Why does SSAO/2 wreck AA for me?

Questions
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1

N00b time again! What am I doing wrong?

Added SSAO2RenderingPipeline (also tried older SSAO(1)). AA gets wrecked.

Before, no rendering pipeline defined, jaggies are noticeable but not terrible:

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After, with SSAO, jaggies become horrible:
const ssao = new SSAO2RenderingPipeline( 'ssaopipe', scene, 0.75, [ camera ] );

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Even flat-out copy-pasting the SSAO setup values from Babylon.js - Screen Space Ambient Occlusion demo (which looks lovely, BTW) changes nothing.

    var ssao = new SSAORenderingPipeline("ssaopipeline", scene, {ssaoRatio: .5, combineRatio: 1});
    ssao.fallOff = 1e-6;
    ssao.area = 1;
    ssao.radius = 4e-4;
    ssao.totalStrength = 2;
    ssao.base = 1.3;
    scene.postProcessRenderPipelineManager.attachCamerasToRenderPipeline("ssaopipeline", camera);

Latest Brave (but Chrome renders no differently), modern Win10 PC, latest NVidia, no WebGL1.0 excuses here.

2

Hey there! I’d wager this is a side-effect of the way the pipeline combines the images :thinking: but let’s check out with @Deltakosh and @sebavan

I can definitely notice this in other SSAO demos, like this one: PGDemo | Babylon.js Playground (babylonjs.com) (you can press 2 to render without SSAO and the difference is noticeable). But you can add an anti-aliasing post process to get the unjaggies back: PGDemo | Babylon.js Playground (babylonjs.com) :smiley:

3

This is because Render target by default do not support MSAA.

I wonder if @CraigFeldspar is aware of a property to enable it in his great SSAO2 ???

4

Thank you for the suggestion, but adding the AA post-process per that demo seems to help only a little. The jaggies from SSAO are just too brutal for some reason. (That demo runs fine on this machine though.)

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Values copied straight from the PGDemo:

    var ssao = new SSAORenderingPipeline("ssaopipeline", scene, {ssaoRatio: .5, combineRatio: 1});
    ssao.fallOff = 1e-6;
    ssao.area = 1;
    ssao.radius = 4e-4;
    ssao.totalStrength = 1;
    ssao.base = 0.5;
    scene.postProcessRenderPipelineManager.attachCamerasToRenderPipeline("ssaopipeline", camera);

    var pipeline = new DefaultRenderingPipeline(
        "defaultPipeline", // The name of the pipeline
        true, // Do you want the pipeline to use HDR texture?
        scene, // The scene instance
        [camera] // The list of cameras to be attached to
    );
    pipeline.samples = 16;
    pipeline.fxaaEnabled = true;
5

Using 2 pipelines here won t help. The source needs to be multi sampled for the best effect.

You can try relying on SSAO2 (webgl2 only) and bump the MSAA number of samples: https://playground.babylonjs.com/#N96NXC#75

6

Copied the SSAO2 setup per your link exactly, but that simply breaks Scene.LoadAssetContainer() with a repeated warning, and results in a black screen.

52 [.WebGL-000033DA0163FF00] GL_INVALID_OPERATION: Cannot generate mipmaps for a zero-size texture in a WebGL context.

    var ssao = new SSAO2RenderingPipeline("ssaopipeline", scene, {ssaoRatio: .5, combineRatio: 1}, [ camera ], false );
    ssao.radius = 15.5;
    ssao.totalStrength = 1.3;
    ssao.expensiveBlur = false;
    ssao.samples = 16;
    scene.prePassRenderer.samples = 16;

We’ve noticed the problem seems to begin with our high-contrast skybox (dense rows of ceiling-mounted shop lights) and the model’s highly-reflective horizontal surfaces, creating the high-contrast reflection that SSAO only makes worse. It may be a dodge, but we’re going to swap the skybox for something less challenging and see.

7

This is really weird it is trying to generate mipmaps for a 0 size texture :frowning: a repro in the playground would help on this one.

8

Hey there @brechindo just checking in, did you manage to solve the problem? Anything you’d like us to help with?

9

Afraid not. We were able to tone down the problem with a lower-contrast skybox, so we’re living with that result for now. May revisit this problem later when doing final product polish prior to release.

10

Feel free to reach out anytime you’d like some help :slight_smile:

11

Months later, this case has been cracked.

ssao.samples = 16;
scene.prePassRenderer!.samples = 16; // OHHH!

The SSAO render pipeline disabled MSAA by default.
The SSAO samples var is not MSAA samples - that’s completely different now, and accessed via the 2nd line above through the prePassRenderer.

SSAO and MSAA are happy now. Jaggies gone.
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