RippleView.swift

//
//  RippleView.swift
//  Salt
//
//  Created by EDI_MBP on 15.01.16.
//  Copyright © 2016 EDO. All rights reserved.
//

import UIKit
import CoreGraphics

class RippleView: UIView {

    var buffer1 = [UInt8]()
    var buffer2 = [UInt8]()

    var image = UIImage()

    let force = 255
    let damp = 1.0

    let cols = 256
    let rows = 256

    var newPoint = CGPoint()

    var hasNew = true


    override init(frame: CGRect) {
        super.init(frame: frame)
        addBehaviour()
    }

    convenience init() {
        self.init(frame:CGRect.zero)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("This class does not support NSCoding")
    }

    func addBehaviour() {

        backgroundColor = UIColor.yellowColor()

        buffer1 = [UInt8](count: cols*rows, repeatedValue: 0)
        buffer2 = [UInt8](count: cols*rows, repeatedValue: 0)

        newPoint = CGPoint(x: 50, y: 50)

        let provider = CGDataProviderCreateWithData(nil, buffer2, buffer2.count, nil)

        let imageRef = CGImageCreate(cols, rows, 8, 8, rows, CGColorSpaceCreateDeviceGray(), CGBitmapInfo.ByteOrderDefault, provider, nil, false, CGColorRenderingIntent.RenderingIntentDefault)

        image = UIImage.init(CGImage: imageRef!)

        NSTimer.scheduledTimerWithTimeInterval(0.001, target: self, selector: "bang", userInfo: nil, repeats: true)

    }

    func bang() {

        self.setNeedsDisplay()

    }

    func swapBuffers() {

        let swap = buffer1
        buffer1 = buffer2
        buffer2 = swap

    }

    func positionX(x: NSInteger, y:NSInteger) -> NSInteger {

        return ((y * cols) + x)

    }

    override func drawRect(rect: CGRect) {

        if(hasNew) {

            let x = NSInteger(newPoint.x)
            let y = NSInteger(newPoint.y)

            //print("Has new Point: (\(x), \(y))")

            let blip = force

            buffer1[positionX(x, y: y)] = UInt8.init(blip)
            buffer1[positionX(x-1, y: y)] = UInt8.init(blip)
            buffer1[positionX(x+1, y: y)] = UInt8.init(blip)

            buffer1[positionX(x-1, y: y-1)] = UInt8.init(blip)
            buffer1[positionX(x, y: y-1)] = UInt8.init(blip)
            buffer1[positionX(x+1, y: y-1)] = UInt8.init(blip)

            buffer1[positionX(x-1, y: y+1)] = UInt8.init(blip)
            buffer1[positionX(x, y: y+1)] = UInt8.init(blip)
            buffer1[positionX(x+1, y: y+1)] = UInt8.init(blip)

            hasNew = false

        }

        // propagate waves
        processRipples(buffer1, dest:&buffer2)

        // apply waves to image
        applyBuffer()

        // draw image
        image.drawAtPoint(CGPointMake(0.0, 0.0))

        // swap buffers
        swapBuffers()

    }

    func applyBuffer() {



    }

    func processRipples(source:[UInt8], inout dest: [UInt8]) {

        var position = 0

        for y in 1...(rows - 2) {

            for x in 1...(cols - 2) {

                position = (y * cols) + x

                let w = Int.init(source[position - cols])
                let a = Int.init(source[position - 1])
                let s = Int.init(source[position + 1])
                let d = Int.init(source[position + cols])

                var sum = w + a + s + d

                sum = sum / 2

                sum = sum - Int.init(dest[position])

                if(sum > 255) {

                    sum = 255

                } else if(sum < 0) {

                    sum = 0

                }

                dest[position] = UInt8.init(sum)

                dest[position] = UInt8.init(Double(dest[position]) * damp)

            }

        }

    }

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

        let point = (touches.first! as UITouch).locationInView(self)

        if(point.x >= 1 && point.x < 255 && point.y >= 1 && point.y < 255) {

            hasNew = true

            newPoint = point

            //newPoint.y = CGFloat(rows) - newPoint.y

        }

    }

    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {

        let point = (touches.first! as UITouch).locationInView(self)

        if(point.x >= 1 && point.x < 255 && point.y >= 1 && point.y < 255) {

            hasNew = true

            newPoint = point

            //newPoint.y = CGFloat(rows) - newPoint.y

        }

    }

}