Import relevant source from Qt 4.8

Change-Id: I5078db4081d95290c54f39d3c0efc2fc2f62e6a6

1 files changed, 196 insertions, 0 deletions

diff --git a/src/imports/shaders/shadereffect.cpp b/src/imports/shaders/shadereffect.cpp
new file mode 100644
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+++ b/src/imports/shaders/shadereffect.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QML Shaders plugin of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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, Nokia gives you certain additional
+** rights. These rights are described in the Nokia 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.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "shadereffect.h"
+#include "shadereffectbuffer.h"
+#include "shadereffectsource.h"
+
+#include <QDeclarativeItem>
+#include <QPainter>
+#include <QtOpenGL>
+
+static QTransform savedWorldTransform;
+
+ShaderEffect::ShaderEffect(QObject *parent)
+    : QGraphicsEffect(parent)
+    , m_changed(true)
+{
+}
+
+ShaderEffect::~ShaderEffect()
+{
+}
+
+void ShaderEffect::prepareBufferedDraw(QPainter *painter)
+{
+#ifndef QT_NO_DYNAMIC_CAST
+    // This workaround needed because QGraphicsEffect seems to always utilize default painters worldtransform
+    // instead of the active painters worldtransform.
+    const ShaderEffectBuffer *effectBuffer = dynamic_cast<ShaderEffectBuffer*> (painter->device());
+    if (effectBuffer) {
+        savedWorldTransform = painter->worldTransform() * savedWorldTransform;
+        painter->setWorldTransform(savedWorldTransform);
+    } else {
+        savedWorldTransform = painter->worldTransform();
+    }
+#else
+    Q_UNUSED(painter);
+#endif
+}
+
+void ShaderEffect::draw (QPainter *painter)
+{
+    const QGLContext *context = QGLContext::currentContext();
+
+    prepareBufferedDraw(painter);
+
+    if (context) {
+        updateRenderTargets();
+    }
+
+    if (!context || m_renderTargets.count() == 0 || !hideOriginal())
+        drawSource(painter);
+}
+
+void ShaderEffect::updateRenderTargets()
+{
+    if (!m_changed)
+        return;
+
+    m_changed = false;
+
+    int count = m_renderTargets.count();
+    for (int i = 0; i < count; i++) {
+        if (m_renderTargets[i]->isLive() || m_renderTargets[i]->isDirtyTexture()) {
+            m_renderTargets[i]->updateBackbuffer();
+            ShaderEffectBuffer* target = m_renderTargets[i]->fbo();
+            if (target && target->isValid() && target->width() > 0 && target->height() > 0) {
+                QPainter p(target);
+                p.setCompositionMode(QPainter::CompositionMode_Clear);
+                p.fillRect(QRect(QPoint(0, 0), target->size()), Qt::transparent);
+                p.setCompositionMode(QPainter::CompositionMode_SourceOver);
+
+                QRectF sourceRect = m_renderTargets[i]->sourceRect();
+                QSize textureSize = m_renderTargets[i]->textureSize();
+
+                qreal yflip = m_renderTargets[i]->isMirrored() ? -1.0 : 1.0; // flip y to match scenegraph, it also flips texturecoordinates
+                qreal xscale = 1.0;
+                qreal yscale = 1.0 * yflip;
+
+                qreal leftMargin = 0.0;
+                qreal rightMargin = 0.0;
+                qreal topMargin = 0.0;
+                qreal bottomMargin = 0.0;
+
+                qreal width = m_renderTargets[i]->sourceItem()->width();
+                qreal height = m_renderTargets[i]->sourceItem()->height();
+
+                if (!sourceRect.isEmpty()) {
+                    leftMargin = -sourceRect.left();
+                    rightMargin = sourceRect.right() - width;
+                    topMargin = -sourceRect.top();
+                    bottomMargin = sourceRect.bottom() - height;
+                }
+
+                if ((width + leftMargin + rightMargin) > 0 && (height + topMargin + bottomMargin) > 0) {
+                    if (!textureSize.isEmpty()) {
+                        qreal textureWidth = textureSize.width();
+                        qreal textureHeight = textureSize.height();
+
+                        xscale = width / (width + leftMargin + rightMargin);
+                        yscale = height / (height + topMargin + bottomMargin);
+
+                        p.translate(textureWidth / 2, textureHeight / 2);
+                        p.scale(xscale, yscale * yflip);
+                        p.translate(-textureWidth / 2, -textureHeight / 2);
+                        p.scale(textureWidth / width, textureHeight / height);
+                    } else {
+                        xscale = width / (width + leftMargin + rightMargin);
+                        yscale = height / (height + topMargin + bottomMargin);
+
+                        p.translate(width / 2, height / 2);
+                        p.scale(xscale, yscale * yflip);
+                        p.translate(-width / 2, -height / 2);
+                    }
+                }
+
+                drawSource(&p);
+                p.end();
+                m_renderTargets[i]->markSceneGraphDirty();
+            }
+        }
+    }
+}
+
+void ShaderEffect::sourceChanged (ChangeFlags flags)
+{
+    Q_UNUSED(flags);
+    m_changed = true;
+}
+
+void ShaderEffect::addRenderTarget(ShaderEffectSource *target)
+{
+    if (!m_renderTargets.contains(target))
+        m_renderTargets.append(target);
+}
+
+void ShaderEffect::removeRenderTarget(ShaderEffectSource *target)
+{
+    int index = m_renderTargets.indexOf(target);
+    if (index >= 0)
+        m_renderTargets.remove(index);
+    else
+        qWarning() << "ShaderEffect::removeRenderTarget - did not find target.";
+}
+
+bool ShaderEffect::hideOriginal() const
+{
+    if (m_renderTargets.count() == 0)
+        return false;
+
+    // Just like scenegraph version, if there is even one source that says "hide original" we hide it.
+    int count = m_renderTargets.count();
+    for (int i = 0; i < count; i++) {
+        if (m_renderTargets[i]->hideSource())
+            return true;
+    }
+    return false;
+}