[ODE] Spaceship movement.

Michael Molkenthin molle at michael-molkenthin.de
Wed Jun 21 00:50:15 MST 2006

Thank you Jon for the reply :)

On Tue, 20 Jun 2006, Jon Watte (ODE) wrote:
> Unless your mass is really high, that's probably a way too large 
> number (by several digits).
okay, perhaps i have to look at masses again

>> Another point that i had to object: My Matrices initially were 
>> used to transform the mesh to world space. ODE seems to use 
>> matrices transforming the world to the local object/mesh space. 
>> So i am transposing the matrices 
> No. Instead, ODE stores the matrices in a different order than your 
> graphics library.
> See http://www.mindcontrol.org/~hplus/graphics/matrix-layout.html 
> for more information (on DX, OpenGL, ODE and others).

interesting link - perhaps this part from it is important 
to me:

"The ODE documentation doesn't use many vectors or matrices in print at 
all, so it's hard to tell whether it intends to use row vectors or column 
vectors. However, the storage of rotation matrices is such, that a 
translation (should it be in the matrix), would live in offsets 3, 7 and 
11. (ODE doesn't actually look at these values; it leaves them un-touched 
for alignment reasons).

This means that you have to transpose a matrix you get out of ODE, if you 
want to put it back into OpenGL or DirectX, because the combination of 
convention and storage for ODE work out to be the opposite of that same 
combination for the latter two."

so long,

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