Fix QQuickPaintedItem performance and memory usage

Keep the existing QSGPainterTexture (QSGPlainTexture). This is
what Qt 5 would do as well. Otherwise we silently get lots of
unnecessary releasing and creating graphics resources
underneath.

Fixes: QTBUG-95132
Change-Id: I88e839793fedd8f2c6d00cd76cd9a653731865f4
Reviewed-by: Jonas Karlsson <jonas.karlsson@qt.io>
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
(cherry picked from commit 146f8cbf865e0061859dd9f1c7a477db91298052)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 5 insertions, 7 deletions

diff --git a/src/quick/scenegraph/util/qsgdefaultpainternode.cpp b/src/quick/scenegraph/util/qsgdefaultpainternode.cpp
index d97d48c78d..fc1b3aec24 100644
--- a/src/quick/scenegraph/util/qsgdefaultpainternode.cpp
+++ b/src/quick/scenegraph/util/qsgdefaultpainternode.cpp
@@ -206,13 +206,11 @@ void QSGDefaultPainterNode::updateRenderTarget()
     m_image = QImage(m_textureSize, QImage::Format_ARGB32_Premultiplied);
     m_image.fill(Qt::transparent);
 
-    QSGPainterTexture *texture = new QSGPainterTexture;
-    texture->setOwnsTexture(true);
-    texture->setTextureSize(m_textureSize);
-    if (m_texture)
-        delete m_texture;
-
-    m_texture = texture;
+    if (!m_texture) {
+        m_texture = new QSGPainterTexture;
+        m_texture->setOwnsTexture(true);
+    }
+    m_texture->setTextureSize(m_textureSize);
 }
 
 void QSGDefaultPainterNode::setPreferredRenderTarget(QQuickPaintedItem::RenderTarget target)