[Shader Graph Gen.] Introduce QShaderGenerator

This class is meant to generate code from shader graphs

Change-Id: I1cf22352387f3f9f55e7589aa77a296689836911
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 181 insertions, 0 deletions

diff --git a/src/gui/util/qshadergenerator.cpp b/src/gui/util/qshadergenerator.cpp
new file mode 100644
index 0000000000..5d6a05e2a0
--- /dev/null
+++ b/src/gui/util/qshadergenerator.cpp
@@ -0,0 +1,104 @@
+/****************************************************************************
+**
+** 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 "qshadergenerator_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QByteArray QShaderGenerator::createShaderCode() const
+{
+    auto code = QByteArrayList();
+
+    if (format.isValid()) {
+        const auto isGLES = format.api() == QShaderFormat::OpenGLES;
+        const auto major = format.version().majorVersion();
+        const auto minor = format.version().minorVersion();
+
+        const auto version = major == 2 && isGLES ? 100
+                           : major == 3 && isGLES ? 300
+                           : major == 2 ? 100 + 10 * (minor + 1)
+                           : major == 3 && minor <= 2 ? 100 + 10 * (minor + 3)
+                           : major * 100 + minor * 10;
+
+        const auto profile = isGLES ? QByteArrayLiteral(" es")
+                           : version >= 150 && format.api() == QShaderFormat::OpenGLCoreProfile ? QByteArrayLiteral(" core")
+                           : version >= 150 && format.api() == QShaderFormat::OpenGLCompatibilityProfile ? QByteArrayLiteral(" compatibility")
+                           : QByteArray();
+
+        code << (QByteArrayLiteral("#version ") + QByteArray::number(version) + profile);
+        code << QByteArray();
+    }
+
+    for (const auto &node : graph.nodes()) {
+        for (const auto &snippet : node.rule(format).headerSnippets) {
+            code << snippet;
+        }
+    }
+
+    code << QByteArray();
+    code << QByteArrayLiteral("void main()");
+    code << QByteArrayLiteral("{");
+
+    for (const auto &statement : graph.createStatements()) {
+        const auto node = statement.node;
+        auto line = node.rule(format).substitution;
+        for (const auto &port : node.ports()) {
+            const auto portName = port.name;
+            const auto portDirection = port.direction;
+            const auto isInput = port.direction == QShaderNodePort::Input;
+
+            const auto portIndex = statement.portIndex(portDirection, portName);
+            const auto variableIndex = isInput ? statement.inputs.at(portIndex)
+                                               : statement.outputs.at(portIndex);
+            if (variableIndex < 0)
+                continue;
+
+            const auto placeholder = QByteArray(QByteArrayLiteral("$") + portName.toUtf8());
+            const auto variable = QByteArray(QByteArrayLiteral("v") + QByteArray::number(variableIndex));
+            line.replace(placeholder, variable);
+        }
+        code << QByteArrayLiteral("    ") + line;
+    }
+
+    code << QByteArrayLiteral("}");
+    code << QByteArray();
+    return code.join('\n');
+}
+
+QT_END_NAMESPACE
diff --git a/src/gui/util/qshadergenerator_p.h b/src/gui/util/qshadergenerator_p.h
new file mode 100644
index 0000000000..392c3532df
--- /dev/null
+++ b/src/gui/util/qshadergenerator_p.h
@@ -0,0 +1,75 @@
+/****************************************************************************
+**
+** 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 QSHADERGENERATOR_P_H
+#define QSHADERGENERATOR_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 QShaderGenerator
+{
+public:
+    Q_GUI_EXPORT QByteArray createShaderCode() const;
+
+    QShaderGraph graph;
+    QShaderFormat format;
+};
+
+Q_DECLARE_TYPEINFO(QShaderGenerator, Q_MOVABLE_TYPE);
+
+QT_END_NAMESPACE
+
+Q_DECLARE_METATYPE(QShaderGenerator)
+
+#endif // QSHADERGENERATOR_P_H
diff --git a/src/gui/util/util.pri b/src/gui/util/util.pri
index 96b25df4f9..e7feda9a4a 100644
--- a/src/gui/util/util.pri
+++ b/src/gui/util/util.pri
@@ -8,6 +8,7 @@ HEADERS += \
         util/qabstractlayoutstyleinfo_p.h \
         util/qlayoutpolicy_p.h \
         util/qshaderformat_p.h \
+        util/qshadergenerator_p.h \
         util/qshadergraph_p.h \
         util/qshadernode_p.h \
         util/qshadernodeport_p.h
@@ -19,6 +20,7 @@ SOURCES += \
         util/qabstractlayoutstyleinfo.cpp \
         util/qlayoutpolicy.cpp \
         util/qshaderformat.cpp \
+        util/qshadergenerator.cpp \
         util/qshadergraph.cpp \
         util/qshadernode.cpp \
         util/qshadernodeport.cpp