Partial update support

This enables partial update support, which leads to only painting into
the backingstore what has changed in the scene each frame, and then only
flushing the changed regions to the window surface.

Change-Id: I2a3c8676bd4539100a4313069f894f157bfb0ea4
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

1 files changed, 311 insertions, 0 deletions

diff --git a/src/plugins/scenegraph/softwarecontext/abstractsoftwarerenderer.cpp b/src/plugins/scenegraph/softwarecontext/abstractsoftwarerenderer.cpp
new file mode 100644
index 0000000000..2963440c41
--- /dev/null
+++ b/src/plugins/scenegraph/softwarecontext/abstractsoftwarerenderer.cpp
@@ -0,0 +1,311 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Quick 2D Renderer module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL$
+** 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 or (at your option) 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.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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "abstractsoftwarerenderer.h"
+
+#include "renderablenodeupdater.h"
+#include "renderlistbuilder.h"
+#include "context.h"
+#include "renderablenode.h"
+
+#include <QtCore/QLoggingCategory>
+#include <QtGui/QWindow>
+#include <QtQuick/QSGSimpleRectNode>
+
+Q_LOGGING_CATEGORY(lc2DRender, "qt.scenegraph.softwarecontext.abstractrenderer")
+
+namespace SoftwareContext{
+
+AbstractSoftwareRenderer::AbstractSoftwareRenderer(QSGRenderContext *context)
+    : QSGRenderer(context)
+    , m_background(new QSGSimpleRectNode)
+    , m_nodeUpdater(new RenderableNodeUpdater(this))
+{
+    // Setup special background node
+    auto backgroundRenderable = new RenderableNode(RenderableNode::SimpleRect, m_background);
+    addNodeMapping(m_background, backgroundRenderable);
+}
+
+AbstractSoftwareRenderer::~AbstractSoftwareRenderer()
+{
+    // Cleanup RenderableNodes
+    delete m_background;
+
+    for (RenderableNode *node : m_nodes.values()) {
+        delete node;
+    }
+
+    delete m_nodeUpdater;
+}
+
+RenderableNode *AbstractSoftwareRenderer::renderableNode(QSGNode *node) const
+{
+    return m_nodes.value(node, nullptr);
+}
+
+void AbstractSoftwareRenderer::addNodeMapping(QSGNode *node, RenderableNode *renderableNode)
+{
+    m_nodes.insert(node, renderableNode);
+}
+
+void AbstractSoftwareRenderer::appendRenderableNode(RenderableNode *node)
+{
+    m_renderableNodes.append(node);
+}
+
+void AbstractSoftwareRenderer::nodeChanged(QSGNode *node, QSGNode::DirtyState state)
+{
+        if (state & QSGNode::DirtyGeometry) {
+            nodeGeometryUpdated(node);
+        }
+        if (state & QSGNode::DirtyMaterial) {
+            nodeMaterialUpdated(node);
+        }
+        if (state & QSGNode::DirtyMatrix) {
+            nodeMatrixUpdated(node);
+        }
+        if (state & QSGNode::DirtyNodeAdded) {
+            nodeAdded(node);
+        }
+        if (state & QSGNode::DirtyNodeRemoved) {
+            nodeRemoved(node);
+        }
+        if (state & QSGNode::DirtyOpacity) {
+            nodeOpacityUpdated(node);
+        }
+        if (state & QSGNode::DirtySubtreeBlocked) {
+            m_nodeUpdater->updateNodes(node);
+        }
+        if (state & QSGNode::DirtyForceUpdate) {
+            m_nodeUpdater->updateNodes(node);
+        }
+        QSGRenderer::nodeChanged(node, state);
+}
+
+QRegion AbstractSoftwareRenderer::renderNodes(QPainter *painter)
+{
+    QRegion dirtyRegion;
+    // If there are no nodes, do nothing
+    if (m_renderableNodes.isEmpty())
+        return dirtyRegion;
+
+    auto iterator = m_renderableNodes.begin();
+    // First node is the background and needs to painted without blending
+    auto backgroundNode = *iterator;
+    dirtyRegion += backgroundNode->renderNode(painter, /*force opaque painting*/ true);
+    iterator++;
+
+    for (; iterator != m_renderableNodes.end(); ++iterator) {
+        auto node = *iterator;
+        dirtyRegion += node->renderNode(painter);
+    }
+
+    return dirtyRegion;
+}
+
+void AbstractSoftwareRenderer::buildRenderList()
+{
+    // Clear the previous renderlist
+    m_renderableNodes.clear();
+    // Add the background renderable (always first)
+    m_renderableNodes.append(renderableNode(m_background));
+    // Build the renderlist
+    RenderListBuilder(this).visitChildren(rootNode());
+}
+
+void AbstractSoftwareRenderer::optimizeRenderList()
+{
+    // Iterate through the renderlist from front to back
+    // Objective is to update the dirty status and rects.
+    for (auto i = m_renderableNodes.rbegin(); i != m_renderableNodes.rend(); ++i) {
+        auto node = *i;
+        if (!m_dirtyRegion.isEmpty()) {
+            // See if the current dirty regions apply to the current node
+            node->addDirtyRegion(m_dirtyRegion, true);
+        }
+
+        if (!m_obscuredRegion.isEmpty()) {
+            // Don't try to paint things that are covered by opaque objects
+            node->subtractDirtyRegion(m_obscuredRegion);
+        }
+
+        // Keep up with obscured regions
+        if (node->isOpaque()) {
+            m_obscuredRegion += QRegion(node->boundingRect());
+        }
+
+        if (node->isDirty()) {
+            // Don't paint things outside of the rendering area
+            if (!m_background->rect().toRect().contains(node->boundingRect(), /*proper*/ true)) {
+                // Some part(s) of node is(are) outside of the rendering area
+                QRegion renderArea(m_background->rect().toRect());
+                QRegion outsideRegions = node->dirtyRegion().subtracted(renderArea);
+                if (!outsideRegions.isEmpty())
+                    node->subtractDirtyRegion(outsideRegions);
+            }
+
+            // Get the dirty region's to pass to the next nodes
+            if (node->isOpaque()) {
+                // if isOpaque, subtract node's dirty rect from m_dirtyRegion
+                m_dirtyRegion -= node->dirtyRegion();
+            } else {
+                // if isAlpha, add node's dirty rect to m_dirtyRegion
+                m_dirtyRegion += node->dirtyRegion();
+            }
+            // if previousDirtyRegion has content outside of boundingRect add to m_dirtyRegion
+            QRegion prevDirty = node->previousDirtyRegion();
+            if (!prevDirty.isNull())
+                m_dirtyRegion += prevDirty;
+        }
+    }
+
+    // Empty dirtyRegion (for second pass)
+    m_dirtyRegion = QRegion();
+    m_obscuredRegion = QRegion();
+
+    // Iterate through the renderlist from back to front
+    // Objective is to make sure all non-opaque items are painted when an item under them is dirty
+    for (auto j = m_renderableNodes.begin(); j != m_renderableNodes.end(); ++j) {
+        auto node = *j;
+
+        if (!node->isOpaque() && !m_dirtyRegion.isEmpty()) {
+            // Only blended nodes need to be updated
+            node->addDirtyRegion(m_dirtyRegion, true);
+        }
+
+        m_dirtyRegion += node->dirtyRegion();
+    }
+
+    // Empty dirtyRegion
+    m_dirtyRegion = QRegion();
+    m_obscuredRegion = QRegion();
+}
+
+void AbstractSoftwareRenderer::setBackgroundColor(const QColor &color)
+{
+    if (m_background->color() == color)
+        return;
+    m_background->setColor(color);
+    renderableNode(m_background)->markMaterialDirty();
+}
+
+void AbstractSoftwareRenderer::setBackgroundSize(const QSize &size)
+{
+    if (m_background->rect().size().toSize() == size)
+        return;
+    m_background->setRect(0.0f, 0.0f, size.width(), size.height());
+    renderableNode(m_background)->markGeometryDirty();
+    // Invalidate the whole scene when the background is resized
+    m_dirtyRegion = QRegion(m_background->rect().toRect());
+}
+
+QColor AbstractSoftwareRenderer::backgroundColor()
+{
+    return m_background->color();
+}
+
+QSize AbstractSoftwareRenderer::backgroundSize()
+{
+    return m_background->rect().size().toSize();
+}
+
+void AbstractSoftwareRenderer::nodeAdded(QSGNode *node)
+{
+    qCDebug(lc2DRender) << "nodeAdded" << (void*)node;
+
+    m_nodeUpdater->updateNodes(node);
+}
+
+void AbstractSoftwareRenderer::nodeRemoved(QSGNode *node)
+{
+    qCDebug(lc2DRender) << "nodeRemoved" << (void*)node;
+
+    auto renderable = renderableNode(node);
+    // remove mapping
+    if (renderable != nullptr) {
+        // Need to mark this region dirty in the other nodes
+        QRegion dirtyRegion = renderable->previousDirtyRegion();
+        if (dirtyRegion.isEmpty())
+            dirtyRegion = renderable->boundingRect();
+        m_dirtyRegion += dirtyRegion;
+        m_nodes.remove(node);
+        delete renderable;
+    }
+
+    // Remove all children nodes as well
+    for (QSGNode *child = node->firstChild(); child; child = child->nextSibling()) {
+        nodeRemoved(child);
+    }
+
+    m_nodeUpdater->updateNodes(node, true);
+}
+
+void AbstractSoftwareRenderer::nodeGeometryUpdated(QSGNode *node)
+{
+    qCDebug(lc2DRender) << "nodeGeometryUpdated";
+
+    // Mark node as dirty
+    auto renderable = renderableNode(node);
+    if (renderable != nullptr) {
+        renderable->markGeometryDirty();
+    } else {
+        m_nodeUpdater->updateNodes(node);
+    }
+}
+
+void AbstractSoftwareRenderer::nodeMaterialUpdated(QSGNode *node)
+{
+    qCDebug(lc2DRender) << "nodeMaterialUpdated";
+
+    // Mark node as dirty
+    auto renderable = renderableNode(node);
+    if (renderable != nullptr) {
+        renderable->markMaterialDirty();
+    } else {
+        m_nodeUpdater->updateNodes(node);
+    }
+}
+
+void AbstractSoftwareRenderer::nodeMatrixUpdated(QSGNode *node)
+{
+    qCDebug(lc2DRender) << "nodeMaterialUpdated";
+
+    // Update children nodes
+    m_nodeUpdater->updateNodes(node);
+}
+
+void AbstractSoftwareRenderer::nodeOpacityUpdated(QSGNode *node)
+{
+    qCDebug(lc2DRender) << "nodeOpacityUpdated";
+
+    // Update children nodes
+    m_nodeUpdater->updateNodes(node);
+}
+
+}