Processing: how to make box() appear solid (non-transparent) in 3d mode

Question

I'm trying to create layers of 3d boxes in Processing. I want them to appear solid, so that you can't see the boxes "behind" other boxes, but the way they're displaying makes them seem transparent; you can see the stroke of boxes behind other boxes. How do I make them appear solid?

// number of boxes
int numBox = 300;

// width of each box
int boxWidth = 30;

// number of boxes per row
float numPerRow;

void setup() {
  size(800, 800, P3D);
  pixelDensity(1);
  colorMode(HSB, 360, 100, 100, 100);
  background(40, 6, 85);
  stroke(216, 0, 55);
  smooth(4);
  fill(0, 0, 90, 100);
  
  numPerRow = width / boxWidth;
  
}

void draw() {
  background(40, 6, 85);
  
  translate((boxWidth / 2), 100);
  rotateX(-PI/6);
  rotateY(PI/8);
  
  for (int i = 0; i < numBox; i++) {
    drawBox(i);
    
    if (i == numBox - 1) {
      noLoop();
    }
  }
}

void drawBox(int i) {
  if ((i % 2) == 0) {
    pushMatrix();
    translate(((boxWidth / 2) * i) % width, 20 * floor(i / (2 * numPerRow)));
    translate(0, -((i % 30) / 2));
    box(boxWidth, i % 30, boxWidth);
    popMatrix();
  };
}

Close-up of how the boxes are being displayed:

Answer 1

The issue is that the boxes are intersecting and the strokes of these intersecting boxes are what give the appearance of "see through".

I'm noticing you are using x and y translation, but not z. If you don't plan to increase x, y spacing to avoid intersections, you can easily offset rows on the z axis so rows of boxes appear in front of each other.

Here's a slightly modified version of your code illustrating this idea:

// number of boxes
int numBox = 300;

// width of each box
int boxWidth = 30;

// number of boxes per row
float numPerRow;

void setup() {
  size(800, 800, P3D);
  pixelDensity(1);
  colorMode(HSB, 360, 100, 100, 100);
  background(40, 6, 85);
  stroke(216, 0, 55);
  smooth(4);
  fill(0, 0, 90, 100);

  numPerRow = width / boxWidth;
}

void draw() {
  background(40, 6, 85);

  translate((boxWidth / 2), 100);
  if(mousePressed){
    rotateX(map(mouseY, 0, height, -PI, PI));
    rotateY(map(mouseX, 0, width, PI, -PI));
  }else{
    rotateX(-PI/6);
    rotateY(PI/8);
  }

  for (int i = 0; i < numBox; i++) {
    drawBox(i);

    //if (i == numBox - 1) {
    //  noLoop();
    //}
  }
}

void drawBox(int i) {
  if ((i % 2) == 0) {
    pushMatrix();
    float x = ((boxWidth / 2) * i) % width;
    float y = 20 * floor(i / (2 * numPerRow));
    float z = y * 1.5;
    translate(x, y, z);
    translate(0, -((i % 30) / 2));
    box(boxWidth, i % 30, boxWidth);
    popMatrix();
  };
}

(Click and drag to rotate and observe the z offset.

Feel free to make z as interestersting as you need it it.

Nice composition and colours! (framing (window size) could use some iteration/tweaking, but I'm guessing this is WIP))