schwa/geometrylite3d

Installation

Add GeometryLite3D to your Swift package dependencies:

dependencies: [
    .package(url: "https://github.com/schwa/GeometryLite3D.git", from: "0.1.1")
]

Then add it as a dependency to your target:

.target(name: "YourTarget", dependencies: ["GeometryLite3D"])

Features

• AngleF: Type-safe angle representation with degree/radian conversion
• Transform3D: Translation, rotation (quaternion), and scale, with matrix conversion and interpolation
• BoundingBox3D: Axis-aligned bounding box with union, center, size, contains, and transformation
• Projection: Perspective and orthographic projections with standard or reversed 0...1 depth
• LookAt: Camera and view matrices, plus simd_quatf.lookRotation and float4x4.viewMatrix(eye:forward:up:)
• ViewProjection: View matrix, projection, and viewport in one value. Gets the depth direction from the projection and provides project, unproject, ray(through:), and frustum
• Ray3D: Rays from view or clip points, with triangle and box intersection
• Frustum: Conservative bounding box culling
• SIMD Extensions: Rotation, translation, and scale matrices; translation, upperLeft3x3, normalMatrix, isMirroring
• Decomposition: Matrix decomposition into perspective, translation, scale, skew, and rotation
• Utilities: Euler angles, clamping, wrapping, packed 3D vector types, and approximate equality

Usage

Angles

import GeometryLite3D

let angle = AngleF.degrees(45)
let radians = angle.radians  // 0.785398...

let sum = AngleF.degrees(30) + AngleF.degrees(60)

Transformations

// Create transformation matrices
let rotation = float4x4(yRotation: .degrees(45))
let translation = float4x4(translation: [10, 0, 5])
let scale = float4x4(scale: [2, 2, 2])

// Combine transformations
let transform = translation * rotation * scale

Camera and Projection

// Set up camera view
let lookAt = LookAt(position: [0, 5, 10], target: [0, 0, 0], up: [0, 1, 0])
let viewMatrix = lookAt.viewMatrix

// Create perspective projection (clip z 0...1, near at 0)
let projection = PerspectiveProjection(verticalAngleOfView: .degrees(60), depthMode: .standard(zClip: 0.1...1000))
let projectionMatrix = projection.projectionMatrix(aspectRatio: 16.0 / 9.0)

// Orthographic projection
let orthographic = OrthographicProjection(halfHeight: 5, depthMode: .standard(zClip: 0.1...100))

All projections give clip z in 0...1, as Metal expects. The .reversed and .reversedInfinite depth modes put the near plane at 1 and the far plane at 0. To use them, set the depth compare function to .greater and clear depth to 0.

Transforms

let transform = Transform3D(translation: [0, 1, 0], rotation: simd_quatf(angle: .pi / 2, axis: [0, 1, 0]), scale: [2, 2, 2])
let matrix = transform.matrix
let halfway = Transform3D.identity.interpolated(to: transform, amount: 0.5)

Bounding Boxes

let box = BoundingBox3D(min: [-1, -1, -1], max: [1, 1, 1])
let transformedBox = box.transformed(by: transform.matrix)
let combined = box.union(transformedBox)
let center = combined.center

Picking and Culling

let ray = Ray3D(viewPoint: [100, 200], viewSize: [800, 600], viewMatrix: viewMatrix, projectionMatrix: projectionMatrix)
if let hit = ray.intersect(triangle: a, b, c) {
    print(hit.distance, hit.barycentrics)
}

let frustum = Frustum(viewProjection: projectionMatrix * viewMatrix)
let visible = frustum.intersects(box)

Requirements

• Swift 6.1+
• macOS 15.0+, iOS 18.0+, tvOS 18.0+, watchOS 11.0+, visionOS 2.0+

License

This project is licensed under the MIT License - see the LICENSE file for details.

Package Metadata

Repository: schwa/geometrylite3d

Default branch: main

README: README.md