function round(value)
{
	return Math.ceil(value * 100.0) / 100.0;
}

function calcul(angle, lux1m, distance)
{
	var Pi = 3.1415926;
	
	if ('' == angle) angle = document.getElementById('angle').value;
	if ('' == lux1m) lux1m = document.getElementById('lux1m').value;
	if ('' == distance) distance = document.getElementById('dist').value;
	
	var angle_rad = (((angle/2) * Pi) / 180);
    
	var rayon_mesure = Math.tan(angle_rad) * 1;
    var surface_mesure = Pi * rayon_mesure * rayon_mesure;
    var produit_surface_luminosite = surface_mesure * lux1m;
	
	var rayon = Math.tan(angle_rad) * distance;
	var diametre = rayon * 2;
	var surface = Pi * rayon * rayon;
    
	var lux = produit_surface_luminosite/surface;
	
	document.getElementById('dia').value = round(diametre);
	document.getElementById('lux').value = round(lux);
	
	document.getElementById('shema_resultdiam').value = round(diametre)+'m';
	document.getElementById('shema_resultlux').value = round(lux)+' lux';
}

function shema_angle()
{
	if(document.getElementById('angle').value != "")
	{
		document.getElementById('shema_angle').value = document.getElementById('angle').value+'°';
	}
	else
	{
		document.getElementById('shema_angle').value = "";
	}
}

function shema_1m()
{
	if(document.getElementById('lux1m').value != "")
	{
		document.getElementById('shema_1m').style.visibility = 'visible';
		document.getElementById('shema_lux1m').value = document.getElementById('lux1m').value+' lux';
	}
	else
	{
		document.getElementById('shema_1m').style.visibility = 'hidden';
		document.getElementById('shema_lux1m').value = "";
	}
}

function shema_distance()
{
	if(document.getElementById('dist').value != "")
	{
		document.getElementById('shema_distance').value = document.getElementById('dist').value+'m';
	}
	else
	{
		document.getElementById('shema_distance').value = "";
	}
}