week 6. 2D array

review:
  draw a rotating shape in the center of screen.

  also use 'scale()' to change the size of the object.


參考:
https://processing.org/examples/array2d.html

用 2D array 設定每個元素的顏色，旋轉速度，屬性。

float[][] distances;
float[][] rotateAngles;
float[][] rotateRates;
float maxDistance;
int spacer;

void setup() {
  size(640, 360);
  maxDistance = dist(width/2, height/2, width, height);
  distances = new float[width][height];
  rotateAngles = new float[width][height];
  rotateRates = new float[width][height];
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      float distance = dist(width/2, height/2, x, y);
      distances[x][y] = distance/maxDistance * 255;
      rotateAngles[x][y] = random(5.0);
      rotateRates[x][y] = random(5.0, 40.0);
    }
  }
  spacer = 30;
  strokeWeight(3);
  //noLoop();  // Run once and stop
}

void draw() {
  background(0);
  // This embedded loop skips over values in the arrays based on
  // the spacer variable, so there are more values in the array
  // than are drawn here. Change the value of the spacer variable
  // to change the density of the points
  for (int y = 0; y < height; y += spacer) {
    for (int x = 0; x < width; x += spacer) {
      pushMatrix();
      translate(x, y);
      rotate(frameCount/rotateRates[x][y]+rotateAngles[x][y]);
      rect(-spacer/2, -spacer/2, spacer, spacer);
      stroke(distances[x][y]);
      popMatrix();
    }
  }
}