/*
* File: Particle.js
* Defines a particle
*/
/*jslint node: true, vars:true , white: true*/
/*global gEngine, vec2, LineRenderable */
/* find out more about jslint: http://www.jslint.com/help.html */
"use strict";
/**
* Default Constructor<p>
* Defines a particle
* @param {vec2} pos Position of particle
* @returns {Particle} New instance of Particle
* @class Particle
*/
function Particle(pos) {
this.kPadding = 0.5; // for drawing particle bounds
this.mPosition = pos; // this is likely to be a reference to xform.mPosition
this.mVelocity = vec2.fromValues(0, 0);
this.mAcceleration = gEngine.ParticleSystem.getSystemtAcceleration();
this.mDrag = 0.95;
this.mPositionMark = new LineRenderable();
this.mDrawBounds = false;
}
/**
* Draw function called by GameLoop
* @param {Camera} aCamera Camera to draw too
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.draw = function (aCamera) {
if (!this.mDrawBounds) {
return;
}
//calculation for the X at the particle position
var x = this.mPosition[0];
var y = this.mPosition[1];
this.mPositionMark.setFirstVertex(x - this.kPadding, y + this.kPadding); //TOP LEFT
this.mPositionMark.setSecondVertex(x + this.kPadding, y - this.kPadding); //BOTTOM RIGHT
this.mPositionMark.draw(aCamera);
this.mPositionMark.setFirstVertex(x + this.kPadding, y + this.kPadding); //TOP RIGHT
this.mPositionMark.setSecondVertex(x - this.kPadding, y - this.kPadding); //BOTTOM LEFT
this.mPositionMark.draw(aCamera);
};
/**
/**
* Update Function called by GameLoop
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.update = function () {
var dt = gEngine.GameLoop.getUpdateIntervalInSeconds();
// Symplectic Euler
// v += a * dt
// x += v * dt
var p = this.getPosition();
vec2.scaleAndAdd(this.mVelocity, this.mVelocity, this.mAcceleration, dt);
vec2.scale(this.mVelocity, this.mVelocity, this.mDrag);
vec2.scaleAndAdd(p, p, this.mVelocity, dt);
};
/**
* Set the particle Color
* @param {Float[]} color new color of particle [R, G, B, A]
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setColor = function (color) {
this.mPositionMark.setColor(color);
};
/**
* Return the current color of the particle
* @returns {Float[]} current color [R, G, B, A]
* @memberOf Particle
*/
Particle.prototype.getColor = function () { return this.mPositionMark.getColor(); };
/**
* Set the bound drawing state
* @param {Boolean} d true if bounds are to be drawn
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setDrawBounds = function(d) { this.mDrawBounds = d; };
/**
* Returns the bound drawing state
* @returns {Boolean} true of bounds are drawn
* @memberOf Particle
*/
Particle.prototype.getDrawBounds = function() { return this.mDrawBounds; };
/**
* Set new position
* @param {Number} xPos New X position
* @param {Number} yPos New Y position
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setPosition = function (xPos, yPos) { this.setXPos(xPos); this.setYPos(yPos); };
/**
* Return current position
* @returns {vec2} current position of particle [X, Y]
* @memberOf Particle
*/
Particle.prototype.getPosition = function () { return this.mPosition; };
/**
* Return the X position
* @returns {Number} current X position
* @memberOf Particle
*/
Particle.prototype.getXPos = function () { return this.mPosition[0]; };
/**
* Set the X position
* @param {Number} xPos new X position
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setXPos = function (xPos) { this.mPosition[0] = xPos; };
/**
* Return the Y position
* @returns {Number} current Y position
* @memberOf Particle
*/
Particle.prototype.getYPos = function () { return this.mPosition[1]; };
/**
* Set the Y position
* @param {Number} yPos new Y position
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setYPos = function (yPos) { this.mPosition[1] = yPos; };
/**
* Set Velocity
* @param {vec2} f new Velocity [X, Y]
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setVelocity = function (f) { this.mVelocity = f; };
/**
* Return Velocity
* @returns {vec2} current Velocity [X, Y]
* @memberOf Particle
*/
Particle.prototype.getVelocity = function () { return this.mVelocity; };
/**
* Set Acceleration
* @param {Float[]} g new Acceleration [X, Y]
* @returns {undefined}
* @memberOf Particle
*/
Particle.prototype.setAcceleration = function (g) { this.mAcceleration = g; };
/**
* Return Acceleration
* @returns {Float[]} current Acceleration [X, Y]
* @memberOf Particle
*/
Particle.prototype.getAcceleration = function () { return this.mAcceleration; };
/**
* Set Drag
* @param {Number} d new Drag value
* @returns {void}
* @memberOf Particle
*/
Particle.prototype.setDrag = function (d) { this.mDrag = d; };
/**
* Return Drag
* @returns {Number} current drag value
* @memberOf Particle
*/
Particle.prototype.getDrag = function () { return this.mDrag; };