Generate image with GPUImagePerlinNoiseFilter

Question

I'm new in GPUImage. I want to create a noisy background at given size. Seems like I should use GPUImagePerlinNoiseFilter, but I have no idea how to generate an image.

let noiseFilter = GPUImagePerlinNoiseFilter()
noiseFilter.colorStart = GPUVector4(1, 1, 1, 0)
noiseFilter.colorStart = GPUVector4(1, 1, 1, 1)
noiseFilter.scale = 0.5

What should I do next?

Answer 1

In provided noise generator they use input image too (you set size and color), so I think I'm correct. Here is my solution:

import UIKit

import GPUImage

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let imageView = UIImageView(frame: CGRectMake(10, 50, 100, 100))
        imageView.image = createNoiseImage(CGSizeMake(100, 100), color: UIColor.whiteColor())
        view.addSubview(imageView)
    }

    private func createNoiseImage(size: CGSize, color: UIColor) -> UIImage {
        UIGraphicsBeginImageContext(size)
        let context = UIGraphicsGetCurrentContext()

        CGContextSetFillColorWithColor(context, color.CGColor)
        CGContextFillRect(context, CGRectMake(0, 0, size.width, size.height))

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext();

        let filter = GPUImagePerlinNoiseFilter()
        return filter.imageByFilteringImage(image)
    }
}

With default filter parameters it produces this: