C++ QOpenGLFunctions::glClear方法代码示例

void Renderer::render()
{
    QMutexLocker locker(&m_windowLock);

    if (m_windows.isEmpty())
        return;

    HelloWindow *surface = m_windows.at(m_currentWindow);
    QColor color = surface->color();

    m_currentWindow = (m_currentWindow + 1) % m_windows.size();

    if (!m_context->makeCurrent(surface))
        return;

    QSize viewSize = surface->size();

    locker.unlock();

    if (!m_initialized) {
        initialize();
        m_initialized = true;
    }

    QOpenGLFunctions *f = m_context->functions();
    f->glViewport(0, 0, viewSize.width() * surface->devicePixelRatio(), viewSize.height() * surface->devicePixelRatio());
    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    f->glClearColor(m_backgroundColor.redF(), m_backgroundColor.greenF(), m_backgroundColor.blueF(), m_backgroundColor.alphaF());
    f->glFrontFace(GL_CW);
    f->glCullFace(GL_FRONT);
    f->glEnable(GL_CULL_FACE);
    f->glEnable(GL_DEPTH_TEST);

    m_program->bind();
    m_vbo.bind();

    m_program->enableAttributeArray(vertexAttr);
    m_program->enableAttributeArray(normalAttr);
    m_program->setAttributeBuffer(vertexAttr, GL_FLOAT, 0, 3);
    const int verticesSize = vertices.count() * 3 * sizeof(GLfloat);
    m_program->setAttributeBuffer(normalAttr, GL_FLOAT, verticesSize, 3);

    QMatrix4x4 modelview;
    modelview.rotate(m_fAngle, 0.0f, 1.0f, 0.0f);
    modelview.rotate(m_fAngle, 1.0f, 0.0f, 0.0f);
    modelview.rotate(m_fAngle, 0.0f, 0.0f, 1.0f);
    modelview.translate(0.0f, -0.2f, 0.0f);

    m_program->setUniformValue(matrixUniform, modelview);
    m_program->setUniformValue(colorUniform, color);

    m_context->functions()->glDrawArrays(GL_TRIANGLES, 0, vertices.size());

    m_context->swapBuffers(surface);

    m_fAngle += 1.0f;

    QTimer::singleShot(0, this, SLOT(render()));
}

void QGLWidgetGLPaintDevice::beginPaint()
{
    QGLPaintDevice::beginPaint();
    QOpenGLFunctions *funcs = QOpenGLContext::currentContext()->functions();
    if (!glWidget->d_func()->disable_clear_on_painter_begin && glWidget->autoFillBackground()) {
        if (glWidget->testAttribute(Qt::WA_TranslucentBackground))
            funcs->glClearColor(0.0, 0.0, 0.0, 0.0);
        else {
            const QColor &c = glWidget->palette().brush(glWidget->backgroundRole()).color();
            float alpha = c.alphaF();
            funcs->glClearColor(c.redF() * alpha, c.greenF() * alpha, c.blueF() * alpha, alpha);
        }
        if (context()->d_func()->workaround_needsFullClearOnEveryFrame)
            funcs->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
        else
            funcs->glClear(GL_COLOR_BUFFER_BIT);
    }
}

void Renderer::render()
{
    QMutexLocker locker(&m_windowLock);

    if (m_windows.isEmpty())
        return;

    HelloWindow *surface = m_windows.at(m_currentWindow);
    QColor color = surface->color();

    m_currentWindow = (m_currentWindow + 1) % m_windows.size();

    if (!m_context->makeCurrent(surface))
        return;

    QSize viewSize = surface->size();

    locker.unlock();

    if (!m_initialized) {
        initialize();
        m_initialized = true;
    }

    QOpenGLFunctions *f = m_context->functions();
    f->glViewport(0, 0, viewSize.width() * surface->devicePixelRatio(), viewSize.height() * surface->devicePixelRatio());

    f->glClearColor(0.1f, 0.1f, 0.2f, 1.0f);
    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    f->glFrontFace(GL_CW);
    f->glCullFace(GL_FRONT);
    f->glEnable(GL_CULL_FACE);
    f->glEnable(GL_DEPTH_TEST);

    QMatrix4x4 modelview;
    modelview.rotate(m_fAngle, 0.0f, 1.0f, 0.0f);
    modelview.rotate(m_fAngle, 1.0f, 0.0f, 0.0f);
    modelview.rotate(m_fAngle, 0.0f, 0.0f, 1.0f);
    modelview.translate(0.0f, -0.2f, 0.0f);

    m_program->bind();
    m_program->setUniformValue(matrixUniform, modelview);
    m_program->setUniformValue(colorUniform, color);
    paintQtLogo();
    m_program->release();

    f->glDisable(GL_DEPTH_TEST);
    f->glDisable(GL_CULL_FACE);

    m_context->swapBuffers(surface);

    m_fAngle += 1.0f;

    QTimer::singleShot(0, this, SLOT(render()));
}

    void exposeEvent(QExposeEvent *)
    {
        if (!isExposed())
            return;

        if (!gl) {
            gl = new QOpenGLContext();
            gl->setFormat(requestedFormat());
            gl->create();
        }

        gl->makeCurrent(this);

        QOpenGLShaderProgram prog;
        prog.addShaderFromSourceCode(QOpenGLShader::Vertex,
                                     "attribute highp vec4 a_Pos;"
                                     "attribute lowp vec4 a_Color;"
                                     "varying lowp vec4 v_Color;"
                                     "void main() {"
                                     "    gl_Position = a_Pos;"
                                     "    v_Color = a_Color;"
                                     "}");
        prog.addShaderFromSourceCode(QOpenGLShader::Fragment,
                                     "varying lowp vec4 v_Color;"
                                     "void main() {"
                                     "    gl_FragColor = v_Color;"
                                     "}");
        prog.bind();

        QOpenGLFunctions *functions = gl->functions();
        functions->glClearColor(0, 0, 0, 0);
        functions->glClear(GL_COLOR_BUFFER_BIT);
        functions->glViewport(0, 0, width(), height());

        prog.enableAttributeArray("a_Pos");
        prog.enableAttributeArray("a_Color");

        float coords[] = { -0.7f,  0.7f,
                            0.8f,  0.8f,
                           -0.8f, -0.8f,
                            0.7f, -0.7f };
        float colors[] = { 1, 0, 0, 1,
                           0, 1, 0, 1,
                           0, 0, 1, 1,
                           0, 0, 0, 0 };

        prog.setAttributeArray("a_Pos", GL_FLOAT, coords, 2, 0);
        prog.setAttributeArray("a_Color", GL_FLOAT, colors, 4, 0);

        functions->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

        prog.disableAttributeArray("a_Pos");
        prog.disableAttributeArray("a_Color");

        gl->swapBuffers(this);
    }

void QtRenderer::render()
{
    QMutexLocker locker(&m_windowLock);

    if (m_windows.isEmpty())
        return;

    HelloWindow *surface = m_windows.at(m_currentWindow);
    QColor color = surface->color();

    m_currentWindow = (m_currentWindow + 1) % m_windows.size();

    if (!m_context->makeCurrent(surface))
        return;
    
    m_fboController->bind(surface->size());
    m_fboController->bindAndDraw();
    m_fboController->release();

    QSize viewSize = surface->size();

    locker.unlock();

    if (!m_initialized) {
        initialize();
        m_initialized = true;
    }


    //f->glClearColor(0.1f, 0.1f, 0.2f, 1.0f);

    QOpenGLFunctions *f = m_context->functions();
    f->glViewport(0, 0, viewSize.width() * surface->devicePixelRatio(), viewSize.height() * surface->devicePixelRatio());
    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    QMatrix4x4 modelview;
    modelview.rotate(m_fAngle, 0.0f, 1.0f, 0.0f);
    modelview.rotate(m_fAngle, 1.0f, 0.0f, 0.0f);
    modelview.rotate(m_fAngle, 0.0f, 0.0f, 1.0f);
    modelview.translate(0.0f, -0.2f, 0.0f);

    m_program->setUniformValue(matrixUniform, modelview);
    m_program->setUniformValue(colorUniform, color);

    m_context->functions()->glDrawArrays(GL_TRIANGLES, 0, vertices.size());

    m_context->swapBuffers(surface);

    m_fAngle += 1.0f;

    QTimer::singleShot(250, this, SLOT(render()));
}

void
WebView::CreateGLContext() {
  QOpenGLContext* context = window_->GLContext();
  context->makeCurrent(window_);

  static bool firstClearDone = false;
  if (!firstClearDone) {
    QOpenGLFunctions* functions = context->functions();
    Q_ASSERT(functions);
    functions->glClearColor(1.0, 1.0, 1.0, 0.0);
    functions->glClear(GL_COLOR_BUFFER_BIT);
    context->swapBuffers(window_);
    firstClearDone = true;
  }
}

void TFInteg2DGL::integrate(const float *colormap, int resolution, float basesize, float stepsize)
{
    if (!texFull || resolution != texFull->width())
        newResources(resolution);
    QOpenGLFunctions* f = QOpenGLContext::currentContext()->functions();
    tex1d->setData(QOpenGLTexture::RGBA, QOpenGLTexture::Float32, colormap);
    // framebuffer object
    GLint oFbo, viewport[4], activeTex, oTex;
    newFbo();
    f->glGetIntegerv(GL_FRAMEBUFFER_BINDING, &oFbo);
    f->glBindFramebuffer(GL_FRAMEBUFFER, *fbo);
    f->glClear(GL_COLOR_BUFFER_BIT);
    // viewport
    f->glGetIntegerv(GL_VIEWPORT, viewport);
    f->glViewport(0, 0, resolution, resolution);
    // 1d texture
    f->glGetIntegerv(GL_ACTIVE_TEXTURE, &activeTex);
    f->glActiveTexture(GL_TEXTURE0);
    f->glGetIntegerv(GL_TEXTURE_1D, &oTex);
    f->glBindTexture(GL_TEXTURE_1D, tex1d->textureId());
    // paint
    painter.recreateVAO();
    painter.paint("tf1d", 0, "resolution", resolution, "basesize", basesize, "segLen", stepsize);
    // clean
    f->glActiveTexture(GL_TEXTURE0);
    f->glBindTexture(GL_TEXTURE_1D, oTex);
    f->glActiveTexture(activeTex);

//    std::unique_ptr<GLubyte[]> pixels(new GLubyte [resolution * resolution * 4]);
//    f->glReadPixels(0, 0, resolution, resolution, GL_RGBA, GL_UNSIGNED_BYTE, pixels.get());
//    QImage image(pixels.get(), resolution, resolution, QImage::Format_RGBA8888);
//    static QLabel label;
//    label.resize(resolution, resolution);
//    label.setPixmap(QPixmap::fromImage(image.mirrored()));
//    label.show();

    f->glViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
    f->glBindFramebuffer(GL_FRAMEBUFFER, oFbo);
}

void QOpenGLTextureBlitWindow::render()
{
    m_context->makeCurrent(this);

    QRect viewport(0,0,dWidth(),dHeight());
    QOpenGLFunctions *functions = m_context->functions();
    functions->glViewport(0,0,dWidth(), dHeight());

    functions->glClearColor(0.f, .6f, .0f, 0.f);
    functions->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    QOpenGLTexture texture(m_image);
    texture.setWrapMode(QOpenGLTexture::ClampToEdge);
    texture.create();

    QOpenGLTexture texture_mirrored(m_image_mirrord);
    texture_mirrored.setWrapMode(QOpenGLTexture::ClampToEdge);
    texture_mirrored.create();

    QRectF topLeftOriginTopLeft(QPointF(0,0), QPointF(dWidth()/2.0, dHeight()/2.0));
    QRectF topRightOriginTopLeft(QPointF(dWidth()/2.0,0), QPointF(dWidth(), dHeight()/2.0));
    QRectF bottomLeftOriginTopLeft(QPointF(0, dHeight()/2.0), QPointF(dWidth() /2.0, dHeight()));
    QRectF bottomRightOriginTopLeft(QPoint(dWidth()/2.0, dHeight()/2.0), QPointF(dWidth(), dHeight()));

    QRectF topLeftOriginBottomLeft = bottomLeftOriginTopLeft; Q_UNUSED(topLeftOriginBottomLeft);
    QRectF topRightOriginBottomLeft = bottomRightOriginTopLeft; Q_UNUSED(topRightOriginBottomLeft);
    QRectF bottomLeftOriginBottomLeft = topLeftOriginTopLeft;
    QRectF bottomRightOriginBottomLeft = topRightOriginTopLeft;

    QOpenGLTextureBlitter::Origin topLeftOrigin = QOpenGLTextureBlitter::OriginTopLeft;
    QOpenGLTextureBlitter::Origin bottomLeftOrigin = QOpenGLTextureBlitter::OriginBottomLeft;

    QMatrix4x4 topRightOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(topRightOriginTopLeft, viewport);
    QMatrix4x4 bottomLeftOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(bottomLeftOriginTopLeft, viewport);
    QMatrix4x4 bottomRightOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(bottomRightOriginTopLeft, viewport);

    QMatrix3x3 texTopLeftOriginTopLeft = QOpenGLTextureBlitter::sourceTransform(topLeftOriginTopLeft, m_image.size(), topLeftOrigin);
    QMatrix3x3 texTopRightOriginBottomLeft = QOpenGLTextureBlitter::sourceTransform(topRightOriginBottomLeft, m_image.size(), bottomLeftOrigin);
    QMatrix3x3 texBottomLeftOriginBottomLeft = QOpenGLTextureBlitter::sourceTransform(bottomLeftOriginBottomLeft, m_image.size(), bottomLeftOrigin);
    QMatrix3x3 texBottomRightOriginBottomLeft = QOpenGLTextureBlitter::sourceTransform(bottomRightOriginBottomLeft, m_image.size(), bottomLeftOrigin);

    QSizeF subSize(topLeftOriginTopLeft.width()/2, topLeftOriginTopLeft.height()/2);
    QRectF subTopLeftOriginTopLeft(topLeftOriginTopLeft.topLeft(), subSize);
    QRectF subTopRightOriginTopLeft(QPointF(topLeftOriginTopLeft.topLeft().x() + topLeftOriginTopLeft.width() / 2,
                               topLeftOriginTopLeft.topLeft().y()), subSize);
    QRectF subBottomLeftOriginTopLeft(QPointF(topLeftOriginTopLeft.topLeft().x(),
                                 topLeftOriginTopLeft.topLeft().y() + topLeftOriginTopLeft.height() / 2), subSize);
    QRectF subBottomRightOriginTopLeft(QPointF(topLeftOriginTopLeft.topLeft().x() + topLeftOriginTopLeft.width() / 2, 
                                  topLeftOriginTopLeft.topLeft().y() + topLeftOriginTopLeft.height() / 2), subSize);

    QMatrix4x4 subTopLeftOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(subTopLeftOriginTopLeft, viewport);
    QMatrix4x4 subTopRightOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(subTopRightOriginTopLeft, viewport);
    QMatrix4x4 subBottomLeftOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(subBottomLeftOriginTopLeft, viewport);
    QMatrix4x4 subBottomRightOriginTopLeftVertex = QOpenGLTextureBlitter::targetTransform(subBottomRightOriginTopLeft, viewport);

    m_blitter.bind();
    m_blitter.blit(texture_mirrored.textureId(), subTopLeftOriginTopLeftVertex, texBottomRightOriginBottomLeft);
    m_blitter.blit(texture_mirrored.textureId(), subTopRightOriginTopLeftVertex, texBottomLeftOriginBottomLeft);
    m_blitter.blit(texture.textureId(), subBottomLeftOriginTopLeftVertex, texTopRightOriginBottomLeft);
    m_blitter.blit(texture.textureId(), subBottomRightOriginTopLeftVertex, texTopLeftOriginTopLeft);

    m_blitter.blit(texture.textureId(), topRightOriginTopLeftVertex, topLeftOrigin);
    m_blitter.blit(texture_mirrored.textureId(), bottomLeftOriginTopLeftVertex, topLeftOrigin);

    m_blitter.setSwizzleRB(true);
    m_blitter.blit(texture.textureId(), bottomRightOriginTopLeftVertex, texTopLeftOriginTopLeft);
    m_blitter.setSwizzleRB(false);
    m_blitter.release();

    if (m_blitter.supportsExternalOESTarget()) {
        // Cannot do much testing here, just verify that bind and release work, meaning that the program is present.
        m_blitter.bind(0x8D65);
        m_blitter.release();
    }

    m_context->swapBuffers(this);
}