Use volume light scattering post-processing clearColor alpha failure

Questions
1

this page:
test | Babylon.js Playground (babylonjs.com)
Is this necessary for volume light scattering post-processing?

2

In VolumtricLightScattering final Pass, its gl_FragColor.alpha is always more than 1., it’s not influenced by realColor.a which is clear by scene.

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image1221Ă—934 44.4 KB

You should do like Fix PG, change the FinalPass shader. replace 1. with realColor.a. It seems some bug when scene.clearColor is not Color4(0,0,0,0), I set it all to zero. The canvas is transparency now.

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image1920Ă—947 168 KB

When scene.clearColor is not all 0, it looks like that web blend rgb of canvas and backGround? Like clearColor.g = 1., mixColor is not correct any more. I am not clear about it. To fix this question , we should look forward to reply from @Evgeni_Popov or others.

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image1920Ă—945 170 KB

3

That’s enough for me, thank you very much!

4

It seems to work for me. Whatever the color you set for r/g/b, if you set a=0, you will only get the color of the element which is “behind” the canvas. You should set something like a=0.2 if you want to mix the clear color with the canvas color.

Note that we will accept a PR that would preserve the alpha value from realColor. To avoid a breaking, it should be enabled through a property like preserveSourceAlpha, or something like that.

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