@_alignment(16) public struct float3 { public var x, y, z: Float }
@_alignment(16) public struct float4 { public var x, y, z, w: Float }
@_alignment(16) public struct double2 { public var x, y: Double }
@_alignment(16) public struct int3 { public var x, y, z: Int32 }
@_alignment(16) public struct uint4 { public var x, y, z, w: UInt32 }