Files
CavesOfSwift/Sources/JolkEngine/Loaders/ObjLoader.swift
2024-05-05 17:01:56 +10:00

93 lines
1.9 KiB
Swift

import Foundation
import OrderedCollections
/*
extension ObjMaterial
{
func convert() -> Material
{
var m = Material()
m.diffuse = self.diffuse.setAlpha(self.alpha)
if ![ .colour, .lambert, .shadowOnly ].contains(self.model)
{
m.specular = self.specular
m.specularExp = self.specularExp
}
return m
}
}
*/
public struct ObjLoader: LoaderProtocol
{
public typealias T = Mesh
public init() {}
public func load(url: URL) -> T?
{
try? Self.read(url: url)
}
private static func read(url: URL) throws -> Mesh
{
return try read(model: try ObjReader.read(url: url))
}
public static func read(model: ObjModel) throws -> Mesh
{
var subMeshes: OrderedDictionary<String, Mesh.SubMesh> = .init()
var vertices = [Mesh.Vertex]()
var indices = [UInt16]()
let readIndex =
{ (v: ObjModel.Index) -> UInt16 in
let vertex = Mesh.Vertex(
position: model.positions[v.p],
normal: model.normals[v.n],
texCoord: model.texCoords[v.t])
if let index = vertices.firstIndex(of: vertex)
{
indices.append(UInt16(index))
return UInt16(index)
}
else
{
let index = UInt16(vertices.count)
indices.append(index)
vertices.append(vertex)
return index
}
}
for mesh in model.objects
{
let start = indices.count
for face: ObjModel.Face in mesh.value.faces
{
switch face
{
case .triangle(let v1, let v2, let v3):
for v in [ v1, v2, v3 ] { _ = readIndex(v) }
case .quad(let v1, let v2, let v3, let v4):
let n1 = readIndex(v1)
_ = readIndex(v2)
indices.append(readIndex(v3))
_ = readIndex(v4)
indices.append(n1)
case .ngon(_): fallthrough
default: break
}
}
let length = indices.count - start
if length > 0
{
subMeshes[mesh.key] = .init(start: start, length: length)
}
}
return Mesh(vertices: vertices, indices: indices, subMeshes: subMeshes)
}
}