Add ETC1 texture provider example.

This code was removed as a labs import in commit
732a86a11dbc20079e33c289af72762ce0125ced. Bring it back as an example.

Change-Id: I057d721117dc75256c4a7229c4f8fad8dc9ac6b2
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>

9 files changed, 464 insertions, 0 deletions

diff --git a/examples/quick/textureprovider/Label.qml b/examples/quick/textureprovider/Label.qml
new file mode 100644
index 0000000000..990ac247dc
--- /dev/null
+++ b/examples/quick/textureprovider/Label.qml
@@ -0,0 +1,49 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Text {
+    font.pixelSize: 26
+    style: Text.Outline; styleColor: "white"
+    anchors.horizontalCenter: parent.horizontalCenter
+    anchors.bottom: parent.bottom
+    anchors.bottomMargin: 20
+}
diff --git a/examples/quick/textureprovider/etcprovider.cpp b/examples/quick/textureprovider/etcprovider.cpp
new file mode 100644
index 0000000000..0bb072ffaf
--- /dev/null
+++ b/examples/quick/textureprovider/etcprovider.cpp
@@ -0,0 +1,193 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the demonstration applications 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "etcprovider.h"
+
+#include <QFile>
+#include <QDebug>
+#include <qopenglfunctions.h>
+
+//#define ETC_DEBUG
+
+#ifndef GL_ETC1_RGB8_OES
+    #define GL_ETC1_RGB8_OES 0x8d64
+#endif
+
+typedef struct {
+    char aName[6];
+    unsigned short iBlank;
+    /* NB: Beware endianness issues here. */
+    unsigned char iPaddedWidthMSB;
+    unsigned char iPaddedWidthLSB;
+    unsigned char iPaddedHeightMSB;
+    unsigned char iPaddedHeightLSB;
+    unsigned char iWidthMSB;
+    unsigned char iWidthLSB;
+    unsigned char iHeightMSB;
+    unsigned char iHeightLSB;
+} ETCHeader;
+
+unsigned short getWidth(ETCHeader *pHeader)
+{
+    return (pHeader->iWidthMSB << 8) | pHeader->iWidthLSB;
+}
+
+unsigned short getHeight(ETCHeader *pHeader)
+{
+    return (pHeader->iHeightMSB << 8) | pHeader->iHeightLSB;
+}
+
+unsigned short getPaddedWidth(ETCHeader *pHeader)
+{
+    return (pHeader->iPaddedWidthMSB << 8) | pHeader->iPaddedWidthLSB;
+}
+
+unsigned short getPaddedHeight(ETCHeader *pHeader)
+{
+    return (pHeader->iPaddedHeightMSB << 8) | pHeader->iPaddedHeightLSB;
+}
+
+EtcTexture::EtcTexture()
+    : m_texture_id(0)
+{
+
+}
+
+EtcTexture::~EtcTexture()
+{
+    if (m_texture_id)
+        glDeleteTextures(1, &m_texture_id);
+}
+
+void EtcTexture::bind()
+{
+    if (m_texture_id) {
+        glBindTexture(GL_TEXTURE_2D, m_texture_id);
+        return;
+    }
+
+    glGenTextures(1, &m_texture_id);
+    glBindTexture(GL_TEXTURE_2D, m_texture_id);
+
+#ifdef ETC_DEBUG
+    qDebug() << "glCompressedTexImage2D, width: " << m_size.width() << "height" << m_size.height() <<
+                "paddedWidth: " << m_paddedSize.width() << "paddedHeight: " << m_paddedSize.height();
+#endif
+
+    QOpenGLContext *ctx = QOpenGLContext::currentContext();
+    Q_ASSERT(ctx != 0);
+    ctx->functions()->glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_ETC1_RGB8_OES,
+                                             m_size.width(), m_size.height(), 0,
+                                             (m_paddedSize.width() * m_paddedSize.height()) >> 1,
+                                             m_data.data() + 16);
+
+    // Gracefully fail in case of an error...
+    GLuint error = glGetError();
+    if (error != GL_NO_ERROR) {
+        qDebug () << "glCompressedTexImage2D for compressed texture failed, error: " << error;
+        glBindTexture(GL_TEXTURE_2D, 0);
+        glDeleteTextures(1, &m_texture_id);
+        m_texture_id = 0;
+        return;
+    }
+
+    updateBindOptions(true);
+}
+
+class QEtcTextureFactory : public QQuickTextureFactory
+{
+public:
+    QByteArray m_data;
+    QSize m_size;
+    QSize m_paddedSize;
+
+    QSize textureSize() const { return m_size; }
+    int textureByteCount() const { return m_data.size(); }
+
+    QSGTexture *createTexture(QQuickWindow *) const {
+        EtcTexture *texture = new EtcTexture;
+        texture->m_data = m_data;
+        texture->m_size = m_size;
+        texture->m_paddedSize = m_paddedSize;
+        return texture;
+    }
+};
+
+QQuickTextureFactory *EtcProvider::requestTexture(const QString &id, QSize *size, const QSize &requestedSize)
+{
+    Q_UNUSED(requestedSize);
+    QEtcTextureFactory *ret = 0;
+
+    size->setHeight(0);
+    size->setWidth(0);
+
+    // resolve paths relative to qrc file
+    QFile file(QLatin1String(":/textureprovider/") + id);
+#ifdef ETC_DEBUG
+    qDebug() << "requestTexture opening file: " << id;
+#endif
+    if (file.open(QIODevice::ReadOnly)) {
+        ret = new QEtcTextureFactory;
+        ret->m_data = file.readAll();
+        if (!ret->m_data.isEmpty()) {
+            ETCHeader *pETCHeader = NULL;
+            pETCHeader = (ETCHeader *)ret->m_data.data();
+            size->setHeight(getHeight(pETCHeader));
+            size->setWidth(getWidth(pETCHeader));
+            ret->m_size = *size;
+            ret->m_paddedSize.setHeight(getPaddedHeight(pETCHeader));
+            ret->m_paddedSize.setWidth(getPaddedWidth(pETCHeader));
+        }
+        else {
+            delete ret;
+            ret = 0;
+        }
+    }
+
+#ifdef ETC_DEBUG
+    if (ret)
+        qDebug() << "requestTexture returning: " << ret->m_data.length() << ", bytes; width: " << size->width() << ", height: " << size->height();
+    else
+        qDebug () << "File not found.";
+#endif
+
+    return ret;
+}
diff --git a/examples/quick/textureprovider/etcprovider.h b/examples/quick/textureprovider/etcprovider.h
new file mode 100644
index 0000000000..4215ea297b
--- /dev/null
+++ b/examples/quick/textureprovider/etcprovider.h
@@ -0,0 +1,80 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the demonstration applications 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef ETCPROVIDER_H
+#define ETCPROVIDER_H
+
+#include <qopengl.h>
+#include <QQuickImageProvider>
+#include <QtQuick/QSGTexture>
+
+class EtcProvider : public QQuickImageProvider
+{
+public:
+    EtcProvider()
+        : QQuickImageProvider(QQuickImageProvider::Texture)
+    {}
+
+    QQuickTextureFactory *requestTexture(const QString &id, QSize *size, const QSize &requestedSize);
+};
+
+class EtcTexture : public QSGTexture
+{
+    Q_OBJECT
+public:
+    EtcTexture();
+    ~EtcTexture();
+
+    void bind();
+
+    QSize textureSize() const { return m_size; }
+    int textureId() const { return m_texture_id; }
+
+    bool hasAlphaChannel() const { return false; }
+    bool hasMipmaps() const { return false; }
+
+    QByteArray m_data;
+    QSize m_size;
+    QSize m_paddedSize;
+    GLuint m_texture_id;
+};
+
+#endif // ETCPROVIDER_H
diff --git a/examples/quick/textureprovider/images/qt-logo.jpg b/examples/quick/textureprovider/images/qt-logo.jpg
new file mode 100644
index 0000000000..32d151c2c5
--- /dev/null
+++ b/examples/quick/textureprovider/images/qt-logo.jpg
diff --git a/examples/quick/textureprovider/images/qt-logo.pkm b/examples/quick/textureprovider/images/qt-logo.pkm
new file mode 100644
index 0000000000..3329031ab2
--- /dev/null
+++ b/examples/quick/textureprovider/images/qt-logo.pkm
diff --git a/examples/quick/textureprovider/main.cpp b/examples/quick/textureprovider/main.cpp
new file mode 100644
index 0000000000..d9d4fb0d38
--- /dev/null
+++ b/examples/quick/textureprovider/main.cpp
@@ -0,0 +1,56 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QGuiApplication>
+#include <QQuickView>
+
+#include "etcprovider.h"
+
+int main(int argc, char* argv[])
+{
+    QGuiApplication app(argc,argv);
+    QQuickView view;
+
+    view.engine()->addImageProvider("etc", new EtcProvider());
+
+    view.setSource(QUrl("qrc:///textureprovider/textureprovider.qml"));
+    view.show();
+    return app.exec();
+}
diff --git a/examples/quick/textureprovider/textureprovider.pro b/examples/quick/textureprovider/textureprovider.pro
new file mode 100644
index 0000000000..5d9825f7ac
--- /dev/null
+++ b/examples/quick/textureprovider/textureprovider.pro
@@ -0,0 +1,13 @@
+TEMPLATE = app
+
+QT += quick qml
+
+HEADERS += etcprovider.h
+
+SOURCES += main.cpp \
+           etcprovider.cpp
+
+RESOURCES += textureprovider.qrc
+
+target.path = $$[QT_INSTALL_EXAMPLES]/quick/textureprovider
+INSTALLS += target
diff --git a/examples/quick/textureprovider/textureprovider.qml b/examples/quick/textureprovider/textureprovider.qml
new file mode 100644
index 0000000000..9854bef229
--- /dev/null
+++ b/examples/quick/textureprovider/textureprovider.qml
@@ -0,0 +1,65 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Row {
+    width: 512
+    height: 256
+
+    Image {
+        source: "images/qt-logo.jpg"
+
+        Label { text: "Original Image" }
+    }
+
+    Image {
+        source: "image://etc/images/qt-logo.pkm"
+
+        Label { id: clabel; text: "Compressed Texture" }
+        Text {
+            text: "(requires ETC1 support)"
+            anchors.horizontalCenter: clabel.horizontalCenter
+            anchors.top: clabel.bottom
+            font.pixelSize: 14
+            color: "white"
+        }
+    }
+}
diff --git a/examples/quick/textureprovider/textureprovider.qrc b/examples/quick/textureprovider/textureprovider.qrc
new file mode 100644
index 0000000000..77a568ba1d
--- /dev/null
+++ b/examples/quick/textureprovider/textureprovider.qrc
@@ -0,0 +1,8 @@
+<RCC>
+    <qresource prefix="/textureprovider">
+        <file>images/qt-logo.jpg</file>
+        <file>images/qt-logo.pkm</file>
+        <file>textureprovider.qml</file>
+        <file>Label.qml</file>
+    </qresource>
+</RCC>