static int draw(RGB32 *src, RGB32 *dest)
{
int x, y;
unsigned char *p, *q, v;
unsigned char sum, sum1, sum2, sum3;
int width;
RGB32 pix;
width = video_width;
p = image_diff_filter(image_bgsubtract_update_y(src));
for(x=0; x<video_area; x++) {
field1[x] |= p[x];
}
p = field1 + 1;
q = field2 + width + 1;
dest += width + 1;
src += width + 1;
/* each value of cell is 0 or 0xff. 0xff can be treated as -1, so
* following equations treat each value as negative number. */
for(y=1; y<video_height-1; y++) {
sum1 = 0;
sum2 = p[0] + p[width] + p[width*2];
for(x=1; x<width-1; x++) {
sum3 = p[1] + p[width+1] + p[width*2+1];
sum = sum1 + sum2 + sum3;
v = 0 - ((sum==0xfd)|((p[width]!=0)&(sum==0xfc)));
*q++ = v;
pix = (signed char)v;
// pix = pix >> 8;
*dest++ = pix | *src++;
sum1 = sum2;
sum2 = sum3;
p++;
}
p += 2;
q += 2;
src += 2;
dest += 2;
}
p = field1;
field1 = field2;
field2 = p;
return 0;
}
static int draw(RGB32 *src, RGB32 *dest)
{
int x, y;
unsigned char *diff;
if(!bgIsSet) {
setBackground(src);
}
diff = image_diff_filter(image_bgsubtract_y(src));
for(y=video_height; y>0; y--) {
for(x=video_width; x>0; x--) {
if(*diff++) {
*dest = 0 - ((inline_fastrand()>>31) & y);
} else {
*dest = *src;
}
src++;
dest++;
}
