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AmigActive 10
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AACD 10.iso
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vidhrdw
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spacefb.c
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C/C++ Source or Header
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2000-04-23
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4KB
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158 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
static int video_control;
/***************************************************************************
Convert the color PROMs into a more useable format.
Space FB has one 32 bytes palette PROM, 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
***************************************************************************/
void spacefb_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
{
int i;
for (i = 0;i < 32;i++)
{
int bit0,bit1,bit2;
bit0 = (color_prom[i] >> 0) & 0x01;
bit1 = (color_prom[i] >> 1) & 0x01;
bit2 = (color_prom[i] >> 2) & 0x01;
palette[3*i + 0] = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
bit0 = (color_prom[i] >> 3) & 0x01;
bit1 = (color_prom[i] >> 4) & 0x01;
bit2 = (color_prom[i] >> 5) & 0x01;
palette[3*i + 1] = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
bit0 = 0;
bit1 = (color_prom[i] >> 6) & 0x01;
bit2 = (color_prom[i] >> 7) & 0x01;
if (bit1 | bit2)
bit0 = 1;
palette[3*i + 2] = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
}
for (i = 0;i < 4 * 8;i++)
{
if (i & 3) colortable[i] = i;
else colortable[i] = 0;
}
}
WRITE_HANDLER( spacefb_video_control_w )
{
video_control = data;
}
WRITE_HANDLER( spacefb_port_2_w )
{
logerror("Port #2 = %02d\n",data);
}
/***************************************************************************
Draw the game screen in the given osd_bitmap.
Do NOT call osd_update_display() from this function, it will be called by
the main emulation engine.
***************************************************************************/
void spacefb_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
int offs;
int spriteno, col_bit2, flipscreen;
/* Clear the bitmap */
fillbitmap(bitmap,Machine->pens[0],&Machine->drv->visible_area);
/* Draw the sprite/chars */
spriteno = (video_control & 0x20) ? 0x80 : 0x00;
flipscreen = video_control & 0x01;
/* A4 of the color PROM, depending on a jumper setting, can either come
from the CREF line or from sprite memory. CREF is the default
according to the schematics */
col_bit2 = (video_control & 0x40) ? 0x04 : 0x00;
for (offs = 0; offs < 128; offs++, spriteno++)
{
int sx,sy,code,cnt,col;
sx = 255 - videoram[spriteno];
sy = videoram[spriteno+0x100];
code = videoram[spriteno+0x200];
cnt = videoram[spriteno+0x300];
col = (~cnt & 0x03) | col_bit2;
if (cnt)
{
if (cnt & 0x20)
{
/* Draw bullets */
if (flipscreen)
{
sx = 260 - sx;
sy = 252 - sy;
}
drawgfx(bitmap,Machine->gfx[1],
code & 0x3f,
col,
flipscreen,flipscreen,
sx,sy,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
}
else if (cnt & 0x40)
{
sy -= 5; /* aligns the spaceship and the bullet */
if (flipscreen)
{
sx = 256 - sx;
sy = 248 - sy;
}
drawgfx(bitmap,Machine->gfx[0],
255 - code,
col,
flipscreen,flipscreen,
sx,sy,
&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
}
}
}