302 lines
9.9 KiB
C++
302 lines
9.9 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2017 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the examples of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** BSD License Usage
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** Alternatively, you may use this file under the terms of the BSD license
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** as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "threadrenderer.h"
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#include "logorenderer.h"
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#include <QtCore/QMutex>
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#include <QtCore/QThread>
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#include <QtGui/QOpenGLContext>
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#include <QtGui/QOpenGLFramebufferObject>
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#include <QtGui/QGuiApplication>
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#include <QtGui/QOffscreenSurface>
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#include <QtQuick/QQuickWindow>
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#include <qsgsimpletexturenode.h>
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QList<QThread *> ThreadRenderer::threads;
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/*
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* The render thread shares a context with the scene graph and will
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* render into two separate FBOs, one to use for display and one
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* to use for rendering
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*/
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class RenderThread : public QThread
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{
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Q_OBJECT
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public:
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RenderThread(const QSize &size)
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: surface(nullptr)
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, context(nullptr)
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, m_renderFbo(nullptr)
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, m_displayFbo(nullptr)
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, m_logoRenderer(nullptr)
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, m_size(size)
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{
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ThreadRenderer::threads << this;
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}
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QOffscreenSurface *surface;
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QOpenGLContext *context;
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public slots:
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void renderNext()
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{
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context->makeCurrent(surface);
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if (!m_renderFbo) {
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// Initialize the buffers and renderer
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QOpenGLFramebufferObjectFormat format;
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format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
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m_renderFbo = new QOpenGLFramebufferObject(m_size, format);
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m_displayFbo = new QOpenGLFramebufferObject(m_size, format);
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m_logoRenderer = new LogoRenderer();
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m_logoRenderer->initialize();
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}
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m_renderFbo->bind();
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context->functions()->glViewport(0, 0, m_size.width(), m_size.height());
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m_logoRenderer->render();
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// We need to flush the contents to the FBO before posting
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// the texture to the other thread, otherwise, we might
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// get unexpected results.
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context->functions()->glFlush();
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m_renderFbo->bindDefault();
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qSwap(m_renderFbo, m_displayFbo);
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emit textureReady(m_displayFbo->texture(), m_size);
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}
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void shutDown()
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{
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context->makeCurrent(surface);
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delete m_renderFbo;
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delete m_displayFbo;
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delete m_logoRenderer;
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context->doneCurrent();
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delete context;
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// schedule this to be deleted only after we're done cleaning up
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surface->deleteLater();
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// Stop event processing, move the thread to GUI and make sure it is deleted.
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exit();
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moveToThread(QGuiApplication::instance()->thread());
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}
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signals:
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void textureReady(int id, const QSize &size);
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private:
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QOpenGLFramebufferObject *m_renderFbo;
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QOpenGLFramebufferObject *m_displayFbo;
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LogoRenderer *m_logoRenderer;
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QSize m_size;
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};
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class TextureNode : public QObject, public QSGSimpleTextureNode
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{
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Q_OBJECT
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public:
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TextureNode(QQuickWindow *window)
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: m_id(0)
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, m_size(0, 0)
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, m_texture(nullptr)
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, m_window(window)
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{
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// Our texture node must have a texture, so use the default 0 texture.
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m_texture = m_window->createTextureFromId(0, QSize(1, 1));
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setTexture(m_texture);
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setFiltering(QSGTexture::Linear);
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}
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~TextureNode() override
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{
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delete m_texture;
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}
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signals:
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void textureInUse();
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void pendingNewTexture();
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public slots:
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// This function gets called on the FBO rendering thread and will store the
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// texture id and size and schedule an update on the window.
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void newTexture(int id, const QSize &size) {
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m_mutex.lock();
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m_id = id;
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m_size = size;
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m_mutex.unlock();
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// We cannot call QQuickWindow::update directly here, as this is only allowed
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// from the rendering thread or GUI thread.
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emit pendingNewTexture();
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}
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// Before the scene graph starts to render, we update to the pending texture
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void prepareNode() {
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m_mutex.lock();
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int newId = m_id;
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QSize size = m_size;
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m_id = 0;
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m_mutex.unlock();
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if (newId) {
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delete m_texture;
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// note: include QQuickWindow::TextureHasAlphaChannel if the rendered content
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// has alpha.
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m_texture = m_window->createTextureFromId(newId, size);
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setTexture(m_texture);
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markDirty(DirtyMaterial);
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// This will notify the rendering thread that the texture is now being rendered
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// and it can start rendering to the other one.
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emit textureInUse();
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}
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}
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private:
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int m_id;
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QSize m_size;
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QMutex m_mutex;
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QSGTexture *m_texture;
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QQuickWindow *m_window;
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};
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ThreadRenderer::ThreadRenderer()
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: m_renderThread(nullptr)
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{
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setFlag(ItemHasContents, true);
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m_renderThread = new RenderThread(QSize(512, 512));
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}
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void ThreadRenderer::ready()
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{
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m_renderThread->surface = new QOffscreenSurface();
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m_renderThread->surface->setFormat(m_renderThread->context->format());
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m_renderThread->surface->create();
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m_renderThread->moveToThread(m_renderThread);
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connect(window(), &QQuickWindow::sceneGraphInvalidated, m_renderThread, &RenderThread::shutDown, Qt::QueuedConnection);
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m_renderThread->start();
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update();
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}
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QSGNode *ThreadRenderer::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
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{
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TextureNode *node = static_cast<TextureNode *>(oldNode);
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if (!m_renderThread->context) {
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QOpenGLContext *current = window()->openglContext();
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// Some GL implementations requres that the currently bound context is
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// made non-current before we set up sharing, so we doneCurrent here
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// and makeCurrent down below while setting up our own context.
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current->doneCurrent();
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m_renderThread->context = new QOpenGLContext();
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m_renderThread->context->setFormat(current->format());
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m_renderThread->context->setShareContext(current);
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m_renderThread->context->create();
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m_renderThread->context->moveToThread(m_renderThread);
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current->makeCurrent(window());
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QMetaObject::invokeMethod(this, "ready");
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return nullptr;
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}
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if (!node) {
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node = new TextureNode(window());
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/* Set up connections to get the production of FBO textures in sync with vsync on the
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* rendering thread.
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*
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* When a new texture is ready on the rendering thread, we use a direct connection to
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* the texture node to let it know a new texture can be used. The node will then
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* emit pendingNewTexture which we bind to QQuickWindow::update to schedule a redraw.
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*
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* When the scene graph starts rendering the next frame, the prepareNode() function
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* is used to update the node with the new texture. Once it completes, it emits
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* textureInUse() which we connect to the FBO rendering thread's renderNext() to have
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* it start producing content into its current "back buffer".
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*
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* This FBO rendering pipeline is throttled by vsync on the scene graph rendering thread.
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*/
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connect(m_renderThread, &RenderThread::textureReady, node, &TextureNode::newTexture, Qt::DirectConnection);
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connect(node, &TextureNode::pendingNewTexture, window(), &QQuickWindow::update, Qt::QueuedConnection);
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connect(window(), &QQuickWindow::beforeRendering, node, &TextureNode::prepareNode, Qt::DirectConnection);
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connect(node, &TextureNode::textureInUse, m_renderThread, &RenderThread::renderNext, Qt::QueuedConnection);
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// Get the production of FBO textures started..
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QMetaObject::invokeMethod(m_renderThread, "renderNext", Qt::QueuedConnection);
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}
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node->setRect(boundingRect());
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return node;
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}
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#include "threadrenderer.moc"
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