I am testing a particle beam effect for a rocket trail (u may already know from my previous thread). I set vel_x/y/z to a vector handling the difference between rocket's position before and after its c_move() call (which normally controls its behaviour through arrow keys). Then, I checked if any of vel_x/y/z doesn't equal zero (which means that the rocket is moving) ,and if so, I randomize the vel_x/y/z vector by vec_randomize().


I use this image as a bmap for the effect:


Download link: http://www.datafilehost.com/d/48c7bd08



The problem is that: the particle doesn't look any good. It looks like cut strips or thin arcs (which is weird for a rocket trail). When I comment out vec_randomize() instruction, it doesn't look good either. It looks like the previous case. It takes the form of cut strips moving behind the rocket. Here are some screenshots:


1) If vec_randomize() is executed:





2) If vec_randomize() is commented out:




So, what am I doing wrong? Here's my code (Note that I don't use BRIGHT flag):

Code:
BMAP* smoke = "smoke.tga";
VECTOR dist_covered;
ENTITY* vehicle;

function p_fade_beamy(PARTICLE* p)
{
	p.alpha -= 3*time_step;
	if(p.alpha <= 0) p.lifespan = 0;
}

function p_beamy(PARTICLE* p)
{
	VECTOR speed;
	
	vec_set(p.vel_x,dist_covered.x);
	if(p.vel_x != 0 || p.vel_y != 0 || p.vel_z != 0) vec_randomize(p.vel_x,1);
	
	p.alpha = 100;
	p.bmap = smoke;
	p.size = 8;
	
	set(p, MOVE | TRANSLUCENT | BEAM );
	p.event = p_fade_beamy;
}


action movable_vehicle()
{
	VECTOR temp;
	VECTOR vtemp1;
	VECTOR vtemp2;
	
	
	vehicle = my;
	
	
	while(1)
	{
		
		vec_set(vtemp1.x,my.x);
		c_move(my,vector((key_cuu-key_cud)*5*time_step,0,0),nullvector,GLIDE | IGNORE_PASSABLE);
		my.pan -= (key_cur-key_cul)*5*time_step;
		vec_set(vtemp2.x,my.x);
		
		vec_diff(dist_covered,vtemp1.x,vtemp2.x);
		
		
		vec_set(temp.x,vector(-37,0,0));
	   vec_rotate(temp.x,my.pan);
	   vec_add(temp.x,my.x);
	
	   effect(p_beamy,40,temp.x,nullvector);
		
		wait(1);
		
	}
}



You can download a testing sample here (open through "main.c"): http://www.datafilehost.com/d/38f7e3bd


Also, I wanted to ask: Does the particle function preserve my/you pointers from the calling
function? I know in C-script the my pointer is used to point to the particle ,but what about Lite-C?


Thank you for reading & any help would be appreciated laugh ....

Nothing to say ....