GU Envmap "issue"

[Shazz]

Hello,

That's not exactly an issue, more a lack of understanding....

Let's say I've got a sphere, which is envmapped (as done i nthe PSPSDK sample) using a classic environment mapping texture (kind of spherical glow). So that works.

But then using the world matrix (sceGumMatrixMode(GU_MODEL);) I set a rotation on the Y axis (So I want the sphere to turn on its Y axis, not the view/camera), I did not apply any rotation to the 2 lights used for the envmap, but visually speaking the "glow" texture is rotating too, and I don't see why (and I don't want too)....

So I understood that playing with the x,y components of the envmap lights, I can set a rotation of the texture. And with the z (=tx,ty) components I can translate the texture on X,Y axis.
So as my rotation around the Y axis, playing with the tx value, I should be able to counter the rotation but, given the MODEL matrix, how can I compute the opposite value ?

Or maybe I'm lost since the beginning.... Eh eh I never implemented anything else the na "fake" envmap based on the normals :D

thanks for giving me a little envmap course :D