Use OpenGL 3.2 instead of 3.3 to make it work on MacOSX

Fix: * Move all GL startup calls to GLScope::fixOpenGLversion * Depending on OpenGL or ES availability initialize the QSurfaceFormat * Don't crash if the shader compilation failed. Show a nice message instead. Optimize: * Don't write the markers to the GPU each frame update, only do this if they actually changed position. Code style: * LevelSlider: Don't return a value for set* Methods. * Don't rely on the LevelSliders step to calculate the marker position in the OpenGL view.

Use OpenGL 3.2 instead of 3.3 to make it work on MacOSX
Fix: * Move all GL startup calls to GLScope::fixOpenGLversion * Depending on OpenGL or ES availability initialize the QSurfaceFormat * Don't crash if the shader compilation failed. Show a nice message instead. Optimize: * Don't write the markers to the GPU each frame update, only do this if they actually changed position. Code style: * LevelSlider: Don't return a value for set* Methods. * Don't rely on the LevelSliders step to calculate the marker position in the OpenGL view.
David Graeff · David Gräff
1 parent 0f3e1d63
Showing 8 changed files with 197 additions and 136 deletions
openhantek/src/dsowidget.cpp
openhantek/src/dsowidget.h
openhantek/src/glscope.cpp
openhantek/src/glscope.h
openhantek/src/main.cpp
openhantek/src/scopesettings.h
openhantek/src/widgets/levelslider.cpp
openhantek/src/widgets/levelslider.h
@@ -5,8 +5,8 @@
 #include <QFileDialog>
 #include <QGridLayout>
 #include <QLabel>
-#include <QTimer>
 #include <QSignalBlocker>
+#include <QTimer>
 #include "dsowidget.h"
@@ -37,11 +37,12 @@ DsoWidget::DsoWidget(DsoSettingsScope *scope, DsoSettingsView *view, const Dso::
     setupSliders(mainSliders);
     setupSliders(zoomSliders);
-    connect(mainScope, &GlScope::markerMoved, [this] (int marker, double position) {
-        double step = this->mainSliders.markerSlider->step(marker);
+    connect(mainScope, &GlScope::markerMoved, [this](int marker, double position) {
+        double value = std::round(position / MARKER_STEP) * MARKER_STEP;
-        this->scope->horizontal.marker[marker] =
-            this->mainSliders.markerSlider->setValue(marker, std::round(position / step) * step);
+        this->scope->horizontal.marker[marker] = value;
+        this->mainSliders.markerSlider->setValue(marker, value);
+        this->mainScope->markerUpdated();
     });
     // The table for the settings
@@ -175,14 +176,6 @@ DsoWidget::DsoWidget(DsoSettingsScope *scope, DsoSettingsView *view, const Dso::
     mainLayout->setRowMinimumHeight(row++, 8);
     mainLayout->addLayout(measurementLayout, row++, 0, 1, 5);
-    // Apply settings and update measured values
-    updateTriggerDetails();
-    updateRecordLength(scope->horizontal.recordLength);
-    updateFrequencybase(scope->horizontal.frequencybase);
-    updateSamplerate(scope->horizontal.samplerate);
-    updateTimebase(scope->horizontal.timebase);
-    updateZoom(view->zoom);
-
     // The widget itself
     setPalette(palette);
     setBackgroundRole(QPalette::Background);
@@ -205,9 +198,6 @@ DsoWidget::DsoWidget(DsoSettingsScope *scope, DsoSettingsView *view, const Dso::
         zoomScope->update();
     });
     zoomSliders.markerSlider->setEnabled(false);
-
-    updateTriggerSource();
-    adaptTriggerPositionSlider();
 }
 void DsoWidget::setupSliders(DsoWidget::Sliders &sliders) {
@@ -242,11 +232,10 @@ void DsoWidget::setupSliders(DsoWidget::Sliders &amp;sliders) {
     sliders.triggerLevelSlider = new LevelSlider(Qt::LeftArrow);
     for (ChannelID channel = 0; channel < spec->channels; ++channel) {
         sliders.triggerLevelSlider->addSlider((int)channel);
-        sliders.triggerLevelSlider->setColor(
-            channel,
-            (!scope->trigger.special && channel == scope->trigger.source)
-                ? view->screen.voltage[channel]
-                : view->screen.voltage[channel].darker());
+        sliders.triggerLevelSlider->setColor(channel,
+                                             (!scope->trigger.special && channel == scope->trigger.source)
+                                                 ? view->screen.voltage[channel]
+                                                 : view->screen.voltage[channel].darker());
         adaptTriggerLevelSlider(sliders, channel);
         sliders.triggerLevelSlider->setValue(channel, scope->voltage[channel].trigger);
         sliders.triggerLevelSlider->setIndexVisible(channel, scope->voltage[channel].used);
@@ -257,7 +246,7 @@ void DsoWidget::setupSliders(DsoWidget::Sliders &amp;sliders) {
     for (int marker = 0; marker < MARKER_COUNT; ++marker) {
         sliders.markerSlider->addSlider(QString::number(marker + 1), marker);
         sliders.markerSlider->setLimits(marker, -DIVS_TIME / 2, DIVS_TIME / 2);
-        sliders.markerSlider->setStep(marker, DIVS_TIME / 100.0);
+        sliders.markerSlider->setStep(marker, MARKER_STEP);
         sliders.markerSlider->setValue(marker, scope->horizontal.marker[marker]);
         sliders.markerSlider->setIndexVisible(marker, true);
     }
@@ -269,9 +258,9 @@ void DsoWidget::setExporterForNextFrame(std::unique_ptr&lt;Exporter&gt; exporter) {
 /// \brief Set the trigger level sliders minimum and maximum to the new values.
 void DsoWidget::adaptTriggerLevelSlider(DsoWidget::Sliders &sliders, ChannelID channel) {
-    sliders.triggerLevelSlider->setLimits(
-        (int)channel, (-DIVS_VOLTAGE / 2 - scope->voltage[channel].offset) * scope->gain(channel),
-        (DIVS_VOLTAGE / 2 - scope->voltage[channel].offset) * scope->gain(channel));
+    sliders.triggerLevelSlider->setLimits((int)channel,
+                                          (-DIVS_VOLTAGE / 2 - scope->voltage[channel].offset) * scope->gain(channel),
+                                          (DIVS_VOLTAGE / 2 - scope->voltage[channel].offset) * scope->gain(channel));
     sliders.triggerLevelSlider->setStep((int)channel, scope->gain(channel) * 0.05);
 }
@@ -292,14 +281,10 @@ void DsoWidget::setMeasurementVisible(ChannelID channel) {
     }
     measurementGainLabel[channel]->setVisible(scope->voltage[channel].used);
-    if (!scope->voltage[channel].used) {
-        measurementGainLabel[channel]->setText(QString());
-    }
+    if (!scope->voltage[channel].used) { measurementGainLabel[channel]->setText(QString()); }
     measurementMagnitudeLabel[channel]->setVisible(scope->spectrum[channel].used);
-    if (!scope->spectrum[channel].used) {
-        measurementMagnitudeLabel[channel]->setText(QString());
-    }
+    if (!scope->spectrum[channel].used) { measurementMagnitudeLabel[channel]->setText(QString()); }
 }
 /// \brief Update the label about the marker measurements
@@ -411,16 +396,15 @@ void DsoWidget::updateTriggerSource() {
     if (scope->trigger.special || scope->trigger.source >= spec->channels) {
         mainSliders.triggerPositionSlider->setColor(0, view->screen.border);
         zoomSliders.triggerPositionSlider->setColor(0, view->screen.border);
-    }
-    else {
+    } else {
         mainSliders.triggerPositionSlider->setColor(0, view->screen.voltage[scope->trigger.source]);
         zoomSliders.triggerPositionSlider->setColor(0, view->screen.voltage[scope->trigger.source]);
     }
     for (ChannelID channel = 0; channel < spec->channels; ++channel) {
         QColor color = (!scope->trigger.special && channel == scope->trigger.source)
-                     ? view->screen.voltage[channel]
-                     : view->screen.voltage[channel].darker();
+                           ? view->screen.voltage[channel]
+                           : view->screen.voltage[channel].darker();
         mainSliders.triggerLevelSlider->setColor(channel, color);
         zoomSliders.triggerLevelSlider->setColor(channel, color);
     }
@@ -484,8 +468,7 @@ void DsoWidget::updateZoom(bool enabled) {
         zoomSliders.offsetSlider->show();
         zoomSliders.triggerPositionSlider->show();
         zoomSliders.triggerLevelSlider->show();
-    }
-    else {
+    } else {
         zoomSliders.offsetSlider->hide();
         zoomSliders.triggerPositionSlider->hide();
         zoomSliders.triggerLevelSlider->hide();
@@ -535,6 +518,20 @@ void DsoWidget::showNew(std::shared_ptr&lt;PPresult&gt; data) {
     }
 }
+void DsoWidget::showEvent(QShowEvent *event) {
+    QWidget::showEvent(event);
+    // Apply settings and update measured values
+    updateTriggerDetails();
+    updateRecordLength(scope->horizontal.recordLength);
+    updateFrequencybase(scope->horizontal.frequencybase);
+    updateSamplerate(scope->horizontal.samplerate);
+    updateTimebase(scope->horizontal.timebase);
+    updateZoom(view->zoom);
+
+    updateTriggerSource();
+    adaptTriggerPositionSlider();
+}
+
 /// \brief Handles valueChanged signal from the offset sliders.
 /// \param channel The channel whose offset was changed.
 /// \param value The new offset for the channel.
@@ -573,8 +570,7 @@ void DsoWidget::adaptTriggerPositionSlider() {
     if (m1 != m2 && m1 <= value && value <= m2) {
         zoomSliders.triggerPositionSlider->setIndexVisible(0, true);
         zoomSliders.triggerPositionSlider->setValue(0, (value - m1) / (m2 - m1));
-    }
-    else {
+    } else {
         zoomSliders.triggerPositionSlider->setIndexVisible(0, false);
     }
 }
@@ -42,6 +42,7 @@ class DsoWidget : public QWidget {
     void showNew(std::shared_ptr<PPresult> data);
   protected:
+    virtual void showEvent(QShowEvent *event);
     void setupSliders(Sliders &sliders);
     void adaptTriggerLevelSlider(DsoWidget::Sliders &sliders, ChannelID channel);
     void adaptTriggerPositionSlider();
@@ -4,12 +4,16 @@
 #include <iostream>
 #include <QColor>
+#include <QCoreApplication>
 #include <QDebug>
 #include <QMatrix4x4>
+#include <QMessageBox>
 #include <QMouseEvent>
 #include <QOpenGLShaderProgram>
+#include <QPainter>
-#include <QOpenGLFunctions_3_3_Core>
+// We can't be more modern than OpenGL 3.2 or ES2 because of MacOSX.
+#include <QOpenGLFunctions_3_2_Core>
 #include <QOpenGLFunctions_ES2>
 #include "glscope.h"
@@ -23,7 +27,7 @@
 #if defined(QT_OPENGL_ES_2)
 typedef QOpenGLFunctions_ES2 OPENGL_VER;
 #else
-typedef QOpenGLFunctions_3_3_Core OPENGL_VER;
+typedef QOpenGLFunctions_3_2_Core OPENGL_VER;
 #endif
 GlScope *GlScope::createNormal(DsoSettingsScope *scope, DsoSettingsView *view, QWidget *parent) {
@@ -38,6 +42,25 @@ GlScope *GlScope::createZoomed(DsoSettingsScope *scope, DsoSettingsView *view, Q
     return s;
 }
+void GlScope::fixOpenGLversion() {
+    QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts, true);
+
+    // Prefer full desktop OpenGL without fixed pipeline
+    QSurfaceFormat format;
+    format.setSamples(4); // Antia-Aliasing, Multisampling
+#if defined(QT_OPENGL_ES_2)
+    format.setVersion(2, 0);
+    format.setProfile(QSurfaceFormat::CoreProfile);
+    format.setRenderableType(QSurfaceFormat::OpenGLES);
+    QCoreApplication::setAttribute(Qt::AA_UseOpenGLES, true);
+#else
+    format.setVersion(3, 2);
+    format.setProfile(QSurfaceFormat::CoreProfile);
+    format.setRenderableType(QSurfaceFormat::OpenGL);
+#endif
+    QSurfaceFormat::setDefaultFormat(format);
+}
+
 GlScope::GlScope(DsoSettingsScope *scope, DsoSettingsView *view, QWidget *parent)
     : QOpenGLWidget(parent), scope(scope), view(view) {
     vaMarker.resize(MARKER_COUNT);
@@ -51,7 +74,7 @@ void GlScope::mousePressEvent(QMouseEvent *event) {
         double distance = DIVS_TIME;
         selectedMarker = NO_MARKER;
         // Capture nearest marker located within snap area (+/- 1% of full scale).
-        for (int marker = 0; marker < MARKER_COUNT; ++marker) {
+        for (unsigned marker = 0; marker < MARKER_COUNT; ++marker) {
             if (!scope->horizontal.marker_visible[marker]) continue;
             if (fabs(scope->horizontal.marker[marker] - position) < std::min(distance, DIVS_TIME / 100.0)) {
                 distance = fabs(scope->horizontal.marker[marker] - position);
@@ -89,13 +112,34 @@ void GlScope::mouseReleaseEvent(QMouseEvent *event) {
     event->accept();
 }
+void GlScope::paintEvent(QPaintEvent *event) {
+    // Draw error message if OpenGL failed
+    if (!shaderCompileSuccess) {
+        QPainter painter(this);
+        painter.setRenderHint(QPainter::Antialiasing, true);
+        QFont font = painter.font();
+        font.setPointSize(18);
+        painter.setFont(font);
+        painter.drawText(rect(), Qt::AlignCenter, errorMessage);
+        event->accept();
+    } else
+        QOpenGLWidget::paintEvent(event);
+}
+
 void GlScope::initializeGL() {
-    auto *gl = context()->versionFunctions<OPENGL_VER>();
+    if (!QOpenGLShaderProgram::hasOpenGLShaderPrograms(context())) {
+        errorMessage = tr("System does not support OpenGL Shading Language (GLSL)");
+        return;
+    }
+    if (m_program) {
+        qWarning() << "OpenGL init called twice!";
+        return;
+    }
-    m_program = std::unique_ptr<QOpenGLShaderProgram>(new QOpenGLShaderProgram(context()));
+    auto program = std::unique_ptr<QOpenGLShaderProgram>(new QOpenGLShaderProgram(context()));
     const char *vshaderES = R"(
-          #version 330
+          #version 100
           attribute highp vec3 vertex;
           uniform mat4 matrix;
           void main()
@@ -104,9 +148,14 @@ void GlScope::initializeGL() {
               gl_PointSize = 1.0;
           }
     )";
+    const char *fshaderES = R"(
+          #version 100
+          uniform highp vec4 colour;
+          void main() { gl_FragColor = colour; }
+    )";
     const char *vshaderCore = R"(
-          #version 330
+          #version 150
           in highp vec3 vertex;
           uniform mat4 matrix;
           void main()
@@ -116,37 +165,39 @@ void GlScope::initializeGL() {
           }
     )";
     const char *fshaderCore = R"(
-          #version 330
+          #version 150
           uniform highp vec4 colour;
-          void main() { gl_FragColor = colour; }
+          out vec4 flatColor;
+          void main() { flatColor = colour; }
     )";
     qDebug() << "compile shaders";
     // Compile vertex shader
     bool coreShaders = QSurfaceFormat::defaultFormat().profile() == QSurfaceFormat::CoreProfile;
-    if (!m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, coreShaders ? vshaderCore : vshaderES) ||
-        !m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fshaderCore)) {
-        qWarning() << "Failed to compile OpenGL shader programs.\n" << m_program->log();
+    if (!program->addShaderFromSourceCode(QOpenGLShader::Vertex, coreShaders ? vshaderCore : vshaderES) ||
+        !program->addShaderFromSourceCode(QOpenGLShader::Fragment, coreShaders ? fshaderCore : fshaderES)) {
+        errorMessage = "Failed to compile OpenGL shader programs.\n" + program->log();
         return;
     }
     // Link shader pipeline
-    if (!m_program->link() || !m_program->bind()) {
-        qWarning() << "Failed to link/bind OpenGL shader programs";
+    if (!program->link() || !program->bind()) {
+        errorMessage = "Failed to link/bind OpenGL shader programs\n" + program->log();
         return;
     }
-    vertexLocation = m_program->attributeLocation("vertex");
-    matrixLocation = m_program->uniformLocation("matrix");
-    colorLocation = m_program->uniformLocation("colour");
+    vertexLocation = program->attributeLocation("vertex");
+    matrixLocation = program->uniformLocation("matrix");
+    colorLocation = program->uniformLocation("colour");
     if (vertexLocation == -1 || colorLocation == -1 || matrixLocation == -1) {
         qWarning() << "Failed to locate shader variable";
         return;
     }
-    m_program->bind();
+    program->bind();
+    auto *gl = context()->versionFunctions<OPENGL_VER>();
     gl->glDisable(GL_DEPTH_TEST);
     gl->glEnable(GL_BLEND);
     // Enable depth buffer
@@ -159,7 +210,7 @@ void GlScope::initializeGL() {
     QColor bg = view->screen.background;
     gl->glClearColor((GLfloat)bg.redF(), (GLfloat)bg.greenF(), (GLfloat)bg.blueF(), (GLfloat)bg.alphaF());
-    generateGrid();
+    generateGrid(program.get());
     {
         m_vaoMarker.create();
@@ -168,15 +219,18 @@ void GlScope::initializeGL() {
         m_marker.bind();
         m_marker.setUsagePattern(QOpenGLBuffer::StaticDraw);
         m_marker.allocate(int(vaMarker.size() * sizeof(Line)));
-        m_program->enableAttributeArray(vertexLocation);
-        m_program->setAttributeBuffer(vertexLocation, GL_FLOAT, 0, 3, 0);
+        program->enableAttributeArray(vertexLocation);
+        program->setAttributeBuffer(vertexLocation, GL_FLOAT, 0, 3, 0);
     }
-    m_program->release();
+    markerUpdated();
+
+    m_program = std::move(program);
+    shaderCompileSuccess = true;
 }
 void GlScope::showData(PPresult *data) {
-    if (!m_program || !m_program->isLinked()) return;
+    if (!shaderCompileSuccess) return;
     makeCurrent();
     // Remove too much entries
     while (view->digitalPhosphorDraws() < m_GraphHistory.size()) m_GraphHistory.pop_back();
@@ -192,8 +246,23 @@ void GlScope::showData(PPresult *data) {
     // doneCurrent();
 }
+void GlScope::markerUpdated()
+{
+
+    for (unsigned marker = 0; marker < vaMarker.size(); ++marker) {
+        if (!scope->horizontal.marker_visible[marker]) continue;
+        vaMarker[marker] = {QVector3D((GLfloat)scope->horizontal.marker[marker], -DIVS_VOLTAGE, 0.0f),
+                            QVector3D((GLfloat)scope->horizontal.marker[marker], DIVS_VOLTAGE, 0.0f)};
+    }
+
+    // Write coordinates to GPU
+    makeCurrent();
+    m_marker.bind();
+    m_marker.write(0, vaMarker.data(), vaMarker.size() * sizeof(Line));
+}
+
 void GlScope::paintGL() {
-    if (!m_program->isLinked()) return;
+    if (!shaderCompileSuccess) return;
     auto *gl = context()->versionFunctions<OPENGL_VER>();
@@ -231,6 +300,7 @@ void GlScope::paintGL() {
 }
 void GlScope::resizeGL(int width, int height) {
+    if (!shaderCompileSuccess) return;
     auto *gl = context()->versionFunctions<OPENGL_VER>();
     gl->glViewport(0, 0, (GLint)width, (GLint)height);
@@ -248,30 +318,7 @@ void GlScope::resizeGL(int width, int height) {
     m_program->release();
 }
-void GlScope::drawGrid() {
-    auto *gl = context()->versionFunctions<OPENGL_VER>();
-    gl->glLineWidth(1);
-
-    // Grid
-    m_vaoGrid[0].bind();
-    m_program->setUniformValue(colorLocation, view->screen.grid);
-    gl->glDrawArrays(GL_POINTS, 0, gridDrawCounts[0]);
-    m_vaoGrid[0].release();
-
-    // Axes
-    m_vaoGrid[1].bind();
-    m_program->setUniformValue(colorLocation, view->screen.axes);
-    gl->glDrawArrays(GL_LINES, 0, gridDrawCounts[1]);
-    m_vaoGrid[1].release();
-
-    // Border
-    m_vaoGrid[2].bind();
-    m_program->setUniformValue(colorLocation, view->screen.border);
-    gl->glDrawArrays(GL_LINE_LOOP, 0, gridDrawCounts[2]);
-    m_vaoGrid[2].release();
-}
-
-void GlScope::generateGrid() {
+void GlScope::generateGrid(QOpenGLShaderProgram *program) {
     gridDrawCounts[0] = 0;
     gridDrawCounts[1] = 0;
     gridDrawCounts[2] = 0;
@@ -286,8 +333,8 @@ void GlScope::generateGrid() {
         m_vaoGrid[0].create();
         QOpenGLVertexArrayObject::Binder b(&m_vaoGrid[0]);
         m_grid.bind();
-        m_program->enableAttributeArray(vertexLocation);
-        m_program->setAttributeBuffer(vertexLocation, GL_FLOAT, 0, 3, 0);
+        program->enableAttributeArray(vertexLocation);
+        program->setAttributeBuffer(vertexLocation, GL_FLOAT, 0, 3, 0);
     }
     // Draw vertical lines
@@ -318,8 +365,8 @@ void GlScope::generateGrid() {
         m_vaoGrid[1].create();
         QOpenGLVertexArrayObject::Binder b(&m_vaoGrid[1]);
         m_grid.bind();
-        m_program->enableAttributeArray(vertexLocation);
-        m_program->setAttributeBuffer(vertexLocation, GL_FLOAT, int(vaGrid.size() * sizeof(QVector3D)), 3);
+        program->enableAttributeArray(vertexLocation);
+        program->setAttributeBuffer(vertexLocation, GL_FLOAT, int(vaGrid.size() * sizeof(QVector3D)), 3);
     }
     // Axes
@@ -353,8 +400,8 @@ void GlScope::generateGrid() {
         m_vaoGrid[2].create();
         QOpenGLVertexArrayObject::Binder b(&m_vaoGrid[2]);
         m_grid.bind();
-        m_program->enableAttributeArray(vertexLocation);
-        m_program->setAttributeBuffer(vertexLocation, GL_FLOAT, int(vaGrid.size() * sizeof(QVector3D)), 3);
+        program->enableAttributeArray(vertexLocation);
+        program->setAttributeBuffer(vertexLocation, GL_FLOAT, int(vaGrid.size() * sizeof(QVector3D)), 3);
     }
     // Border
@@ -368,6 +415,29 @@ void GlScope::generateGrid() {
     m_grid.release();
 }
+void GlScope::drawGrid() {
+    auto *gl = context()->versionFunctions<OPENGL_VER>();
+    gl->glLineWidth(1);
+
+    // Grid
+    m_vaoGrid[0].bind();
+    m_program->setUniformValue(colorLocation, view->screen.grid);
+    gl->glDrawArrays(GL_POINTS, 0, gridDrawCounts[0]);
+    m_vaoGrid[0].release();
+
+    // Axes
+    m_vaoGrid[1].bind();
+    m_program->setUniformValue(colorLocation, view->screen.axes);
+    gl->glDrawArrays(GL_LINES, 0, gridDrawCounts[1]);
+    m_vaoGrid[1].release();
+
+    // Border
+    m_vaoGrid[2].bind();
+    m_program->setUniformValue(colorLocation, view->screen.border);
+    gl->glDrawArrays(GL_LINE_LOOP, 0, gridDrawCounts[2]);
+    m_vaoGrid[2].release();
+}
+
 void GlScope::drawMarkers() {
     auto *gl = context()->versionFunctions<OPENGL_VER>();
     QColor trColor = view->screen.markers;
@@ -375,23 +445,13 @@ void GlScope::drawMarkers() {
     m_vaoMarker.bind();
-    for (unsigned marker = 0; marker < vaMarker.size(); ++marker) {
-        if (!scope->horizontal.marker_visible[marker]) continue;
-        vaMarker[marker] = {QVector3D((GLfloat)scope->horizontal.marker[marker], -DIVS_VOLTAGE, 0.0f),
-                            QVector3D((GLfloat)scope->horizontal.marker[marker], DIVS_VOLTAGE, 0.0f)};
-    }
-
-    // Write coordinates to GPU
-    m_marker.bind();
-    m_marker.write(0, vaMarker.data(), vaMarker.size() * sizeof(Line));
-
     // Draw all
     gl->glLineWidth(1);
     gl->glDrawArrays(GL_LINES, 0, (GLsizei)vaMarker.size() * 2);
-    m_marker.release();
     // Draw selected
     if (selectedMarker != NO_MARKER) {
+        qWarning() << selectedMarker;
         gl->glLineWidth(3);
         gl->glDrawArrays(GL_LINES, selectedMarker * 2, (GLsizei)2);
     }
@@ -31,10 +31,16 @@ class GlScope : public QOpenGLWidget {
                                  QWidget *parent = 0);
     /**
+     * We need at least OpenGL 3.2 with shader version 150 or
+     * OpenGL ES 2.0 with shader version 100.
+     */
+    static void fixOpenGLversion();
+    /**
      * Show new post processed data
      * @param data
      */
     void showData(PPresult* data);
+    void markerUpdated();
   protected:
     /// \brief Initializes the scope widget.
@@ -42,21 +48,23 @@ class GlScope : public QOpenGLWidget {
     /// \param parent The parent widget.
     GlScope(DsoSettingsScope *scope, DsoSettingsView *view, QWidget *parent = 0);
     virtual ~GlScope();
+    GlScope(const GlScope&) = delete;
     /// \brief Initializes OpenGL output.
-    void initializeGL() override;
+    virtual void initializeGL() override;
     /// \brief Draw the graphs, marker and the grid.
-    void paintGL() override;
+    virtual void paintGL() override;
     /// \brief Resize the widget.
     /// \param width The new width of the widget.
     /// \param height The new height of the widget.
-    void resizeGL(int width, int height) override;
+    virtual void resizeGL(int width, int height) override;
-    void mousePressEvent(QMouseEvent *event) override;
-    void mouseMoveEvent(QMouseEvent *event) override;
-    void mouseReleaseEvent(QMouseEvent *event) override;
+    virtual void mousePressEvent(QMouseEvent *event) override;
+    virtual void mouseMoveEvent(QMouseEvent *event) override;
+    virtual void mouseReleaseEvent(QMouseEvent *event) override;
+    virtual void paintEvent(QPaintEvent *event) override;
     /// \brief Draw the grid.
     void drawGrid();
@@ -91,13 +99,15 @@ class GlScope : public QOpenGLWidget {
     QOpenGLBuffer m_grid;
     QOpenGLVertexArrayObject m_vaoGrid[3];
     GLsizei gridDrawCounts[3];
-    void generateGrid();
+    void generateGrid(QOpenGLShaderProgram *program);
     // Graphs
     std::list<Graph> m_GraphHistory;
     unsigned currentGraphInHistory = 0;
     // OpenGL shader, matrix, var-locations
+    bool shaderCompileSuccess = false;
+    QString errorMessage;
     std::unique_ptr<QOpenGLShaderProgram> m_program;
     QMatrix4x4 pmvMatrix; ///< projection, view matrix
     int colorLocation;
@@ -24,6 +24,8 @@
 #include "usb/usbdevice.h"
 #include "viewconstants.h"
+#include "glscope.h"
+
 #ifndef VERSION
 #error "You need to run the cmake buildsystem!"
 #endif
@@ -69,14 +71,8 @@ int main(int argc, char *argv[]) {
     QCoreApplication::setApplicationName("OpenHantek");
     QCoreApplication::setApplicationVersion(VERSION);
-    QCoreApplication::setAttribute(Qt::AA_UseOpenGLES, true);
-    QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts, true);
+    GlScope::fixOpenGLversion();
-    // Prefer full desktop OpenGL without fixed pipeline
-    QSurfaceFormat format;
-    format.setProfile(QSurfaceFormat::CoreProfile);
-    format.setSamples(4); // Antia-Aliasing, Multisampling
-    QSurfaceFormat::setDefaultFormat(format);
     QApplication openHantekApplication(argc, argv);
     //////// Load translations ////////
@@ -155,5 +151,10 @@ int main(int argc, char *argv[]) {
     postProcessingThread.quit();
     postProcessingThread.wait(10000);
+
+    if (context && device != nullptr) {
+        libusb_exit(context);
+    }
+
     return res;
 }
@@ -11,6 +11,7 @@
 #include <vector>
 #define MARKER_COUNT 2 ///< Number of markers
+#define MARKER_STEP (DIVS_TIME / 100.0)
 /// \brief Holds the settings for the horizontal axis.
 struct DsoSettingsScopeHorizontal {
@@ -196,17 +196,14 @@ double LevelSlider::maximum(int index) const {
 /// \param minimum The value a slider has at the bottommost/leftmost position.
 /// \param maximum The value a slider has at the topmost/rightmost position.
 /// \return -1 on error, fixValue result on success.
-int LevelSlider::setLimits(int index, double minimum, double maximum) {
-    if (index < 0 || index >= this->slider.count()) return -1;
+void LevelSlider::setLimits(int index, double minimum, double maximum) {
+    if (index < 0 || index >= this->slider.count()) return;
     this->slider[index]->minimum = minimum;
     this->slider[index]->maximum = maximum;
-    int result = this->fixValue(index);
-
+    this->fixValue(index);
     this->calculateRect(index);
     this->repaint();
-
-    return result;
 }
 /// \brief Return the step width of the sliders.
@@ -243,8 +240,8 @@ double LevelSlider::value(int index) const {
 /// \param index The index of the slider whose value should be set.
 /// \param value The new value of the slider.
 /// \return The new value of the slider.
-double LevelSlider::setValue(int index, double value) {
-    if (index < 0 || index >= this->slider.count()) return -1;
+void LevelSlider::setValue(int index, double value) {
+    if (index < 0 || index >= this->slider.count()) return;
     // Apply new value
     this->slider[index]->value = value;
@@ -254,8 +251,6 @@ double LevelSlider::setValue(int index, double value) {
     this->repaint();
     if (this->pressedSlider < 0) emit valueChanged(index, value);
-
-    return this->slider[index]->value;
 }
 /// \brief Return the direction of the sliders.
@@ -563,17 +558,14 @@ int LevelSlider::calculateWidth() {
 /// \brief Fix the value if it's outside the limits.
 /// \param index The index of the slider who should be fixed.
 /// \return 0 when ok, -1 on error, 1 when increased and 2 when decreased.
-int LevelSlider::fixValue(int index) {
-    if (index < 0 || index >= this->slider.count()) return -1;
+void LevelSlider::fixValue(int index) {
+    if (index < 0 || index >= this->slider.count()) return;
     double lowest = qMin(this->slider[index]->minimum, this->slider[index]->maximum);
     double highest = qMax(this->slider[index]->minimum, this->slider[index]->maximum);
     if (this->slider[index]->value < lowest) {
         this->slider[index]->value = lowest;
-        return 1;
     } else if (this->slider[index]->value > highest) {
         this->slider[index]->value = highest;
-        return 2;
     }
-    return 0;
 }
@@ -51,11 +51,11 @@ class LevelSlider : public QWidget {
     double minimum(int index) const;
     double maximum(int index) const;
-    int setLimits(int index, double minimum, double maximum);
+    void setLimits(int index, double minimum, double maximum);
     double step(int index) const;
     double setStep(int index, double step);
     double value(int index) const;
-    double setValue(int index, double value);
+    void setValue(int index, double value);
     // Parameters for all sliders
     Qt::ArrowType direction() const;
@@ -71,7 +71,7 @@ class LevelSlider : public QWidget {
     QRect calculateRect(int sliderId);
     int calculateWidth();
-    int fixValue(int index);
+    void fixValue(int index);
     QList<LevelSliderParameters *> slider; ///< The parameters for each slider
     int pressedSlider;                     ///< The currently pressed (moved) slider