Applying texture on a sphere [raytracing]

I don't have my code at the moment, but I remember that there is a simple addition to the intersection formula that gives u,v parameters of the intersection point. You just have to specify a couple of vectors defining the orientation of te sphere.

Those uv can then be scaled/translated/rotated/clipped any way you want and in the end you do a get(u,v) on the texture (where u and v are presumably normalized so that 0 is completely left and 1 is completely right - same thing for top and bottom).

Hope this helps

I have to specify a couple of vector to define the sphere ? On the 0.x axe and 0.y axe ? And is it on a cartesian reference ?

This should be of some help...

http://www.flipcode.com/archives/Raytracing_Topics_Techniques-Part_6_Textures_Cameras_and_Speed.shtml

I have to specify a couple of vector to define the sphere ? On the 0.x axe and 0.y axe ? And is it on a cartesian reference ?

I think that you need to define at least the north (and perhaps even the west) vectors, so that rotations applied to the sphere reflect on the texture orientation...

Two words: spherical coordinates.
One link: sphere texture mapping.