PImage tex;
  float rotx = PI/4;
  float roty = PI/4;
  
  void setup() 
  {
    size(640, 360, P3D);
    tex = loadImage("berlin-1.jpg");
    textureMode(NORMALIZED);
    fill(255);
    stroke(color(44,48,32));
  }
  
  void draw() 
  {
    background(0);
    noStroke();
    translate(width/2.0, height/2.0, -100);
    rotateX(rotx);
    rotateY(roty);
    scale(90);
    TexturedCube(tex);
  }
  
  void TexturedCube(PImage tex) {
    beginShape(QUADS);
    texture(tex);
  
    // Given one texture and six faces, we can easily set up the uv coordinates
    // such that four of the faces tile "perfectly" along either u or v, but the other
    // two faces cannot be so aligned.  This code tiles "along" u, "around" the X/Z faces
    // and fudges the Y faces - the Y faces are arbitrarily aligned such that a
    // rotation along the X axis will put the "top" of either texture at the "top"
    // of the screen, but is not otherwised aligned with the X/Z faces. (This
    // just affects what type of symmetry is required if you need seamless
    // tiling all the way around the cube)
    
    // +Z "front" face
    vertex(-1, -1,  1, 0, 0);
    vertex( 1, -1,  1, 1, 0);
    vertex( 1,  1,  1, 1, 1);
    vertex(-1,  1,  1, 0, 1);
  
    // -Z "back" face
    vertex( 1, -1, -1, 0, 0);
    vertex(-1, -1, -1, 1, 0);
    vertex(-1,  1, -1, 1, 1);
    vertex( 1,  1, -1, 0, 1);
  
    // +Y "bottom" face
    vertex(-1,  1,  1, 0, 0);
    vertex( 1,  1,  1, 1, 0);
    vertex( 1,  1, -1, 1, 1);
    vertex(-1,  1, -1, 0, 1);
  
    // -Y "top" face
    vertex(-1, -1, -1, 0, 0);
    vertex( 1, -1, -1, 1, 0);
    vertex( 1, -1,  1, 1, 1);
    vertex(-1, -1,  1, 0, 1);
  
    // +X "right" face
    vertex( 1, -1,  1, 0, 0);
    vertex( 1, -1, -1, 1, 0);
    vertex( 1,  1, -1, 1, 1);
    vertex( 1,  1,  1, 0, 1);
  
    // -X "left" face
    vertex(-1, -1, -1, 0, 0);
    vertex(-1, -1,  1, 1, 0);
    vertex(-1,  1,  1, 1, 1);
    vertex(-1,  1, -1, 0, 1);
  
    endShape();
  }
  
  void mouseDragged() {
    float rate = 0.01;
    rotx += (pmouseY-mouseY) * rate;
    roty += (mouseX-pmouseX) * rate;
  }