DemoSpectralBlend01.kt

import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.draw.createEquivalent
import org.openrndr.drawImage
import org.openrndr.extra.fx.blend.BlendSpectral
import org.openrndr.extra.fx.blur.BoxBlur
import org.openrndr.extra.fx.patterns.Checkers
import org.openrndr.math.Vector2
import kotlin.math.sin

fun main() {
    application {
        configure {
            width = 800
            height = 800
        }
        program {
            val a = drawImage(width, height) {
                drawer.stroke = null
                drawer.fill = ColorRGBa.BLUE
                drawer.circle(drawer.bounds.center - Vector2(100.0, 0.0), drawer.width * 0.25)
            }
            val b = drawImage(width, height) {
                drawer.clear(ColorRGBa.TRANSPARENT)
                drawer.stroke = ColorRGBa.RED
                drawer.strokeWeight = 10.0
                drawer.fill = ColorRGBa.YELLOW.opacify(1.0)
                drawer.circle(drawer.bounds.center + Vector2(100.0, 0.0), drawer.width * 0.25)
            }
            BoxBlur().apply { window = 10 }.apply(b, b)
            val checked = a.createEquivalent()
            Checkers().apply(emptyArray(), checked)

            val mixed = a.createEquivalent()
            val blendSpectral = BlendSpectral()
            extend {
                drawer.image(checked)
                blendSpectral.fill = sin(seconds) * 0.5 + 0.5
                blendSpectral.clip = seconds.mod(4.0) > 2.0
                blendSpectral.apply(a, b, mixed)
                drawer.image(mixed)
            }
        }
    }
}