[Shader Graph Gen.] Introduce QShaderGraphLoader

This class allows to load a shader graph from its JSON representation.
To avoid duplicating the shader snippets inside of the JSON which would
be a maintenance nightmare, we instead allow to register a set of node
prototypes by their name and only refer to said names inside the JSON.

Change-Id: I3e7b39e8b3c25f51f331a0a59dda883ac8e2bc57
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

6 files changed, 863 insertions, 0 deletions

diff --git a/src/gui/util/qshadergraphloader.cpp b/src/gui/util/qshadergraphloader.cpp
new file mode 100644
index 0000000000..d246654b9c
--- /dev/null
+++ b/src/gui/util/qshadergraphloader.cpp
@@ -0,0 +1,204 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui 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 "qshadergraphloader_p.h"
+
+#include <QtCore/qdebug.h>
+#include <QtCore/qiodevice.h>
+#include <QtCore/qjsonarray.h>
+#include <QtCore/qjsondocument.h>
+#include <QtCore/qjsonobject.h>
+
+QT_BEGIN_NAMESPACE
+
+QShaderGraphLoader::QShaderGraphLoader() Q_DECL_NOTHROW
+    : m_status(Null),
+      m_device(nullptr)
+{
+}
+
+QShaderGraphLoader::Status QShaderGraphLoader::status() const Q_DECL_NOTHROW
+{
+    return m_status;
+}
+
+QShaderGraph QShaderGraphLoader::graph() const Q_DECL_NOTHROW
+{
+    return m_graph;
+}
+
+QIODevice *QShaderGraphLoader::device() const Q_DECL_NOTHROW
+{
+    return m_device;
+}
+
+void QShaderGraphLoader::setDevice(QIODevice *device) Q_DECL_NOTHROW
+{
+    m_device = device;
+    m_graph = QShaderGraph();
+    m_status = !m_device ? Null
+             : (m_device->openMode() & QIODevice::ReadOnly) ? Waiting
+             : Error;
+}
+
+QHash<QString, QShaderNode> QShaderGraphLoader::prototypes() const Q_DECL_NOTHROW
+{
+    return m_prototypes;
+}
+
+void QShaderGraphLoader::setPrototypes(const QHash<QString, QShaderNode> &prototypes) Q_DECL_NOTHROW
+{
+    m_prototypes = prototypes;
+}
+
+void QShaderGraphLoader::load()
+{
+    if (m_status == Error)
+        return;
+
+    auto error = QJsonParseError();
+    const auto document = QJsonDocument::fromJson(m_device->readAll(), &error);
+
+    if (error.error != QJsonParseError::NoError) {
+        qWarning() << "Invalid JSON document:" << error.errorString();
+        m_status = Error;
+        return;
+    }
+
+    if (document.isEmpty() || !document.isObject()) {
+        qWarning() << "Invalid JSON document, root should be an object";
+        m_status = Error;
+        return;
+    }
+
+    const auto root = document.object();
+
+    const auto nodesValue = root.value(QStringLiteral("nodes"));
+    if (!nodesValue.isArray()) {
+        qWarning() << "Invalid nodes property, should be an array";
+        m_status = Error;
+        return;
+    }
+
+    const auto edgesValue = root.value(QStringLiteral("edges"));
+    if (!edgesValue.isArray()) {
+        qWarning() << "Invalid edges property, should be an array";
+        m_status = Error;
+        return;
+    }
+
+    bool hasError = false;
+
+    const auto nodes = nodesValue.toArray();
+    for (const auto &nodeValue : nodes) {
+        if (!nodeValue.isObject()) {
+            qWarning() << "Invalid node found";
+            hasError = true;
+            continue;
+        }
+
+        const auto nodeObject = nodeValue.toObject();
+
+        const auto uuidString = nodeObject.value(QStringLiteral("uuid")).toString();
+        const auto uuid = QUuid(uuidString);
+        if (uuid.isNull()) {
+            qWarning() << "Invalid UUID found in node:" << uuidString;
+            hasError = true;
+            continue;
+        }
+
+        const auto type = nodeObject.value(QStringLiteral("type")).toString();
+        if (!m_prototypes.contains(type)) {
+            qWarning() << "Unsupported node type found:" << type;
+            hasError = true;
+            continue;
+        }
+
+        auto node = m_prototypes.value(type);
+        node.setUuid(uuid);
+        m_graph.addNode(node);
+    }
+
+    const auto edges = edgesValue.toArray();
+    for (const auto &edgeValue : edges) {
+        if (!edgeValue.isObject()) {
+            qWarning() << "Invalid edge found";
+            hasError = true;
+            continue;
+        }
+
+        const auto edgeObject = edgeValue.toObject();
+
+        const auto sourceUuidString = edgeObject.value(QStringLiteral("sourceUuid")).toString();
+        const auto sourceUuid = QUuid(sourceUuidString);
+        if (sourceUuid.isNull()) {
+            qWarning() << "Invalid source UUID found in edge:" << sourceUuidString;
+            hasError = true;
+            continue;
+        }
+
+        const auto sourcePort = edgeObject.value(QStringLiteral("sourcePort")).toString();
+
+        const auto targetUuidString = edgeObject.value(QStringLiteral("targetUuid")).toString();
+        const auto targetUuid = QUuid(targetUuidString);
+        if (targetUuid.isNull()) {
+            qWarning() << "Invalid target UUID found in edge:" << targetUuidString;
+            hasError = true;
+            continue;
+        }
+
+        const auto targetPort = edgeObject.value(QStringLiteral("targetPort")).toString();
+
+        auto edge = QShaderGraph::Edge();
+        edge.sourceNodeUuid = sourceUuid;
+        edge.sourcePortName = sourcePort;
+        edge.targetNodeUuid = targetUuid;
+        edge.targetPortName = targetPort;
+        m_graph.addEdge(edge);
+    }
+
+    if (hasError) {
+        m_status = Error;
+        m_graph = QShaderGraph();
+    } else {
+        m_status = Ready;
+    }
+}
+
+QT_END_NAMESPACE
diff --git a/src/gui/util/qshadergraphloader_p.h b/src/gui/util/qshadergraphloader_p.h
new file mode 100644
index 0000000000..97cbd8d18c
--- /dev/null
+++ b/src/gui/util/qshadergraphloader_p.h
@@ -0,0 +1,99 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui 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 QSHADERGRAPHLOADER_P_H
+#define QSHADERGRAPHLOADER_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 <QtGui/private/qtguiglobal_p.h>
+
+#include <QtGui/private/qshadergraph_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QIODevice;
+
+class QShaderGraphLoader
+{
+public:
+    enum Status : char {
+        Null,
+        Waiting,
+        Ready,
+        Error
+    };
+
+    Q_GUI_EXPORT QShaderGraphLoader() Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT Status status() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT QShaderGraph graph() const Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT QIODevice *device() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT void setDevice(QIODevice *device) Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT QHash<QString, QShaderNode> prototypes() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT void setPrototypes(const QHash<QString, QShaderNode> &prototypes) Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT void load();
+
+private:
+    Status m_status;
+    QIODevice *m_device;
+    QHash<QString, QShaderNode> m_prototypes;
+    QShaderGraph m_graph;
+};
+
+Q_DECLARE_TYPEINFO(QShaderGraphLoader, Q_MOVABLE_TYPE);
+
+QT_END_NAMESPACE
+
+Q_DECLARE_METATYPE(QShaderGraphLoader)
+Q_DECLARE_METATYPE(QShaderGraphLoader::Status)
+
+#endif // QSHADERGRAPHLOADER_P_H
diff --git a/src/gui/util/util.pri b/src/gui/util/util.pri
index e7feda9a4a..bb7a802fd8 100644
--- a/src/gui/util/util.pri
+++ b/src/gui/util/util.pri
@@ -10,6 +10,7 @@ HEADERS += \
         util/qshaderformat_p.h \
         util/qshadergenerator_p.h \
         util/qshadergraph_p.h \
+        util/qshadergraphloader_p.h \
         util/qshadernode_p.h \
         util/qshadernodeport_p.h
 
@@ -22,5 +23,6 @@ SOURCES += \
         util/qshaderformat.cpp \
         util/qshadergenerator.cpp \
         util/qshadergraph.cpp \
+        util/qshadergraphloader.cpp \
         util/qshadernode.cpp \
         util/qshadernodeport.cpp
diff --git a/tests/auto/gui/util/qshadergraphloader/qshadergraphloader.pro b/tests/auto/gui/util/qshadergraphloader/qshadergraphloader.pro
new file mode 100644
index 0000000000..e80a93f9e8
--- /dev/null
+++ b/tests/auto/gui/util/qshadergraphloader/qshadergraphloader.pro
@@ -0,0 +1,5 @@
+CONFIG += testcase
+QT += testlib gui-private
+
+SOURCES += tst_qshadergraphloader.cpp
+TARGET = tst_qshadergraphloader
diff --git a/tests/auto/gui/util/qshadergraphloader/tst_qshadergraphloader.cpp b/tests/auto/gui/util/qshadergraphloader/tst_qshadergraphloader.cpp
new file mode 100644
index 0000000000..418370fa2a
--- /dev/null
+++ b/tests/auto/gui/util/qshadergraphloader/tst_qshadergraphloader.cpp
@@ -0,0 +1,552 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include <QtTest/QtTest>
+
+#include <QtCore/qbuffer.h>
+
+#include <QtGui/private/qshadergraphloader_p.h>
+
+using QBufferPointer = QSharedPointer<QBuffer>;
+Q_DECLARE_METATYPE(QBufferPointer);
+
+using PrototypeHash = QHash<QString, QShaderNode>;
+Q_DECLARE_METATYPE(PrototypeHash);
+
+namespace
+{
+    QBufferPointer createBuffer(const QByteArray &data, QIODevice::OpenMode openMode = QIODevice::ReadOnly)
+    {
+        auto buffer = QBufferPointer::create();
+        buffer->setData(data);
+        if (openMode != QIODevice::NotOpen)
+            buffer->open(openMode);
+        return buffer;
+    }
+
+    QShaderFormat createFormat(QShaderFormat::Api api, int majorVersion, int minorVersion)
+    {
+        auto format = QShaderFormat();
+        format.setApi(api);
+        format.setVersion(QVersionNumber(majorVersion, minorVersion));
+        return format;
+    }
+
+    QShaderNodePort createPort(QShaderNodePort::Direction portDirection, const QString &portName)
+    {
+        auto port = QShaderNodePort();
+        port.direction = portDirection;
+        port.name = portName;
+        return port;
+    }
+
+    QShaderNode createNode(const QVector<QShaderNodePort> &ports)
+    {
+        auto node = QShaderNode();
+        node.setUuid(QUuid::createUuid());
+        for (const auto &port : ports)
+            node.addPort(port);
+        return node;
+    }
+
+    QShaderGraph::Edge createEdge(const QUuid &sourceUuid, const QString &sourceName,
+                                  const QUuid &targetUuid, const QString &targetName)
+    {
+        auto edge = QShaderGraph::Edge();
+        edge.sourceNodeUuid = sourceUuid;
+        edge.sourcePortName = sourceName;
+        edge.targetNodeUuid = targetUuid;
+        edge.targetPortName = targetName;
+        return edge;
+    }
+
+    QShaderGraph createGraph()
+    {
+        const auto openGLES2 = createFormat(QShaderFormat::OpenGLES, 2, 0);
+        const auto openGL3 = createFormat(QShaderFormat::OpenGLCoreProfile, 3, 0);
+
+        auto graph = QShaderGraph();
+
+        auto worldPosition = createNode({
+            createPort(QShaderNodePort::Output, "worldPosition")
+        });
+        worldPosition.setUuid(QUuid("{00000000-0000-0000-0000-000000000001}"));
+        worldPosition.addRule(openGLES2, QShaderNode::Rule("highp vec3 $worldPosition = worldPosition;",
+                                                           QByteArrayList() << "varying highp vec3 worldPosition;"));
+        worldPosition.addRule(openGL3, QShaderNode::Rule("vec3 $worldPosition = worldPosition;",
+                                                         QByteArrayList() << "in vec3 worldPosition;"));
+
+        auto texture = createNode({
+            createPort(QShaderNodePort::Output, "texture")
+        });
+        texture.setUuid(QUuid("{00000000-0000-0000-0000-000000000002}"));
+        texture.addRule(openGLES2, QShaderNode::Rule("sampler2D $texture = texture;",
+                                                     QByteArrayList() << "uniform sampler2D texture;"));
+        texture.addRule(openGL3, QShaderNode::Rule("sampler2D $texture = texture;",
+                                                   QByteArrayList() << "uniform sampler2D texture;"));
+
+        auto texCoord = createNode({
+            createPort(QShaderNodePort::Output, "texCoord")
+        });
+        texCoord.setUuid(QUuid("{00000000-0000-0000-0000-000000000003}"));
+        texCoord.addRule(openGLES2, QShaderNode::Rule("highp vec2 $texCoord = texCoord;",
+                                                      QByteArrayList() << "varying highp vec2 texCoord;"));
+        texCoord.addRule(openGL3, QShaderNode::Rule("vec2 $texCoord = texCoord;",
+                                                    QByteArrayList() << "in vec2 texCoord;"));
+
+        auto lightIntensity = createNode({
+            createPort(QShaderNodePort::Output, "lightIntensity")
+        });
+        lightIntensity.setUuid(QUuid("{00000000-0000-0000-0000-000000000004}"));
+        lightIntensity.addRule(openGLES2, QShaderNode::Rule("highp float $lightIntensity = lightIntensity;",
+                                                            QByteArrayList() << "uniform highp float lightIntensity;"));
+        lightIntensity.addRule(openGL3, QShaderNode::Rule("float $lightIntensity = lightIntensity;",
+                                                          QByteArrayList() << "uniform float lightIntensity;"));
+
+        auto exposure = createNode({
+            createPort(QShaderNodePort::Output, "exposure")
+        });
+        exposure.setUuid(QUuid("{00000000-0000-0000-0000-000000000005}"));
+        exposure.addRule(openGLES2, QShaderNode::Rule("highp float $exposure = exposure;",
+                                                      QByteArrayList() << "uniform highp float exposure;"));
+        exposure.addRule(openGL3, QShaderNode::Rule("float $exposure = exposure;",
+                                                    QByteArrayList() << "uniform float exposure;"));
+
+        auto fragColor = createNode({
+            createPort(QShaderNodePort::Input, "fragColor")
+        });
+        fragColor.setUuid(QUuid("{00000000-0000-0000-0000-000000000006}"));
+        fragColor.addRule(openGLES2, QShaderNode::Rule("gl_fragColor = $fragColor;"));
+        fragColor.addRule(openGL3, QShaderNode::Rule("fragColor = $fragColor;",
+                                                     QByteArrayList() << "out vec4 fragColor;"));
+
+        auto sampleTexture = createNode({
+            createPort(QShaderNodePort::Input, "sampler"),
+            createPort(QShaderNodePort::Input, "coord"),
+            createPort(QShaderNodePort::Output, "color")
+        });
+        sampleTexture.setUuid(QUuid("{00000000-0000-0000-0000-000000000007}"));
+        sampleTexture.addRule(openGLES2, QShaderNode::Rule("highp vec4 $color = texture2D($sampler, $coord);"));
+        sampleTexture.addRule(openGL3, QShaderNode::Rule("vec4 $color = texture2D($sampler, $coord);"));
+
+        auto lightFunction = createNode({
+            createPort(QShaderNodePort::Input, "baseColor"),
+            createPort(QShaderNodePort::Input, "position"),
+            createPort(QShaderNodePort::Input, "lightIntensity"),
+            createPort(QShaderNodePort::Output, "outputColor")
+        });
+        lightFunction.setUuid(QUuid("{00000000-0000-0000-0000-000000000008}"));
+        lightFunction.addRule(openGLES2, QShaderNode::Rule("highp vec4 $outputColor = lightModel($baseColor, $position, $lightIntensity);",
+                                                           QByteArrayList() << "#pragma include es2/lightmodel.frag.inc"));
+        lightFunction.addRule(openGL3, QShaderNode::Rule("vec4 $outputColor = lightModel($baseColor, $position, $lightIntensity);",
+                                                         QByteArrayList() << "#pragma include gl3/lightmodel.frag.inc"));
+
+        auto exposureFunction = createNode({
+            createPort(QShaderNodePort::Input, "inputColor"),
+            createPort(QShaderNodePort::Input, "exposure"),
+            createPort(QShaderNodePort::Output, "outputColor")
+        });
+        exposureFunction.setUuid(QUuid("{00000000-0000-0000-0000-000000000009}"));
+        exposureFunction.addRule(openGLES2, QShaderNode::Rule("highp vec4 $outputColor = $inputColor * pow(2.0, $exposure);"));
+        exposureFunction.addRule(openGL3, QShaderNode::Rule("vec4 $outputColor = $inputColor * pow(2.0, $exposure);"));
+
+        graph.addNode(worldPosition);
+        graph.addNode(texture);
+        graph.addNode(texCoord);
+        graph.addNode(lightIntensity);
+        graph.addNode(exposure);
+        graph.addNode(fragColor);
+        graph.addNode(sampleTexture);
+        graph.addNode(lightFunction);
+        graph.addNode(exposureFunction);
+
+        graph.addEdge(createEdge(texture.uuid(), "texture", sampleTexture.uuid(), "sampler"));
+        graph.addEdge(createEdge(texCoord.uuid(), "texCoord", sampleTexture.uuid(), "coord"));
+
+        graph.addEdge(createEdge(worldPosition.uuid(), "worldPosition", lightFunction.uuid(), "position"));
+        graph.addEdge(createEdge(sampleTexture.uuid(), "color", lightFunction.uuid(), "baseColor"));
+        graph.addEdge(createEdge(lightIntensity.uuid(), "lightIntensity", lightFunction.uuid(), "lightIntensity"));
+
+        graph.addEdge(createEdge(lightFunction.uuid(), "outputColor", exposureFunction.uuid(), "inputColor"));
+        graph.addEdge(createEdge(exposure.uuid(), "exposure", exposureFunction.uuid(), "exposure"));
+
+        graph.addEdge(createEdge(exposureFunction.uuid(), "outputColor", fragColor.uuid(), "fragColor"));
+
+        return graph;
+    }
+
+    void debugStatement(const QString &prefix, const QShaderGraph::Statement &statement)
+    {
+        qDebug() << prefix << statement.inputs << statement.uuid().toString() << statement.outputs;
+    }
+
+    void dumpStatementsIfNeeded(const QVector<QShaderGraph::Statement> &statements, const QVector<QShaderGraph::Statement> &expected)
+    {
+        if (statements != expected) {
+            for (int i = 0; i < qMax(statements.size(), expected.size()); i++) {
+                qDebug() << "----" << i << "----";
+                if (i < statements.size())
+                    debugStatement("A:", statements.at(i));
+                if (i < expected.size())
+                    debugStatement("E:", expected.at(i));
+                qDebug() << "-----------";
+            }
+        }
+    }
+}
+
+class tst_QShaderGraphLoader : public QObject
+{
+    Q_OBJECT
+private slots:
+    void shouldManipulateLoaderMembers();
+    void shouldLoadFromJsonStream_data();
+    void shouldLoadFromJsonStream();
+};
+
+void tst_QShaderGraphLoader::shouldManipulateLoaderMembers()
+{
+    // GIVEN
+    auto loader = QShaderGraphLoader();
+
+    // THEN (default state)
+    QCOMPARE(loader.status(), QShaderGraphLoader::Null);
+    QVERIFY(!loader.device());
+    QVERIFY(loader.graph().nodes().isEmpty());
+    QVERIFY(loader.graph().edges().isEmpty());
+    QVERIFY(loader.prototypes().isEmpty());
+
+    // WHEN
+    auto device1 = createBuffer(QByteArray("..........."), QIODevice::NotOpen);
+    loader.setDevice(device1.data());
+
+    // THEN
+    QCOMPARE(loader.status(), QShaderGraphLoader::Error);
+    QCOMPARE(loader.device(), device1.data());
+    QVERIFY(loader.graph().nodes().isEmpty());
+    QVERIFY(loader.graph().edges().isEmpty());
+
+    // WHEN
+    auto device2 = createBuffer(QByteArray("..........."), QIODevice::ReadOnly);
+    loader.setDevice(device2.data());
+
+    // THEN
+    QCOMPARE(loader.status(), QShaderGraphLoader::Waiting);
+    QCOMPARE(loader.device(), device2.data());
+    QVERIFY(loader.graph().nodes().isEmpty());
+    QVERIFY(loader.graph().edges().isEmpty());
+
+
+    // WHEN
+    const auto prototypes = [this]{
+        auto res = QHash<QString, QShaderNode>();
+        res.insert("foo", createNode({}));
+        return res;
+    }();
+    loader.setPrototypes(prototypes);
+
+    // THEN
+    QCOMPARE(loader.prototypes().size(), prototypes.size());
+    QVERIFY(loader.prototypes().contains("foo"));
+    QCOMPARE(loader.prototypes().value("foo").uuid(), prototypes.value("foo").uuid());
+}
+
+void tst_QShaderGraphLoader::shouldLoadFromJsonStream_data()
+{
+    QTest::addColumn<QBufferPointer>("device");
+    QTest::addColumn<PrototypeHash>("prototypes");
+    QTest::addColumn<QShaderGraph>("graph");
+    QTest::addColumn<QShaderGraphLoader::Status>("status");
+
+    QTest::newRow("empty") << createBuffer("", QIODevice::ReadOnly) << PrototypeHash()
+                           << QShaderGraph() << QShaderGraphLoader::Error;
+
+    const auto smallJson = "{"
+                           "    \"nodes\": ["
+                           "        {"
+                           "            \"uuid\": \"{00000000-0000-0000-0000-000000000001}\","
+                           "            \"type\": \"MyInput\""
+                           "        },"
+                           "        {"
+                           "            \"uuid\": \"{00000000-0000-0000-0000-000000000002}\","
+                           "            \"type\": \"MyOutput\""
+                           "        },"
+                           "        {"
+                           "            \"uuid\": \"{00000000-0000-0000-0000-000000000003}\","
+                           "            \"type\": \"MyFunction\""
+                           "        }"
+                           "    ],"
+                           "    \"edges\": ["
+                           "        {"
+                           "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000001}\","
+                           "            \"sourcePort\": \"input\","
+                           "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000003}\","
+                           "            \"targetPort\": \"functionInput\""
+                           "        },"
+                           "        {"
+                           "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000003}\","
+                           "            \"sourcePort\": \"functionOutput\","
+                           "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000002}\","
+                           "            \"targetPort\": \"output\""
+                           "        }"
+                           "    ]"
+                           "}";
+
+    const auto smallProtos = [this]{
+        auto protos = PrototypeHash();
+
+        auto input = createNode({
+            createPort(QShaderNodePort::Output, "input")
+        });
+        protos.insert("MyInput", input);
+
+        auto output = createNode({
+            createPort(QShaderNodePort::Input, "output")
+        });
+        protos.insert("MyOutput", output);
+
+        auto function = createNode({
+            createPort(QShaderNodePort::Input, "functionInput"),
+            createPort(QShaderNodePort::Output, "functionOutput")
+        });
+        protos.insert("MyFunction", function);
+        return protos;
+    }();
+
+    const auto smallGraph = [this]{
+        auto graph = QShaderGraph();
+
+        auto input = createNode({
+            createPort(QShaderNodePort::Output, "input")
+        });
+        input.setUuid(QUuid("{00000000-0000-0000-0000-000000000001}"));
+        auto output = createNode({
+            createPort(QShaderNodePort::Input, "output")
+        });
+        output.setUuid(QUuid("{00000000-0000-0000-0000-000000000002}"));
+        auto function = createNode({
+            createPort(QShaderNodePort::Input, "functionInput"),
+            createPort(QShaderNodePort::Output, "functionOutput")
+        });
+        function.setUuid(QUuid("{00000000-0000-0000-0000-000000000003}"));
+
+        graph.addNode(input);
+        graph.addNode(output);
+        graph.addNode(function);
+        graph.addEdge(createEdge(input.uuid(), "input", function.uuid(), "functionInput"));
+        graph.addEdge(createEdge(function.uuid(), "functionOutput", output.uuid(), "output"));
+
+        return graph;
+    }();
+
+    QTest::newRow("TwoNodesOneEdge") << createBuffer(smallJson) << smallProtos << smallGraph << QShaderGraphLoader::Ready;
+    QTest::newRow("NotOpen") << createBuffer(smallJson, QIODevice::NotOpen) << smallProtos << QShaderGraph() << QShaderGraphLoader::Error;
+    QTest::newRow("NoPrototype") << createBuffer(smallJson) << PrototypeHash() << QShaderGraph() << QShaderGraphLoader::Error;
+
+    const auto complexJson = "{"
+                             "    \"nodes\": ["
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000001}\","
+                             "            \"type\": \"worldPosition\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000002}\","
+                             "            \"type\": \"texture\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000003}\","
+                             "            \"type\": \"texCoord\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000004}\","
+                             "            \"type\": \"lightIntensity\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000005}\","
+                             "            \"type\": \"exposure\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000006}\","
+                             "            \"type\": \"fragColor\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000007}\","
+                             "            \"type\": \"sampleTexture\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000008}\","
+                             "            \"type\": \"lightModel\""
+                             "        },"
+                             "        {"
+                             "            \"uuid\": \"{00000000-0000-0000-0000-000000000009}\","
+                             "            \"type\": \"exposureFunction\""
+                             "        }"
+                             "    ],"
+                             "    \"edges\": ["
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000002}\","
+                             "            \"sourcePort\": \"texture\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000007}\","
+                             "            \"targetPort\": \"sampler\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000003}\","
+                             "            \"sourcePort\": \"texCoord\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000007}\","
+                             "            \"targetPort\": \"coord\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000001}\","
+                             "            \"sourcePort\": \"worldPosition\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000008}\","
+                             "            \"targetPort\": \"position\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000007}\","
+                             "            \"sourcePort\": \"color\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000008}\","
+                             "            \"targetPort\": \"baseColor\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000004}\","
+                             "            \"sourcePort\": \"lightIntensity\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000008}\","
+                             "            \"targetPort\": \"lightIntensity\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000008}\","
+                             "            \"sourcePort\": \"outputColor\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000009}\","
+                             "            \"targetPort\": \"inputColor\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000005}\","
+                             "            \"sourcePort\": \"exposure\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000009}\","
+                             "            \"targetPort\": \"exposure\""
+                             "        },"
+                             "        {"
+                             "            \"sourceUuid\": \"{00000000-0000-0000-0000-000000000009}\","
+                             "            \"sourcePort\": \"outputColor\","
+                             "            \"targetUuid\": \"{00000000-0000-0000-0000-000000000006}\","
+                             "            \"targetPort\": \"fragColor\""
+                             "        }"
+                             "    ]"
+                             "}";
+
+    const auto complexProtos = [this]{
+        auto protos = PrototypeHash();
+
+        auto worldPosition = createNode({
+            createPort(QShaderNodePort::Output, "worldPosition")
+        });
+        protos.insert("worldPosition", worldPosition);
+
+        auto texture = createNode({
+            createPort(QShaderNodePort::Output, "texture")
+        });
+        protos.insert("texture", texture);
+
+        auto texCoord = createNode({
+            createPort(QShaderNodePort::Output, "texCoord")
+        });
+        protos.insert("texCoord", texCoord);
+
+        auto lightIntensity = createNode({
+            createPort(QShaderNodePort::Output, "lightIntensity")
+        });
+        protos.insert("lightIntensity", lightIntensity);
+
+        auto exposure = createNode({
+            createPort(QShaderNodePort::Output, "exposure")
+        });
+        protos.insert("exposure", exposure);
+
+        auto fragColor = createNode({
+            createPort(QShaderNodePort::Input, "fragColor")
+        });
+        protos.insert("fragColor", fragColor);
+
+        auto sampleTexture = createNode({
+            createPort(QShaderNodePort::Input, "sampler"),
+            createPort(QShaderNodePort::Input, "coord"),
+            createPort(QShaderNodePort::Output, "color")
+        });
+        protos.insert("sampleTexture", sampleTexture);
+
+        auto lightModel = createNode({
+            createPort(QShaderNodePort::Input, "baseColor"),
+            createPort(QShaderNodePort::Input, "position"),
+            createPort(QShaderNodePort::Input, "lightIntensity"),
+            createPort(QShaderNodePort::Output, "outputColor")
+        });
+        protos.insert("lightModel", lightModel);
+
+        auto exposureFunction = createNode({
+            createPort(QShaderNodePort::Input, "inputColor"),
+            createPort(QShaderNodePort::Input, "exposure"),
+            createPort(QShaderNodePort::Output, "outputColor")
+        });
+        protos.insert("exposureFunction", exposureFunction);
+
+        return protos;
+    }();
+
+    const auto complexGraph = createGraph();
+
+    QTest::newRow("ComplexGraph") << createBuffer(complexJson) << complexProtos << complexGraph << QShaderGraphLoader::Ready;
+}
+
+void tst_QShaderGraphLoader::shouldLoadFromJsonStream()
+{
+    // GIVEN
+    QFETCH(QBufferPointer, device);
+    QFETCH(PrototypeHash, prototypes);
+
+    auto loader = QShaderGraphLoader();
+
+    // WHEN
+    loader.setPrototypes(prototypes);
+    loader.setDevice(device.data());
+    loader.load();
+
+    // THEN
+    QFETCH(QShaderGraphLoader::Status, status);
+    QCOMPARE(loader.status(), status);
+
+    QFETCH(QShaderGraph, graph);
+    const auto statements = loader.graph().createStatements();
+    const auto expected = graph.createStatements();
+    dumpStatementsIfNeeded(statements, expected);
+    QCOMPARE(statements, expected);
+}
+
+QTEST_MAIN(tst_QShaderGraphLoader)
+
+#include "tst_qshadergraphloader.moc"
diff --git a/tests/auto/gui/util/util.pro b/tests/auto/gui/util/util.pro
index d7aacd7e06..128001a98c 100644
--- a/tests/auto/gui/util/util.pro
+++ b/tests/auto/gui/util/util.pro
@@ -7,5 +7,6 @@ SUBDIRS= \
     qregularexpressionvalidator \
     qshadergenerator \
     qshadergraph \
+    qshadergraphloader \
     qshadernodes \