C++ QPlatformWindowFormat::redBufferSize方法代码示例

QT_BEGIN_NAMESPACE

QGLFormat QGLFormat::fromPlatformWindowFormat(const QPlatformWindowFormat &format)
{
    QGLFormat retFormat;
    retFormat.setAccum(format.accum());
    if (format.accumBufferSize() >= 0)
        retFormat.setAccumBufferSize(format.accumBufferSize());
    retFormat.setAlpha(format.alpha());
    if (format.alphaBufferSize() >= 0)
        retFormat.setAlphaBufferSize(format.alphaBufferSize());
    if (format.blueBufferSize() >= 0)
        retFormat.setBlueBufferSize(format.blueBufferSize());
    retFormat.setDepth(format.depth());
    if (format.depthBufferSize() >= 0)
        retFormat.setDepthBufferSize(format.depthBufferSize());
    retFormat.setDirectRendering(format.directRendering());
    retFormat.setDoubleBuffer(format.doubleBuffer());
    if (format.greenBufferSize() >= 0)
        retFormat.setGreenBufferSize(format.greenBufferSize());
    if (format.redBufferSize() >= 0)
        retFormat.setRedBufferSize(format.redBufferSize());
    retFormat.setRgba(format.rgba());
    retFormat.setSampleBuffers(format.sampleBuffers());
    retFormat.setSamples(format.sampleBuffers());
    retFormat.setStencil(format.stencil());
    if (format.stencilBufferSize() >= 0)
        retFormat.setStencilBufferSize(format.stencilBufferSize());
    retFormat.setStereo(format.stereo());
    retFormat.setSwapInterval(format.swapInterval());
    return retFormat;
}

QVector<int> qglx_buildSpec(const QPlatformWindowFormat &format, int drawableBit)
{
    QVector<int> spec(48);
    int i = 0;

    spec[i++] = GLX_LEVEL;
    spec[i++] = 0;
    spec[i++] = GLX_DRAWABLE_TYPE; spec[i++] = drawableBit;

    if (format.rgba()) {
        spec[i++] = GLX_RENDER_TYPE; spec[i++] = GLX_RGBA_BIT;
        spec[i++] = GLX_RED_SIZE; spec[i++] = (format.redBufferSize() == -1) ? 1 : format.redBufferSize();
        spec[i++] = GLX_GREEN_SIZE; spec[i++] =  (format.greenBufferSize() == -1) ? 1 : format.greenBufferSize();
        spec[i++] = GLX_BLUE_SIZE; spec[i++] = (format.blueBufferSize() == -1) ? 1 : format.blueBufferSize();
        if (format.alpha()) {
                spec[i++] = GLX_ALPHA_SIZE; spec[i++] = (format.alphaBufferSize() == -1) ? 1 : format.alphaBufferSize();
            }

        if (format.accum()) {
            spec[i++] = GLX_ACCUM_RED_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
            spec[i++] = GLX_ACCUM_GREEN_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
            spec[i++] = GLX_ACCUM_BLUE_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();

            if (format.alpha()) {
                spec[i++] = GLX_ACCUM_ALPHA_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
            }
        }
    } else {
        spec[i++] = GLX_RENDER_TYPE; spec[i++] = GLX_COLOR_INDEX_BIT; //I'm really not sure if this works....
        spec[i++] = GLX_BUFFER_SIZE; spec[i++] = 8;
    }

    spec[i++] = GLX_DOUBLEBUFFER; spec[i++] = format.doubleBuffer() ? True : False;
    spec[i++] = GLX_STEREO; spec[i++] =  format.stereo() ? True : False;

    if (format.depth()) {
        spec[i++] = GLX_DEPTH_SIZE; spec[i++] = (format.depthBufferSize() == -1) ? 1 : format.depthBufferSize();
    }

    if (format.stencil()) {
        spec[i++] = GLX_STENCIL_SIZE; spec[i++] =  (format.stencilBufferSize() == -1) ? 1 : format.stencilBufferSize();
    }
    if (format.sampleBuffers()) {
        spec[i++] = GLX_SAMPLE_BUFFERS_ARB;
        spec[i++] = 1;
        spec[i++] = GLX_SAMPLES_ARB;
        spec[i++] = format.samples() == -1 ? 4 : format.samples();
    }

    spec[i++] = XNone;
    return spec;
}

QPlatformWindowFormat QXlibWindow::correctColorBuffers(const QPlatformWindowFormat &platformWindowFormat) const
{
    // I have only tested this setup on a dodgy intel setup, where I didn't use standard libs,
    // so this might be not what we want to do :)
    if ( !(platformWindowFormat.redBufferSize() == -1   &&
            platformWindowFormat.greenBufferSize() == -1 &&
            platformWindowFormat.blueBufferSize() == -1))
        return platformWindowFormat;

    QPlatformWindowFormat windowFormat = platformWindowFormat;
    if (mScreen->depth() == 16) {
        windowFormat.setRedBufferSize(5);
        windowFormat.setGreenBufferSize(6);
        windowFormat.setBlueBufferSize(5);
    } else {
        windowFormat.setRedBufferSize(8);
        windowFormat.setGreenBufferSize(8);
        windowFormat.setBlueBufferSize(8);
    }

    return windowFormat;
}

QT_BEGIN_NAMESPACE

QVector<EGLint> q_createConfigAttributesFromFormat(const QPlatformWindowFormat &format)
{
    int redSize     = format.redBufferSize();
    int greenSize   = format.greenBufferSize();
    int blueSize    = format.blueBufferSize();
    int alphaSize   = format.alphaBufferSize();
    int depthSize   = format.depthBufferSize();
    int stencilSize = format.stencilBufferSize();
    int sampleCount = format.samples();

    // QPlatformWindowFormat uses a magic value of -1 to indicate "don't care", even when a buffer of that
    // type has been requested. So we must check QPlatformWindowFormat's booleans too if size is -1:
    if (format.alpha() && alphaSize <= 0)
        alphaSize = 1;
    if (format.depth() && depthSize <= 0)
        depthSize = 1;
    if (format.stencil() && stencilSize <= 0)
        stencilSize = 1;
    if (format.sampleBuffers() && sampleCount <= 0)
        sampleCount = 1;

    // We want to make sure 16-bit configs are chosen over 32-bit configs as they will provide
    // the best performance. The EGL config selection algorithm is a bit stange in this regard:
    // The selection criteria for EGL_BUFFER_SIZE is "AtLeast", so we can't use it to discard
    // 32-bit configs completely from the selection. So it then comes to the sorting algorithm.
    // The red/green/blue sizes have a sort priority of 3, so they are sorted by first. The sort
    // order is special and described as "by larger _total_ number of color bits.". So EGL will
    // put 32-bit configs in the list before the 16-bit configs. However, the spec also goes on
    // to say "If the requested number of bits in attrib_list for a particular component is 0,
    // then the number of bits for that component is not considered". This part of the spec also
    // seems to imply that setting the red/green/blue bits to zero means none of the components
    // are considered and EGL disregards the entire sorting rule. It then looks to the next
    // highest priority rule, which is EGL_BUFFER_SIZE. Despite the selection criteria being
    // "AtLeast" for EGL_BUFFER_SIZE, it's sort order is "smaller" meaning 16-bit configs are
    // put in the list before 32-bit configs. So, to make sure 16-bit is preffered over 32-bit,
    // we must set the red/green/blue sizes to zero. This has an unfortunate consequence that
    // if the application sets the red/green/blue size to 5/6/5 on the QPlatformWindowFormat,
    // they will probably get a 32-bit config, even when there's an RGB565 config available.

    // Now normalize the values so -1 becomes 0
    redSize   = redSize   > 0 ? redSize   : 0;
    greenSize = greenSize > 0 ? greenSize : 0;
    blueSize  = blueSize  > 0 ? blueSize  : 0;
    alphaSize = alphaSize > 0 ? alphaSize : 0;
    depthSize = depthSize > 0 ? depthSize : 0;
    stencilSize = stencilSize > 0 ? stencilSize : 0;
    sampleCount = sampleCount > 0 ? sampleCount : 0;

    QVector<EGLint> configAttributes;

    configAttributes.append(EGL_RED_SIZE);
    configAttributes.append(redSize);

    configAttributes.append(EGL_GREEN_SIZE);
    configAttributes.append(greenSize);

    configAttributes.append(EGL_BLUE_SIZE);
    configAttributes.append(blueSize);

    configAttributes.append(EGL_ALPHA_SIZE);
    configAttributes.append(alphaSize);

    configAttributes.append(EGL_DEPTH_SIZE);
    configAttributes.append(depthSize);

    configAttributes.append(EGL_STENCIL_SIZE);
    configAttributes.append(stencilSize);

    configAttributes.append(EGL_SAMPLES);
    configAttributes.append(sampleCount);

    configAttributes.append(EGL_SAMPLE_BUFFERS);
    configAttributes.append(sampleCount? 1:0);

    return configAttributes;
}