Quick3DBuffer: add helper method to read binary file

Change-Id: Ib96806720171cddc990f4b0df59a8690d56bc605
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

src/quick3d/quick3drender/items/quick3dbuffer.cpp

@@ -45,6 +45,8 @@
 #include <QtQml/private/qjsvalue_p.h>
 #include <QtQml/private/qv4typedarray_p.h>
 #include <QtQml/private/qv4arraybuffer_p.h>
+#include <Qt3DRender/private/qurlhelper_p.h>
+#include <QtCore/qfile.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -107,6 +109,25 @@ void Quick3DBuffer::updateData(int offset, const QVariant &bufferData)
     }
 }
 
+/*!
+    \qmlmethod string Quick3DBuffer::readBinaryFile(url &fileUrl)
+
+    Reads the binary at \a fileUrl and return it as a QByteArray wrapped in a
+    QVariant
+
+    \note this is provided as convenience for QML where reading files and creating
+    QByteArray is not possible
+ */
+QVariant Quick3DBuffer::readBinaryFile(const QUrl &fileUrl)
+{
+    QFile f(Qt3DRender::QUrlHelper::urlToLocalFileOrQrc(fileUrl));
+    QByteArray data;
+
+    if (f.open(QIODevice::ReadOnly))
+        data = f.readAll();
+    return QVariant(data);
+}
+
 void Quick3DBuffer::initEngines()
 {
     if (m_engine == nullptr) {

src/quick3d/quick3drender/items/quick3dbuffer_p.h

@@ -79,6 +79,8 @@ public:
     QVariant bufferData() const;
     void setBufferData(const QVariant &bufferData);
 
+    Q_INVOKABLE QVariant readBinaryFile(const QUrl &fileUrl);
+
 public Q_SLOTS:
     void updateData(int offset, const QVariant &bytes);