BoxMesh.pde

PShape box;
int vertexCount;

float xRotation;
float yRotation;
float zRotation;

ArrayList<PVector> coords = new ArrayList();

boolean mouseRotate = true;
boolean showNearest = false;
boolean showIndexLabels = false;
boolean showNodes = true;

void setup() {
  size(500, 500, P3D);
  makeBox();
}

void draw() {
  background(255);

  pushMatrix();

  translate(width/2, height/2, 0); 
  
  if(mouseRotate){
    xRotation = (mouseY/360.0)*-(TWO_PI) + PI;
    yRotation = (mouseX/420.0)*(TWO_PI) - PI;
    zRotation = PI/36;
  }

  rotateX(xRotation);
  rotateY(yRotation);
  rotateZ(zRotation);

  scale(150);

  //3D shape:
  //sphere.setStroke(color(0, 40));
  //shape(shape);
  
  coords.clear();

  //For each vertex find where they'd be rendered on a 2D screen
  for (int i = 0; i < vertexCount; i++) {
    PVector vertex = box.getVertex(i);
    float x = screenX(vertex.x, vertex.y, vertex.z);
    float y = screenY(vertex.x, vertex.y, vertex.z);
    coords.add(new PVector(x, y));
  }

  popMatrix();
  
  draw2DBox();
}

void draw2DBox() {
  float prevX = -1;
  float prevY = -1;
  
  float textPad = 0;
  
  stroke(0, 0, 0, 60);
      
  for (int v = 0; v < vertexCount-2; v = v+4) {
    float x = coords.get(v).x;
    float y = coords.get(v).y;
      
    if(showNodes){
      fill(0);
      ellipse(x, y, 5, 5);
      //We're stepping by 4 so have to get the next 3 here:
      ellipse(coords.get(v+1).x, coords.get(v+1).y, 5, 5);
      ellipse(coords.get(v+2).x, coords.get(v+2).y, 5, 5);
      ellipse(coords.get(v+3).x, coords.get(v+3).y, 5, 5);
      noFill();
    }
      
    if(showIndexLabels){
      if(prevX == x && prevY == y){
        textPad = textPad + textWidth("" + (v-1)) + 3;
      }else{
        textPad = 0;
      }
      
      text("" + v, x + textPad, y);
      
      prevX = x;
      prevY = y;
    }
      
    //Draw the face:
      line(coords.get(v).x, coords.get(v).y, coords.get(v+1).x, coords.get(v+1).y);
      line(coords.get(v+1).x, coords.get(v+1).y, coords.get(v+2).x, coords.get(v+2).y);
      line(coords.get(v+2).x, coords.get(v+2).y, coords.get(v+3).x, coords.get(v+3).y);
      line(coords.get(v+3).x, coords.get(v+3).y, coords.get(v).x, coords.get(v).y);
    }

  if(showNearest){
    int nearestIndex = -1;
    float nearestDistance = Integer.MAX_VALUE;
    int c = coords.size();

    for (int i = 0; i < c; i++) {
      float x = coords.get(i).x;
      float y = coords.get(i).y;
  
      float distance = dist(x, y, mouseX, mouseY);
  
      if(distance < nearestDistance){
        nearestDistance = distance;
        nearestIndex = i;
      }
    }

    stroke(0, 255, 255);
    fill(0,255,255);
    ellipse(coords.get(nearestIndex).x, coords.get(nearestIndex).y, 15, 15);
    noFill();
  }
}
  
void keyPressed() {
  switch(key){
    case 'a':
      mouseRotate = !mouseRotate;
      break;
    case's':
      showNearest = !showNearest;
      break;
    case 'd':
      showIndexLabels = !showIndexLabels;
      break;
    case 'f':
      showNodes = !showNodes;
      break;
  }
}

void makeBox() {
  stroke(0, 30);
  box = createShape(BOX, 1.2);
  vertexCount = box.getVertexCount();
}