splines/catmull_rom

Centripetal Catmull-Rom splines

Catmull-Rom splines are useful for paths of objects because they preserve velocity through points on the path. This implementation uses the “centripetal” formulation that requires 4 control points, with the curve spanning the two central points.

Types

CatmullRom

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A centripetal Catmull-Rom spline over a generic domain. See new_2d and new_3d to construct one.

pub type CatmullRom(a) {
  CatmullRom(
    points: vec4.Vec4(a),
    scale: fn(a, Float) -> a,
    sum: fn(List(a)) -> a,
  )
}

Constructors

CatmullRom(
  points: vec4.Vec4(a),
  scale: fn(a, Float) -> a,
  sum: fn(List(a)) -> a,
)

Values

new_2d

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pub fn new_2d(
  p0: vec2.Vec2(Float),
  p1: vec2.Vec2(Float),
  p2: vec2.Vec2(Float),
  p3: vec2.Vec2(Float),
) -> CatmullRom(vec2.Vec2(Float))

Constructs a 2d Catmull-Rom spline, given the four control-points as Vec2fs.

new_3d

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pub fn new_3d(
  p0: vec3.Vec3(Float),
  p1: vec3.Vec3(Float),
  p2: vec3.Vec3(Float),
  p3: vec3.Vec3(Float),
) -> CatmullRom(vec3.Vec3(Float))

Constructs a 3d Catmull-Rom spline, given the four control-points as Vec3fs.

sample

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pub fn sample(curve: CatmullRom(a), t: Float) -> a

Samples any Catmull-Rom spline at time t, where 0.0 <= t <= 1.0 (usually).