Adding a few functions to the python bindings

[saeedhd96]

Hi,

I can (and I normally do) add new python bindings for the functions in C++ that are not already introduced in the bindings.
However, there are some functions that I think are very useful for everybody and would be awesome if you could add it too, so everybode doesn't have to touch the mitsuba code.

1. In ShapePtr::sample_position()
2. In BSDF::eval_diffuse_reflectance()

Thanks,
-Saeed

[saeedhd96]

Oh I just noticed the eval_diffuse_reflectance is recently added. So just number 1.

[saeedhd96]

This is how I do it myself in the shape_v.cpp:

mitsuba3/src/render/python/shape_v.cpp

Line 135 in 199b607

if constexpr (dr::is_array_v<ShapePtr>) {

if constexpr (ek::is_array_v<ShapePtr>) {
    py::object ek       = py::module_::import("enoki"),
               ek_array = ek.attr("ArrayBase");

    py::class_<ShapePtr> cls(m, "ShapePtr", ek_array);
    //BEGIN CHANGED
    cls
    .def("sample_position",
            [](ShapePtr ptr, Float time, const Point2f &sample, Mask active) {
                return ptr->sample_position(time, sample, active);
            },
            "time"_a, "sample"_a, "active"_a = true,
            D(Shape, sample_position));        
    //END CHANGED        
    bind_shape_generic<ShapePtr>(cls);
}

But It'd be nice to have this in the version of mitsuba we get through pip too (pip is more convienient since it can be easily imported on any cluster and container)

[saeedhd96]

Hi, just a quick reminder on this. Is this possible to do?

This is helpful when calling sample position on the result of scene.shapes_dr(), 'cause curretnly it throws an error saying ShapePtr doesn't have sample_position().

[njroussel]

Indeed! Nice catch, I'll add that right away.

[njroussel]

The missing bindings have been added in this commit: bdce950
They will be available in the pip build of the next release.

[saeedhd96]

Amazing! Thanks!