Forum

vector math, combining angles and offsets

Discuss programming in the QuakeC language.

Moderator: InsideQC Admins

vector math, combining angles and offsets

Postby daemon » Sat Mar 22, 2008 5:18 pm

I'm trying to locate the position of a weapon blade in the world based on a few angles and offsets.

I have:

self - (the player)
wep.targorigin - (the origin the weapon in the player's hand is moving toward)

wep is an attachment on the player, so it's origin is relative.
in order to find it's real origin in the world I do this:

---
ang = self.angles + vectoangles(wep.targorigin); // the angle in the world from the player origin to the weapon origin
ang_x = -ang_x; // negate the pitch
makevectors(ang); // get v_forward
wep_position = self.origin + v_forward*vlen(wep.targorigin); // the weapon origin in the world
---

now I have wep_position to base my next calculation from.
and also:
wep.targangles - (the angles the weapon is turning toward)
wep.damagepoint_ofs - (the offset of the weapon blade)

Image
wep.damagepoint_ofs being shown here as '8.7 0.2 23.23'

so I do the following to find the position of the weapon blade:

---
ang = self.angles + wep.targangles + vectoangles(wep.damagepoint_ofs); // the angle in the world from the weapon position to the weapon blade
ang_x = -ang_x; // negate the pitch again
makevectors(ang); // get v_forward
swing_end = wep_position + v_forward*vlen(wep.damagepoint_ofs); // the position of the blade in the world
---

for some reason this doesn't work out. the position of the blade ends up being calculated way off. I can't figure out what I'm doing wrong or what I need to do to make this work.

I suspect that it has something to do with this line:
ang = self.angles + wep.targangles + vectoangles(wep.damagepoint_ofs);

pitch, yaw, and roll are all tilted in wep.targangles, but self.angles and vectoangles(wep.damagepoint_ofs) only have a pitch and a yaw...

any ideas?
-daemon [ daemonforge.org ]
User avatar
daemon
 
Posts: 63
Joined: Wed Nov 07, 2007 11:10 pm

Postby daemon » Sun Mar 23, 2008 12:21 am

ok, ignore that post above. here is the updated code for the weapon position ONLY:

Code: Select all
   pivot_ofs = '0 0 16';
   pivotpoint = self.origin + pivot_ofs;
   wep_targorg = wep.targorigin - pivot_ofs;
   self_ang = self.angles;
   
   ang = self_ang + vectoangles(wep_targorg);
   ang_x = -ang_x;
   makevectors(ang);
   wep_pos = pivotpoint + v_forward*vlen(wep_targorg);


when i look up and down the wep_pos becomes inaccurate...
-daemon [ daemonforge.org ]
User avatar
daemon
 
Posts: 63
Joined: Wed Nov 07, 2007 11:10 pm

Postby daemon » Sun Mar 23, 2008 3:04 am

well.. here's the working copy if anyone is interested. Thanks to KrimZon for help with combining angles. I don't understand why I had to subtract v_right, but that's the only way I could get it to work correctly.

Code: Select all
void UpdateDamagePoint(entity wep) =
{
   local vector ang, wep_pos, dmg_ang;

   ang = self.angles;
   ang_x = -ang_x;
   makevectors(ang);
   ang = vectoangles(v_forward*wep.targorigin_x - v_right*wep.targorigin_y + v_up*wep.targorigin_z); // angle from player origin to weapon handle in modelspace
   
   ang_x = -ang_x;
   makevectors(ang);
   wep_pos = self.origin + v_forward*vlen(wep.targorigin); // position of weapon handle in worldspace
   
   dmg_ang = wep.targangles;
   dmg_ang_x = -dmg_ang_x;
   makevectors(dmg_ang);
   dmg_ang = (v_forward*wep.damagepoint_ofs_x - v_right*wep.damagepoint_ofs_y + v_up*wep.damagepoint_ofs_z); // angle from weapon handle to weapon damagepoint in modelspace
   
   ang = self.angles;
   ang_x = -ang_x;
   makevectors(ang);
   ang = vectoangles(v_forward*dmg_ang_x - v_right*dmg_ang_y + v_up*dmg_ang_z); // angle from weapon handle to weapon damagepoint in worldspace
   
   ang_x = -ang_x;
   makevectors(ang);
   wep.damagepoint = wep_pos + v_forward*vlen(wep.damagepoint_ofs);// position of weapon damagepoint in worldspace
}   
-daemon [ daemonforge.org ]
User avatar
daemon
 
Posts: 63
Joined: Wed Nov 07, 2007 11:10 pm


Return to QuakeC Programming

Who is online

Users browsing this forum: Bing [Bot] and 1 guest