Loading the Game Scene - WebGL Game Development - page 107

Applying Lights.js
This class holds the objects of all the lights added to our game scene. We have
defined a function getDataByType() to return the array of the component of the
light. For example, if we invoke lights.getDataByType("ambient") , it will sum
all the components (R, G, B) of the light ambient colors to return an array of three
values (r, g, b). If we invoke lights.getDataByType("position") and if we have
defined three positional lights, it will return an array with nine elements ([x0, y0, z0,
x1, y1, z1, x2, y2, z2], the positions of the three lights in a single array). Similarly for
the directional light, it will return a single array. If we invoke lights.getDataByT
ype("diffuse","position") , it will return a diffuse component (R, G, B) of each
positional light concatenated in a single array. The Light class is as follows:
Lights = function ( ) {
this.lights=[];
};
Lights.prototype = {
constructor: Lights,
addLight:function(light){
this.lights.push(light);
},
getDataByType:function(type,lightType){
var sum=[];
if(type=="position"){
for(var i=0;i<this.lights.length;++i){
if(this.lights[i].position.length>0){
sum=sum.concat(this.lights[i][type])
}
}
} else if(type=="direction"){
for(var i=0;i<this.lights.length;++i){
if(this.lights[i].direction.length>0){
sum= sum.concat(this.lights[i][type])
}
}
}
else if(type=="ambientColor"){
sum=[0,0,0];
for(var i=0;i<this.lights.length;++i){
sum[0]=sum[0]+this.lights[i].ambientColor[0];
sum[1]=sum[1]+this.lights[i].ambientColor[1];
sum[2]=sum[2]+this.lights[i].ambientColor[2];
}
}