From 27752fa6e3bd76d5c8d8d4f9f58725b0031410e8 Mon Sep 17 00:00:00 2001
From: Thomas FORGIONE <thomas.forgione@gmail.com>
Date: Thu, 4 Jun 2015 15:08:23 +0200
Subject: [PATCH] Improved perf of previewer (remove useless clear)

---
 js/prototype/Previewer.js | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/js/prototype/Previewer.js b/js/prototype/Previewer.js
index ad62e2a..39ad4e8 100644
--- a/js/prototype/Previewer.js
+++ b/js/prototype/Previewer.js
@@ -8,6 +8,8 @@ var Previewer = function(renderer, scene) {
     this.renderer = renderer;
     this.fixed = false;
     this.scene = scene;
+    this.drawn = false;
+    this.drawnBefore = false;
 }
 
 Previewer.prototype.render = function(prev, container_width, container_height) {
@@ -60,10 +62,12 @@ Previewer.prototype.render = function(prev, container_width, container_height) {
         this.renderer.setViewport(left, bottom, width, height);
         this.renderer.render(this.scene, prev.camera);
 
-        if (!this.fixed) {
-            this.clearNeeded = true;
-        }
-    } else if (this.fixed) {
+        this.update(true);
+    } else {
+        this.update(false);
+    }
+
+    if (this.drawnBefore && !this.drawn) {
         this.clearNeeded = true;
     }
 }
@@ -78,3 +82,8 @@ Previewer.prototype.clear = function() {
 Previewer.prototype.fixedRecommendation = function(bool) {
     this.fixed = bool;
 }
+
+Previewer.prototype.update = function(arg) {
+    this.drawnBefore = this.drawn;
+    this.drawn = arg;
+}