Compressed textures: Replace file decoding code with QtGui functionality

The functionality for reading and decoding texture files (currently
pkm and ktx formats) is now available in QtGui util API. Utilize that
instead of keeping equivalent code here.

Task-number: QTBUG-67026
Change-Id: Icb7c348eaa51cd15e41031508ef54164fc876c9e
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

12 files changed, 60 insertions, 690 deletions

diff --git a/src/quick/scenegraph/compressedtexture/qsgcompressedatlastexture.cpp b/src/quick/scenegraph/compressedtexture/qsgcompressedatlastexture.cpp
index e868a4380e..796bc870de 100644
--- a/src/quick/scenegraph/compressedtexture/qsgcompressedatlastexture.cpp
+++ b/src/quick/scenegraph/compressedtexture/qsgcompressedatlastexture.cpp
@@ -56,7 +56,6 @@
 #include <private/qquickprofiler_p.h>
 #include <private/qsgtexture_p.h>
 #include <private/qsgcompressedtexture_p.h>
-#include <private/qsgpkmhandler_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -154,13 +153,12 @@ QSGTexture *Texture::removedFromAtlas() const
     }
 
     if (!m_data.isEmpty()) {
-        QSGCompressedTexture::DataPtr texData(QSGCompressedTexture::DataPtr::create());
-        texData->data = m_data;
-        texData->size = m_size;
-        texData->format = static_cast<Atlas*>(m_atlas)->format();
-        texData->hasAlpha = hasAlphaChannel();
-        texData->dataLength = m_dataLength;
-        texData->dataOffset = m_dataOffset;
+        QTextureFileData texData;
+        texData.setData(m_data);
+        texData.setSize(m_size);
+        texData.setGLInternalFormat(static_cast<Atlas*>(m_atlas)->format());
+        texData.setDataLength(m_dataLength);
+        texData.setDataOffset(m_dataOffset);
         m_nonatlas_texture = new QSGCompressedTexture(texData);
         m_nonatlas_texture->setMipmapFiltering(mipmapFiltering());
         m_nonatlas_texture->setFiltering(filtering());
diff --git a/src/quick/scenegraph/compressedtexture/qsgcompressedtexture.cpp b/src/quick/scenegraph/compressedtexture/qsgcompressedtexture.cpp
index 839c562989..d3310bc11c 100644
--- a/src/quick/scenegraph/compressedtexture/qsgcompressedtexture.cpp
+++ b/src/quick/scenegraph/compressedtexture/qsgcompressedtexture.cpp
@@ -49,50 +49,11 @@ QT_BEGIN_NAMESPACE
 
 Q_LOGGING_CATEGORY(QSG_LOG_TEXTUREIO, "qt.scenegraph.textureio");
 
-bool QSGCompressedTextureData::isValid() const
-{
-    if (data.isNull() || size.isEmpty() || !format)
-        return false;
-    if (dataLength < 0 || dataOffset < 0 || dataOffset >= data.length())
-        return false;
-    if (dataLength > 0 && qint64(dataOffset) + qint64(dataLength) > qint64(data.length()))
-        return false;
-
-    return true;
-}
-
-int QSGCompressedTextureData::sizeInBytes() const
-{
-    if (!isValid())
-        return 0;
-    return dataLength > 0 ? dataLength : data.length() - dataOffset;
-}
-
-Q_QUICK_PRIVATE_EXPORT QDebug operator<<(QDebug dbg, const QSGCompressedTextureData *d)
-{
-    QDebugStateSaver saver(dbg);
-
-    dbg.nospace() << "QSGCompressedTextureData(";
-    if (d) {
-        dbg << d->logName << ' ';
-        dbg << static_cast<QOpenGLTexture::TextureFormat>(d->format)
-            << "[0x" << hex << d->format << dec << "]";
-        dbg.space() << (d->hasAlpha ? "with" : "no") << "alpha" << d->size
-                    << "databuffer" << d->data.size() << "offset" << d->dataOffset << "length";
-        dbg.nospace() << d->dataLength << ")";
-    } else {
-        dbg << "null)";
-    }
-    return dbg;
-}
-
-QSGCompressedTexture::QSGCompressedTexture(const DataPtr& texData)
+QSGCompressedTexture::QSGCompressedTexture(const QTextureFileData &texData)
     : m_textureData(texData)
 {
-    if (m_textureData) {
-        m_size = m_textureData->size;
-        m_hasAlpha = m_textureData->hasAlpha;
-    }
+    m_size = m_textureData.size();
+    m_hasAlpha = !formatIsOpaque(m_textureData.glInternalFormat());
 }
 
 QSGCompressedTexture::~QSGCompressedTexture()
@@ -155,37 +116,40 @@ void QSGCompressedTexture::bind()
     if (m_uploaded)
         return;
 
-    QByteArray logName(m_textureData ? m_textureData->logName : QByteArrayLiteral("(unset)"));
-
-    if (!m_textureData || !m_textureData->isValid()) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Invalid texture data for %s", logName.constData());
+    if (!m_textureData.isValid()) {
+        qCDebug(QSG_LOG_TEXTUREIO, "Invalid texture data for %s", m_textureData.logName().constData());
         funcs->glBindTexture(GL_TEXTURE_2D, 0);
         return;
     }
 
     if (Q_UNLIKELY(QSG_LOG_TEXTUREIO().isDebugEnabled())) {
-        qCDebug(QSG_LOG_TEXTUREIO) << "Uploading texture" << m_textureData.data();
+        qCDebug(QSG_LOG_TEXTUREIO) << "Uploading texture" << m_textureData;
         while (funcs->glGetError() != GL_NO_ERROR);
     }
 
-    funcs->glCompressedTexImage2D(GL_TEXTURE_2D, 0, m_textureData->format,
-                                  m_size.width(), m_size.height(), 0, m_textureData->sizeInBytes(),
-                                  m_textureData->data.constData() + m_textureData->dataOffset);
+    funcs->glCompressedTexImage2D(GL_TEXTURE_2D, 0, m_textureData.glInternalFormat(),
+                                  m_size.width(), m_size.height(), 0, m_textureData.dataLength(),
+                                  m_textureData.data().constData() + m_textureData.dataOffset());
 
     if (Q_UNLIKELY(QSG_LOG_TEXTUREIO().isDebugEnabled())) {
         GLuint error = funcs->glGetError();
         if (error != GL_NO_ERROR) {
-            qCDebug(QSG_LOG_TEXTUREIO, "glCompressedTexImage2D failed for %s, error 0x%x", logName.constData(), error);
+            qCDebug(QSG_LOG_TEXTUREIO, "glCompressedTexImage2D failed for %s, error 0x%x", m_textureData.logName().constData(), error);
         }
     }
 
-    m_textureData.clear();  // Release this memory, not needed anymore
+    m_textureData = QTextureFileData();  // Release this memory, not needed anymore
 
     updateBindOptions(true);
     m_uploaded = true;
 #endif // QT_CONFIG(opengl)
 }
 
+QTextureFileData QSGCompressedTexture::textureData() const
+{
+    return m_textureData;
+}
+
 bool QSGCompressedTexture::formatIsOpaque(quint32 glTextureFormat)
 {
     switch (glTextureFormat) {
@@ -211,14 +175,14 @@ bool QSGCompressedTexture::formatIsOpaque(quint32 glTextureFormat)
     }
 }
 
-QSGCompressedTextureFactory::QSGCompressedTextureFactory(const QSGCompressedTexture::DataPtr &texData)
+QSGCompressedTextureFactory::QSGCompressedTextureFactory(const QTextureFileData &texData)
     : m_textureData(texData)
 {
 }
 
 QSGTexture *QSGCompressedTextureFactory::createTexture(QQuickWindow *window) const
 {
-    if (!m_textureData || !m_textureData->isValid())
+    if (!m_textureData.isValid())
         return nullptr;
 
     // attempt to atlas the texture
@@ -232,15 +196,12 @@ QSGTexture *QSGCompressedTextureFactory::createTexture(QQuickWindow *window) con
 
 int QSGCompressedTextureFactory::textureByteCount() const
 {
-    return m_textureData ? m_textureData->sizeInBytes() : 0;
+    return qMax(0, m_textureData.data().size() - m_textureData.dataOffset());
 }
 
-
 QSize QSGCompressedTextureFactory::textureSize() const
 {
-    if (m_textureData && m_textureData->isValid())
-        return m_textureData->size;
-    return QSize();
+    return m_textureData.size();
 }
 
 QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/compressedtexture/qsgcompressedtexture_p.h b/src/quick/scenegraph/compressedtexture/qsgcompressedtexture_p.h
index aa87316809..c3b58a2389 100644
--- a/src/quick/scenegraph/compressedtexture/qsgcompressedtexture_p.h
+++ b/src/quick/scenegraph/compressedtexture/qsgcompressedtexture_p.h
@@ -51,6 +51,7 @@
 // We mean it.
 //
 
+#include <private/qtexturefiledata_p.h>
 #include <QSGTexture>
 #include <QtQuick/private/qsgcontext_p.h>
 #include <QQuickTextureFactory>
@@ -58,30 +59,11 @@
 
 QT_BEGIN_NAMESPACE
 
-struct Q_QUICK_PRIVATE_EXPORT QSGCompressedTextureData
-{
-    QByteArray logName;
-    QByteArray data;
-    QSize size;
-    uint format = 0;
-    int dataOffset = 0;
-    int dataLength = 0;
-    bool hasAlpha = false;
-
-    bool isValid() const;
-    int sizeInBytes() const;
-};
-
-Q_QUICK_PRIVATE_EXPORT QDebug operator<<(QDebug, const QSGCompressedTextureData *);
-
-
 class Q_QUICK_PRIVATE_EXPORT QSGCompressedTexture : public QSGTexture
 {
     Q_OBJECT
 public:
-    typedef QSharedPointer<QSGCompressedTextureData> DataPtr;
-
-    QSGCompressedTexture(const DataPtr& texData);
+    QSGCompressedTexture(const QTextureFileData& texData);
     virtual ~QSGCompressedTexture();
 
     int textureId() const override;
@@ -91,12 +73,12 @@ public:
 
     void bind() override;
 
-    const QSGCompressedTextureData *textureData();
+    QTextureFileData textureData() const;
 
     static bool formatIsOpaque(quint32 glTextureFormat);
 
 protected:
-    DataPtr m_textureData;
+    QTextureFileData m_textureData;
     QSize m_size;
     mutable uint m_textureId = 0;
     bool m_hasAlpha = false;
@@ -110,13 +92,14 @@ namespace QSGAtlasTexture {
 class Q_QUICK_PRIVATE_EXPORT QSGCompressedTextureFactory : public QQuickTextureFactory
 {
 public:
-    QSGCompressedTextureFactory(const QSGCompressedTexture::DataPtr& texData);
+    QSGCompressedTextureFactory(const QTextureFileData& texData);
     QSGTexture *createTexture(QQuickWindow *) const override;
     int textureByteCount() const override;
     QSize textureSize() const override;
 
 protected:
-    QSGCompressedTexture::DataPtr m_textureData;
+    QTextureFileData m_textureData;
+
 private:
     friend class QSGAtlasTexture::Manager;
 };
diff --git a/src/quick/scenegraph/compressedtexture/qsgktxhandler.cpp b/src/quick/scenegraph/compressedtexture/qsgktxhandler.cpp
deleted file mode 100644
index e3e4ca6824..0000000000
--- a/src/quick/scenegraph/compressedtexture/qsgktxhandler.cpp
+++ /dev/null
@@ -1,186 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2017 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#include "qsgktxhandler_p.h"
-#include "qsgcompressedtexture_p.h"
-#include <QOpenGLTexture>
-#include <QtEndian>
-
-//#define KTX_DEBUG
-
-QT_BEGIN_NAMESPACE
-
-#define KTX_IDENTIFIER_LENGTH 12
-static const char ktxIdentifier[KTX_IDENTIFIER_LENGTH] = { '\xAB', 'K', 'T', 'X', ' ', '1', '1', '\xBB', '\r', '\n', '\x1A', '\n' };
-static const quint32 platformEndianIdentifier = 0x04030201;
-static const quint32 inversePlatformEndianIdentifier = 0x01020304;
-
-struct KTXHeader {
-    quint8 identifier[KTX_IDENTIFIER_LENGTH]; //Must match ktxIdentifier
-    quint32 endianness; //Either platformEndianIdentifier or inversePlatformEndianIdentifier, other values not allowed.
-    quint32 glType;
-    quint32 glTypeSize;
-    quint32 glFormat;
-    quint32 glInternalFormat;
-    quint32 glBaseInternalFormat;
-    quint32 pixelWidth;
-    quint32 pixelHeight;
-    quint32 pixelDepth;
-    quint32 numberOfArrayElements;
-    quint32 numberOfFaces;
-    quint32 numberOfMipmapLevels;
-    quint32 bytesOfKeyValueData;
-};
-
-static const int headerSize = sizeof(KTXHeader);
-
-// Currently unused, declared for future reference
-struct KTXKeyValuePairItem {
-    quint32   keyAndValueByteSize;
-    /*
-    quint8 keyAndValue[keyAndValueByteSize];
-    quint8 valuePadding[3 - ((keyAndValueByteSize + 3) % 4)];
-    */
-};
-
-struct KTXMipmapLevel {
-    quint32 imageSize;
-    /*
-    for each array_element in numberOfArrayElements*
-        for each face in numberOfFaces
-            for each z_slice in pixelDepth*
-                for each row or row_of_blocks in pixelHeight*
-                    for each pixel or block_of_pixels in pixelWidth
-                        Byte data[format-specific-number-of-bytes]**
-                    end
-                end
-            end
-            Byte cubePadding[0-3]
-        end
-    end
-    quint8 mipPadding[3 - ((imageSize + 3) % 4)]
-    */
-};
-
-bool QSGKtxHandler::canRead(const QByteArray &suffix, const QByteArray &block)
-{
-    Q_UNUSED(suffix)
-
-    return (qstrncmp(block.constData(), ktxIdentifier, KTX_IDENTIFIER_LENGTH) == 0);
-}
-
-QQuickTextureFactory *QSGKtxHandler::read()
-{
-    if (!device())
-        return nullptr;
-
-    QByteArray buf = device()->readAll();
-    if (buf.size() < headerSize || !canRead(QByteArray(), buf)) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Invalid KTX file %s", logName().constData());
-        return nullptr;
-    }
-
-    const KTXHeader *header = reinterpret_cast<const KTXHeader *>(buf.constData());
-    if (!checkHeader(*header)) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Unsupported KTX file format in %s", logName().constData());
-        return nullptr;
-    }
-
-    QSGCompressedTexture::DataPtr texData(QSGCompressedTexture::DataPtr::create());
-
-    texData->size = QSize(decode(header->pixelWidth), decode(header->pixelHeight));
-    texData->format = decode(header->glInternalFormat);
-    texData->hasAlpha = !QSGCompressedTexture::formatIsOpaque(texData->format);
-
-    // For now, ignore any additional mipmap levels
-    int preambleSize = headerSize + decode(header->bytesOfKeyValueData);
-    if (buf.size() >= preambleSize + int(sizeof(KTXMipmapLevel))) {
-        texData->data = buf;
-        texData->dataOffset = preambleSize + sizeof(quint32); // for the imageSize
-        const KTXMipmapLevel *level = reinterpret_cast<const KTXMipmapLevel *>(buf.constData() + preambleSize);
-        texData->dataLength = decode(level->imageSize);
-    }
-
-    if (!texData->isValid()) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Invalid values in header of KTX file %s", logName().constData());
-        return nullptr;
-    }
-
-    texData->logName = logName();
-#ifdef KTX_DEBUG
-    qDebug() << "KTX file handler read" << texData.data();
-#endif
-
-    return new QSGCompressedTextureFactory(texData);
-}
-
-bool QSGKtxHandler::checkHeader(const KTXHeader &header)
-{
-    if (header.endianness != platformEndianIdentifier && header.endianness != inversePlatformEndianIdentifier)
-        return false;
-    inverseEndian = (header.endianness == inversePlatformEndianIdentifier);
-#ifdef KTX_DEBUG
-    QMetaEnum tfme = QMetaEnum::fromType<QOpenGLTexture::TextureFormat>();
-    QMetaEnum ptme = QMetaEnum::fromType<QOpenGLTexture::PixelType>();
-    qDebug("Header of %s:", logName().constData());
-    qDebug("  glType: 0x%x (%s)", decode(header.glType), ptme.valueToKey(decode(header.glType)));
-    qDebug("  glTypeSize: %u", decode(header.glTypeSize));
-    qDebug("  glFormat: 0x%x (%s)", decode(header.glFormat), tfme.valueToKey(decode(header.glFormat)));
-    qDebug("  glInternalFormat: 0x%x (%s)", decode(header.glInternalFormat), tfme.valueToKey(decode(header.glInternalFormat)));
-    qDebug("  glBaseInternalFormat: 0x%x (%s)", decode(header.glBaseInternalFormat), tfme.valueToKey(decode(header.glBaseInternalFormat)));
-    qDebug("  pixelWidth: %u", decode(header.pixelWidth));
-    qDebug("  pixelHeight: %u", decode(header.pixelHeight));
-    qDebug("  pixelDepth: %u", decode(header.pixelDepth));
-    qDebug("  numberOfArrayElements: %u", decode(header.numberOfArrayElements));
-    qDebug("  numberOfFaces: %u", decode(header.numberOfFaces));
-    qDebug("  numberOfMipmapLevels: %u", decode(header.numberOfMipmapLevels));
-    qDebug("  bytesOfKeyValueData: %u", decode(header.bytesOfKeyValueData));
-#endif
-    return ((decode(header.glType) == 0) &&
-            (decode(header.glFormat) == 0) &&
-            (decode(header.pixelDepth) == 0) &&
-            (decode(header.numberOfFaces) == 1));
-}
-
-quint32 QSGKtxHandler::decode(quint32 val)
-{
-    return inverseEndian ? qbswap<quint32>(val) : val;
-}
-
-QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/compressedtexture/qsgktxhandler_p.h b/src/quick/scenegraph/compressedtexture/qsgktxhandler_p.h
deleted file mode 100644
index 22f4db65b2..0000000000
--- a/src/quick/scenegraph/compressedtexture/qsgktxhandler_p.h
+++ /dev/null
@@ -1,78 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2017 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QSGKTXHANDLER_H
-#define QSGKTXHANDLER_H
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the Qt API.  It exists purely as an
-// implementation detail.  This header file may change from version to
-// version without notice, or even be removed.
-//
-// We mean it.
-//
-
-#include "qsgtexturefilehandler_p.h"
-
-QT_BEGIN_NAMESPACE
-
-struct KTXHeader;
-
-class QSGKtxHandler : public QSGTextureFileHandler
-{
-public:
-    using QSGTextureFileHandler::QSGTextureFileHandler;
-
-    static bool canRead(const QByteArray &suffix, const QByteArray &block);
-
-    QQuickTextureFactory *read() override;
-
-private:
-    bool checkHeader(const KTXHeader &header);
-    quint32 decode(quint32 val);
-
-    bool inverseEndian = false;
-};
-
-QT_END_NAMESPACE
-
-#endif // QSGKTXHANDLER_H
diff --git a/src/quick/scenegraph/compressedtexture/qsgpkmhandler.cpp b/src/quick/scenegraph/compressedtexture/qsgpkmhandler.cpp
deleted file mode 100644
index 618c0db045..0000000000
--- a/src/quick/scenegraph/compressedtexture/qsgpkmhandler.cpp
+++ /dev/null
@@ -1,118 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2017 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#include "qsgpkmhandler_p.h"
-#include "qsgcompressedtexture_p.h"
-
-#include <QFile>
-#include <QDebug>
-#include <qendian.h>
-#include <qopenglfunctions.h>
-#include <qqmlfile.h>
-#include <QOpenGLTexture>
-
-//#define ETC_DEBUG
-
-QT_BEGIN_NAMESPACE
-
-static const int headerSize = 16;
-
-static unsigned int typeMap[5] = {
-    QOpenGLTexture::RGB8_ETC1,                     // GL_ETC1_RGB8_OES,
-    QOpenGLTexture::RGB8_ETC2,                     // GL_COMPRESSED_RGB8_ETC2,
-    0,                                             // unused (obsolete)
-    QOpenGLTexture::RGBA8_ETC2_EAC,                // GL_COMPRESSED_RGBA8_ETC2_EAC,
-    QOpenGLTexture::RGB8_PunchThrough_Alpha1_ETC2  // GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
-};
-
-bool QSGPkmHandler::canRead(const QByteArray &suffix, const QByteArray &block)
-{
-    Q_UNUSED(suffix)
-
-    return block.startsWith("PKM ");
-}
-
-QQuickTextureFactory *QSGPkmHandler::read()
-{
-    if (!device())
-        return nullptr;
-
-    QSGCompressedTexture::DataPtr texData(QSGCompressedTexture::DataPtr::create());
-
-    texData->data = device()->readAll();
-    if (texData->data.size() < headerSize || !canRead(QByteArray(), texData->data)) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Invalid PKM file %s", logName().constData());
-        return nullptr;
-    }
-
-    const char *rawData = texData->data.constData();
-
-    // ignore version (rawData + 4 & 5)
-
-    // texture type
-    quint16 type = qFromBigEndian<quint16>(rawData + 6);
-    if (type > sizeof(typeMap)/sizeof(typeMap[0])) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Unknown compression format in PKM file %s", logName().constData());
-        return nullptr;
-    }
-    texData->format = typeMap[type];
-    texData->hasAlpha = !QSGCompressedTexture::formatIsOpaque(texData->format);
-
-    // texture size
-    const int bpb = (texData->format == QOpenGLTexture::RGBA8_ETC2_EAC) ? 16 : 8;
-    QSize paddedSize(qFromBigEndian<quint16>(rawData + 8), qFromBigEndian<quint16>(rawData + 10));
-    texData->dataLength = (paddedSize.width() / 4) * (paddedSize.height() / 4) * bpb;
-    QSize texSize(qFromBigEndian<quint16>(rawData + 12), qFromBigEndian<quint16>(rawData + 14));
-    texData->size = texSize;
-
-    texData->dataOffset = headerSize;
-
-    if (!texData->isValid()) {
-        qCDebug(QSG_LOG_TEXTUREIO, "Invalid values in header of PKM file %s", logName().constData());
-        return nullptr;
-    }
-
-    texData->logName = logName();
-#ifdef ETC_DEBUG
-    qDebug() << "PKM file handler read" << texData.data();
-#endif
-    return new QSGCompressedTextureFactory(texData);
-}
-
-QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/compressedtexture/qsgpkmhandler_p.h b/src/quick/scenegraph/compressedtexture/qsgpkmhandler_p.h
deleted file mode 100644
index 6154c51b84..0000000000
--- a/src/quick/scenegraph/compressedtexture/qsgpkmhandler_p.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2017 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QSGPKMHANDLER_H
-#define QSGPKMHANDLER_H
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the Qt API.  It exists purely as an
-// implementation detail.  This header file may change from version to
-// version without notice, or even be removed.
-//
-// We mean it.
-//
-
-#include "qsgtexturefilehandler_p.h"
-
-QT_BEGIN_NAMESPACE
-
-class QSGPkmHandler : public QSGTextureFileHandler
-{
-public:
-    using QSGTextureFileHandler::QSGTextureFileHandler;
-
-    static bool canRead(const QByteArray &suffix, const QByteArray &block);
-
-    QQuickTextureFactory *read() override;
-};
-
-QT_END_NAMESPACE
-
-#endif // QSGPKMHANDLER_H
diff --git a/src/quick/scenegraph/compressedtexture/qsgtexturefilehandler_p.h b/src/quick/scenegraph/compressedtexture/qsgtexturefilehandler_p.h
deleted file mode 100644
index 8b831aebb9..0000000000
--- a/src/quick/scenegraph/compressedtexture/qsgtexturefilehandler_p.h
+++ /dev/null
@@ -1,83 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2017 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QSGTEXTUREFILEHANDLER_P_H
-#define QSGTEXTUREFILEHANDLER_P_H
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the Qt API.  It exists purely as an
-// implementation detail.  This header file may change from version to
-// version without notice, or even be removed.
-//
-// We mean it.
-//
-
-#include <QLoggingCategory>
-
-QT_BEGIN_NAMESPACE
-
-Q_DECLARE_LOGGING_CATEGORY(QSG_LOG_TEXTUREIO)
-
-class QQuickTextureFactory;
-
-class QSGTextureFileHandler
-{
-public:
-    QSGTextureFileHandler(QIODevice *device, const QByteArray &logName = QByteArray())
-        : m_device(device)
-    {
-        m_logName = !logName.isEmpty() ? logName : QByteArrayLiteral("(unknown)");
-    }
-    virtual ~QSGTextureFileHandler() {}
-
-    virtual QQuickTextureFactory *read() = 0;
-    QIODevice *device() const { return m_device; }
-    QByteArray logName() const { return m_logName; }
-
-private:
-    QIODevice *m_device = nullptr;
-    QByteArray m_logName;
-};
-
-QT_END_NAMESPACE
-
-#endif // QSGTEXTUREFILEHANDLER_P_H
diff --git a/src/quick/scenegraph/scenegraph.pri b/src/quick/scenegraph/scenegraph.pri
index 4f98638487..f08e8b7863 100644
--- a/src/quick/scenegraph/scenegraph.pri
+++ b/src/quick/scenegraph/scenegraph.pri
@@ -230,14 +230,9 @@ SOURCES += \
 qtConfig(opengl(es1|es2)?) {
     HEADERS += \
         $$PWD/compressedtexture/qsgcompressedatlastexture_p.h \
-        $$PWD/compressedtexture/qsgcompressedtexture_p.h \
-        $$PWD/compressedtexture/qsgtexturefilehandler_p.h \
-        $$PWD/compressedtexture/qsgpkmhandler_p.h \
-        $$PWD/compressedtexture/qsgktxhandler_p.h
+        $$PWD/compressedtexture/qsgcompressedtexture_p.h
 
     SOURCES += \
         $$PWD/compressedtexture/qsgcompressedatlastexture.cpp \
-        $$PWD/compressedtexture/qsgcompressedtexture.cpp \
-        $$PWD/compressedtexture/qsgpkmhandler.cpp \
-        $$PWD/compressedtexture/qsgktxhandler.cpp
+        $$PWD/compressedtexture/qsgcompressedtexture.cpp
 }
diff --git a/src/quick/scenegraph/util/qsgatlastexture.cpp b/src/quick/scenegraph/util/qsgatlastexture.cpp
index 97203db867..66c6d3a882 100644
--- a/src/quick/scenegraph/util/qsgatlastexture.cpp
+++ b/src/quick/scenegraph/util/qsgatlastexture.cpp
@@ -143,11 +143,11 @@ QSGTexture *Manager::create(const QImage &image, bool hasAlphaChannel)
 QSGTexture *Manager::create(const QSGCompressedTextureFactory *factory)
 {
     QSGTexture *t = nullptr;
-    if (!qsgEnableCompressedAtlas() || !factory->m_textureData || !factory->m_textureData->isValid())
+    if (!qsgEnableCompressedAtlas() || !factory->m_textureData.isValid())
         return t;
 
     // TODO: further abstract the atlas and remove this restriction
-    unsigned int format = factory->m_textureData->format;
+    unsigned int format = factory->m_textureData.glInternalFormat();
     switch (format) {
     case QOpenGLTexture::RGB8_ETC1:
     case QOpenGLTexture::RGB8_ETC2:
@@ -158,15 +158,15 @@ QSGTexture *Manager::create(const QSGCompressedTextureFactory *factory)
         return t;
     }
 
-    QSize size = factory->m_textureData->size;
+    QSize size = factory->m_textureData.size();
     if (size.width() < m_atlas_size_limit && size.height() < m_atlas_size_limit) {
         QHash<unsigned int, QSGCompressedAtlasTexture::Atlas*>::iterator i = m_atlases.find(format);
         if (i == m_atlases.end())
             i = m_atlases.insert(format, new QSGCompressedAtlasTexture::Atlas(m_atlas_size, format));
         // must be multiple of 4
         QSize paddedSize(((size.width() + 3) / 4) * 4, ((size.height() + 3) / 4) * 4);
-        QByteArray data = factory->m_textureData->data;
-        t = i.value()->create(data, factory->m_textureData->sizeInBytes(), factory->m_textureData->dataOffset, size, paddedSize);
+        QByteArray data = factory->m_textureData.data();
+        t = i.value()->create(data, factory->m_textureData.dataLength(), factory->m_textureData.dataOffset(), size, paddedSize);
     }
     return t;
 }
diff --git a/src/quick/scenegraph/util/qsgtexturereader.cpp b/src/quick/scenegraph/util/qsgtexturereader.cpp
index 8e95f27120..27ba119f63 100644
--- a/src/quick/scenegraph/util/qsgtexturereader.cpp
+++ b/src/quick/scenegraph/util/qsgtexturereader.cpp
@@ -38,36 +38,37 @@
 ****************************************************************************/
 
 #include "qsgtexturereader_p.h"
-
-#include <private/qtquickglobal_p.h>
-
-#include <private/qsgtexturefilehandler_p.h>
-
-#if QT_CONFIG(opengl)
-#include <private/qsgpkmhandler_p.h>
-#include <private/qsgktxhandler_p.h>
-#endif
-
-#include <QFileInfo>
+#include <private/qsgcompressedtexture_p.h>
+#include <private/qtexturefilereader_p.h>
 
 QT_BEGIN_NAMESPACE
 
 QSGTextureReader::QSGTextureReader(QIODevice *device, const QString &fileName)
-    : m_device(device), m_fileInfo(fileName)
 {
+#if QT_CONFIG(opengl)
+    m_reader = new QTextureFileReader(device, fileName);
+#else
+    Q_UNUSED(device);
+    Q_UNUSED(fileName);
+#endif
 }
 
 QSGTextureReader::~QSGTextureReader()
 {
-    delete m_handler;
+    delete m_reader;
 }
 
 QQuickTextureFactory *QSGTextureReader::read()
 {
 #if QT_CONFIG(opengl)
-    if (!isTexture())
+    if (!m_reader)
+        return nullptr;
+
+    QTextureFileData texData = m_reader->read();
+    if (!texData.isValid())
         return nullptr;
-    return m_handler->read();
+
+    return new QSGCompressedTextureFactory(texData);
 #else
     return nullptr;
 #endif
@@ -75,41 +76,12 @@ QQuickTextureFactory *QSGTextureReader::read()
 
 bool QSGTextureReader::isTexture()
 {
-#if QT_CONFIG(opengl)
-    if (!checked) {
-        checked = true;
-        if (!init())
-            return false;
-
-        QByteArray headerBlock = m_device->peek(64);
-        QByteArray suffix = m_fileInfo.suffix().toLower().toLatin1();
-        QByteArray logName = m_fileInfo.fileName().toUtf8();
-
-        // Currently the handlers are hardcoded; later maybe a list of plugins
-        if (QSGPkmHandler::canRead(suffix, headerBlock)) {
-            m_handler = new QSGPkmHandler(m_device, logName);
-        } else if (QSGKtxHandler::canRead(suffix, headerBlock)) {
-            m_handler = new QSGKtxHandler(m_device, logName);
-        }
-        // else if OtherHandler::canRead() ...etc.
-    }
-    return (m_handler != nullptr);
-#else
-    return false;
-#endif
+    return m_reader ? m_reader->canRead() : false;
 }
 
 QList<QByteArray> QSGTextureReader::supportedFileFormats()
 {
-    // Hardcoded for now
-    return {QByteArrayLiteral("pkm"), QByteArrayLiteral("ktx")};
-}
-
-bool QSGTextureReader::init()
-{
-    if (!m_device)
-        return false;
-    return m_device->isReadable();
+    return QTextureFileReader::supportedFileFormats();
 }
 
 QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/util/qsgtexturereader_p.h b/src/quick/scenegraph/util/qsgtexturereader_p.h
index 19e33bf5c3..20c17fce50 100644
--- a/src/quick/scenegraph/util/qsgtexturereader_p.h
+++ b/src/quick/scenegraph/util/qsgtexturereader_p.h
@@ -58,7 +58,7 @@ QT_BEGIN_NAMESPACE
 
 class QIODevice;
 class QQuickTextureFactory;
-class QSGTextureFileHandler;
+class QTextureFileReader;
 
 class QSGTextureReader
 {
@@ -75,11 +75,7 @@ public:
     static QList<QByteArray> supportedFileFormats();
 
 private:
-    bool init();
-    QIODevice *m_device = nullptr;
-    QFileInfo m_fileInfo;
-    QSGTextureFileHandler *m_handler = nullptr;
-    bool checked = false;
+    QTextureFileReader *m_reader = nullptr;
 };
 
 QT_END_NAMESPACE