Create Plane USDA

generatePlaneMesh.swift

import simd

func generatePlaneMesh(lengthInMeter: Float = 1, divisions: Int = 100, name: String = "GeneratedPlane") {
    let n = divisions
    let xys: [(Int, Int)] = (0..<n).flatMap { y in (0..<n).map { x in (x, y) }}
    let points: [SIMD3<Float>] = xys.map { x, y in
        SIMD3(Float(x) / Float(n - 1) - 0.5, Float(y) / Float(n - 1) - 0.5, 0) * lengthInMeter
    }
    let faceVertexIndices: [Int] = xys.flatMap { x, y in
        guard x < n - 1, y < n - 1 else { return [Int]() }
        let o = x + y * n
        return [o, o + 1, o + 1 + n, o + n]
    }
    let faceVertexCounts: [Int] = .init(repeating: 4, count: faceVertexIndices.count / 4)
    // USDA
    print("")
    print("#usda 1.0")
    print("")
    print("def Mesh \"\(name)\" {")
    print("  float3[] points = \(points.map {($0.x, $0.y, $0.z)})")
    print("  int[] faceVertexIndices = \(faceVertexIndices)")
    print("  int[] faceVertexCounts = \(faceVertexCounts)")
    print("}")
    print("")
}

generatePlaneMesh()