/**
 * a wrapper around a PImage that knows how to get() and draw() itself for feedback
 * and track the mouse (in reverse)
 */
class MousedFeedbackTexture {
  PApplet applet;
  PGraphics g;
  PImage img;
  /**
   * intended for the OpenGL renderer, but will work with others
   */
  MousedFeedbackTexture(PApplet applet) {
    this.applet = applet;
    this.g = applet.g;
    grab();
  } 
  void draw() {
    if (img==null) return;
    fill(255,245);
    stroke(0);
    pushMatrix();
    translate(g.width/2f-mouseX+img.width/2f, g.height/2f-mouseY+img.height/2f, 0);
    beginShape(QUADS);
    texture(img);
    textureMode(NORMALIZED);
    // drawing at 140x140 is roughly equivalent to scale(1.1) when half screen
    // width/height == 128, just wanted to show another way of doing zoom in fx
    float dim = 140;
    vertex(-dim, -dim, 0, 0);
    vertex(dim, -dim, 1, 0);
    vertex(dim, dim, 1, 1);
    vertex(-dim, dim, 0, 1);
    endShape();
    popMatrix();
  }
  void grab() {
    img = g.get();
  }
}