overte-HifiExperiments/examples/toys/bubblewand/wand.js

//  wand.js
//  part of bubblewand
//
//  Script Type: Entity Script
//  Created by James B. Pollack @imgntn -- 09/03/2015
//  Copyright 2015 High Fidelity, Inc.
//
//  Makes bubbles when you wave the object around.
//  
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html


(function() {

    Script.include("../../utilities.js");
    Script.include("../../libraries/utils.js");

    var BUBBLE_MODEL = "http://hifi-public.s3.amazonaws.com/james/bubblewand/models/bubble/bubble.fbx";

    var BUBBLE_INITIAL_DIMENSIONS = {
        x: 0.01,
        y: 0.01,
        z: 0.01
    }

    var BUBBLE_LIFETIME_MIN = 3;
    var BUBBLE_LIFETIME_MAX = 8;
    var BUBBLE_SIZE_MIN = 1;
    var BUBBLE_SIZE_MAX = 5;
    var BUBBLE_DIVISOR = 50;
    var BUBBLE_LINEAR_DAMPING = 0.4;
    var GROWTH_FACTOR = 0.005;
    var SHRINK_FACTOR = 0.001;
    var SHRINK_LOWER_LIMIT = 0.02;
    var WAND_TIP_OFFSET = 0.095;
    var VELOCITY_THRESHOLD = 0.5;

    function interval() {
        var lastTime = new Date().getTime() / 1000;

        return function getInterval() {
            var newTime = new Date().getTime() / 1000;
            var delta = newTime - lastTime;
            lastTime = newTime;
            return delta;
        };
    }

    var checkInterval = interval();

    var _this;

    var BubbleWand = function() {
        _this = this;
    }

    BubbleWand.prototype = {
        timePassed: null,
        currentBubble: null,
        preload: function(entityID) {
            this.entityID = entityID;
            Script.update.connect(this.update);
        },
        unload: function() {
            Script.update.disconnect(this.update);
        },
        getWandTipPosition: function(properties) {
            //the tip of the wand is going to be in a different place than the center, so we move in space relative to the model to find that position
            var upVector = Quat.getUp(properties.rotation);
            var frontVector = Quat.getFront(properties.rotation);
            var upOffset = Vec3.multiply(upVector, WAND_TIP_OFFSET);
            var wandTipPosition = Vec3.sum(properties.position, upOffset);
            return wandTipPosition
        },
        addCollisionsToBubbleAfterCreation: function(bubble) {
            //if the bubble collide immediately, we get weird effects.  so we add collisions after release
            Entities.editEntity(bubble, {
                collisionsWillMove: true
            })
        },
        randomizeBubbleGravity: function() {
            //change up the gravity a little bit for variation in floating effects
            var randomNumber = randInt(0, 3);
            var gravity = {
                x: 0,
                y: -randomNumber / 10,
                z: 0
            }
            return gravity
        },
        growBubbleWithWandVelocity: function(properties, deltaTime) {
            //get the wand and tip position for calculations
            var wandPosition = properties.position;
            var wandTipPosition = this.getWandTipPosition(properties)

            // velocity = distance / time
            var distance = Vec3.subtract(wandPosition, this.lastPosition);
            var velocity = Vec3.multiply(distance, 1 / deltaTime);

            var velocityStrength = Vec3.length(velocity);
            velocityStrength = velocityStrength;

            //store the last position of the wand for velocity calculations
            this.lastPosition = wandPosition;

            //actually grow the bubble
            var dimensions = Entities.getEntityProperties(this.currentBubble, "dimensions").dimensions;

            if (velocityStrength > VELOCITY_THRESHOLD) {
                //add some variation in bubble sizes
                var bubbleSize = randInt(BUBBLE_SIZE_MIN, BUBBLE_SIZE_MAX);
                bubbleSize = bubbleSize / BUBBLE_DIVISOR;

                //release the bubble if its dimensions are bigger than the bubble size
                if (dimensions.x > bubbleSize) {

                    //bubbles pop after existing for a bit -- so set a random lifetime
                    var lifetime = randInt(BUBBLE_LIFETIME_MIN, BUBBLE_LIFETIME_MAX);

                    //edit the bubble properties at release
                    Entities.editEntity(this.currentBubble, {
                        velocity: velocity,
                        lifetime: lifetime,
                        gravity: this.randomizeBubbleGravity()
                    });

                    //wait to make the bubbles collidable, so that they dont hit each other and the wand
                    Script.setTimeout(this.addCollisionsToBubbleAfterCreation(this.currentBubble), lifetime / 2);

                    //release the bubble -- when we create a new bubble, it will carry on and this update loop will affect the new bubble
                    this.createBubbleAtTipOfWand();
                    return
                } else {
                    //grow small bubbles
                    dimensions.x += GROWTH_FACTOR * velocityStrength;
                    dimensions.y += GROWTH_FACTOR * velocityStrength;
                    dimensions.z += GROWTH_FACTOR * velocityStrength;

                }
            } else {
                // if the wand is not moving, make the current bubble smaller
                if (dimensions.x >= SHRINK_LOWER_LIMIT) {
                    dimensions.x -= SHRINK_FACTOR;
                    dimensions.y -= SHRINK_FACTOR;
                    dimensions.z -= SHRINK_FACTOR;
                }

            }

            //adjust the bubble dimensions
            Entities.editEntity(this.currentBubble, {
                dimensions: dimensions
            });
        },
        createBubbleAtTipOfWand: function() {

            //create a new bubble at the tip of the wand
            var properties = Entities.getEntityProperties(this.entityID, ["position", "rotation"]);
            var wandPosition = properties.position;

            wandTipPosition = this.getWandTipPosition(properties);

            //store the position of the tip for use in velocity calculations
            this.lastPosition = wandPosition;

            //create a bubble at the wand tip
            this.currentBubble = Entities.addEntity({
                name: 'Bubble',
                type: 'Model',
                modelURL: BUBBLE_MODEL,
                position: wandTipPosition,
                dimensions: BUBBLE_INITIAL_DIMENSIONS,
                collisionsWillMove: false,
                ignoreForCollisions: false,
                linearDamping: BUBBLE_LINEAR_DAMPING,
                shapeType: "sphere"
            });

        },
        startNearGrab: function() {
            if (this.currentBubble === null) {
                this.createBubbleAtTipOfWand();
            }
        },
        continueNearGrab: function() {
            var deltaTime = checkInterval()
            var properties = Entities.getEntityProperties(this.entityID, ["position", "rotation"]);

            this.growBubbleWithWandVelocity(properties, deltaTime);

            var wandTipPosition = this.getWandTipPosition(properties);

            //update the bubble to stay with the wand tip
            Entities.editEntity(this.currentBubble, {
                position: wandTipPosition,
            });
        },
        releaseGrab: function() {
            //delete the  current buble and reset state when the wand is released
            Entities.deleteEntity(this.currentBubble);
            this.currentBubble = null
        },

    }

    return new BubbleWand();

})