Crate nsi

Expand description

§Nodal Scene Interface – ɴsɪ

A flexible, modern API for offline 3D renderers

Nsɪ is built around the concept of nodes. Each node has a unique handle to identify it. It also has a type which describes its intended function in the scene.

Nodes are abstract containers for data. The interpretation depends on the node type. Nodes can also be connected to each other to express relationships.

Data is stored on nodes as attributes. Each attribute has a name which is unique on the node and a type which describes the kind of data it holds (strings, integer numbers, floating point numbers, etc).

Relationships and data flow between nodes are represented as connections. Connections have a source and a destination. Both can be either a node or a specific attribute of a node. There are no type restrictions for connections in the interface itself. It is acceptable to connect attributes of different types or even attributes to nodes. The validity of such connections depends on the types of the nodes involved.

What we refer to as the ɴsɪ has two major components:

Methods to create nodes, attributes and their connections. These are attached to a rendering Context.
Nodes understood by the renderer.

Much of the complexity and expressiveness of the interface comes from the supported nodes.

The first part was kept deliberately simple to make it easy to support multiple ways of creating nodes.

§Examples

// Create a context to send the scene to.
let ctx = nsi::Context::new(None).expect("Could not create NSI context.");

// Create a dodecahedron.

// 12 regular pentagon faces.
let face_index: [i32; 60] = [
    0, 16, 2, 10, 8, 0, 8, 4, 14, 12, 16, 17, 1, 12, 0, 1, 9, 11, 3, 17, 1,
    12, 14, 5, 9, 2, 13, 15, 6, 10, 13, 3, 17, 16, 2, 3, 11, 7, 15, 13, 4,
    8, 10, 6, 18, 14, 5, 19, 18, 4, 5, 19, 7, 11, 9, 15, 7, 19, 18, 6,
];

// Golden ratio.
let phi: f32 = 0.5 * (1.0 + 5_f32.sqrt());

// Golden ratio conjugate.
let phi_c: f32 = phi - 1.0;

// 20 points @ 3 vertices.
let positions: [f32; 60] = [
    1., 1., 1., 1., 1., -1., 1., -1., 1., 1., -1., -1., -1., 1., 1., -1.,
    1., -1., -1., -1., 1., -1., -1., -1., 0., phi_c, phi, 0., phi_c, -phi,
    0., -phi_c, phi, 0., -phi_c, -phi, phi_c, phi, 0., phi_c, -phi, 0.,
    -phi_c, phi, 0., -phi_c, -phi, 0., phi, 0., phi_c, phi, 0., -phi_c,
    -phi, 0., phi_c, -phi, 0., -phi_c,
];

// Create a new mesh node and call it 'dodecahedron'.
ctx.create("dodecahedron", nsi::MESH, None);

// Connect the 'dodecahedron' node to the scene's root.
ctx.connect("dodecahedron", None, nsi::ROOT, "objects", None);

// Define the geometry of the 'dodecahedron' node.
ctx.set_attribute(
    "dodecahedron",
    &[
        nsi::points!("P", &positions),
        nsi::integers!("P.indices", &face_index),
        // 5 vertices per each face.
        nsi::integers!("nvertices", &[5; 12]),
        // Render this as a subdivison surface.
        nsi::string!("subdivision.scheme", "catmull-clark"),
        // Crease each of our 30 edges a bit.
        nsi::integers!("subdivision.creasevertices", &face_index),
        nsi::floats!("subdivision.creasesharpness", &[10.; 30]),
    ],
);

§More Examples

These can be found in the examples folder.

All the examples in this crate require a (free) 3Delight installation to run!

§Interactive

Demonstrates using the FnStatus callback closure during rendering and a channel for communicating between main- and rendering thread(s).

§Jupyter

Render directly into a Jupyter notebook.

Follow these instructions to get a Rust Jupyter kernel up and running first.

§Output

This is a full output example showing color conversion and writing data out to 8bit/channel PNG and 32bit/channel (float) OpenEXR formats.

§Volume

Demonstrates rendering an OpenVDB asset. Mostly through the toolbelt helpers.

§Getting Pixels

The crate has support for streaming pixels from the renderer, via callbacks (i.e. closures) during and/or after rendering via the output module. This module is enabled through the feature of the same name (see below).

It should be straightforward to create an async implementation with this or use channels to stream pixels back to a main thread (see the interactive example).

§Cargo Features

output – Add support for streaming pixels from the renderer to the calling context via closures.
jupyter – Add support for rendering to Jupyter notebooks (when using a Rust Jupyter kernel).
toolbelt – Add convenience methods that work with a Context.
delight – Add some nodes & shaders specifi to 3Delight.
nightly – Enable some unstable features (suggested if you build with a nightly toolchain)
ustr_handles – use ustr for node handles. This will give a you a speed boost if your node names aren’t changing while an app using ɴsɪ is running but is not advised otherwise (ustr are never freed).

§Linking Style

The 3Delight dynamic library (lib3delight) can either be linked to during build or loaded at runtime.

By default the lib is loaded at runtime.

Load lib3deligh at runtime (default). This has several advantages:
1. If you ship your application or library you can ship it without the library. It can still run and will print an informative error if the library cannot be loaded.
2. A user can install an updated version of the renderer and stuff will ‘just work’.
Dynamically link against lib3delight.
- lib3delight becomes a dependency. If it cannot be found your lib/app will not load/start.
- The feature is called link_lib3delight.
- You should disable default features (they are not needed/used) in this case:
```
[dependencies]
nsi = { version = "0.7", default-features = false, features = ["link_lib3delight"] }
```
Download lib3delight during build.
- lib3delight is downloaded during build. Note that this may be an outdated version. This feature mainly exists for CI purposes.
- The feature is called download_lib3delight.

Modules§

argument: Optional arguments passed to methods of an ɴsɪ context.
context: An ɴsɪ context.
delight: Helpers for using ɴsɪ with 3Delight.
jupyter: Jupyter Notebook support.
node: Standard ɴsɪ node types.
output: Output driver callbacks.
toolbelt: Convenience methods for an ɴsɪ context.

Macros§

callback: Create a Callback argument.
color: Create a Color argument.
colors: Create a Colors array argument.
double: Create a Double precision argument.
double_matrices: Create a DoubleMatrices row-major, 4×4 transformation matrices argument. Each matrix is given as 16 f64 values.
double_matrix: Create a DoubleMatrix row-major, 4×4 transformation matrix argument. The matrix is given as 16 f64 values.
doubles: Create a Doubles precision array argument.
float: Create a Float argument.
floats: Create a Floats array argument.
integer: Create a Integer argument.
integers: Create a Integers array argument.
matrices: Create a Matrices row-major, 4×4 transformation matrices argument. Each matrix is given as 16 f32 values.
matrix: Create a Matrix row-major, 4×4 transformation matrix argument. The matrix is given as 16 f32 values.
normal: Create a Normal argument.
normals: Create a Normals array argument.
point: Create a Point argument.
points: Create a Points array argument.
reference: Create a Reference argument.
references: Create a Reference array argument.
string: Create a String argument.
strings: Create a String array argument.
vector: Create a Vector argument.
vectors: Create a Vectors array argument.

Structs§

Arg: An (optional) argument passed to a method of Context.
Callback: See ArgData for details.
Color: See ArgData for details.
Colors: See ArgData for details.
Context: An ɴꜱɪ Context.
Double: See ArgData for details.
DoubleMatrices: See ArgData for details.
DoubleMatrix: See ArgData for details.
Doubles: See ArgData for details.
ErrorCallback: Wrapper to pass a FnError closure to a Context.
FinishCallback: Wrapper to pass an FnFinish closure to an OutputDriver node.
Float: See ArgData for details.
Floats: See ArgData for details.
Integer: See ArgData for details.
Integers: See ArgData for details.
Layer: Description of an OutputLayer node inside a flat, raw pixel.
Matrices: See ArgData for details.
Matrix: See ArgData for details.
Normal: See ArgData for details.
Normals: See ArgData for details.
OpenCallback: Wrapper to pass an FnOpen closure to an OutputDriver node.
PixelFormat: Accessor for the pixel format the renderer sends in FnOpen, FnWrite and FnFinish
Point: See ArgData for details.
Points: See ArgData for details.
Reference: See ArgData for details.
References: See ArgData for details.
StatusCallback: Wrapper to pass a FnStatus closure to a Context.
String: See ArgData for details.
Strings: See ArgData for details.
Vector: See ArgData for details.
Vectors: See ArgData for details.
WriteCallback: Wrapper to pass an FnWrite closure to an OutputDriver node.

Enums§

Action: The render action to perform when calling render_control().
ArgData: A variant describing data passed to the renderer.
Error: An error type the callbacks return to communicate with the renderer.
LayerDepth: The depth (number and type of channels) a pixel in a Layer is composed of.
RenderStatus: The status of a interactive render session.

Constants§

ALL: Wildcard node that references all existing nodes at once (.all).
ATTRIBUTES: Container for generic attributes (e.g. visibility). Documentation.
CURVES: Linear, b-spline and Catmull-Rom curves. Documentation.
CYLINDRICAL_CAMERA: A cylindrical camera. Documentation.
ENVIRONMENT: Geometry type to define environment lighting. Documentation.
FACESET: Assign attributes to part of a mesh, curves or particles. Documentation.
FISHEYE_CAMERA: A fisheye camera. Documentation.
GLOBAL: Global settings node (.global). Documentation.
INSTANCES: Specifies instances of other nodes. Documentation.
MESH: Polygonal mesh or subdivision surface. Documentation.
ORTHOGRAPHIC_CAMERA: An orthographic camera. Documentation.
OUTPUT_DRIVER: A target where to output rendered pixels. Documentation.
OUTPUT_LAYER: Describes one render layer to be connected to an outputdriver node. Documentation.
PARTICLES: Collection of particles. Documentation.
PERSPECTIVE_CAMERA: A perspective camera. Documentation.
PLANE: An infinite plane. Documentation.
PROCEDURAL: Geometry to be loaded or generated in delayed fashion. Documentation.
ROOT: The scene’s root (.root). Documentation.
SCREEN: Describes how the view from a camera node will be rasterized into an outputlayer node. Documentation.
SET: Expresses relationships of groups of nodes. Documentation.
SHADER: ᴏsʟ shader or layer in a shader group. Documentation.
SPHERICAL_CAMERA: A spherical camera. Documentation.
TRANSFORM: Transformation to place objects in the scene. Documentation.
VOLUME: A volume loaded from an OpenVDB file. Documentation.

Statics§

FERRIS: This is the name of the crate’s built-in output driver that understands the “closure.*” attributes.

Traits§

CallbackPtr
FnError: A closure which is called to inform about the errors during scene defintion or a render.
FnFinish: A closure which is called once per OutputDriver instance.
FnOpen: A closure which is called once per OutputDriver instance.
FnStatus: A closure which is called to inform about the status of an ongoing render.
FnWrite: A closure which is called for each bucket of pixels the OutputDriver instance sends during rendering.

Type Aliases§

ArgSlice: A slice of (optional) arguments passed to a method of Context.
ArgVec: A vector of (optional) arguments passed to a method of Context.

Crate nsi

Crate nsi Copy item path

§Nodal Scene Interface – ɴsɪ

§Examples

§More Examples

§Interactive

§Jupyter

§Output

§Volume

§Getting Pixels

§Cargo Features

§Linking Style

Modules§

Macros§

Structs§

Enums§

Constants§

Statics§

Traits§

Type Aliases§

Crate nsi