SwiftGLTF

A project that enables using glTF files in Swift.

Features

SwiftGLTF offers:

• High-performance rendering fully powered by Metal
• Lightweight and modular design, easy to integrate into any Swift project
• Wide glTF specification support, covering materials, animations, cameras, and more
• Optimized GPU resource management, enabling fast and efficient rendering on Apple platforms

Performance

SwiftGLTF has been tested using the official NodePerformanceTest model from the glTF Sample Assets, demonstrating the following performance results: This model contains:

• 10,000 nodes
• 10,000 meshes / primitives / materials
• 100 textures with randomized usage

Despite the extremely high node and material count, SwiftGLTF is capable of:

• Maintaining a stable 60 FPS during rendering on supported Apple platforms

MacBookPro (M1 Pro)

swiftgltf_performance_test_mac.mov

iPhone16 (A18)

swiftgltf_performance_test_iphone.mov

Usage

Platform

• iOS 16.0+
• macOS 13.0+
• Metal 3 & 4

Installation

Swift Package Manager

dependencies: [
    .package(url: "https://github.com/nhiroyasu/SwiftGLTF.git", branch: "main")
]

Sample Code

UIKit

import SwiftGLTF

let gltfUrl = // URL to your glTF or GLB file
let gltfView = GLTFView(frame: view.frame)
await gltfView.load(gltf: gltfUrl)
view.addSubview(gltfView)

SwiftUI

import SwiftGLTF

var body: some View {
    @State private var gltfUrl = // URL to your glTF or GLB file
    GLTFSwiftUIView(url: gltfUrl)
}

Supported glTF Features

• Unsupported features are planned to be added in future updates.

File Formats

Format	Supported
glTF Binary (.glb)	✅
glTF JSON (.gltf)	✅

Buffer Formats

Format	Supported
External .bin file	✅
Embedded (data URI in .gltf)	✅

Image Formats

Format	Supported
PNG	✅
JPEG	✅
KTX2	❌

Mesh Compression

Extension	Supported
KHR_draco_mesh_compression	❌

PBR Materials (metallic-roughness)

Property	Supported
baseColorFactor	✅
baseColorTexture	✅
metallicFactor	✅
roughnessFactor	✅
metallicRoughnessTexture	✅

Additional Material Properties

Property	Supported
normalTexture	✅
occlusionTexture	✅
emissiveTexture	✅
emissiveFactor	✅
alphaMode	✅
alphaCutoff	✅
doubleSided	✅
extensions	✅ (see blow)

Supported Extensions for Materials

• KHR_materials_transmission
• KHR_materials_volume
• KHR_materials_ior
• KHR_materials_clearcoat
• KHR_materials_specular
• KHR_materials_sheen
• KHR_materials_unlit
• KHR_materials_variants
• KHR_texture_transform

Vertex Attributes

Attribute	Supported
POSITION	✅
NORMAL	✅
TANGENT	✅
TEXCOORD_0	✅
TEXCOORD_1	✅
COLOR_0	✅
JOINTS_0	✅
WEIGHTS_0	✅

Node Hierarchy and Transforms

Feature	Supported
Node hierarchy	✅
matrix (4x4 transform matrix)	✅
translation / rotation / scale (TRS)	✅

Animation

Channel	Supported
translation	✅
rotation	✅
scale	✅
morph target weights	✅

Scenes

Feature	Supported
Multiple scenes	✅

Cameras

Feature	Supported
Perspective	✅
Orthographic	✅

Build

Sample Project

• You can build the sample project by opening SwiftGLTFSample.xcodeproj.

Project Structure

SwiftGLTF

• Provides GLTFView and GLTFMetalView components to display glTF files in UIKit and SwiftUI views.

SwiftGLTFRenderer

• A library for rendering glTF files using Metal.

SwiftGLTFParser

• A library that parses glTF and converts it into MDLAsset for use in Swift.

SwiftGLTFCore

• A library that defines the core data structures of glTF.

MikkTSpace

• Performs normal vector computation for glTF
• Based on mmikk/MikkTSpace