如何通过 SceneKit & 在 .OBJ 3d 模型上应用 .MTL 文件模型输入/输出

问题描述

我正在尝试通过 SceneKit & 在 .obj 3d 模型上应用 .mtl 文件纹理.模型 I/0.

当我尝试在其上应用 .jpg 纹理时，下面的代码工作正常:

 let url = NSBundle.mainBundle().URLForResource("chair", withExtension: "obj")让资产 = MDLAsset(URL: NSURL(string:url)!)守卫让对象 = asset.objectAtIndex(0) as?MDLMesh 其他 {//fatalError("无法从资产中获取网格.")返回}如果 shouldApplyTexture == true {var textureFileName = "chair.mtl"//从各种纹理创建一个材质让散射函数 = MDLScatteringFunction()让材料 = MDLMaterial(名称:baseMaterial"，scatteringFunction:scatteringFunction)material.setTextureProperties(纹理:[.BaseColor:textureFileName])//将纹理应用于资产的每个子网格用于 object.submeshes 中的子网格！{如果让 submesh = submesh as?MDLSubmesh {submesh.material = 材料}}}//将 ModelIO 对象包装在 SceneKit 对象中让节点 = SCNNode(MDLObject: object)如果(scene.rootNode.childNodes.count > 0){scene.rootNode.enumerateChildNodesUsingBlock {(节点，停止)->作废node.removeFromParentNode()}}场景.rootNode.addChildNode(节点)

我正在为 setTextureProperties 使用以下 MDMaterial 扩展:

extension MDLMaterial {func setTextureProperties([MDLMaterialSemantic:String]) ->空白 {对于(键，值)在纹理{var finalURL = NSBundle.mainBundle().URLForResource(value, withExtension: "")守卫让 url = finalURL else {//致命错误(无法找到资源 (值)的 URL.")返回}让属性 = MDLMaterialProperty(名称:文件名！，语义:键，网址:网址)self.setProperty(属性)}}}

我应该如何加载 .mtl 文件并将其应用到我的模型上以在其上添加纹理?为了从 .mtl 文件中获取纹理数据，我应该声明 SCNMaterial 的哪些属性?

解决方案

可能有点晚了，但我面临着同样的问题，我可以加载 .mtl 信息的方式是通过创建对象和场景，例如，我正在加载

I am trying to apply an .mtl file texture on .obj 3d model via SceneKit & Model I/0.

My code below works fine when I try to apply .jpg of a texture on it:

       let url = NSBundle.mainBundle().URLForResource("chair", withExtension: "obj")
       let asset = MDLAsset(URL: NSURL(string:url)!)
        guard let object = asset.objectAtIndex(0) as? MDLMesh else {
            //fatalError("Failed to get mesh from asset.")
            return
        }

        if shouldApplyTexture == true {
            var textureFileName = "chair.mtl"

            // Create a material from the various textures
            let scatteringFunction = MDLScatteringFunction()
            let material = MDLMaterial(name: "baseMaterial", scatteringFunction: scatteringFunction)

            material.setTextureProperties(textures: [
                                            .BaseColor:textureFileName])

            // Apply the texture to every submesh of the asset
            for  submesh in object.submeshes!  {
                if let submesh = submesh as? MDLSubmesh {
                    submesh.material = material
                }
            }

        }

        // Wrap the ModelIO object in a SceneKit object
        let node = SCNNode(MDLObject: object)

        if (scene.rootNode.childNodes.count > 0){
            scene.rootNode.enumerateChildNodesUsingBlock { (node, stop) -> Void in
                node.removeFromParentNode()
            }
        }
        scene.rootNode.addChildNode(node)

I am using the following MDMaterial extension for setTextureProperties:

extension MDLMaterial {
func setTextureProperties([MDLMaterialSemantic:String]) -> Void {

    for (key,value) in textures {
        var finalURL = NSBundle.mainBundle().URLForResource(value, withExtension: "")
       guard let url = finalURL else {
           // fatalError("Failed to find URL for resource (value).")
            return
        }

        let property = MDLMaterialProperty(name:fileName!, semantic: key, URL: url)
        self.setProperty(property)
    }
  }
}

How should I load an .mtl file and apply it on my model to have texture on it?What properties of SCNMaterial should I declare for getting texture data from a .mtl file?

解决方案

It might be a bit late, but I'm facing the same issue and the way in which I could load the .mtl information was to create the object through and scene, for example, I'm loading this model

let scene = SCNScene(named: "rose.obj")

Make sure to have the .mtl and the jpg with the textures in your bundle.

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