1 /** 2 * The Render Engine 3 * Emitter 4 * 5 * @fileoverview A particle emitter class 6 * 7 * @author: Brett Fattori (brettf@renderengine.com) 8 * 9 * @author: $Author: bfattori $ 10 * @version: $Revision: 1555 $ 11 * 12 * Copyright (c) 2011 Brett Fattori (brettf@renderengine.com) 13 * 14 * Permission is hereby granted, free of charge, to any person obtaining a copy 15 * of this software and associated documentation files (the "Software"), to deal 16 * in the Software without restriction, including without limitation the rights 17 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 18 * copies of the Software, and to permit persons to whom the Software is 19 * furnished to do so, subject to the following conditions: 20 * 21 * The above copyright notice and this permission notice shall be included in 22 * all copies or substantial portions of the Software. 23 * 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 29 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 30 * THE SOFTWARE. 31 * 32 */ 33 34 // The class this file defines and its required classes 35 R.Engine.define({ 36 "class":"R.particles.Emitter", 37 "requires":[ 38 "R.engine.PooledObject" 39 ] 40 }); 41 42 /** 43 * @class Particle emitter class. Emits particles at a regular 44 * interval as long as it is active. The function that is passed to generate 45 * the particles will be called with three arguments: an offset position, the 46 * current world time, and the delta from when the last frame was drawn. The function 47 * can either return a single particle or an <code>Array</code> of particles. 48 * Within the scope of the function, "this" refers to the {@link R.particles.Emitter} 49 * object. 50 * <pre> 51 * // Create the particle emitter which returns the type of particle 52 * // we want to emit. 5 is the delay between particle emissions and 53 * // 350 is the life of the particle (both in milliseconds) 54 * var emitter = R.particles.Emitter.create(function(offset) { 55 * // Create a particle 56 * return FuseParticle.create(offset, 350); 57 * }, 5); 58 * 59 * // Assign the emitter to the particle engine which will draw it 60 * emitter.setParticleEngine(Tutorial13.pEngine); 61 * </pre> 62 * 63 * @param emitFunc {Function} A function that emits new particles. 64 * @param interval {Number} The time between emissions 65 * @param [active] {Boolean} A flag indicating whether the emitter should emit particles 66 * @extends R.engine.PooledObject 67 * @constructor 68 * @description Create a particle emitter 69 */ 70 R.particles.Emitter = function () { 71 return R.engine.PooledObject.extend(/** @scope R.particles.Emitter.prototype */{ 72 73 active:true, 74 emitFn:null, 75 interval:null, 76 nextEmit:0, 77 engine:null, 78 79 /** @private */ 80 constructor:function (emitFunc, interval, active) { 81 this.base("ParticleEmitter"); 82 this.emitFn = emitFunc; 83 this.interval = interval; 84 this.active = active === undefined ? true : active; 85 this.nextEmit = 0; 86 this.engine = null; 87 }, 88 89 /** 90 * Release the particle back into the pool. 91 */ 92 release:function () { 93 this.base(); 94 this.interval = null; 95 this.emitFn = null; 96 this.active = true; 97 this.nextEmit = 0; 98 this.engine = null; 99 }, 100 101 /** 102 * Set the active state of the particle emitter 103 * @param state {Boolean} <code>true</code> to enable emission of particles, <code>false</code> to 104 * disable emission. 105 */ 106 setActive:function (state) { 107 this.active = state; 108 }, 109 110 /** 111 * Method to check if the emitter is active. 112 * @return {Boolean} 113 */ 114 isActive:function () { 115 return this.active; 116 }, 117 118 /** 119 * Set the interval at which particles are emitted. 120 * @param interval {Number} The number of milliseconds between emissions 121 */ 122 setInterval:function (interval) { 123 this.interval = interval; 124 }, 125 126 /** 127 * Return the interval at which particles are emitted. 128 * @return {Number} 129 */ 130 getInterval:function () { 131 return this.interval; 132 }, 133 134 /** 135 * Set the particle engine the particle emitter should emit particles to. 136 * @param particleEngine {R.particles.ParticleEngine} 137 */ 138 setParticleEngine:function (particleEngine) { 139 this.engine = particleEngine; 140 }, 141 142 /** 143 * Emit a particle to the particle engine, if the emitter is active. 144 * @param offset {R.math.Point2D} Offset from the particle's position to render at 145 * @param time {Number} The world time, in milliseconds 146 * @param dt {Number} The delta between the world time and the last time the world was updated 147 * in milliseconds. 148 * @private 149 */ 150 emit:function (offset, time, dt) { 151 if (this.active && time > this.nextEmit) { 152 this.nextEmit = time + this.interval; 153 var particles = this.emitFn.call(this, offset, time, dt); 154 if (particles.length) { 155 this.engine.addParticles(particles); 156 } else { 157 this.engine.addParticle(particles); 158 } 159 } 160 } 161 162 }, /** @scope R.particles.Emitter.prototype */ { 163 /** 164 * Get the class name of this object 165 * 166 * @return {String} "R.particles.Emitter" 167 */ 168 getClassName:function () { 169 return "R.particles.Emitter"; 170 } 171 }); 172 173 }