From bb5e1fcbbb84f86ba37b1381b00fbb5df205dc96 Mon Sep 17 00:00:00 2001
From: stepan-beresnev <stepan.beresnev@productmadness.com>
Date: Tue, 4 Nov 2014 12:31:16 +0000
Subject: [PATCH] Optimization: double vertex and index buffers usage during
 Stage.drawToBitmapData

---
 starling/src/starling/core/Starling.as | 36 +++++++++++++++++---------
 starling/src/starling/display/Stage.as | 26 ++++++++++---------
 2 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/starling/src/starling/core/Starling.as b/starling/src/starling/core/Starling.as
index ae884a7af..a8fff444c 100644
--- a/starling/src/starling/core/Starling.as
+++ b/starling/src/starling/core/Starling.as
@@ -52,6 +52,8 @@ package starling.core
     import starling.utils.VAlign;
     import starling.utils.execute;
     
+    use namespace starling_internal;
+    
     /** Dispatched when a new render context is created. The 'data' property references the context. */
     [Event(name="context3DCreate", type="starling.events.Event")]
     
@@ -486,9 +488,27 @@ package starling.core
         /** Renders the complete display list. Before rendering, the context is cleared; afterwards,
          *  it is presented. This can be avoided by enabling <code>shareContext</code>.*/ 
         public function render():void
+        {
+            if (prerender())
+            {
+                if (!mShareContext)
+                    RenderSupport.clear(mStage.color, 1.0);
+                
+                mStage.render(mSupport, 1.0);
+                mSupport.finishQuadBatch();
+                
+                if (mStatsDisplay)
+                    mStatsDisplay.drawCount = mSupport.drawCount;
+                
+                if (!mShareContext)
+                    mContext.present();
+            }
+        }
+        
+        starling_internal function prerender():Boolean
         {
             if (!contextValid)
-                return;
+                return false;
             
             makeCurrent();
             updateViewPort();
@@ -509,17 +529,7 @@ package starling.core
                 mClippedViewPort.height / scaleY,
                 mStage.stageWidth, mStage.stageHeight, mStage.cameraPosition);
             
-            if (!mShareContext)
-                RenderSupport.clear(mStage.color, 1.0);
-            
-            mStage.render(mSupport, 1.0);
-            mSupport.finishQuadBatch();
-            
-            if (mStatsDisplay)
-                mStatsDisplay.drawCount = mSupport.drawCount;
-            
-            if (!mShareContext)
-                mContext.present();
+            return true;
         }
         
         private function updateViewPort(forceUpdate:Boolean=false):void
@@ -1014,6 +1024,8 @@ package starling.core
             }
         }
         
+        starling_internal function get support():RenderSupport { return mSupport; }
+        
         /** The Starling stage object, which is the root of the display tree that is rendered. */
         public function get stage():Stage { return mStage; }
 
diff --git a/starling/src/starling/display/Stage.as b/starling/src/starling/display/Stage.as
index a6d8b45db..cae203f95 100644
--- a/starling/src/starling/display/Stage.as
+++ b/starling/src/starling/display/Stage.as
@@ -123,23 +123,25 @@ package starling.display
         public function drawToBitmapData(destination:BitmapData=null,
                                          transparent:Boolean=true):BitmapData
         {
-            var support:RenderSupport = new RenderSupport();
             var star:Starling = Starling.current;
+            var prendered:Boolean = star.prerender();
             
             if (destination == null)
                 destination = new BitmapData(star.backBufferWidth, star.backBufferHeight, transparent);
             
-            support.renderTarget = null;
-            support.setProjectionMatrix(0, 0, mWidth, mHeight, mWidth, mHeight, cameraPosition);
-            
-            if (transparent) support.clear();
-            else             support.clear(mColor, 1);
-            
-            render(support, 1.0);
-            support.finishQuadBatch();
-            
-            Starling.current.context.drawToBitmapData(destination);
-            Starling.current.context.present(); // required on some platforms to avoid flickering
+            if (prendered)
+            {
+                var support:RenderSupport = star.support;
+                
+                if (transparent) support.clear();
+                else             support.clear(mColor, 1);
+                
+                render(support, 1.0);
+                support.finishQuadBatch();
+                
+                star.context.drawToBitmapData(destination);
+                star.context.present(); // required on some platforms to avoid flickering
+            }
             
             return destination;
         }