QSBatchRenderer: Replace Node::children QList with a singly linked list.

This reduces transient allocations by 10mb on the Rectangle creation benchmark,
at the cost of an additional two pointers per shadow node (and just that pointer --
no additional allocation ala QList is required, so this will actually end up
around the same size if not better.)

Change-Id: I6c25c93fe31ed892e3c42ed66d6c6656e5d7b38a
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h b/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
index 8cd9e7e3ff..4a819a5fa5 100644
--- a/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
+++ b/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
@@ -1,6 +1,8 @@
 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
+** Copyright (C) 2014 Jolla Ltd, author: <gunnar.sletta@jollamobile.com>
+** Copyright (C) 2015 Robin Burchell <robin.burchell@viroteck.net>
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the QtQuick module of the Qt Toolkit.
@@ -438,6 +440,9 @@ struct Node
         : sgNode(0)
         , parent(0)
         , data(0)
+        , firstChild(0)
+        , nextSibling(0)
+        , lastChild(0)
         , dirtyState(0)
         , isOpaque(false)
         , isBatchRoot(false)
@@ -447,7 +452,9 @@ struct Node
     QSGNode *sgNode;
     Node *parent;
     void *data;
-    QList<Node *> children;
+    Node *firstChild;
+    Node *nextSibling;
+    Node *lastChild;
 
     QSGNode::DirtyState dirtyState;