I was trying to join discord so that I can ask why is my Chapter1 playground not working.
**import** MetalKit
**guard** **let** device = MTLCreateSystemDefaultDevice() **else** {
fatalError("GPU is not supported")
}
**let** frame = CGRect(x: 0, y: 0, width: 600, height: 600)
**let** view = MTKView(frame: frame, device: device)
view.clearColor = MTLClearColor(red: 1, green: 1, blue: 0.8, alpha: 1)
//1
**let** allocator = MTKMeshBufferAllocator(device: device)
//2
**let** mdlMesh = MDLMesh(
sphereWithExtent: [0.75, 0.75, 0.75],
segments: [100, 100],
inwardNormals: **false**,
geometryType: .triangles,
allocator: allocator
)
//3
**let** mesh = **try** MTKMesh(mesh: mdlMesh, device: device)
**guard** **let** commandQueue = device.makeCommandQueue() **else** {
fatalError("Could not create a command queue")
}
**let** shader = """
#include <metal_stdlib>
using namespace metal;
struct VertexIn {
float4 position [[attribute(0)]];
};
vertex float4 vertex_main(const VertexIn vertex_in [[stage_in]]) {
return vertex_in.position;
}
fragment float4 fragment_main() {
return float4(1, 0, 0, 1);
}
"""
**let** library = **try** device.makeLibrary(source: shader, options: **nil**)
**let** vertexFunction = library.makeFunction(name: "vertex_main")
**let** fragmentFunction = library.makeFunction(name: "fragment_main")
**let** pipelineDescriptor = MTLRenderPipelineDescriptor()
pipelineDescriptor.colorAttachments[0].pixelFormat = .bgra8Unorm
pipelineDescriptor.vertexFunction = vertexFunction
pipelineDescriptor.fragmentFunction = fragmentFunction
pipelineDescriptor.vertexDescriptor = MTKMetalVertexDescriptorFromModelIO(mesh.vertexDescriptor)
**let** pipelineState = **try** device.makeRenderPipelineState(descriptor: pipelineDescriptor)
//1
**guard** **let** commandBuffer = commandQueue.makeCommandBuffer(),
// 2
**let** renderPassDescriptor = view.currentRenderPassDescriptor,
// 3
**let** renderEncoder = commandBuffer.makeRenderCommandEncoder(descriptor: renderPassDescriptor)
**else** { fatalError() }
renderEncoder.setRenderPipelineState(pipelineState)
renderEncoder.setVertexBuffer(mesh.vertexBuffers[0].buffer, offset: 0, index: 0)
**guard** **let** submesh = mesh.submeshes.first **else** {
fatalError()
}
renderEncoder.drawIndexedPrimitives(type: .triangle, indexCount: submesh.indexCount, indexType: submesh.indexType, indexBuffer: submesh.indexBuffer.buffer, indexBufferOffset: 0)
// 1
renderEncoder.endEncoding()
// 2
**guard** **let** drawable = view.currentDrawable **else** {
fatalError()
}
//3
commandBuffer.present(drawable)
commandBuffer.commit()
PlaygroundPage.current.liveView = view```