Hey Helghast & folks, look at the video. i have create an animated sprite. it's not perfectly but looks pretty good. (looks really like silent hill 2 now grin )
Sprites are here. (Alternative here )
And some hints to explain how to use it;
Code:
function animate_for_fog()
{
	wait(-integer(random(3)));
	my.frame =0;
	while (1) 
	{ 
		my.frame += 0.6*time_step; 
		if (my.frame >= 32) { my.frame = 1; }
		wait(1); 
	} 
}
void autofog()
{
..........
animate_for_fog();
	if(integer(random(10))>5)
	{
		vec_scale(my.scale_x, 7.8);	
	}
	else
	{
		vec_scale(my.scale_x, random(4));	
	}
..........
}
void generate_fog()
{
..........
if(randint == 0){ ent_create("dust+32.tga", pos_place, autofog); }
if(randint == 1){ ent_create("dustdense+32.tga", pos_place, autofog); }
..........
}

but we need better sprite than my sprite anyway .