2_SIDE_TRENCH_DARK_RGB32_PEN;
}
/* bottom of trench? */
else if (draw_floor)
{
line_buf[x] = line_buf[x - 1];
if (!bit)
pen = line_buf[x] ? PHANTOM2_BOTTOM_TRENCH_LIGHT_RGB32_PEN : PHANTOM2_BOTTOM_TRENCH_DARK_RGB32_PEN;
}
*BITMAP_ADDR32(bitmap, 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;
/* end of line? */
if (x == 0)
{
offs_t offs;
UINT8 trench_control;
/* yes, flush out the shift register */
int i;
for (i = 0; i < 4; i++)
{
pen = (video_data & 0x01) ? RGB_WHITE : RGB_BLACK;
*BITMAP_ADDR32(bitmap, y - MW8080BW_VCOUNTER_START_NO_VBLANK, 256 + i) = pen;
video_data = video_data >> 1;
}
/* update the trench control for the next line */
offs = ((offs_t)y << 5) | 0x1f;
trench_control = state->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 + (state->m_spcenctr_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 + ((state->m_spcenctr_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;
}
/* 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 = state->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 MAKE_RGB(0xc0, 0xc0, 0xc0)
SCREEN_UPDATE( phantom2 )
{
mw8080bw_state *state = screen->machine().driver_data<mw8080bw_state>();
UINT8 x = 0;
UINT8 y = MW8080BW_VCOUNTER_START_NO_VBLANK;
UINT8 video_data = 0;
UINT8 cloud_data = 0;
UINT16 cloud_counter = state->m_phantom2_cloud_counter;
UINT8 *cloud_region = screen->machine().region("proms")->base();
while (1)
{
int load_shift_reg;
UINT8 cloud_data_to_load = 0;
pen_t pen;
/* plot the current pixel */
UINT8 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_WHITE : RGB_BLACK;
*BITMAP_ADDR32(bitmap, 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_WHITE : RGB_BLACK;
*BITMAP_ADDR32(bitmap, 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 = state->m_main_ram[offs];
}
}
return 0;
}
SCREEN_EOF( phantom2 )
{
mw8080bw_state *state = machine.driver_data<mw8080bw_state>();
state->m_phantom2_cloud_counter += MW8080BW_VTOTAL;
if (state->m_phantom2_cloud_counter >= PHANTOM2_CLOUD_COUNTER_END)
state->m_phantom2_cloud_counter = PHANTOM2_CLOUD_COUNTER_START + (state->m_phantom2_cloud_counter - PHANTOM2_CLOUD_COUNTER_END);
}
/*************************************
*
* Space Invaders
*
*************************************/
/* the flip screen circuit is just a couple of relays on the monitor PCB */
SCREEN_UPDATE( invaders )
{
mw8080bw_state *state = screen->machine().driver_data<mw8080bw_state>();
UINT8 x = 0;
UINT8 y = MW8080BW_VCOUNTER_START_NO_VBLANK;
UINT8 video_data = 0;
UINT8 flip = state->m_invaders_flip_screen;
while (1)
{
/* plot the current pixel */
pen_t pen = (video_data & 0x01) ? RGB_WHITE : RGB_BLACK;
if (flip)
*BITMAP_ADDR32(bitmap, MW8080BW_VBSTART - 1 - (y - MW8080BW_VCOUNTER_START_NO_VBLANK), MW8080BW_HPIXCOUNT - 1 - x) = pen;
else
*BITMAP_ADDR32(bitmap, 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 */
int i;
for (i = 0; i < 4; i++)
{
pen = (video_data & 0x01) ? RGB_WHITE : RGB_BLACK;
if (flip)
*BITMAP_ADDR32(bitmap, MW8080BW_VBSTART - 1 - (y - MW8080BW_VCOUNTER_START_NO_VBLANK), MW8080BW_HPIXCOUNT - 1 - (256 + i)) = pen;
else
*BITMAP_ADDR32(bitmap, 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 offs = ((offs_t)y << 5) | (x >> 3);
video_data = state->m_main_ram[offs];
}
}
return 0;
}