 	fileprivate var scalars: [String : Scalar] = [:]
 	
 	
-	func vertexShader(_ v: InputVertex) -> OutputVertex { fatalError("Must Override") }
+	func vertexShader(_ input: InputVertex) -> OutputVertex { fatalError("Must Override") }
 	
-	func fragmentShader(_ p: InputFragment) -> Color { fatalError("Must Override") }
+	func fragmentShader(_ input: InputFragment) -> Color? { fatalError("Must Override") }
 	
 	func register(name: String, value: Texture) { textures[name] = value }
 	

		return OutputVertex(v: position, t: input.t, n: input.n, others: [])
	}
	
	override func fragmentShader(_ p: InputFragment)-> Color{
		let tex = textures["texture"]!
		return (0,128,0)//tex[p.0, p.1].rgb
	}
	
}

		return OutputVertex(v: position, t: input.t, n: input.n, others: [])
	}
	
	override func fragmentShader(_ input: InputFragment)-> Color! {
		return (textures["texture"]!)[input.t.0, input.t.1].rgb
	}
	
