//----------------------------------------------------------
// helper Globals
//----------------------------------------------------------		

var shaderProgram;
var gl;

var fps = 0;
var fpsmax = 0;
var timecount = 0;
var fpssum = 0;
var fpscount = 1;
var benchtime = 0;

var username = "";

//----------------------------------------------------------
// getShader collects shader and compiles it. Errors are printed in alert
//----------------------------------------------------------		

function getShader(gl, id) {
	var shaderScript = document.getElementById(id);
	if (!shaderScript) {
		return null;
	}

	var str = "";
	var k = shaderScript.firstChild;
	while (k) {
		if (k.nodeType == 3) {
			str += k.textContent;
		}
		k = k.nextSibling;
	}

	var shader;
	if (shaderScript.type == "x-shader/x-fragment") {
		shader = gl.createShader(gl.FRAGMENT_SHADER);
	} else if (shaderScript.type == "x-shader/x-vertex") {
		shader = gl.createShader(gl.VERTEX_SHADER);
	} else {
		return null;
	}

	gl.shaderSource(shader, str);
	gl.compileShader(shader);

	if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
		alert(gl.getShaderInfoLog(shader));
		return null;
	}

	return shader;
}

//----------------------------------------------------------
// Matrix stack variables
//----------------------------------------------------------		

var mvMatrix = mat4.create();
var mvMatrixStack = [];
var pMatrix = mat4.create();

//----------------------------------------------------------
// Push Matrix
//----------------------------------------------------------		

function mvPushMatrix() {
	var copy = mat4.create();
	mat4.set(mvMatrix, copy);
	mvMatrixStack.push(copy);
}

//----------------------------------------------------------
// Pop Matrix
//----------------------------------------------------------		

function mvPopMatrix() {
	if (mvMatrixStack.length == 0) {
		throw "Invalid popMatrix!";
	}
	mvMatrix = mvMatrixStack.pop();
}

//----------------------------------------------------------
// Startup webGL and alert if not available
//----------------------------------------------------------		

function initGL(canvas) {
	try {
		gl = canvas.getContext("experimental-webgl");
		gl.viewportWidth = canvas.width;
		gl.viewportHeight = canvas.height;
	} catch (e) {
	} 

	if (!gl) {
		alert("Could not initialise WebGL, sorry :-(");
	}
}

//----------------------------------------------------------
// Measure fps and update div if available
//----------------------------------------------------------		

function updatefps(elapsed,fpsdiv) {
	if(!isNaN(elapsed)) {
		timecount += (elapsed / 1000.0);
		fpssum += (elapsed / 10.0);											
	} 
	if(elapsed < 1) {
		elapsed = 1;
	} 

	fpscount++;
	fps = Math.round((100.0 / (fpssum / fpscount)) * 10.0) / 10.0;

	if(fps > fpsmax&&timecount > 5.0) {
		fpsmax = fps;
	}

	fpsd = document.getElementById(fpsdiv);
	if(fpsd != null) {
		fpsd.innerHTML = fps;
	}

}

//----------------------------------------------------------
// Sends benchmark every X seconds
//----------------------------------------------------------		

function sendbenchmark(delay,app) {
	// Every 8 seconds send benchmark data to server!
	if(Math.abs(timecount - benchtime) > delay) {
		benchtime = timecount;
		benchmark(username, app, fps, fpsmax, Math.round(timecount * 10.0) / 10.0);
	}                                                                                                                                                   		
}

//----------------------------------------------------------
// Generate benchmark userID
//----------------------------------------------------------		

function genID(app) {                                                                                                                                            
	username = localStorage.getItem("Benchuser"); //Try to fetch username data                                                             
	if (username == null || username == "") {
		var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
		text = "";
		for(var i = 0; i < 16; i++) {
			text += possible.charAt(Math.floor(Math.random() * possible.length));
		}
		username =  text;
		localStorage.setItem("Benchuser", username);
	}

	benchmark(username, app, fps, fpsmax, Math.round(timecount * 10.0) / 10.0);                                                                                                                                    
}                                                                                                                                            

//----------------------------------------------------------
// Send benchmark using httpajax.js
//----------------------------------------------------------		

function benchmark(username, app, fps, maxfps, runtime) {
	var paramstr = 'User=' + escape(username);
	paramstr += "&App=" + escape(app);
	paramstr += "&Fps=" + escape(fps);		
	paramstr += "&MaxFps=" + escape(maxfps);		
	paramstr += "&RunTime=" + escape(runtime);
	AjaxService("Benchy.php", paramstr);				
}