[ODE] OPCODE vs. double

DjArcas djarcas at hotmail.com
Sun Jul 6 10:43:03 2003


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The simplest solution is to create your 3d device with =
D3DCREATE_FPU_PRESERVE when your program requires great accuracy, IE a =
physics system. There is a performance hit, at least theoretically - =
I've not seen anything change on my system, and I'm chunking a lot of =
polys at the screen. Changing ODE's accuracy to cope with something that =
D3D can be told NOT to do doesn't seem like the best solution, IMO.


----- Original Message -----=20
From: "Timothy J. Wood" <tjw@omnigroup.com>
To: <ode@q12.org>
Sent: Sunday, July 06, 2003 6:19 PM
Subject: [ODE] OPCODE vs. double


>=20
>=20
>    I'm sort of worried since I've seen people on this list mentioned=20
> that D3D breaks their simulation (since it gets rid of the extra=20
> precision by default), but then OPCODE requires single precision.
>=20
>    So, what's going to give?  Are we just supposed to abandon double=20
> support in ODE or should OPCODE be made to work with double for when=20
> you need precision more than space?  Can ODE be made to lose less=20
> precision in floats (seems unlikely)?  Other solutions?
>=20
> -tim
>=20
> _______________________________________________
> ODE mailing list
> ODE@q12.org
> http://q12.org/mailman/listinfo/ode
> 
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<DIV><FONT face=3DArial size=3D2>The simplest solution is to create your =
3d device=20
with </FONT><FONT face=3DArial size=3D2>D3DCREATE_FPU_PRESERVE when your =
program=20
requires great accuracy, IE a physics system. There is a performance =
hit, at=20
least theoretically - I've not seen anything change on my system, and =
I'm=20
chunking a lot of polys at the screen. Changing ODE's accuracy to cope =
with=20
something that D3D can be told NOT to do doesn't seem like the best =
solution,=20
IMO.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>----- Original Message ----- </FONT>
<DIV><FONT face=3DArial size=3D2>From: "Timothy J. Wood" &lt;</FONT><A=20
href=3D"mailto:tjw@omnigroup.com"><FONT face=3DArial=20
size=3D2>tjw@omnigroup.com</FONT></A><FONT face=3DArial =
size=3D2>&gt;</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>To: &lt;</FONT><A =
href=3D"mailto:ode@q12.org"><FONT=20
face=3DArial size=3D2>ode@q12.org</FONT></A><FONT face=3DArial=20
size=3D2>&gt;</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Sent: Sunday, July 06, 2003 6:19 =
PM</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Subject: [ODE] OPCODE vs. =
double</FONT></DIV></DIV>
<DIV><FONT face=3DArial><BR><FONT size=3D2></FONT></FONT></DIV><FONT =
face=3DArial=20
size=3D2>&gt; <BR>&gt; <BR>&gt; &nbsp;&nbsp; I'm sort of worried since =
I've seen=20
people on this list mentioned <BR>&gt; that D3D breaks their simulation =
(since=20
it gets rid of the extra <BR>&gt; precision by default), but then OPCODE =

requires single precision.<BR>&gt; <BR>&gt; &nbsp;&nbsp; So, what's =
going to=20
give?&nbsp; Are we just supposed to abandon double <BR>&gt; support in =
ODE or=20
should OPCODE be made to work with double for when <BR>&gt; you need =
precision=20
more than space?&nbsp; Can ODE be made to lose less <BR>&gt; precision =
in floats=20
(seems unlikely)?&nbsp; Other solutions?<BR>&gt; <BR>&gt; -tim<BR>&gt; =
<BR>&gt;=20
_______________________________________________<BR>&gt; ODE mailing =
list<BR>&gt;=20
</FONT><A href=3D"mailto:ODE@q12.org"><FONT face=3DArial=20
size=3D2>ODE@q12.org</FONT></A><BR><FONT face=3DArial size=3D2>&gt; =
</FONT><A=20
href=3D"http://q12.org/mailman/listinfo/ode"><FONT face=3DArial=20
size=3D2>http://q12.org/mailman/listinfo/ode</FONT></A><BR><FONT =
face=3DArial=20
size=3D2>&gt; </FONT></BODY></HTML>

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