SimpleShaderRenderer.swift

func draw(in view: MTKView) {
    guard let drawable = view.currentDrawable else { return }
    
    let renderPassDescriptor = MTLRenderPassDescriptor()
    renderPassDescriptor.colorAttachments[0].texture = drawable.texture
    renderPassDescriptor.colorAttachments[0].loadAction = .clear
    renderPassDescriptor.colorAttachments[0].storeAction = .store
    renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(0.0, 0.0, 0.0, 1.0)
    
    let commandBuffer = commandQueue.makeCommandBuffer()!
    let commandEncoder = commandBuffer.   
          makeRenderCommandEncoder(descriptor: renderPassDescriptor)!
   
    commandEncoder.setRenderPipelineState(pipelineState)
    
    commandEncoder.setVertexBuffer(node.buffer, offset: 0, index: 0)
    
    commandEncoder.drawPrimitives(type: .triangleStrip vertexStart: 0, vertexCount: node.vertexCount)
    
    commandEncoder.endEncoding()
    commandBuffer.present(drawable)
    commandBuffer.commit()
}