macOS Metal 空间工程师

// Metal 渲染核心架构
class MetalGraphRenderer {
    private let device: MTLDevice
    private let commandQueue: MTLCommandQueue
    private var pipelineState: MTLRenderPipelineState
    private var depthState: MTLDepthStencilState

    // 实例化节点渲染
    struct NodeInstance {
        var position: SIMD3<Float>
        var color: SIMD4<Float>
        var scale: Float
        var symbolId: UInt32
    }

    // GPU 缓冲区
    private var nodeBuffer: MTLBuffer        // 每个实例的数据
    private var edgeBuffer: MTLBuffer        // 边连接关系
    private var uniformBuffer: MTLBuffer     // 视图/投影矩阵

    func render(nodes: [GraphNode], edges: [GraphEdge], camera: Camera) {
        guard let commandBuffer = commandQueue.makeCommandBuffer(),
              let descriptor = view.currentRenderPassDescriptor,
              let encoder = commandBuffer.makeRenderCommandEncoder(descriptor: descriptor) else {
            return
        }

        // 更新 uniform 数据
        var uniforms = Uniforms(
            viewMatrix: camera.viewMatrix,
            projectionMatrix: camera.projectionMatrix,
            time: CACurrentMediaTime()
        )
        uniformBuffer.contents().copyMemory(from: &uniforms, byteCount: MemoryLayout<Uniforms>.stride)

        // 实例化绘制节点
        encoder.setRenderPipelineState(nodePipelineState)
        encoder.setVertexBuffer(nodeBuffer, offset: 0, index: 0)
        encoder.setVertexBuffer(uniformBuffer, offset: 0, index: 1)
        encoder.drawPrimitives(type: .triangleStrip, vertexStart: 0,
                              vertexCount: 4, instanceCount: nodes.count)

        // 用几何着色器绘制边
        encoder.setRenderPipelineState(edgePipelineState)
        encoder.setVertexBuffer(edgeBuffer, offset: 0, index: 0)
        encoder.drawPrimitives(type: .line, vertexStart: 0, vertexCount: edges.count * 2)

        encoder.endEncoding()
        commandBuffer.present(drawable)
        commandBuffer.commit()
    }
}

// 用 Compositor Services 向 Vision Pro 推流
import CompositorServices

class VisionProCompositor {
    private let layerRenderer: LayerRenderer
    private let remoteSpace: RemoteImmersiveSpace

    init() async throws {
        // 用立体配置初始化 compositor
        let configuration = LayerRenderer.Configuration(
            mode: .stereo,
            colorFormat: .rgba16Float,
            depthFormat: .depth32Float,
            layout: .dedicated
        )

        self.layerRenderer = try await LayerRenderer(configuration)

        // 搭建远程沉浸空间
        self.remoteSpace = try await RemoteImmersiveSpace(
            id: "CodeGraphImmersive",
            bundleIdentifier: "com.cod3d.vision"
        )
    }

    func streamFrame(leftEye: MTLTexture, rightEye: MTLTexture) async {
        let frame = layerRenderer.queryNextFrame()

        // 提交立体纹理
        frame.setTexture(leftEye, for: .leftEye)
        frame.setTexture(rightEye, for: .rightEye)

        // 带上深度信息做遮挡处理
        if let depthTexture = renderDepthTexture() {
            frame.setDepthTexture(depthTexture)
        }

        // 把帧提交到 Vision Pro
        try? await frame.submit()
    }
}

// Vision Pro 的注视和手势处理
class SpatialInteractionHandler {
    struct RaycastHit {
        let nodeId: String
        let distance: Float
        let worldPosition: SIMD3<Float>
    }

    func handleGaze(origin: SIMD3<Float>, direction: SIMD3<Float>) -> RaycastHit? {
        // 执行 GPU 加速的射线检测
        let hits = performGPURaycast(origin: origin, direction: direction)

        // 找到最近的命中
        return hits.min(by: { $0.distance < $1.distance })
    }

    func handlePinch(location: SIMD3<Float>, state: GestureState) {
        switch state {
        case .began:
            // 开始选择或操作
            if let hit = raycastAtLocation(location) {
                beginSelection(nodeId: hit.nodeId)
            }

        case .changed:
            // 更新操作状态
            updateSelection(location: location)

        case .ended:
            // 提交操作
            if let selectedNode = currentSelection {
                delegate?.didSelectNode(selectedNode)
            }
        }
    }
}

// GPU 上的力导向布局算法
kernel void updateGraphLayout(
    device Node* nodes [[buffer(0)]],
    device Edge* edges [[buffer(1)]],
    constant Params& params [[buffer(2)]],
    uint id [[thread_position_in_grid]])
{
    if (id >= params.nodeCount) return;

    float3 force = float3(0);
    Node node = nodes[id];

    // 所有节点之间的斥力
    for (uint i = 0; i < params.nodeCount; i++) {
        if (i == id) continue;

        float3 diff = node.position - nodes[i].position;
        float dist = length(diff);
        float repulsion = params.repulsionStrength / (dist * dist + 0.1);
        force += normalize(diff) * repulsion;
    }

    // 沿着边的引力
    for (uint i = 0; i < params.edgeCount; i++) {
        Edge edge = edges[i];
        if (edge.source == id) {
            float3 diff = nodes[edge.target].position - node.position;
            float attraction = length(diff) * params.attractionStrength;
            force += normalize(diff) * attraction;
        }
    }

    // 施加阻尼并更新位置
    node.velocity = node.velocity * params.damping + force * params.deltaTime;
    node.position += node.velocity * params.deltaTime;

    // 写回结果
    nodes[id] = node;
}

# 创建带 Metal 支持的 Xcode 项目
xcodegen generate --spec project.yml

# 添加所需框架
# - Metal
# - MetalKit
# - CompositorServices
# - RealityKit（用于空间锚点）