added brownianFun script to apply random forces to balls in a pen

examples/example/brownianFun.js

@@ -0,0 +1,247 @@
+var HIFI_PUBLIC_BUCKET = "http://s3.amazonaws.com/hifi-public/";
+var SOUND_PATH = HIFI_PUBLIC_BUCKET + "sounds/Collisions-hitsandslaps/";
+var soundURLS = ["67LCollision01.wav", "67LCollision02.wav", "airhockey_hit1.wav"];
+var FLOOR_SIZE = 10;
+var center = Vec3.sum(MyAvatar.position, Vec3.multiply(FLOOR_SIZE * 1.5, Quat.getFront(Camera.getOrientation())));
+var WALL_WIDTH = .1;
+var FLOOR_HEIGHT_OFFSET = -2;
+var WALL_HEIGHT = FLOOR_SIZE / 4;
+var BALL_DROP_HEIGHT = center.y + WALL_HEIGHT;
+var NUM_BALLS = 50;
+var BALL_RADIUS = 1;
+var BROWNIAN_INTERVAL_TIME = 16;
+var BROWNIAN_FORCE_RANGE = 5;
+var SPAWN_TIME = 50;
+var spawnCount = 0;
+
+var brownianMotionActivated = false;
+var buttonOffColor = {
+  red: 250,
+  green: 10,
+  blue: 10
+};
+var buttonOnColor = {
+  red: 10,
+  green: 200,
+  blue: 100
+};
+
+var bounds = {
+  xMin: center.x - FLOOR_SIZE / 2,
+  xMax: center.x + FLOOR_SIZE / 2,
+  zMin: center.z - FLOOR_SIZE / 2,
+  zMax: center.z + FLOOR_SIZE / 2
+};
+var balls = [];
+
+var screenSize = Controller.getViewportDimensions();
+var BUTTON_SIZE = 32;
+var PADDING = 3;
+
+var brownianButton = Overlays.addOverlay("image", {
+  x: screenSize.x / 2 - BUTTON_SIZE,
+  y: screenSize.y - (BUTTON_SIZE + PADDING),
+  width: BUTTON_SIZE,
+  height: BUTTON_SIZE,
+  imageURL: HIFI_PUBLIC_BUCKET + "images/blocks.png",
+  color: buttonOffColor,
+  alpha: 1
+});
+
+var floor = Entities.addEntity({
+  type: 'Box',
+  position: Vec3.sum(center, {
+    x: 0,
+    y: FLOOR_HEIGHT_OFFSET,
+    z: 0
+  }),
+  dimensions: {
+    x: FLOOR_SIZE,
+    y: WALL_WIDTH,
+    z: FLOOR_SIZE
+  },
+  color: {
+    red: 100,
+    green: 100,
+    blue: 100
+  }
+});
+
+var rightWall = Entities.addEntity({
+  type: 'Box',
+  position: Vec3.sum(center, {
+    x: FLOOR_SIZE / 2,
+    y: FLOOR_HEIGHT_OFFSET / 2,
+    z: 0
+  }),
+  dimensions: {
+    x: WALL_WIDTH,
+    y: WALL_HEIGHT,
+    z: FLOOR_SIZE
+  },
+  color: {
+    red: 120,
+    green: 100,
+    blue: 120
+  }
+});
+
+var leftWall = Entities.addEntity({
+  type: 'Box',
+  position: Vec3.sum(center, {
+    x: -FLOOR_SIZE / 2,
+    y: FLOOR_HEIGHT_OFFSET / 2,
+    z: 0
+  }),
+  dimensions: {
+    x: WALL_WIDTH,
+    y: WALL_HEIGHT,
+    z: FLOOR_SIZE
+  },
+  color: {
+    red: 120,
+    green: 100,
+    blue: 120
+  }
+});
+
+var backWall = Entities.addEntity({
+  type: 'Box',
+  position: Vec3.sum(center, {
+    x: 0,
+    y: FLOOR_HEIGHT_OFFSET / 2,
+    z: -FLOOR_SIZE / 2,
+  }),
+  dimensions: {
+    x: FLOOR_SIZE,
+    y: WALL_HEIGHT,
+    z: WALL_WIDTH
+  },
+  color: {
+    red: 120,
+    green: 100,
+    blue: 120
+  }
+});
+
+var frontWall = Entities.addEntity({
+  type: 'Box',
+  position: Vec3.sum(center, {
+    x: 0,
+    y: FLOOR_HEIGHT_OFFSET / 2,
+    z: FLOOR_SIZE / 2,
+  }),
+  dimensions: {
+    x: FLOOR_SIZE,
+    y: WALL_HEIGHT,
+    z: WALL_WIDTH
+  },
+  color: {
+    red: 120,
+    green: 100,
+    blue: 120
+  }
+});
+
+var spawnInterval = Script.setInterval(spawnBalls, SPAWN_TIME);
+
+function spawnBalls() {
+  balls.push(Entities.addEntity({
+    type: "Sphere",
+    shapeType: "sphere",
+    position: {
+      x: randFloat(bounds.xMin, bounds.xMax),
+      y: BALL_DROP_HEIGHT,
+      z: randFloat(bounds.zMin, bounds.zMax)
+    },
+    dimensions: {
+      x: BALL_RADIUS,
+      y: BALL_RADIUS,
+      z: BALL_RADIUS
+    },
+    color: {
+      red: randFloat(100, 150),
+      green: randFloat(20, 80),
+      blue: randFloat(10, 180)
+    },
+    ignoreCollisions: false,
+    collisionsWillMove: true,
+    gravity: {
+      x: 0,
+      y: -9.9,
+      z: 0
+    },
+    velocity: {
+      x: 0,
+      y: -.25,
+      z: 0
+    },
+    collisionSoundURL: SOUND_PATH + soundURLS[randInt(0, soundURLS.length - 1)]
+  }));
+  spawnCount++;
+  if (spawnCount === NUM_BALLS) {
+    Script.clearInterval(spawnInterval);
+  }
+}
+
+function mousePressEvent(event) {
+  var clickedOverlay = Overlays.getOverlayAtPoint({
+    x: event.x,
+    y: event.y
+  });
+  if (clickedOverlay == brownianButton) {
+    brownianMotionActivated = !brownianMotionActivated;
+    if (brownianMotionActivated) {
+      brownianInterval = Script.setInterval(bumpBalls, BROWNIAN_INTERVAL_TIME);
+      Overlays.editOverlay(brownianButton, {
+        color: buttonOnColor
+      })
+    } else {
+      Script.clearInterval(brownianInterval);
+      Overlays.editOverlay(brownianButton, {
+        color: buttonOffColor
+      })
+    }
+  }
+}
+
+function bumpBalls() {
+  balls.forEach(function(ball) {
+    var props = Entities.getEntityProperties(ball);
+    var newVelocity = Vec3.sum(props.velocity, {
+      x: (Math.random() - 0.5) * BROWNIAN_FORCE_RANGE,
+      y: 0,
+      z: (Math.random() - 0.5) * BROWNIAN_FORCE_RANGE
+    });
+    Entities.editEntity(ball, {
+      velocity: newVelocity
+    });
+  });
+}
+
+function cleanup() {
+  Entities.deleteEntity(floor);
+  Entities.deleteEntity(rightWall);
+  Entities.deleteEntity(leftWall);
+  Entities.deleteEntity(backWall);
+  Entities.deleteEntity(frontWall);
+  balls.forEach(function(ball) {
+    Entities.deleteEntity(ball);
+  });
+  Overlays.deleteOverlay(brownianButton);
+}
+
+function randFloat(low, high) {
+  return Math.floor(low + Math.random() * (high - low));
+}
+
+
+function randInt(low, high) {
+  return Math.floor(randFloat(low, high));
+}
+
+Script.scriptEnding.connect(cleanup);
+
+
+Script.scriptEnding.connect(cleanup);
+Controller.mousePressEvent.connect(mousePressEvent);