示例#1
0
static void uploadTextures(QOpenGLContext* context, SharedFrame& frame, GLuint texture[])
{
    int width = frame.get_image_width();
    int height = frame.get_image_height();
    const uint8_t* image = frame.get_image();
    QOpenGLFunctions* f = context->functions();

    // Upload each plane of YUV to a texture.
    if (texture[0] && texture[1] && texture[2])
        f->glDeleteTextures(3, texture);
    check_error(f);
    f->glGenTextures(3, texture);
    check_error(f);
    f->glPixelStorei(GL_UNPACK_ROW_LENGTH, width);

    f->glBindTexture  (GL_TEXTURE_2D, texture[0]);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    check_error(f);
    f->glTexImage2D   (GL_TEXTURE_2D, 0, GL_RED, width, height, 0,
                    GL_RED, GL_UNSIGNED_BYTE, image);
    check_error(f);

    f->glBindTexture  (GL_TEXTURE_2D, texture[1]);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    check_error(f);
    int y = context->isOpenGLES() ? 2 : 4;
    f->glTexImage2D   (GL_TEXTURE_2D, 0, GL_RED, width/2, height/y, 0,
                    GL_RED, GL_UNSIGNED_BYTE, image + width * height);
    check_error(f);

    f->glBindTexture  (GL_TEXTURE_2D, texture[2]);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    check_error(f);
    f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    check_error(f);
    f->glTexImage2D   (GL_TEXTURE_2D, 0, GL_RED, width/2, height/y, 0,
                    GL_RED, GL_UNSIGNED_BYTE, image + width * height + width/2 * height/2);
    check_error(f);
}
示例#2
0
GLuint QGLPixelBuffer::generateDynamicTexture() const
{
    Q_D(const QGLPixelBuffer);
    if (!d->fbo)
        return 0;

    if (d->fbo->format().samples() > 0
        && QOpenGLExtensions(QOpenGLContext::currentContext())
           .hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit))
    {
        if (!d->blit_fbo)
            const_cast<QOpenGLFramebufferObject *&>(d->blit_fbo) = new QOpenGLFramebufferObject(d->req_size);
    } else {
        return d->fbo->texture();
    }

    GLuint texture;
    QOpenGLFunctions *funcs = QOpenGLContext::currentContext()->functions();

    funcs->glGenTextures(1, &texture);
    funcs->glBindTexture(GL_TEXTURE_2D, texture);

    funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, d->req_size.width(), d->req_size.height(), 0,
                        GL_RGBA, GL_UNSIGNED_BYTE, 0);

    return texture;
}
示例#3
0
void QSGVideoMaterial_YUV::bindTexture(int id, int w, int h, const uchar *bits, GLenum format)
{
    QOpenGLFunctions *functions = QOpenGLContext::currentContext()->functions();

    functions->glBindTexture(GL_TEXTURE_2D, id);
    functions->glTexImage2D(GL_TEXTURE_2D, 0, format, w, h, 0, format, GL_UNSIGNED_BYTE, bits);
    functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
}
示例#4
0
void SSGTexture::bind()
{
    QOpenGLContext *context = QOpenGLContext::currentContext();
    QOpenGLFunctions *funcs = context->functions();
    if (!m_dirty_texture) {
        funcs->glBindTexture(GL_TEXTURE_2D, m_texture_id);
        if ((minMipmapFiltering() != SSGTexture::None || magMipmapFiltering() != SSGTexture::None) && !m_mipmaps_generated) {
            funcs->glGenerateMipmap(GL_TEXTURE_2D);
            m_mipmaps_generated = true;
        }
        updateBindOptions(m_dirty_bind_options);
        m_dirty_bind_options = false;
        return;
    }

    m_dirty_texture = false;

    if (!m_image || !m_image->isValid()) {
        if (m_texture_id && m_owns_texture) {
            funcs->glDeleteTextures(1, &m_texture_id);
        }
        m_texture_id = 0;
        m_texture_size = QSize();
        m_has_alpha = false;

        return;
    }

    if (m_texture_id == 0)
        funcs->glGenTextures(1, &m_texture_id);
    funcs->glBindTexture(GL_TEXTURE_2D, m_texture_id);

    updateBindOptions(m_dirty_bind_options);

    funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, m_texture_size.width(), m_texture_size.height(), 0, GL_RGBA, GL_UNSIGNED_SHORT, m_image->rawData().get());

    if (minMipmapFiltering() != SSGTexture::None || magMipmapFiltering() != SSGTexture::None) {
        funcs->glGenerateMipmap(GL_TEXTURE_2D);
        m_mipmaps_generated = true;
    }

    m_texture_rect = QRectF(0, 0, 1, 1);

    m_dirty_bind_options = false;
//    if (!m_retain_image)
//        m_image.reset();
}
示例#5
0
void SSGQuickLayer::bind()
{
#ifndef QT_NO_DEBUG
    if (!m_recursive && m_fbo && ((m_multisampling && m_secondaryFbo->isBound()) || m_fbo->isBound()))
        qWarning("ShaderEffectSource: \'recursive\' must be set to true when rendering recursively.");
#endif
    QOpenGLFunctions *funcs = QOpenGLContext::currentContext()->functions();
    if (!m_fbo && m_format == GL_RGBA32F) {
        if (m_transparentTexture == 0) {
            funcs->glGenTextures(1, &m_transparentTexture);
            funcs->glBindTexture(GL_TEXTURE_2D, m_transparentTexture);
            const float zero[4] = {0, 0, 0, 0};
            funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, 1, 1, 0, GL_RGBA, GL_FLOAT, zero);
        } else {
            funcs->glBindTexture(GL_TEXTURE_2D, m_transparentTexture);
        }
    } else {
        funcs->glBindTexture(GL_TEXTURE_2D, m_fbo ? m_fbo->texture() : 0);
        updateBindOptions();
    }
}
GLuint QOpenGL2GradientCache::addCacheElement(quint64 hash_val, const QGradient &gradient, qreal opacity)
{
    QOpenGLFunctions *funcs = QOpenGLContext::currentContext()->functions();
    if (cache.size() == maxCacheSize()) {
        int elem_to_remove = qrand() % maxCacheSize();
        quint64 key = cache.keys()[elem_to_remove];

        // need to call glDeleteTextures on each removed cache entry:
        QOpenGLGradientColorTableHash::const_iterator it = cache.constFind(key);
        do {
            funcs->glDeleteTextures(1, &it.value().texId);
        } while (++it != cache.constEnd() && it.key() == key);
        cache.remove(key); // may remove more than 1, but OK
    }

    CacheInfo cache_entry(gradient.stops(), opacity, gradient.interpolationMode());
    uint buffer[1024];
    generateGradientColorTable(gradient, buffer, paletteSize(), opacity);
    funcs->glGenTextures(1, &cache_entry.texId);
    funcs->glBindTexture(GL_TEXTURE_2D, cache_entry.texId);
    funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, paletteSize(), 1,
                        0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
    return cache.insert(hash_val, cache_entry).value().texId;
}
示例#7
0
    void bind()
    {
        QOpenGLFunctions *functions = QOpenGLContext::currentContext()->functions();

        QMutexLocker lock(&m_frameMutex);
        if (m_frame.isValid()) {
            if (m_frame.map(QAbstractVideoBuffer::ReadOnly)) {
                QSize textureSize = m_frame.size();

                int stride = m_frame.bytesPerLine();
                switch (m_frame.pixelFormat()) {
                case QVideoFrame::Format_RGB565:
                    stride /= 2;
                    break;
                default:
                    stride /= 4;
                }

                m_width = qreal(m_frame.width()) / stride;
                textureSize.setWidth(stride);

                if (m_textureSize != textureSize) {
                    if (!m_textureSize.isEmpty())
                        functions->glDeleteTextures(1, &m_textureId);
                    functions->glGenTextures(1, &m_textureId);
                    m_textureSize = textureSize;
                }

                GLint dataType = GL_UNSIGNED_BYTE;
                GLint dataFormat = GL_RGBA;

                if (m_frame.pixelFormat() == QVideoFrame::Format_RGB565) {
                    dataType = GL_UNSIGNED_SHORT_5_6_5;
                    dataFormat = GL_RGB;
                }

                GLint previousAlignment;
                functions->glGetIntegerv(GL_UNPACK_ALIGNMENT, &previousAlignment);
                functions->glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

                functions->glActiveTexture(GL_TEXTURE0);
                functions->glBindTexture(GL_TEXTURE_2D, m_textureId);
                functions->glTexImage2D(GL_TEXTURE_2D, 0, dataFormat,
                                        m_textureSize.width(), m_textureSize.height(),
                                        0, dataFormat, dataType, m_frame.bits());

                functions->glPixelStorei(GL_UNPACK_ALIGNMENT, previousAlignment);

                functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
                functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
                functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
                functions->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

                m_frame.unmap();
            }
            m_frame = QVideoFrame();
        } else {
            functions->glActiveTexture(GL_TEXTURE0);
            functions->glBindTexture(GL_TEXTURE_2D, m_textureId);
        }
    }
示例#8
0
GLuint QOpenGLTextureCache::bindTexture(QOpenGLContext *context, qint64 key, const QImage &image, BindOptions options)
{
    GLuint id;
    QOpenGLFunctions *funcs = context->functions();
    funcs->glGenTextures(1, &id);
    funcs->glBindTexture(GL_TEXTURE_2D, id);

    QImage tx;
    GLenum externalFormat;
    GLenum internalFormat;
    GLuint pixelType;
    QImage::Format targetFormat = QImage::Format_Invalid;
    const bool isOpenGL12orBetter = !context->isOpenGLES() && (context->format().majorVersion() >= 2 || context->format().minorVersion() >= 2);

    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        if (isOpenGL12orBetter) {
            externalFormat = GL_BGRA;
            internalFormat = GL_RGBA;
            pixelType = GL_UNSIGNED_INT_8_8_8_8_REV;
        } else  {
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
            // Without GL_UNSIGNED_INT_8_8_8_8_REV, BGRA only matches ARGB on little endian.
            break;
#endif
            if (static_cast<QOpenGLExtensions*>(context->functions())->hasOpenGLExtension(QOpenGLExtensions::BGRATextureFormat)) {
                // GL_EXT_bgra or GL_EXT_texture_format_BGRA8888 extensions.
                if (context->isOpenGLES()) {
                    // The GL_EXT_texture_format_BGRA8888 extension requires the internal format to match the external.
                    externalFormat = internalFormat = GL_BGRA;
                } else {
                    // OpenGL BGRA/BGR format is not allowed as an internal format
                    externalFormat = GL_BGRA;
                    internalFormat = GL_RGBA;
                }
                pixelType = GL_UNSIGNED_BYTE;
            } else if (context->isOpenGLES() && context->hasExtension(QByteArrayLiteral("GL_APPLE_texture_format_BGRA8888"))) {
                // Is only allowed as an external format like OpenGL.
                externalFormat = GL_BGRA;
                internalFormat = GL_RGBA;
                pixelType = GL_UNSIGNED_BYTE;
            } else {
                // No support for direct ARGB32 upload.
                break;
            }
        }
        targetFormat = image.format();
        break;
    case QImage::Format_BGR30:
    case QImage::Format_A2BGR30_Premultiplied:
        if (isOpenGL12orBetter || (context->isOpenGLES() && context->format().majorVersion() >= 3)) {
            pixelType = GL_UNSIGNED_INT_2_10_10_10_REV;
            externalFormat = GL_RGBA;
            internalFormat = GL_RGB10_A2;
            targetFormat =  image.format();
        }
        break;
    case QImage::Format_RGB30:
    case QImage::Format_A2RGB30_Premultiplied:
        if (isOpenGL12orBetter) {
            pixelType = GL_UNSIGNED_INT_2_10_10_10_REV;
            externalFormat = GL_BGRA;
            internalFormat = GL_RGB10_A2;
            targetFormat = image.format();
        } else if (context->isOpenGLES() && context->format().majorVersion() >= 3) {
            pixelType = GL_UNSIGNED_INT_2_10_10_10_REV;
            externalFormat = GL_RGBA;
            internalFormat = GL_RGB10_A2;
            targetFormat = QImage::Format_A2BGR30_Premultiplied;
        }
        break;
    case QImage::Format_RGB444:
    case QImage::Format_RGB555:
    case QImage::Format_RGB16:
        if (isOpenGL12orBetter || context->isOpenGLES()) {
            externalFormat = internalFormat = GL_RGB;
            pixelType = GL_UNSIGNED_SHORT_5_6_5;
            targetFormat = QImage::Format_RGB16;
        }
        break;
    case QImage::Format_RGB666:
    case QImage::Format_RGB888:
        externalFormat = internalFormat = GL_RGB;
        pixelType = GL_UNSIGNED_BYTE;
        targetFormat = QImage::Format_RGB888;
        break;
    case QImage::Format_RGBX8888:
    case QImage::Format_RGBA8888:
    case QImage::Format_RGBA8888_Premultiplied:
        externalFormat = internalFormat = GL_RGBA;
        pixelType = GL_UNSIGNED_BYTE;
        targetFormat = image.format();
        break;
    case QImage::Format_Indexed8:
        if (options & UseRedFor8BitBindOption) {
            externalFormat = internalFormat = GL_RED;
            pixelType = GL_UNSIGNED_BYTE;
            targetFormat = image.format();
        }
        break;
    case QImage::Format_Alpha8:
        if (options & UseRedFor8BitBindOption) {
            externalFormat = internalFormat = GL_RED;
            pixelType = GL_UNSIGNED_BYTE;
            targetFormat = image.format();
        } else if (context->isOpenGLES() || context->format().profile() != QSurfaceFormat::CoreProfile) {
            externalFormat = internalFormat = GL_ALPHA;
            pixelType = GL_UNSIGNED_BYTE;
            targetFormat = image.format();
        }
        break;
    case QImage::Format_Grayscale8:
        if (options & UseRedFor8BitBindOption) {
            externalFormat = internalFormat = GL_RED;
            pixelType = GL_UNSIGNED_BYTE;
            targetFormat = image.format();
        } else if (context->isOpenGLES() || context->format().profile() != QSurfaceFormat::CoreProfile) {
            externalFormat = internalFormat = GL_LUMINANCE;
            pixelType = GL_UNSIGNED_BYTE;
            targetFormat = image.format();
        }
        break;
    default:
        break;
    }

    if (targetFormat == QImage::Format_Invalid) {
        externalFormat = internalFormat = GL_RGBA;
        pixelType = GL_UNSIGNED_BYTE;
        if (!image.hasAlphaChannel())
            targetFormat = QImage::Format_RGBX8888;
        else
            targetFormat = QImage::Format_RGBA8888;
    }

    if (options & PremultipliedAlphaBindOption) {
        if (targetFormat == QImage::Format_ARGB32)
            targetFormat = QImage::Format_ARGB32_Premultiplied;
        else if (targetFormat == QImage::Format_RGBA8888)
            targetFormat = QImage::Format_RGBA8888_Premultiplied;
    } else {
        if (targetFormat == QImage::Format_ARGB32_Premultiplied)
            targetFormat = QImage::Format_ARGB32;
        else if (targetFormat == QImage::Format_RGBA8888_Premultiplied)
            targetFormat = QImage::Format_RGBA8888;
    }

    if (image.format() != targetFormat)
        tx = image.convertToFormat(targetFormat);
    else
        tx = image;

    funcs->glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, tx.width(), tx.height(), 0, externalFormat, pixelType, const_cast<const QImage &>(tx).bits());

    int cost = tx.width() * tx.height() * tx.depth() / (1024 * 8);
    m_cache.insert(key, new QOpenGLCachedTexture(id, options, context), cost);

    return id;
}
示例#9
0
void QSGDistanceFieldGlyphCache::saveTexture(GLuint textureId, int width, int height) const
{
    QOpenGLFunctions *functions = QOpenGLContext::currentContext()->functions();

    GLuint fboId;
    functions->glGenFramebuffers(1, &fboId);

    GLuint tmpTexture = 0;
    functions->glGenTextures(1, &tmpTexture);
    functions->glBindTexture(GL_TEXTURE_2D, tmpTexture);
    functions->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
    functions->glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    functions->glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    functions->glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    functions->glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    functions->glBindTexture(GL_TEXTURE_2D, 0);

    functions->glBindFramebuffer(GL_FRAMEBUFFER_EXT, fboId);
    functions->glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D,
                                      tmpTexture, 0);

    functions->glActiveTexture(GL_TEXTURE0);
    functions->glBindTexture(GL_TEXTURE_2D, textureId);

    functions->glDisable(GL_STENCIL_TEST);
    functions->glDisable(GL_DEPTH_TEST);
    functions->glDisable(GL_SCISSOR_TEST);
    functions->glDisable(GL_BLEND);

    GLfloat textureCoordinateArray[8];
    textureCoordinateArray[0] = 0.0f;
    textureCoordinateArray[1] = 0.0f;
    textureCoordinateArray[2] = 1.0f;
    textureCoordinateArray[3] = 0.0f;
    textureCoordinateArray[4] = 1.0f;
    textureCoordinateArray[5] = 1.0f;
    textureCoordinateArray[6] = 0.0f;
    textureCoordinateArray[7] = 1.0f;

    GLfloat vertexCoordinateArray[8];
    vertexCoordinateArray[0] = -1.0f;
    vertexCoordinateArray[1] = -1.0f;
    vertexCoordinateArray[2] =  1.0f;
    vertexCoordinateArray[3] = -1.0f;
    vertexCoordinateArray[4] =  1.0f;
    vertexCoordinateArray[5] =  1.0f;
    vertexCoordinateArray[6] = -1.0f;
    vertexCoordinateArray[7] =  1.0f;

    functions->glViewport(0, 0, width, height);
    functions->glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, vertexCoordinateArray);
    functions->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, textureCoordinateArray);

    {
        static const char *vertexShaderSource =
                "attribute vec4      vertexCoordsArray; \n"
                "attribute vec2      textureCoordArray; \n"
                "varying   vec2      textureCoords;     \n"
                "void main(void) \n"
                "{ \n"
                "    gl_Position = vertexCoordsArray;   \n"
                "    textureCoords = textureCoordArray; \n"
                "} \n";

        static const char *fragmentShaderSource =
                "varying   vec2      textureCoords; \n"
                "uniform   sampler2D         texture;       \n"
                "void main() \n"
                "{ \n"
                "    gl_FragColor = texture2D(texture, textureCoords); \n"
                "} \n";

        GLuint vertexShader = functions->glCreateShader(GL_VERTEX_SHADER);
        GLuint fragmentShader = functions->glCreateShader(GL_FRAGMENT_SHADER);

        if (vertexShader == 0 || fragmentShader == 0) {
            GLenum error = functions->glGetError();
            qWarning("QSGDistanceFieldGlyphCache::saveTexture: Failed to create shaders. (GL error: %x)",
                     error);
            return;
        }

        functions->glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
        functions->glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
        functions->glCompileShader(vertexShader);

        GLint len = 1;
        functions->glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &len);

        char infoLog[2048];
        functions->glGetShaderInfoLog(vertexShader, 2048, NULL, infoLog);
        if (qstrlen(infoLog) > 0)
            qWarning("Problems compiling vertex shader:\n %s", infoLog);

        functions->glCompileShader(fragmentShader);
        functions->glGetShaderInfoLog(fragmentShader, 2048, NULL, infoLog);
        if (qstrlen(infoLog) > 0)
            qWarning("Problems compiling fragment shader:\n %s", infoLog);

        GLuint shaderProgram = functions->glCreateProgram();
        functions->glAttachShader(shaderProgram, vertexShader);
        functions->glAttachShader(shaderProgram, fragmentShader);

        functions->glBindAttribLocation(shaderProgram, 0, "vertexCoordsArray");
        functions->glBindAttribLocation(shaderProgram, 1, "textureCoordArray");

        functions->glLinkProgram(shaderProgram);
        functions->glGetProgramInfoLog(shaderProgram, 2048, NULL, infoLog);
        if (qstrlen(infoLog) > 0)
            qWarning("Problems linking shaders:\n %s", infoLog);

        functions->glUseProgram(shaderProgram);
        functions->glEnableVertexAttribArray(0);
        functions->glEnableVertexAttribArray(1);

        int textureUniformLocation = functions->glGetUniformLocation(shaderProgram, "texture");
        functions->glUniform1i(textureUniformLocation, 0);
    }

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

    {
        GLenum error = functions->glGetError();
        if (error != GL_NO_ERROR)
            qWarning("glDrawArrays reported error 0x%x", error);
    }

    uchar *data = new uchar[width * height * 4];

    functions->glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);

    QImage image(data, width, height, QImage::Format_ARGB32);

    QByteArray fileName = m_referenceFont.familyName().toLatin1() + '_' + QByteArray::number(textureId);
    fileName = fileName.replace('/', '_').replace(' ', '_') + ".png";

    image.save(QString::fromLocal8Bit(fileName));

    {
        GLenum error = functions->glGetError();
        if (error != GL_NO_ERROR)
            qWarning("glReadPixels reported error 0x%x", error);
    }

    functions->glDisableVertexAttribArray(0);
    functions->glDisableVertexAttribArray(1);

    functions->glDeleteFramebuffers(1, &fboId);
    functions->glDeleteTextures(1, &tmpTexture);

    delete[] data;
}