iridescent.pde

/**
Wave iridescent gradient
*/

int size = 200;
int waveTime = 40;

void setup() {
  size(400, 400);
  pixelDensity(displayDensity());
}

void draw() {
  background(0);
  blendMode(ADD);

  pushMatrix();
  translate(width / 2, height / 2 - size / 2);

  for (int i = 0; i < size / 4; ++i) {
    float offset = i * PI / 180;
    float offset2 = (i * PI / 180) + HALF_PI * 0.85; // map(mouseY, 0, height, HALF_PI / 8, TWO_PI);
    float offset3 = (i * PI / 180)  + map(sin(frameCount * TWO_PI / waveTime / 2), -1, 1, HALF_PI, HALF_PI * 3.5); //map(mouseX, 0, width, HALF_PI / 8, TWO_PI);

    float theta =  pow(sin(frameCount * TWO_PI / waveTime + offset), 2);
    float theta2 =  pow(sin(frameCount * TWO_PI / waveTime + offset2), 2);
    float theta3 =  pow(sin(frameCount * TWO_PI / waveTime + offset3), 2);

    float y = i * 4;

    strokeWeight(0.75);
    stroke(color(255, 20 + (theta * 150)));
    line(-size / 2, y, size / 2, y);
    
    stroke(color(255, 0, 0, 20 + (theta2 * 180)));
    line(-size / 2, y, size / 2, y);
    
    stroke(color(0, 0, 255, 20 + (theta3 * 200)));
    line(-size / 2, y, size / 2, y);
  }
  popMatrix();

}