function afficher_controles_jeu () {
	var element_chargement = document.getElementById ('chargement');
	Debug.assert (element_chargement);
	element_chargement.style.display = 'none';

	var element_controles = document.getElementById ('controles_jeu');
	Debug.assert (element_controles);
	element_controles.style.display = '';

	var element_plein_ecran = document.getElementById ('plein_ecran');
	Debug.assert (element_plein_ecran);
// 	if (window.screen.availWidth < 1480)
		element_plein_ecran.style.display = 'none';
}

var rectangle_precedent;
function inverser_plein_ecran () {
	/* FIXME : non global */
	Debug.assert (window.jeu);
	var camera = window.jeu.valCamera ();
	var est_plein_ecran = camera.valZoom () == 1.0;

	var element = document.body;
	Debug.assert (element);

	alert ('Cette action n\'est pas encore fonctionnelle.');

	if (est_plein_ecran) {
		element.className = element.className.replace (
			/\s*plein_ecran\b/g,
			''
			);
		camera.modifierZoom (0.5);

		Debug.assert (rectangle_precedent instanceof Rectangle);
		window.resizeTo (rectangle_precedent.largeur (),
				 rectangle_precedent.hauteur ());
		window.moveTo (rectangle_precedent.minX (),
			       rectangle_precedent.minY ());

		rectangle_precedent = null;
	} else {
		element.className += ' plein_ecran';
		camera.modifierZoom (1.0);

/* 		Debug.journal (window.screenX + ' ' + */
/* 			       window.screenY + ' ' + */
/* 			       window.outerWidth + ' ' + */
/* 			       window.outerHeight); */

		Debug.assert (rectangle_precedent == null);
		rectangle_precedent = new Rectangle (window.screenX,
						     window.screenY,
						     window.outerWidth,
						     window.outerHeight);

		window.moveTo (0, 0);
		window.resizeTo (window.screen.availWidth,
				 window.screen.availHeight);
	}
}

function inverser_volume () 
{
	Debug.assert (soundManager instanceof SoundManager);
	var est_muet = soundManager.defaultOptions.volume == 0;

	var element = document.getElementById ('volume');
	Debug.assert (element);
	
	if (est_muet) {
		element.className = element.className.replace (
			/\s*muet\b/g,
			''
			);
		Debug.assert (typeof soundManager.defaultOptions == 'object'
			      && (typeof soundManager.defaultOptions.volume
				  == 'number'));
		soundManager.defaultOptions.volume = 100;
		Debug.assert (soundManager.soundIDs instanceof Array);
		for (var i=0; i < soundManager.soundIDs.length; i++) {
			var sID = soundManager.soundIDs[i];
			if (sID)
				soundManager.setVolume (sID, 100);
		}
	} else {
		element.className += ' muet';
		Debug.assert (typeof soundManager.defaultOptions == 'object'
			      && (typeof soundManager.defaultOptions.volume
				  == 'number'));
		soundManager.defaultOptions.volume = 0;
		Debug.assert (soundManager.soundIDs instanceof Array);
		for (var i=0; i < soundManager.soundIDs.length; i++) {
			var sID = soundManager.soundIDs[i];
			if (sID)
				soundManager.setVolume (sID, 0);
		}
	}
}