Re: [Tuxracer-devel] too many Particles and libtcl8.x

[Jasmin P. <jf...@mu...>]

On 29 Feb 2000, Ingo Ruhnke wrote:

> There is no core file generated. So I played a bit around with gdb:
[snip] 
> | #0  create_new_particles (loc={x = 0.67505081281655532, 
> |       y = -20.186827572125033, z = -50.121188293065998}, vel={x = 0, y = 1, 
> |       z = 0}, num=186591) at part_sys.c:66
> |                   ^^^^^^ <-------------------- This looks far to big
[snip]
> 
> Looks like plyr->control.turn_fact is the cause for this:
> 
> ,----
> | (gdb) print generate_particles::plyr->control.turn_fact
> | $5 = 48711.292061943917
> `----

Spot on.  Thanks!  I've tracked it down to a problem with the automatic
centering of steering.  This bug was actually framerate dependent; it
would only be triggered by framerates below 18 Hz.  I almost always get
over 20 Hz so that explains why I only saw this happen once.

> > By the way, if you want to suppress particle generation altogether,
> > simply comment out the call to generate_particles() in phys_sim.c.
>  
> That didn't help. Tux gets totally out of controll if I press J or L,
> looks like the problem is not the particle system, but instead that
> there is something wrong with the controls.

Yup, that's consistent with the bug I found.  Please try the attached
patch and let me know if things are better.

Thanks,
Jasmin


*** racing.c.0.10	Tue Feb 29 22:15:08 2000
--- racing.c	Tue Feb 29 22:37:27 2000
***************
*** 31,36 ****
--- 31,40 ----
  #include "tux_shadow.h"
  #include "phys_sim.h"
  #include "part_sys.h"
+ #include "screenshot.h"
+ 
+ /* Time constant for automatic steering centering (s) */
+ #define TURN_DECAY_TIME_CONSTANT 0.2
  
  static bool_t right_turn;
  static bool_t left_turn;
***************
*** 76,82 ****
  	increment_turn_fact( plyr, 
  			     ( left_turn ? -1 : 1 ) * 0.2 * time_step / 0.05 );
      } else {
! 	plyr->control.turn_fact *= 0.9 * time_step / 0.05;
      }
  
      update_player_pos( plyr, time_step );
--- 80,91 ----
  	increment_turn_fact( plyr, 
  			     ( left_turn ? -1 : 1 ) * 0.2 * time_step / 0.05 );
      } else {
!         /* Automatically centre steering */
!         if ( time_step < TURN_DECAY_TIME_CONSTANT ) {
! 	    plyr->control.turn_fact *= 1.0 - time_step/TURN_DECAY_TIME_CONSTANT;
!         } else {
! 	    plyr->control.turn_fact = 0.0;
!         }
      }
  
      update_player_pos( plyr, time_step );