sdf

stable

Signed Distance Function primitives for 2D and 3D shapes, plus Boolean CSG operations (union, intersection, subtraction) with optional smooth blending.

use plugin sdf::{sdf_circle, sdf_box_2d, sdf_sphere, …}

15 functions Graphics

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Functions (15)

sdf_circle Signed distance from a point to a 2D circle
sdf_box_2d Signed distance from a point to a 2D box
sdf_sphere Signed distance from a point to a 3D sphere
sdf_box_3d Signed distance from a point to a 3D box
sdf_torus Signed distance from a point to a 3D torus
sdf_cylinder Signed distance from a point to a 3D cylinder
sdf_plane Signed distance from a point to a 3D plane
sdf_union CSG union of two distances
sdf_intersection CSG intersection of two distances
sdf_subtraction CSG subtraction of two distances
sdf_smooth_union Smooth CSG union with blending factor
sdf_smooth_intersection Smooth CSG intersection with blending factor
sdf_smooth_subtraction Smooth CSG subtraction with blending factor
sdf_round Round a shape by offsetting its surface
sdf_annular Make a shape hollow (annular shell)

sdf_circle(px, py, cx, cy, radius) → float

Signed distance from a point to a 2D circle

Returns the signed distance from point (px, py) to a circle centered at (cx, cy) with the given radius. Negative values mean the point is inside the circle.

use plugin sdf::{sdf_circle}

let d = sdf_circle(0.0, 0.0, 0.0, 0.0, 5.0)
print(d)  // -5.0 (at center, inside)

let d2 = sdf_circle(7.0, 0.0, 0.0, 0.0, 5.0)
print(d2)  // 2.0 (outside, 2 units past edge)

sdf_box_2d(px, py, cx, cy, half_w, half_h) → float

Signed distance from a point to a 2D box

Returns the signed distance from point (px, py) to an axis-aligned 2D box centered at (cx, cy) with half-extents half_w and half_h.

use plugin sdf::{sdf_box_2d}

let d = sdf_box_2d(0.0, 0.0, 0.0, 0.0, 2.0, 1.0)
print(d)  // -1.0 (inside, closest edge is 1 unit away)

let d2 = sdf_box_2d(4.0, 0.0, 0.0, 0.0, 2.0, 1.0)
print(d2)  // 2.0 (outside, 2 units past the right edge)

sdf_sphere(px, py, pz, cx, cy, cz, radius) → float

Signed distance from a point to a 3D sphere

Returns the signed distance from point (px, py, pz) to a 3D sphere centered at (cx, cy, cz).

use plugin sdf::{sdf_sphere}

let d = sdf_sphere(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 3.0)
print(d)  // -3.0 (at center)

let d2 = sdf_sphere(5.0, 0.0, 0.0, 0.0, 0.0, 0.0, 3.0)
print(d2)  // 2.0 (outside)

sdf_box_3d(px, py, pz, cx, cy, cz, hw, hh, hd) → float

Signed distance from a point to a 3D box

Returns the signed distance from point (px, py, pz) to an axis-aligned 3D box. hw, hh, hd are the half-extents along X, Y, Z respectively.

use plugin sdf::{sdf_box_3d}

let d = sdf_box_3d(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0)
print(d)  // -1.0 (inside unit cube at center)

sdf_torus(px, py, pz, R, r) → float

Signed distance from a point to a 3D torus

Returns the signed distance from point (px, py, pz) to a torus centered at the origin lying in the XZ plane. R is the major radius (center of tube) and r is the minor radius (tube thickness).

use plugin sdf::{sdf_torus}

let d = sdf_torus(3.0, 0.0, 0.0, 3.0, 0.5)
print(d)  // ~-0.5 (on the ring center, inside the tube)

sdf_cylinder(px, py, pz, radius, half_height) → float

Signed distance from a point to a 3D cylinder

Returns the signed distance from point (px, py, pz) to a finite cylinder centered at the origin aligned along the Y axis.

use plugin sdf::{sdf_cylinder}

let d = sdf_cylinder(0.0, 0.0, 0.0, 1.0, 2.0)
print(d)  // -1.0 (at center, inside)

let d2 = sdf_cylinder(2.0, 0.0, 0.0, 1.0, 2.0)
print(d2)  // 1.0 (outside radially)

sdf_plane(px, py, pz, nx, ny, nz, offset) → float

Signed distance from a point to a 3D plane

Returns the signed distance from point (px, py, pz) to an infinite plane defined by normal (nx, ny, nz) and a scalar offset from the origin.

use plugin sdf::{sdf_plane}

// Horizontal plane at y=0, normal pointing up
let d = sdf_plane(0.0, 3.0, 0.0, 0.0, 1.0, 0.0, 0.0)
print(d)  // 3.0 (3 units above the plane)

let d2 = sdf_plane(0.0, -1.0, 0.0, 0.0, 1.0, 0.0, 0.0)
print(d2)  // -1.0 (below the plane)

sdf_union(d1, d2) → float

CSG union of two distances

Returns the union (minimum) of two signed distances. Represents the surface that encloses both shapes.

use plugin sdf::{sdf_circle, sdf_union}

let d1 = sdf_circle(3.0, 0.0, 0.0, 0.0, 2.0)
let d2 = sdf_circle(3.0, 0.0, 5.0, 0.0, 2.0)
let combined = sdf_union(d1, d2)

sdf_intersection(d1, d2) → float

CSG intersection of two distances

Returns the intersection (maximum) of two signed distances. Represents only the region inside both shapes simultaneously.

use plugin sdf::{sdf_sphere, sdf_box_3d, sdf_intersection}

let d1 = sdf_sphere(1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 2.0)
let d2 = sdf_box_3d(1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.5, 1.5, 1.5)
let carved = sdf_intersection(d1, d2)

sdf_subtraction(d1, d2) → float

CSG subtraction of two distances

Subtracts shape d1 from shape d2. The result is the region inside d2 but outside d1.

use plugin sdf::{sdf_sphere, sdf_subtraction}

let outer = sdf_sphere(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 3.0)
let inner = sdf_sphere(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.5)
let shell = sdf_subtraction(inner, outer)

sdf_smooth_union(d1, d2, k) → float

Smooth CSG union with blending factor

Smooth union with blending radius k. When k > 0, the boundary between the two shapes is blended rather than sharply joined. Larger k produces a rounder blend.

use plugin sdf::{sdf_circle, sdf_smooth_union}

let d1 = sdf_circle(2.0, 0.0, 0.0, 0.0, 1.5)
let d2 = sdf_circle(2.0, 0.0, 4.0, 0.0, 1.5)
let blended = sdf_smooth_union(d1, d2, 0.8)

sdf_smooth_intersection(d1, d2, k) → float

Smooth CSG intersection with blending factor

Smooth intersection of two distances with blending radius k. The transition zone at the boundary is smoothed instead of sharp.

use plugin sdf::{sdf_sphere, sdf_smooth_intersection}

let d1 = sdf_sphere(1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 2.0)
let d2 = sdf_sphere(1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 2.0)
let blended = sdf_smooth_intersection(d1, d2, 0.5)

sdf_smooth_subtraction(d1, d2, k) → float

Smooth CSG subtraction with blending factor

Smooth subtraction of d1 from d2 with blending radius k.

use plugin sdf::{sdf_sphere, sdf_smooth_subtraction}

let outer = sdf_sphere(0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 3.0)
let hole = sdf_sphere(0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 1.5)
let result = sdf_smooth_subtraction(hole, outer, 0.3)

sdf_round(d, r) → float

Round a shape by offsetting its surface

Rounds a shape by subtracting r from its distance. This expands the surface outward by r units, giving sharp edges a rounded appearance.

use plugin sdf::{sdf_box_2d, sdf_round}

let box_d = sdf_box_2d(3.0, 0.0, 0.0, 0.0, 2.0, 1.0)
let rounded = sdf_round(box_d, 0.2)  // corners rounded by 0.2

sdf_annular(d, r) → float

Make a shape hollow (annular shell)

Creates a hollow shell (annular) version of a shape. Takes the absolute value of the distance and subtracts r, producing a thin surface at distance r from the original boundary.

use plugin sdf::{sdf_circle, sdf_annular}

let circle_d = sdf_circle(5.0, 0.0, 0.0, 0.0, 3.0)
let ring = sdf_annular(circle_d, 0.1)  // thin ring shell

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