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SceneKit particleSystem.handle Swift3 implementation of Objective-C code @ https://developer.apple.com/documentation/scenekit/scnparticlesystem/1523251-handle
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particleSystem.handle(SCNParticleEvent.birth, forProperties [SCNParticleSystem.ParticleProperty.color]) { | |
(data:UnsafeMutablePointer<UnsafeMutableRawPointer>, dataStride:UnsafeMutablePointer<Int>, indicies:UnsafeMutablePointer<UInt32>?, count:Int) in | |
for i in 0..<count { | |
// get an UnsafeMutableRawPointer to the i-th rgba element in the data | |
let colorsPointer:UnsafeMutableRawPointer = data[0] + dataStride[0] * i | |
// convert the UnsafeMutableRawPointer to a typed pointer by binding it to a type: | |
let floatPtr = colorsPointer.bindMemory(to: Float.self, capacity: dataStride[0]) | |
// convert that to a an UnsafeMutableBufferPointer | |
var rgbaBuffer = UnsafeMutableBufferPointer(start: floatPtr, count: dataStride[0]) | |
// At this point, I could convert the buffer to an Array, but doing so copies the data into the array | |
// and any changes made in the array are not reflected in the original data. | |
// about half the time, mess with the red and green components | |
if(arc4random_uniform(2) == 1) { | |
rgbaBuffer[0] = rgbaBuffer[1] | |
rgbaBuffer[1] = 0 | |
} | |
} | |
} |
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