Qt3D: Antialising in deferred rendering

AntiXeon

Hello all,

I am writing an application in which I want to use deferred rendering.

When using forward rendering, we can see that multisample antialiasing (MSAA) is enabled.
However, I am trying to have MSAA in my deferred rendering application and I am not able to do this.

As my framegraph is pretty complex (see below), I just show important parts of my code where I have tried to enable MSAA.

First of all, I have followed the answer of this topic before creating the Qt3DWindow.
Then, in my framegraph I have enabled MSAA by adding a QMultiSampleAntiAliasing in the QRenderStateSet

    auto globalRenderStateSet = new Qt3DRender::QRenderStateSet(viewport);
    auto depthTestState = new Qt3DRender::QDepthTest();
    depthTestState -> setDepthFunction(Qt3DRender::QDepthTest::LessOrEqual);
    auto msaaState = new Qt3DRender::QMultiSampleAntiAliasing();
    globalRenderStateSet -> addRenderState(depthTestState);
    globalRenderStateSet -> addRenderState(msaaState);

I have a GBuffer (QRenderTarget) in which I use only QTexture2DMultisample objects, all with the same amount of samples (the same as in the QSurfaceFormat of the first point as well).

    _textures = new Qt3DRender::QTexture2DMultisample*[attachmentsCount];
    _attachments = new Qt3DRender::QRenderTargetOutput*[attachmentsCount];
    for (int attachmentIndex = 0 ; attachmentIndex < attachmentsCount ; attachmentIndex++)
    {
        const TargetOutputParameters& parameter = parameters[attachmentIndex];

        _attachments[attachmentIndex] = new Qt3DRender::QRenderTargetOutput(this);
        _textures[attachmentIndex] = new Qt3DRender::QTexture2DMultisample();
        _textures[attachmentIndex] -> setFormat(parameter.format());
        _textures[attachmentIndex] -> setWidth(TextureWidth);
        _textures[attachmentIndex] -> setHeight(TextureHeight);
        _textures[attachmentIndex] -> setGenerateMipMaps(false);
        _textures[attachmentIndex] -> setWrapMode(Qt3DRender::QTextureWrapMode(Qt3DRender::QTextureWrapMode::ClampToEdge));
        _textures[attachmentIndex] -> setMinificationFilter(Qt3DRender::QAbstractTexture::Linear);
        _textures[attachmentIndex] -> setMagnificationFilter(Qt3DRender::QAbstractTexture::Linear);
        _textures[attachmentIndex] -> setSamples(8);

        _attachments[attachmentIndex] -> setTexture(_textures[attachmentIndex]);
        _attachments[attachmentIndex] -> setAttachmentPoint(parameter.attachmentPoint());
        _attachments[attachmentIndex] -> setObjectName(parameter.name());

        addOutput(_attachments[attachmentIndex]);
    }

I have another QRenderTarget (MSAADestinationRenderTarget) in which I only have QTexture2D objects. I perform a QBlitFramebuffer to copy the MSAA color texture into the single-sample render target.

            auto noDraw = new Qt3DRender::QNoDraw(cameraSelector);
            auto sceneBlitColorFBOs = new Qt3DRender::QBlitFramebuffer(noDraw);

            _gBuffer = new GBuffer();
            _msaaRenderTarget = new MSAADestinationRenderTarget();

            auto msaaRenderTargetSelector = new Qt3DRender::QRenderTargetSelector(cameraSelector);
            msaaRenderTargetSelector -> setTarget(_msaaRenderTarget);

            sceneBlitColorFBOs -> setSource(_gBuffer);
            sceneBlitColorFBOs -> setSourceAttachmentPoint(Qt3DRender::QRenderTargetOutput::Color0);
            sceneBlitColorFBOs -> setSourceRect(QRect(0, 0, _view -> width(), _view->height()));
            sceneBlitColorFBOs -> setDestination(_msaaRenderTarget);
            sceneBlitColorFBOs -> setDestinationAttachmentPoint(Qt3DRender::QRenderTargetOutput::Color0);
            sceneBlitColorFBOs -> setDestinationRect(QRect(0, 0, _view -> width(), _view->height()));

All of this seems to be working well as I can display this texture on a quad and see the scene, move the camera, etc. But, it is not antialiased.

Am I missing something?
Thank you for any help.

Denis

Framegraph:

AntiXeon

Hi,

I have not found any solution from C++ code itself.
So I have implemented FXAA into my fragment shader to get an antialiased picture.

Denis

Solved Qt3D: Antialising in deferred rendering