CreatePLYMesh

[wahn]

From the pbrt-v3 Input File Format documentation:

Shapes are specified with the Shape directive:

> rg 'Shape "plymesh"' assets/scenes/veach-mis/mis.pbrt
53:    Shape "plymesh" "string filename" ["geometry/plate1.ply"]
58:    Shape "plymesh" "string filename" ["geometry/plate2.ply"]
63:    Shape "plymesh" "string filename" ["geometry/plate3.ply"]
68:    Shape "plymesh" "string filename" ["geometry/plate4.ply"]
73:    Shape "plymesh" "string filename" ["geometry/floor.ply"]

A few additional shapes are available for convenience; these immediately convert themselves to instances of the Triangle shape when the scene description is loaded.

pbrt can also directly read triangle meshes specified in the PLY mesh file format, via the "plymesh" shape.

There are a couple of scene files using this method, so it would be nice to implement the C++ function CreatePLYMesh:

std::vector<std::shared_ptr<Shape>> CreatePLYMesh(
    const Transform *o2w, const Transform *w2o, bool reverseOrientation,
    const ParamSet &params,
    std::map<std::string, std::shared_ptr<Texture<Float>>> *floatTextures =
        nullptr);

[wahn]

Since commit cb3cf4f can we read the header of PLY files:

> ./target/release/examples/pest_test -i assets/scenes/veach-mis/mis.pbrt
...
header = Header { encoding: BinaryLittleEndian, 
                  version: Version { major: 1, minor: 0 }, obj_infos: [], 
                  elements: {"vertex": ElementDef { name: "vertex", count: 4, properties: {"x": PropertyDef { name: "x", data_type: Scalar(Float) }, "y": PropertyDef { name: "y", data_type: Scalar(Float) }, "z": PropertyDef { name: "z", data_type: Scalar(Float) }} }, 
                             "face": ElementDef { name: "face", count: 2, properties: {"vertex_indices": PropertyDef { name: "vertex_indices", data_type: List(UChar, Int) }} }}, 
                  comments: ["generated by Mitsuba 0.5.0"] }
...

[wahn]

The function seems to import the geometry correctly, even so the test scene does not render the same as using the C++ counterpart:

See issue #28 ...

But because pub fn create_ply_mesh(...) is implemented on the Rust side, let's close the issue for now.