FrameBuffer - draw directly to PImage or Texture

Processing Coding Questions
1

how would i set up a FrameBuffer such that, i can draw directly to some Texture or PImage and then immediatly image that to my screen

for example

PGraphics g2;

void settings() {
  size(400, 400, P3D);
}

void setup() {
  background(0);
  g2 = createGraphics(500,500, P3D);
  noLoop();
}

void exit() {
//  g2.endDraw();
  super.exit();
}

void draw() {
  // setup g2 to draw to texture or PImage
  g2.beginDraw();
  g2.clip(0,0,50,50);
  g2.background(0, 128, 128);
  image(PImage_Or_Texture, 0, 0);
  g2.clip(0,0,25,25);
  g2.background(0);
  image(PImage_Or_Texture, 0, 0);
  g2.clip(35,35,65,65);
  g2.background(0, 228, 128);
  image(PImage_Or_Texture, 0, 0);
  g2.endDraw();
}