added memory

memory_part_2.playground/Contents.swift

@@ -0,0 +1,34 @@
+
+import MetalKit
+
+guard let device = MTLCreateSystemDefaultDevice() else { fatalError() }
+
+let count = 2000
+let length = count * MemoryLayout< Float >.stride
+
+//  1. makeBuffer(length:)
+//
+//let myBuffer = device.makeBuffer(length: length, options: [])
+//print(myBuffer.contents())
+
+//  2. makeBuffer(bytes:)
+//
+//var myVector = [Float](repeating: 0, count: count)
+//let myBuffer = device.makeBuffer(bytes: myVector, length: length, options: [])
+//withUnsafePointer(to: &myVector) { print($0) }
+//print(myBuffer.contents())
+
+//  3. makeBuffer(bytesNoCopy:)
+//
+var memory: UnsafeMutableRawPointer? = nil
+let alignment = 0x1000
+let allocationSize = (length + alignment - 1) & (~(alignment - 1))
+posix_memalign(&memory, alignment, allocationSize)
+let myBuffer = device.makeBuffer(bytesNoCopy: memory!,
+                                 length: allocationSize,
+                                 options: [],
+                                 deallocator: { (pointer: UnsafeMutableRawPointer, _: Int) in
+                                    free(pointer)
+                                 })
+print(memory!)
+print(myBuffer.contents())

memory_part_2.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>