poincare-lib

A GPU-accelerated 3D graphing library for embedding interactive mathematical plots in any wgpu / egui application. Built on viewport-lib.

Plot types

• Surfaces: Cartesian z = f(x, y), parametric, spherical, cylindrical, implicit
• Curves: 3D parametric curves and piecewise polylines
• Scatter / point clouds: per-point colour and size
• Vector fields: arrow glyphs and LIC (line integral convolution)
• Streamlines: seeded integration through a vector field
• Volumes and isosurfaces: scalar field rendering
• Contours and density plots

Styles include solid colour, colourmap, matcap shading, opacity, two-sided lighting, and parameter-space visualisation. Expressions are parsed at runtime with no recompilation needed.

Usage

Add to Cargo.toml:

[dependencies]
poincare-lib = "0.5"
viewport-lib = "0.15"   # for ViewportRenderer and Camera

Minimal example

use poincare_lib::{
    AxisConfig, ColourMode, Domain, GraphSpec, PlotDefinition, PlotSpec,
    PlotStyle, Resolution,
};
use viewport_lib::{Camera, ViewportRenderer};

// 1. Declare the scene. No GPU work happens here.
let spec = GraphSpec {
    axis_config: AxisConfig { show_box: true, show_labels: true, ..Default::default() },
    plots: vec![PlotSpec {
        name: "z = sin(x*y)".into(),
        visible: true,
        domain: Domain { x: -4.0..=4.0, y: -4.0..=4.0, z: -4.0..=4.0 },
        resolution: Resolution { u: 80, v: 80 },
        style: PlotStyle {
            colour_mode: ColourMode::Solid([0.2, 0.65, 1.0, 1.0]),
            two_sided: true,
            ..Default::default()
        },
        definition: PlotDefinition::ExprCartesian {
            expression: "sin(x * y)".into(),
            parameters: vec![],
        },
    }],
};

// 2. Tessellate expressions into CPU-side triangle meshes.
let mut scene = spec.build_scene().expect("build failed");

// 3. Upload meshes to the GPU once at startup (needs wgpu device + ViewportRenderer).
//    GraphScene caches the returned MeshIds for use in build_frame().
scene.upload_meshes(&device, &queue, renderer.resources_mut()).unwrap();

// 4. Each frame, build FrameData and hand it to the renderer.
let mut frame = scene.build_frame(&camera);
frame.camera.viewport_size = [width as f32, height as f32];
frame.camera.pixels_per_point = pixels_per_point;
frame.viewport.background_colour = Some([0.05, 0.05, 0.07, 1.0]);
// ... submit frame to ViewportRenderer via your egui_wgpu callback

See poincare-dvd for a minimal self-contained application that uses this API to render a bouncing 3D graph window, showing that poincare-lib works independently of the main Poincaré application.

Relationship to other crates