SwiftGLTF

A project that enables using glTF files in Swift.

<div> <img height="400" alt="preview1" src="https://github.com/user-attachments/assets/c84b561e-7260-4221-8535-b3b894dfe660" /> <img height="400" alt="preview2" src="https://github.com/user-attachments/assets/ca5b82de-4fc1-4b0e-8a61-dc1c855a1e3b" /> <img height="400" alt="preview1" src="https://github.com/user-attachments/assets/9bc8de85-b574-431e-ac05-49439461c704" /> </div>

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)

https://github.com/user-attachments/assets/07112f37-ad10-40d4-b14a-dbed75b3cd17

iPhone16 (A18)

https://github.com/user-attachments/assets/0cba90bc-c30a-467b-bbeb-3e26714e4960

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