The following table is an extension to the previous. These variables give information about the intersection point for texture mapping. They are defined when the ray has hit a textured object:
|miVector *||tex_list||list of texture coordinates|
|miVector *||bump_x_list||list of X bump basis vectors|
|miVector *||bump_y_list||list of Y bump basis vectors|
|miVector||tex||texture coord (tex shaders)|
|miVector||motion||interpolated motion vector|
|miVector *||derivs||list of surface derivatives|
tex_listand copying it to
tex. Texture spaces in a miBox may have arbitrary dimension. The
tex_listentries contain only coordinates from up to three dimensional texture spaces. For higher dimensions, the
tex_listentries are set to zero and the function mi_texture_interpolate should be used instead.
.x, .y, .z, .x,and so on. In contrast to regular geometry hair uses scalars not vectors, and their number does not have to be a multiple of three. It is often useful to cast
miScalarpointer for access.
derivs … derivscontain ∂x⁄∂u, ∂x⁄∂v, ∂²x⁄∂u², ∂²x⁄∂v², ∂²x⁄∂u∂v, respectively. Here x denotes the intersection point. For polygonal objects the surface derivatives are taken from the .mi file. If the object has no first derivative vectors, the first two vectors are null vectors. If the object has no second derivative vectors, the last three vectors are null vectors. Since surface derivatives are calculated approximately, the vectors ∂x⁄∂u, ∂x⁄∂v and the normal vector at the intersection point are not necessarily orthogonal to each other.
derivscontains the interpolated tangent at the point of intersection.
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