Pendulum physics

[Nahuel]

hello to all!!
is it possible to make something like physics of a pendulum? I do not speak about the Rogue pendulum, i want a "realistic" pendulum .
I made a few destroyable light bulbs with rt_lights for darkplaces. But I want to add physics to the bulbs. it is possible? can anybody give me any suggestion?
Check my video-test of the lights (sorry for the sound and the CS S model it´s just a test) http://www.youtube.com/watch?v=scCLaEbS-mw

[thorn3001]

Hello!

Do you will make something like this?

http://www.youtube.com/watch?v=51DSDtnoPVg

it seem very difficult, maybe on Darkplaces engine

[frag.machine]

hello to all!!
is it possible to make something like physics of a pendulum? I do not speak about the Rogue pendulum, i want a "realistic" pendulum .
I made a few destroyable light bulbs with rt_lights for darkplaces. But I want to add physics to the bulbs. it is possible? can anybody give me any suggestion?
Check my video-test of the lights (sorry for the sound and the CS S model it´s just a test) http://www.youtube.com/watch?v=scCLaEbS-mw

IIRC the RMQ grappling hook has it.

[toneddu2000]

Wow, wonderful demo Nahuel, as always! You (maybe) could use Ode to make a pendulum with hinges, IIRC. But my question is: after you make it, how do you think to attach dynamic lights to it?

[goldenboy]

rope physics? I think Necros experimented with ropes in Quake, ask him. Unless my memory is failing me.

The RMQ grapple allows the player to dangle and swing from the grapple line, yeah, but no idea how helpful the code is for making dangling light bulbs. It has nothing to do with physics, really.

If you find a solution, do post it, I'd like to know ^^

[Nahuel]

Wow, wonderful demo Nahuel, as always! You (maybe) could use Ode to make a pendulum with hinges, IIRC. But my question is: after you make it, how do you think to attach dynamic lights to it?

I use PFLAGS_. These lights can move,
If you want here you can download my lights, i do not use some "DP features" like "style" or "skin". Check the source, all you need is in "rtlights.qc". I included the map of the video "rtest"
http://www.mediafire.com/?244msx05jmytrjt

rope physics? I think Necros experimented with ropes in Quake, ask him. Unless my memory is failing me.

The RMQ grapple allows the player to dangle and swing from the grapple line, yeah, but no idea how helpful the code is for making dangling light bulbs. It has nothing to do with physics, really.

If you find a solution, do post it, I'd like to know ^^

If you say it!! I will ask! i think that the rope physics are not imposible !!!

[toneddu2000]

wow, thanks a lot Nahuel! It's a very interesting technique. I like very much the light break effect

EDIT: can you please explain how PFLAGS variables work(or post a link where they are described)?I noticed that the're used a lot in darkplaces c code (cl_main.c, cl_parse.c,clvm_cmds.c,protocol.h,r_shadow.c,sv_main.c and sv_phys.c)and I presume they need for dynamic light computation but I can't get how to use them and why

[necros]

i've tried a couple of seperate ways to do it, but the results are not 100%.

you can see it in action here:
http://www.youtube.com/watch?v=21D-21MLrAE

currently, the video i linked uses the .velocity method:

essentially, what is done, is you build the rope out of a chain of seperate entities. it's a good idea to provide 31 frames, a frame for when the rope segment is 1 unit long, 2, 3... up to 32 units long.

next, use an engine with higher precision angles (DP, RMQe, QBism's 8Bit Engine to name a few).
low precision angles will make the rope segments align badly and make it really obvious your rope is just made out of small pieces.

next, you need to first figure out and set the start and end of the rope to movetype_none.

from there, you iterate through the rope, adding velocity to each segment both to the previous rope segement and the next. you're essentially creating a 'real time' solver.

problems: if your engine, for whatever reason, gets low frame rate, the velocities required to keep the rope together grow increasingly higher. eventually, the rope can shatter to pieces if your code deems it necessary to apply 10000 u/sec to a segment.
you can add velocity limits, of course, but then your rope just falls apart at low framerate.

btw, the 'shivers' you see are when fraps caused a sudden dip in framerate. this was an earlier version that only interated once, and set segment angles at the same time it was adding velocity.
by interating twice, once to add velocities, and again to correct angles, you can get rid of this.

finally, the main problem, and the reason i never really bothered trying very hard to get this going, is it takes up massive amounts of QC time. A medium sized rope might have 16 or more segments, and the velocity and angles iterations must be done every frame.
it's just not feasible because it's almost always going to be active.

the second method i tried, was setting origin directly. this has the advantage of not being framerate dependant and being detached from the physics engine.

however, this also means you don't get basic things like collision necessitating extra traceline checks and possibly pointcontent checks to try to simulate collision in QC.

and this is only for the simplest rope: single rope connected to on both ends.
dangling ropes with a weight attached is probably much worse because now you've got momentum and angular momentum and oh my god my head exploded.


i would be interested in knowing how you made your directional flash light though. looks just like the d3 flashlight!

[toneddu2000]

Oh, my god! Ropes in quake! I never thought it was possible! Great technique, compliments!

[goldenboy]

Is that a texture for the flashlight?

[Seven]

First of all I must say:
You make AMAZING things, Nahuel and Necros !!!

Regarding Nahuel´s flashlight:
I think he made it via a cubemap, right ?
This is the thread, with his first version (if I am not mistaken):
viewtopic.php?t=3451

Please keep on doing the wonderful things you do guys.

Best wishes,
Seven

[goldenboy]

I see. Very nice.

[necros]

interesting... checked out the qc for the link you gave above.

something in there called pflags which i guess is a DP specific flag set. i'll have to experiment with that i guess.

[OneManClan]

Oh, my god! Ropes in quake! I never thought it was possible! Great technique, compliments!

+1 .... amazing!

[Nahuel]

[quote="necros"][/quote]
incredible rope necros!!!!!! what think of that only I used 2 segments? bony a segmentp as origin (in the roof with MOVETYPE_NONE) and other would be the light bulb. or Perhaps it would be better to use 3 segments.........
-------------------------------------------
segment 0-------roof
segment 1
|
|
|
|
segment 2 (light bulb)
----------------------------------------------
Maybee the "pain" of the entity light might be the "velocity increase" and the angles based on the origin of the attacker....

What do you think about that? Might it be possible?? or is it a foolery? can two separated entities be segments of the same rope?? or does not it treat about another thing?
I am lost with this
------------------------------------------------------------------------------
i am using the cubemap of the flashlight of d3 in this thread http://forums.inside3d.com/viewtopic.php?t=4274
the early flashlight is some ugly , otherwise these flashlight can not be perfect, i have problems with the shadow of the player
I use this "fixed" code now

Code: Select all

void() flash_update =
{
        if (self.owner.deadflag != DEAD_NO)
                return;
if (self.owner.classname != "player")
      return;
        makevectors (self.owner.v_angle);
        traceline (self.owner.origin , (self.owner.origin+(v_forward * 10)), FALSE , self);
        setorigin (self, trace_endpos+ '0 0 16' );//+(v_forward * - 6));
self.angles_x = (((self.owner.angles_x) * - 3) - 180);
self.angles_y = self.owner.angles_y - 3 ;
self.angles_z = self.owner.angles_z;
self.pflags = PFLAGS_FULLDYNAMIC;
   self.light_lev = 1950;
   self.color = '1 1 1';
   self.skin = 200; 
   self.scale = 15; 

        self.nextthink = time + 0.002;


};

void() flash_on =
{
           local entity myflash;

        myflash = spawn ();
        myflash.movetype = MOVETYPE_NONE;
        myflash.solid = SOLID_NOT;
             setmodel (myflash, "progs/nada.spr");
        setsize (myflash, '0 0 0', '0 0 0');


        myflash.owner = self;
        self.flash = myflash;
       

        myflash.classname = "flash";
       
        makevectors (self.v_angle);
traceline (self.owner.origin , (self.owner.origin+(v_forward * 10)), FALSE , self);

        setorigin (myflash, trace_endpos);


        myflash.think = flash_update;
        myflash.nextthink = time + 0.002;

};


void () flash_toggle =
{


        if (self.flash_flag == FALSE)
        {       
                self.flash_flag = TRUE;
                flash_on();
   sound (self, CHAN_WEAPON, "misc/click.wav", 1, ATTN_NORM);   

        }

        else
        {
                self.flash_flag = FALSE;
                W_SetCurrentAmmo ();
                self.flash.think = SUB_Remove;
                self.flash.nextthink = time + 0.1;
   sound (self, CHAN_WEAPON, "misc/clickoff.wav", 1, ATTN_NORM);   

        }


};


and i modified the tga; a big chanel alpha with a little image inside you can download the correct size (example) here
http://www.mediafire.com/?i9sm5c047cq59wn (no copyright problems with this tga )
Yes!!!!!!! i am using the tenebrae of darkplaces it is great!!!!!!!