Game Porting Toolkit 4 Agentic Skills

import Metal
import Foundation

// MARK: - Metal 4 Residency Set Pattern
// (Core pattern taught by GPTK 4 Resources expert skill)

func buildResidencySet(device: MTLDevice,
                       textures: [MTLTexture],
                       buffers: [MTLBuffer]) throws -> MTLResidencySet {
    // Metal 4: All GPU-accessed resources must be registered in a residency set
    // before any command buffer that uses them is committed.
    let descriptor = MTLResidencySetDescriptor()
    descriptor.label = "GameResidencySet"
    descriptor.initialCapacity = textures.count + buffers.count

    let residencySet = try device.makeResidencySet(descriptor: descriptor)

    for texture in textures {
        residencySet.addAllocation(texture)
    }
    for buffer in buffers {
        residencySet.addAllocation(buffer)
    }
    residencySet.commit()
    return residencySet
}

// MARK: - Encode a command buffer with residency set attached
func encodeFrame(commandQueue: MTLCommandQueue,
                 residencySet: MTLResidencySet,
                 renderPassDescriptor: MTLRenderPassDescriptor,
                 pipelineState: MTLRenderPipelineState,
                 vertexBuffer: MTLBuffer) {
    guard let commandBuffer = commandQueue.makeCommandBuffer() else { return }
    commandBuffer.label = "FrameCommandBuffer"

    // Attach residency set so GPU can access all registered resources
    commandBuffer.addResidencySet(residencySet)

    guard let encoder = commandBuffer.makeRenderCommandEncoder(
        descriptor: renderPassDescriptor) else { return }
    encoder.setRenderPipelineState(pipelineState)
    encoder.setVertexBuffer(vertexBuffer, offset: 0, index: 0)
    encoder.drawPrimitives(type: .triangle, vertexStart: 0, vertexCount: 3)
    encoder.endEncoding()

    commandBuffer.commit()
}

// MARK: - gpucapture CLI invocation (macOS 27, new in GPTK 4 agentic workflow)
// Enables a coding agent to autonomously capture a GPU frame for debugging.
@discardableResult
func captureGPUFrame(outputPath: String, duration: Int = 1) -> Int32 {
    let process = Process()
    process.executableURL = URL(fileURLWithPath: "/usr/bin/gpucapture")
    process.arguments = [
        "--output", outputPath,
        "--frames", String(duration)
    ]
    do {
        try process.run()
        process.waitUntilExit()
    } catch {
        print("gpucapture not available: \(error)")
        return -1
    }
    return process.terminationStatus
}

// MARK: - gpudebug CLI invocation for autonomous analysis
func analyzeCapture(capturePath: String) -> String {
    let process = Process()
    let pipe = Pipe()
    process.executableURL = URL(fileURLWithPath: "/usr/bin/gpudebug")
    process.arguments = ["--analyze", capturePath, "--format", "json"]
    process.standardOutput = pipe
    do {
        try process.run()
        process.waitUntilExit()
        let data = pipe.fileHandleForReading.readDataToEndOfFile()
        return String(data: data, encoding: .utf8) ?? ""
    } catch {
        return "gpudebug not available: \(error)"
    }
}