Use different buffer for indices and vertices only in the WebGL plugin

This patch partially reverts 098ba086530ccd555369a9ea88f3c6668726ab81.
Only QtWebGL will use separate buffers for indices and vertices. This
patch gives a performance boost.

Task-number: QTBUG-66191
Task-number: QTBUG-67147
Change-Id: I58b4db2bdf44cd954390e85e079de82031caf9e5
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/quick/scenegraph/qsgdefaultrendercontext.cpp b/src/quick/scenegraph/qsgdefaultrendercontext.cpp
index 7882496062..22e97a2dc9 100644
--- a/src/quick/scenegraph/qsgdefaultrendercontext.cpp
+++ b/src/quick/scenegraph/qsgdefaultrendercontext.cpp
@@ -39,6 +39,7 @@
 
 #include "qsgdefaultrendercontext_p.h"
 
+#include <QtGui/QGuiApplication>
 #include <QtGui/QOpenGLFramebufferObject>
 
 #include <QtQuick/private/qsgbatchrenderer_p.h>
@@ -317,6 +318,17 @@ QSGDefaultRenderContext *QSGDefaultRenderContext::from(QOpenGLContext *context)
     return qobject_cast<QSGDefaultRenderContext *>(context->property(QSG_RENDERCONTEXT_PROPERTY).value<QObject *>());
 }
 
+bool QSGDefaultRenderContext::separateIndexBuffer() const
+{
+    // WebGL: A given WebGLBuffer object may only be bound to one of
+    // the ARRAY_BUFFER or ELEMENT_ARRAY_BUFFER target in its
+    // lifetime. An attempt to bind a buffer object to the other
+    // target will generate an INVALID_OPERATION error, and the
+    // current binding will remain untouched.
+    static const bool isWebGL = qGuiApp->platformName().compare(QLatin1String("webgl")) == 0;
+    return isWebGL;
+}
+
 QSGDistanceFieldGlyphCache *QSGDefaultRenderContext::distanceFieldGlyphCache(const QRawFont &font)
 {
     QString key = fontKey(font);