CODEWITHSUNDEEP
swiftscenekittexture-mapping
kopacabana
kopacabana

Reputation: 467

SceneKit using 2 materials with different Texture Coordinates on same geometry

I try to apply two different materials on a same geometry. One material for tiling and second for Ambient Occlusion and other effects. example

I export a model with 2 UVSet (it's OK) in DAE format. When I try to apply the second material, it never appear. On second material, I try to apply blendMode, transparencyMode, png file, etc. Nothing works :(( If I change mappingChannel on the first material, mapping is OK !

let mat1 = SCNMaterial()
mat1.name = "Mat1"
mat1.diffuse.mappingChannel = 0
mat1.diffuse.contents = UIImage(named: "somePNGFile.png")


let mat2 = SCNMaterial()
mat2.name = "Mat2"
mat2.diffuse.mappingChannel = 1
mat2.diffuse.contents = UIImage(named: "otherPNGFile.png")

cube.geometry!.materials = [mat1, mat2]

Here is my SCN file : https://drive.google.com/open?id=1ddbE815hlS0VbKPsbwcJoS9cL8hOf6Mt

What's wrong in my code ? Maybe the 3D File... If you have an idea, a suggestion, a solution, it's great.

Thanks

Upvotes: 2

Views: 1451

Answers (1)

kopacabana
kopacabana

Reputation: 467

Finally, I found a solution with shaderModifiers.

It's possible to assign different mappingChannel on different slots (ambient, diffuse, specular, etc). Reference doc from Apple : https://developer.apple.com/documentation/scenekit/scnshadermodifierentrypointsurface?language=objc

Here is my code :

    var mat:SCNMaterial!
    var model:SCNReferenceNode!

    override init() {
        super.init()

        // INIT
        initModel()
        initShader()
        assignTextures()
    }

    func initModel() {
        let url = Bundle.main.url(forResource: "Test_MixMaterials", withExtension: "scn", subdirectory: "Test.scnassets")!
        model = SCNReferenceNode(url: url)!
        model.load()
        self.addChildNode(model)

        if let cube = model.childNode(withName: "pCube1", recursively: true) {
            mat = SCNMaterial()
            // Define mapping Channel 0 on diffuse slot
            mat.diffuse.mappingChannel = 0
            // Define mapping Channel 1 on ambient slot
            mat.ambient.mappingChannel = 1
            // Assign material
            cube.geometry!.firstMaterial = mat
        }
    }

    func initShader() {
        let shader = """

        // Samplers 2D.
        uniform sampler2D texture_UV1;
        uniform sampler2D texture_UV2;

        // Directives
        #pragma transparent
        #pragma body

        // Source Diffuse  ------------------------------------------------------------------------------------------------------------
        vec4 source = texture2D(texture_UV1, _surface.diffuseTexcoord);

        // Destination Diffuse --------------------------------------------------------------------------------------------------------
        vec4 dest = texture2D(texture_UV2, _surface.ambientTexcoord);

        // MULTIPLY Diffuses ---------------------------------------------------------------------------------------------------------------
        _surface.diffuse = source * dest;
        """

        mat.shaderModifiers = [
            .surface:shader
        ]
    }

    func assignTextures() {
        let setTexture_1 = SCNMaterialProperty(contents: UIImage(named: "someImage.png")!)
        let setTexture_2 = SCNMaterialProperty(contents: UIImage(named: "otherImage.png")!)

        mat.setValue(setTexture_1, forKey: "texture_UV1")
        mat.setValue(setTexture_2, forKey: "texture_UV2")
    }

And that's work...

If you want to test, here is the model I used : https://drive.google.com/open?id=1ddbE815hlS0VbKPsbwcJoS9cL8hOf6Mt

Upvotes: 2

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