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rothomp3/swift-buffer-example.swift

Last active January 1, 2020 17:09
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Swift example of writing to memory buffer
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swift-buffer-example.swift
let bitmapBuffer = UnsafePointer<UInt8>.alloc(Int(height * width * 4))
let pixelNumber = (x * 4) + (y * width * 4)
bitmapBuffer[pixelNumber + 3] = 255 // Alpha
bitmapBuffer[pixelNumber + 2] = redValue
bitmapBuffer[pixelNumber + 1] = greenValue
bitmapBuffer[pixelNumber + 0] = blueValue
@mattneub
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Very helpful, thanks.

@RLovelett
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I think this is missing a dealloc. Or put another way; I think this is leaking memory.

Using Swift 2 syntax I think this is a little bit better:

let bufferSize = Int(height * width * 4)
let bitmapBuffer = UnsafePointer<UInt8>.alloc(bufferSize)
defer { bitmapBuffer.dealloc(bufferSize) }

let pixelNumber = (x * 4) + (y * width * 4)

bitmapBuffer[pixelNumber + 3] = 255 // Alpha
bitmapBuffer[pixelNumber + 2] = redValue
bitmapBuffer[pixelNumber + 1] = greenValue
bitmapBuffer[pixelNumber + 0] = blueValue

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