SCNShadable Shader Modifiers Test

GameViewController.swift

import SceneKit
import QuartzCore

class GameViewController: NSViewController {
    
    @IBOutlet weak var gameView: GameView!
    
    override func awakeFromNib(){
        
        let numSphere = 10
        let camDistance:CGFloat = 5.0
        
        // create a new scene
        let scene = SCNScene()
        
        // create and add a camera t the scene
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        scene.rootNode.addChildNode(cameraNode)
        
        cameraNode.position = SCNVector3(x:0, y:0, z:camDistance)
        
        
        // create and add Spheres to the scene
        for x in 0..<numSphere {
            let node = SCNNode()
            let rdx = randomCGFloat() * camDistance - camDistance / 2
            let rdy = randomCGFloat() * camDistance - camDistance / 2
            let rdz = randomCGFloat() * camDistance - camDistance / 2
            node.position = SCNVector3Make(rdx, rdy, rdz)
            node.geometry = SCNSphere(radius: 1.0)
            scene.rootNode.addChildNode(node)
            
            // create and configure a material
            let material = SCNMaterial()
            material.specular.contents = NSColor.blueColor()
            material.locksAmbientWithDiffuse = true
            
            // set shaderModifiers properties
            material.shaderModifiers = [
                
                SCNShaderModifierEntryPointSurface:
                    "uniform float Scale = 12.0;\n" +
                    "uniform float Width = 0.5;\n" +
                    "uniform float Blend = 0.0;\n" +
                    "vec2 position = fract(_surface.diffuseTexcoord * Scale);" +
                    "float f1 = clamp(position.y / Blend, 0.0, 1.0);" +
                    "float f2 = clamp((position.y - Width) / Blend, 0.0, 1.0);" +
                    "f1 = f1 * (1.0 - f2);" +
                    "f1 = f1 * f1 * 2.0 * (3. * 2. * f1);" +
                    "_surface.diffuse = mix(vec4(1.0), vec4(0.0), f1);"
            ]
            
            // set the material to the 3D object geometry
            node.geometry?.firstMaterial = material
            
            // animate the 3D object
            let animation:CABasicAnimation = CABasicAnimation(keyPath:"rotation")
            animation.toValue = NSValue(SCNVector4:SCNVector4(x:CGFloat(1.0), y:CGFloat(1.0), z:CGFloat(0.0), w:CGFloat(M_PI * 2)))
            animation.duration = 5
            animation.repeatCount = MAXFLOAT // repeat forever

            node.addAnimation(animation, forKey:nil)
            
        }

        // set the scene to the view
        self.gameView!.scene = scene
        
        // allows the user to manipulate the camera
        self.gameView!.allowsCameraControl = true
        
        // show statistics such as fps and timing information
        self.gameView!.showsStatistics = true
        
        // configure the view
        self.gameView!.backgroundColor = NSColor.blackColor()
    }
    
    func randomCGFloat() -> CGFloat {
        return CGFloat(arc4random()) /  CGFloat(UInt32.max)
    }

}