Add missing file for lesson 2

lesson_002/gl.js

@@ -0,0 +1,47 @@
+function GLInstance(canvasID){
+	var canvas = document.getElementById(canvasID),
+		gl = canvas.getContext("webgl2");
+
+	if(!gl){ console.error("WebGL context is not available."); return null; }
+
+	//...................................................
+	//Setup GL, Set all the default configurations we need.
+	gl.clearColor(1.0,1.0,1.0,1.0);		//Set clear color
+
+
+	//...................................................
+	//Methods
+
+	//Reset the canvas with our set background color.	
+	gl.fClear = function(){ this.clear(this.COLOR_BUFFER_BIT | this.DEPTH_BUFFER_BIT); return this; }
+
+	//Create and fill our Array buffer.
+	gl.fCreateArrayBuffer = function(floatAry,isStatic){
+		if(isStatic === undefined) isStatic = true; //So we can call this function without setting isStatic
+
+		var buf = this.createBuffer();
+		this.bindBuffer(this.ARRAY_BUFFER,buf);
+		this.bufferData(this.ARRAY_BUFFER, floatAry, (isStatic)? this.STATIC_DRAW : this.DYNAMIC_DRAW );
+		this.bindBuffer(this.ARRAY_BUFFER,null);
+		return buf;
+	}
+
+	//...................................................
+	//Setters - Getters
+
+	//Set the size of the canvas html element and the rendering view port
+	gl.fSetSize = function(w,h){
+		//set the size of the canvas, on chrome we need to set it 3 ways to make it work perfectly.
+		this.canvas.style.width = w + "px";
+		this.canvas.style.height = h + "px";
+		this.canvas.width = w;
+		this.canvas.height = h;
+
+		//when updating the canvas size, must reset the viewport of the canvas 
+		//else the resolution webgl renders at will not change
+		this.viewport(0,0,w,h);
+		return this;
+	}
+
+	return gl;
+}