Untitled

void setup() {
  smooth();
  size(542, 475, P3D);
  background(255);
  stroke(0);
  strokeWeight(3);

  superQuad(new PVector(364.0, 235.0),
            new PVector(314.0, 295.0),
            new PVector(114.0, 272.0),
            new PVector(169.0, 123.0));
}

void superQuad(PVector a, PVector b, PVector c, PVector d) {
  PGraphics pattern = generatePattern(atan(slope(a, b)));
  beginShape();
  texture(pattern);
  vertex(a.x, a.y, a.x, a.y);
  vertex(b.x, b.y, b.x, b.y);
  vertex(c.x, c.y, c.x, c.y);
  vertex(d.x, d.y, d.x, d.y);
  endShape(CLOSE);
}

float slope(PVector i, PVector f) {
  float dy = f.y - i.y;
  float dx = f.x - i.x;
  return dy / dx;
}

PGraphics generatePattern(float rotation) {
  PGraphics pattern = createGraphics(width, height, P2D);
  pattern.beginDraw();
  pattern.rotate(rotation);
  pattern.stroke(0);
  pattern.strokeWeight(3);
  for(int y = 0; y < height; y += 10) {
    pattern.line(0, y, width, y);
  }
  pattern.endDraw();
  return pattern;
}