/**************************************************************************** ** ** 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 "threadrenderer.h" #include "logorenderer.h" #include #include #include #include #include #include /* * The render thread shares a context with the scene graph and will * render into two separate FBOs, one to use for display and one * to use for rendering */ class RenderThread : public QThread { Q_OBJECT public: RenderThread(const QSize &size) : m_renderFbo(0) , m_displayFbo(0) , m_logoRenderer(0) , m_size(size) { // Since we're using queued connections, we need affinity to the rendering thread. moveToThread(this); // Set up the QOpenGLContext to use for rendering in this thread. It is sharing // memory space with the GL context of the scene graph. This constructor is called // during updatePaintNode, so we are currently on the scene graph thread with the // scene graph's OpenGL context current. QOpenGLContext *current = QOpenGLContext::currentContext(); m_context = new QOpenGLContext(); m_context->setShareContext(current); m_context->setFormat(current->format()); m_context->create(); m_context->moveToThread(this); // We need a non-visible surface to make current... m_fakeSurface = new QWindow(); m_fakeSurface->setGeometry(0, 0, 64, 64); m_fakeSurface->setSurfaceType(QWindow::OpenGLSurface); m_fakeSurface->setFormat(current->format()); m_fakeSurface->create(); } public slots: void renderNext() { m_context->makeCurrent(m_fakeSurface); if (!m_renderFbo) { // Initialize the buffers and renderer QOpenGLFramebufferObjectFormat format; format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil); m_renderFbo = new QOpenGLFramebufferObject(m_size, format); m_displayFbo = new QOpenGLFramebufferObject(m_size, format); m_logoRenderer = new LogoRenderer(); m_logoRenderer->initialize(); } m_renderFbo->bind(); glViewport(0, 0, m_size.width(), m_size.height()); m_logoRenderer->render(); // We need to flush the contents to the FBO before posting // the texture to the other thread, otherwise, we might // get unexpected results. glFlush(); m_renderFbo->bindDefault(); qSwap(m_renderFbo, m_displayFbo); emit textureReady(m_displayFbo->texture(), m_size); } signals: void textureReady(int id, const QSize &size); private: QOpenGLFramebufferObject *m_renderFbo; QOpenGLFramebufferObject *m_displayFbo; LogoRenderer *m_logoRenderer; QWindow *m_fakeSurface; QOpenGLContext *m_context; QSize m_size; }; class TextureNode : public QObject, public QSGSimpleTextureNode { Q_OBJECT public: TextureNode(QQuickWindow *window) : m_id(0) , m_size(0, 0) , m_texture(0) , m_window(window) { // Our texture node must have a texture, so use the default 0 texture. m_texture = m_window->createTextureFromId(0, QSize(1, 1)); setTexture(m_texture); setFiltering(QSGTexture::Linear); } ~TextureNode() { delete m_texture; } signals: void textureInUse(); void pendingNewTexture(); public slots: // This function gets called on the FBO rendering thread and will store the // texture id and size and schedule an update on the window. void newTexture(int id, const QSize &size) { m_mutex.lock(); m_id = id; m_size = size; m_mutex.unlock(); // We cannot call QQuickWindow::update directly here, as this is only allowed // from the rendering thread or GUI thread. emit pendingNewTexture(); } // Before the scene graph starts to render, we update to the pending texture void prepareNode() { m_mutex.lock(); int newId = m_id; QSize size = m_size; m_id = 0; m_mutex.unlock(); if (newId) { delete m_texture; m_texture = m_window->createTextureFromId(newId, size); setTexture(m_texture); // This will notify the rendering thread that the texture is now being rendered // and it can start rendering to the other one. emit textureInUse(); } } private: int m_id; QSize m_size; QMutex m_mutex; QSGTexture *m_texture; QQuickWindow *m_window; }; ThreadRenderer::ThreadRenderer() { setFlag(ItemHasContents, true); } QSGNode *ThreadRenderer::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *) { TextureNode *node = static_cast(oldNode); if (!node) { node = new TextureNode(window()); m_renderThread = new RenderThread(QSize(512, 512)); /* Set up connections to get the production of FBO textures in sync with vsync on the * rendering thread. * * When a new texture is ready on the rendering thread, we use a direct connection to * the texture node to let it know a new texture can be used. The node will then * emit pendingNewTexture which we bind to QQuickWindow::update to schedule a redraw. * * When the scene graph starts rendering the next frame, the prepareNode() function * is used to update the node with the new texture. Once it completes, it emits * textureInUse() which we connect to the FBO rendering thread's renderNext() to have * it start producing content into its current "back buffer". * * This FBO rendering pipeline is throttled by vsync on the scene graph rendering thread. */ connect(m_renderThread, SIGNAL(textureReady(int,QSize)), node, SLOT(newTexture(int,QSize)), Qt::DirectConnection); connect(node, SIGNAL(pendingNewTexture()), window(), SLOT(update()), Qt::QueuedConnection); connect(window(), SIGNAL(beforeRendering()), node, SLOT(prepareNode()), Qt::DirectConnection); connect(node, SIGNAL(textureInUse()), m_renderThread, SLOT(renderNext()), Qt::QueuedConnection); // Start the render thread and enter let it process events. m_renderThread->start(); // Get the production of FBO textures started.. QMetaObject::invokeMethod(m_renderThread, "renderNext", Qt::QueuedConnection); } node->setRect(boundingRect()); return node; } #include "threadrenderer.moc"