How to get values from simd_float4 in objective-c

Question

I got a simd_float4*4 matrix from ARKit. I want to check the values of the matrix but found myself do not know how to do it in Objective-C. In Swift, this can be written as matrix.columns.3 to fetch a vector of values. But I do not know how to do it in Objective-C. Could someone point me a direction please. Thanks!

Answer 1

simd_float4x4 is a struct (like 4 simd_float4), and you can use

simd_float4x4.columns[index]

to access column in matrix.

/*! @abstract A matrix with 4 rows and 4 columns.*/
struct simd_float4x4 {
    public var columns: (simd_float4, simd_float4, simd_float4, simd_float4)
    public init()
    public init(columns: (simd_float4, simd_float4, simd_float4, simd_float4))
}

Apple document link: https://developer.apple.com/documentation/simd/simd_float4x4?language=objc

hope helpful!