Master

GravityBallCode/GravityBallCode.pde

@@ -1,38 +1,62 @@
 //declare variables
-float x, y, velX, velY, diam;
+int num = 100;
+float [] x = new float[num];
+float [] y = new float[num];
+float [] velX = new float[num];
+float [] velY = new float[num];
+float [] diam = new float[num];
+color [] c = new color[num];
+float g = 1;
 
 void setup() {
-  //set size of canvas
+  //set size of canvas and background
   size(800, 600);
+  background(0);
 
   //initialize variables
-  x = width/2;
-  y = height/2;
-  diam = 80;
-  velX = random(-5, 5);
-  velY = random(-5, 5);
+  for(int i = 0; i < num; i++) {
+    c[i] = color(random(128,255),128);
+    diam[i] = random(20,50);
+    x[i] = random(diam[i]/2,width-diam[i]/2);
+    y[i] = random(diam[i]/2,height-diam[i]/2);
+    velX[i] = -2+round(random(0,1))*random(2, 10);    //make sure velocity is never too small or 0
+    velY[i] = -2+round(random(0,1))*random(2, 10);    //make sure velocity is never too small or 0
+  }
 }
 
 void draw() {
-  //draw background to cover previous frame
-  background(0);
+  //draw a translucent rectangle to cover previous frame
+  fill(0,100);
+  rect(-1,-1,width+2,height+2);
+
+  strokeWeight(5);
+  stroke(255,0,0);
+  line(pmouseX,pmouseY,mouseX,mouseY);      //draw a streak
+
+  noStroke();
+  for(int i = 0; i < num; i++) {
+    if(dist(x[i], round(y[i]), mouseX, mouseY) <= diam[i]/2) {
+      c[i] = color(255,0,0);      //color the balls that the mouse touches red
+    } else {
+      c[i] = color(random(128,255),128);
+    }
+
+    //draw ball
+    fill(c[i]);
+    ellipse(x[i], y[i], diam[i], diam[i]);
 
-  //draw ball
-  ellipse(x, y, diam, diam);
-
-  //add velocity to position
-  x += velX;
-  y += velY;
-
-  //bounce ball if it hits walls
-  if (x + diam/2 >= width) {
-    velX = -abs(velX);    //if the ball hits the right wall, assign x velocity the negative version of itself
-  } else if (x - diam/2 <= 0) {
-    velX = abs(velX);     //if the ball hits the left wall, assign x velocity the positive version of itself
-  }
-  if (y + diam/2 >= height) {
-    velY = -abs(velY);
-  } else if (y - diam/2 <= 0) {
-    velY = abs(velY);
+    //add velocity to position
+    x[i] += velX[i];
+    y[i] += velY[i];
+
+    //bounce ball if it hits walls
+    if (x[i] + diam[i]/2 >= width || x[i] - diam[i]/2 <= 0) {
+      velX[i] *= -1;    //if the ball hits the side wall, assign x velocity the negative version of itself
+    }
+    if (y[i] + diam[i]/2 >= height || y[i] - diam[i]/2 <= 0) {
+      velY[i] *= -1;    //if the ball hits the top or bottom; assign x velocity the negative version of itself
+    } else {
+      velY[i] += g;
+    }
   }
 }

README.md

@@ -9,7 +9,3 @@
 * On this branch, modify your code to have 30 of these gravity balls (or some other number in that range). Once again, remember to commit and sync
 * Merge this new branch back in to the master branch
 * You're done for the day!
-
-
-##Acceleration
-Just as _velocity_ is change in position over time, _acceleration_ is change in _velocity_ over time. Creating acceleration is going to be very similar to creating velocity. I recommend a variable - perhaps call it "gravity"? I also recommend a small value - perhaps somewhere around .1