Some threading improvements to the GL module

 - Make bindTexture threadsafe
 - Document which areas of QGLWidget needs locking in order
   to do out-of-gui thread rendering
 - Testcases to prove that these cases work

Reviewed-by: Trond

4 files changed, 519 insertions, 0 deletions

diff --git a/tests/auto/auto.pro b/tests/auto/auto.pro
index 9c4b4f0..8bfd151 100644
--- a/tests/auto/auto.pro
+++ b/tests/auto/auto.pro
@@ -153,6 +153,8 @@ SUBDIRS += \
            qfontmetrics \
            qftp \
            qgetputenv \
+           qgl \
+	   qgl_threads \
            qglobal \
            qgraphicseffect \
            qgraphicseffectsource \
diff --git a/tests/auto/qgl_threads/tst_openglthreading.cpp b/tests/auto/qgl_threads/tst_openglthreading.cpp
new file mode 100644
index 0000000..f0c889c
--- /dev/null
+++ b/tests/auto/qgl_threads/tst_openglthreading.cpp
@@ -0,0 +1,452 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtTest/QtTest>
+#include <QtCore/QtCore>
+#include <QtGui/QtGui>
+#include <QtOpenGL/QtOpenGL>
+#include "tst_openglthreading.h"
+
+#define RUNNING_TIME 5000
+
+tst_OpenGLThreading::tst_OpenGLThreading(QObject *parent)
+    : QObject(parent)
+{
+}
+
+
+
+/*
+
+   swapInThread
+
+   The purpose of this testcase is to verify that it is possible to do rendering into
+   a GL context from the GUI thread, then swap the contents in from a background thread.
+
+   The usecase for this is to have the background thread do the waiting for vertical
+   sync while the GUI thread is idle.
+
+   Currently the locking is handled directly in the paintEvent(). For the actual usecase
+   in Qt, the locking is done in the windowsurface before starting any drawing while
+   unlocking is done after all drawing has been done.
+ */
+
+
+class SwapThread : public QThread
+{
+    Q_OBJECT
+public:
+    SwapThread(QGLWidget *widget)
+        : m_widget(widget)
+    {
+        moveToThread(this);
+    }
+
+    void run() {
+        QTime time;
+        time.start();
+        while (time.elapsed() < RUNNING_TIME) {
+            lock();
+            wait();
+
+            m_widget->makeCurrent();
+            m_widget->swapBuffers();
+            m_widget->doneCurrent();
+            unlock();
+        }
+    }
+
+    void lock() { m_mutex.lock(); }
+    void unlock() { m_mutex.unlock(); }
+
+    void wait() { m_wait_condition.wait(&m_mutex); }
+    void notify() { m_wait_condition.wakeAll(); }
+
+private:
+    QGLWidget *m_widget;
+    QMutex m_mutex;
+    QWaitCondition m_wait_condition;
+};
+
+class ForegroundWidget : public QGLWidget
+{
+public:
+    ForegroundWidget(const QGLFormat &format)
+        : QGLWidget(format), m_thread(0)
+    {
+        setAutoBufferSwap(false);
+    }
+    
+    void paintEvent(QPaintEvent *)
+    {        
+        m_thread->lock();
+        makeCurrent();
+        QPainter p(this);
+        p.fillRect(rect(), QColor(rand() % 256, rand() % 256, rand() % 256));
+        p.setPen(Qt::red);
+        p.setFont(QFont("SansSerif", 24));
+        p.drawText(rect(), Qt::AlignCenter, "This is an autotest");
+        p.end();
+        doneCurrent();
+        m_thread->notify();
+        m_thread->unlock();
+
+        update();
+    }
+
+    void setThread(SwapThread *thread) {
+        m_thread = thread;
+    }
+
+    SwapThread *m_thread;
+};
+
+void tst_OpenGLThreading::swapInThread()
+{
+    QGLFormat format;
+    format.setSwapInterval(1);
+    ForegroundWidget widget(format);
+    SwapThread thread(&widget);
+    widget.setThread(&thread);
+    widget.show();
+
+    QTest::qWaitForWindowShown(&widget);
+    thread.start();
+
+    while (thread.isRunning()) {
+        qApp->processEvents();
+    }
+
+    widget.hide();
+
+    QVERIFY(true);
+}
+
+
+
+
+
+
+
+/*
+   textureUploadInThread
+
+   The purpose of this testcase is to verify that doing texture uploads in a background
+   thread is possible and that it works.
+ */
+
+class CreateAndUploadThread : public QThread
+{
+    Q_OBJECT
+public:
+    CreateAndUploadThread(QGLWidget *shareWidget)
+    {
+        m_gl = new QGLWidget(0, shareWidget);
+        moveToThread(this);
+    }
+
+    ~CreateAndUploadThread()
+    {
+        delete m_gl;
+    }
+
+    void run() {
+        m_gl->makeCurrent();
+        QTime time;
+        time.start();
+        while (time.elapsed() < RUNNING_TIME) {
+            QImage image(400, 300, QImage::Format_RGB32);
+            QPainter p(&image);
+            p.fillRect(image.rect(), QColor(rand() % 256, rand() % 256, rand() % 256));
+            p.setPen(Qt::red);
+            p.setFont(QFont("SansSerif", 24));
+            p.drawText(image.rect(), Qt::AlignCenter, "This is an autotest");
+            p.end();
+            m_gl->bindTexture(image, GL_TEXTURE_2D, GL_RGBA, QGLContext::InternalBindOption);
+            createdAndUploaded(image);
+        }
+    }
+
+signals:
+    void createdAndUploaded(const QImage &image);
+
+private:
+    QGLWidget *m_gl;
+};
+
+class TextureDisplay : public QGLWidget
+{
+    Q_OBJECT
+public:
+    void paintEvent(QPaintEvent *) {
+        QPainter p(this);
+        for (int i=0; i<m_images.size(); ++i) {
+            p.drawImage(m_positions.at(i), m_images.at(i));
+            m_positions[i] += QPoint(1, 1);
+        }
+        update();
+    }
+
+public slots:
+    void receiveImage(const QImage &image) {
+        m_images << image;
+        m_positions << QPoint(-rand() % width() / 2, -rand() % height() / 2);
+
+        if (m_images.size() > 100) {
+            m_images.takeFirst();
+            m_positions.takeFirst();
+        }
+    }
+
+private:
+    QList <QImage> m_images;
+    QList <QPoint> m_positions;
+};
+
+void tst_OpenGLThreading::textureUploadInThread()
+{
+    TextureDisplay display;
+    CreateAndUploadThread thread(&display);
+
+    connect(&thread, SIGNAL(createdAndUploaded(QImage)), &display, SLOT(receiveImage(QImage)));
+
+    display.show();
+    QTest::qWaitForWindowShown(&display);
+
+    thread.start();
+
+    while (thread.isRunning()) {
+        qApp->processEvents();
+    }
+
+    QVERIFY(true);
+}
+
+
+
+
+
+
+/*
+   renderInThread
+
+   This test sets up a scene and renders it in a different thread.
+   For simplicity, the scene is simply a bunch of rectangles, but
+   if that works, we're in good shape..
+ */
+
+static inline float random() { return (rand() % 100) / 100.f; }
+
+void renderAScene(int w, int h)
+{
+#ifdef QT_OPENGL_ES_2
+            QGLShaderProgram program;
+            program.addShaderFromSourceCode(QGLShader::Vertex, "attribute highp vec2 pos; void main() { gl_Position = position; }");
+            program.addShaderFromSourceCode(QGLShader::Fragment, "uniform lowp vec4 color; void main() { gl_FragColor = color; }");
+            program.bind();
+            int colorId = program.uniformLocation("color");
+            program.bindAttributeLocation("pos", 0);
+
+            glEnableClientState(GL_VERTEX_ARRAY);
+
+            for (int i=0; i<1000; ++i) {
+                float pos[] = {
+                    (rand() % 100) / 100.,
+                    (rand() % 100) / 100.,
+                    (rand() % 100) / 100.,
+                    (rand() % 100) / 100.,
+                    (rand() % 100) / 100.,
+                    (rand() % 100) / 100.
+                };
+
+                glVertexAttributePointer(0, 2, GL_FLOAT, false, 0, pos);
+                glDrawArrays(GL_TRIANGLE_STRIP, 0, 3);
+            }
+#else
+            glViewport(0, 0, w, h);
+
+            glMatrixMode(GL_PROJECTION);
+            glLoadIdentity();
+            glFrustum(0, w, h, 0, 1, 100);
+            glTranslated(0, 0, -1);
+
+            glMatrixMode(GL_MODELVIEW);
+            glLoadIdentity();
+
+            for (int i=0;i<1000; ++i) {
+                glBegin(GL_TRIANGLES);
+                glColor3f(random(), random(), random());
+                glVertex2f(random() * w, random() * h);
+                glColor3f(random(), random(), random());
+                glVertex2f(random() * w, random() * h);
+                glColor3f(random(), random(), random());
+                glVertex2f(random() * w, random() * h);
+                glEnd();
+            }
+#endif
+}
+
+class ThreadSafeGLWidget : public QGLWidget
+{
+public:
+    void paintEvent(QPaintEvent *)
+    {
+        // ignored as we're anyway swapping as fast as we can
+    };
+
+    void resizeEvent(QResizeEvent *e)
+    {
+        mutex.lock();
+        newSize = e->size();
+        mutex.unlock();
+    };
+
+    void sendResizeEvent(QResizeEvent *e) {
+        QGLWidget::resizeEvent(e);
+    }
+
+    QMutex mutex;
+    QSize newSize;
+};
+
+class SceneRenderingThread : public QThread
+{
+    Q_OBJECT
+public:
+    SceneRenderingThread(ThreadSafeGLWidget *widget)
+        : m_widget(widget)
+    {
+        moveToThread(this);
+        m_size = widget->size();
+    }
+
+    void run() {
+        QTime time;
+        time.start();
+        failure = false;
+
+        m_widget->makeCurrent();
+
+        while (time.elapsed() < RUNNING_TIME && !failure) {
+
+            m_widget->mutex.lock();
+            QSize s = m_widget->newSize;
+            m_widget->mutex.unlock();
+            if (s != m_size) {
+                QResizeEvent e(s, m_size);
+                m_widget->sendResizeEvent(&e);
+                m_size = s;
+            }
+
+            if (QGLContext::currentContext() != m_widget->context()) {
+                failure = true;
+                break;
+            }
+
+            glClear(GL_COLOR_BUFFER_BIT);
+
+            int w = m_widget->width();
+            int h = m_widget->height();
+
+            renderAScene(w, h);
+
+            int color;
+            glReadPixels(w / 2, h / 2, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &color);
+
+            m_widget->swapBuffers();
+
+
+        }
+    }
+
+    bool failure;
+
+private:
+    ThreadSafeGLWidget *m_widget;
+    QSize m_size;
+};
+
+void tst_OpenGLThreading::renderInThread_data()
+{
+    QTest::addColumn<bool>("resize");
+    QTest::addColumn<bool>("update");
+
+    QTest::newRow("basic") << false << false;
+    QTest::newRow("with-resize") << true << false;
+    QTest::newRow("with-update") << false << true;
+    QTest::newRow("with-resize-and-update") << true << true;
+}
+
+void tst_OpenGLThreading::renderInThread()
+{
+    QFETCH(bool, resize);
+    QFETCH(bool, update);
+
+    ThreadSafeGLWidget widget;
+    widget.resize(200, 200);
+    SceneRenderingThread thread(&widget);
+
+    widget.show();
+    QTest::qWaitForWindowShown(&widget);
+    widget.doneCurrent();
+
+    thread.start();
+
+    int value = 10;
+    while (thread.isRunning()) {
+        if (resize)
+            widget.resize(200 + value, 200 + value);
+        if (update)
+            widget.update(100 + value, 100 + value, 20, 20);
+        qApp->processEvents();
+        value = -value;
+    }
+
+    QVERIFY(!thread.failure);
+}
+
+
+
+
+
+QTEST_MAIN(tst_OpenGLThreading);
+
+#include "tst_openglthreading.moc"
diff --git a/tests/auto/qgl_threads/tst_openglthreading.h b/tests/auto/qgl_threads/tst_openglthreading.h
new file mode 100644
index 0000000..c4b55cd
--- /dev/null
+++ b/tests/auto/qgl_threads/tst_openglthreading.h
@@ -0,0 +1,61 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef TST_OPENGLTHREADING_H
+#define TST_OPENGLTHREADING_H
+
+#include <QObject>
+
+class tst_OpenGLThreading : public QObject
+{
+Q_OBJECT
+public:
+    explicit tst_OpenGLThreading(QObject *parent = 0);
+
+private slots:
+    void swapInThread();
+    void textureUploadInThread();
+
+    void renderInThread_data();
+    void renderInThread();
+};
+
+#endif // TST_OPENGLTHREADING_H
diff --git a/tests/auto/qgl_threads/tst_openglthreading.pro b/tests/auto/qgl_threads/tst_openglthreading.pro
new file mode 100644
index 0000000..b60bc10
--- /dev/null
+++ b/tests/auto/qgl_threads/tst_openglthreading.pro
@@ -0,0 +1,4 @@
+HEADERS += tst_openglthreading.h
+SOURCES += tst_openglthreading.cpp
+
+QT += testlib opengl