/* built with Studio Sketchpad: 
 *   https://sketchpad.cc
 * 
 * observe the evolution of this sketch: 
 *   https://studio.sketchpad.cc/sp/pad/view/ro.R-67T8CyDi5/rev.109
 * 
 * authors: 
 *   
 *   Hyeongjik Song
 *   tester

 * license (unless otherwise specified): 
 *   creative commons attribution-share alike 3.0 license.
 *   https://creativecommons.org/licenses/by-sa/3.0/ 
 */ 



int numBlobs = 3;

int[] blogPx = { 0, 90, 120 };
int[] blogPy = { 0, 120, 45 };

// Movement vector for each blob
int[] blogDx = { 1, 0.8, 0.6 };
int[] blogDy = { 1, 1, -0.3 };

PGraphics pg;
int[][] vy,vx; 
String name = "metaball";

void setup() {
  size(400, 400);
  pg = createGraphics(90, 90); 
  vy = new int[numBlobs][pg.height];
  vx = new int[numBlobs][pg.width];
  frameRate(30);
}

void draw() {
  for (int i=0; i<numBlobs; ++i) {
    blogPx[i]+=blogDx[i];
    blogPy[i]+=blogDy[i];

    // bounce across screen
    if (blogPx[i] < 0) {
      blogDx[i] = 1;
    }
    if (blogPx[i] > pg.width) {
      blogDx[i] = -1;
    }
    if (blogPy[i] < 0) {
      blogDy[i] = 1;
    }
    if (blogPy[i] > pg.height) {
      blogDy[i]=-1;
    }

    for (int x = 0; x < pg.width; x++) {
      vx[i][x] = int(sq(blogPx[i]-x));
    }

    for (int y = 0; y < pg.height; y++) {
      vy[i][y] = int(sq(blogPy[i]-y)); 
    }
  }

  // Output into a buffered image for reuse
  pg.beginDraw();
  pg.loadPixels();
  for (int y = 0; y < pg.height; y++) {
    for (int x = 0; x < pg.width; x++) {
      int m = 1;
      for (int i = 0; i < numBlobs; i++) {
        // Increase this number to make your blobs bigger
        m += 60000/(vy[i][y] + vx[i][x]+1);
      }
      pg.pixels[x+y*pg.width] = color(0, m+x, (x+m+y)/2);
    }
  }
  pg.updatePixels();
  pg.endDraw();

  // Display the results
  image(pg, 0, 0, width, height); 
}