renderers are now destroyed at the right time if offscreen

src/client/js/rendering/particles.js

@@ -38,13 +38,23 @@ define([
 		},
 
 		update: function() {
+			var renderer = this.r;
 			var now = Date.now();
 
 			var emitters = this.emitters;
 			var eLen = emitters.length;
 			for (var i = 0; i < eLen; i++) {
 				var e = emitters[i];
-				var destroy = ((!e.emit) && (e.particleCount == 0));
+
+				var visible = null;
+				var destroy = !e.emit;
+				if (destroy) {
+					if (e.particleCount > 0) {
+						visible = renderer.isVisible(e.spawnPos.x, e.spawnPos.y);
+						if (visible)
+							destroy = false;
+					}
+				}
 
 				if (destroy) {
 					emitters.splice(i, 1);
@@ -56,6 +66,11 @@ define([
 					continue;
 				} 
 
+				if (visible === null)
+					visible = renderer.isVisible(e.spawnPos.x, e.spawnPos.y);
+				if (!visible)
+					continue;
+
 				var r = e.update((now - this.lastTick) * 0.001);
 				r.forEach(function(rr) {
 					if (e.blendMode == 'overlay')