[Groovy 및 Processing] 도형 이동

package episode007

import groovy.swing.SwingBuilder
import processing.core.PApplet

import javax.swing.*

class DisplayTest extends PApplet {

    def lastFrame

    def posX, posY
    def dx = 1, dy = 1

    def void setup() {
        frameRate(60)

        lastFrame = System.currentTimeMillis()
        posX = 100
        posY = 100
    }

    def void draw() {
        background(0, 0, 0)

        def delta = delta   // getDelta()
        posX += delta * dx * 0.1
        posY += delta * dy * 0.1

        noStroke()
        fill(255, 255, 255)
        rect(posX, posY, 50, 50)
    }

    def getDelta() {
        def currentTime = System.currentTimeMillis()
        def delta = currentTime - lastFrame
        lastFrame = currentTime
        delta
    }

    def static void main(args) {
        def display = new DisplayTest()
        new SwingBuilder().frame(
                title: 'Episode 3',
                defaultCloseOperation: JFrame.EXIT_ON_CLOSE,
                size: [640, 480], show: true) {
            widget(display)
        }
        display.init()
    }
}