Alpha Blend Auxilary Pass Required

[rohit.gonsalves_]

Hello There,

Please check the attached world. Download it from here https://we.tl/fvHeC5OccT

I have used the auxiliary buffer. The auxiliary texture is set which is with alpha channel.

But it seems that Auxiliary pass is rendered with Alpha test only and not with Alpha blending. As we are going to use this texture for compositing unigine final out with Input of ours using Aux texture; we need smooth alpha blended auxiliary texture. Otherwise out compositing have hard edges due to no alpha information in aux texture.

Please suggest. This is very important thing we require.

regards,

Rohit

[rohit.gonsalves_]

Hello There,

How to achieve this .. Please let us know.

Rohit

[rohit.gonsalves_]

Hi There,

Its been a month. But nobody answered this yet. Please answer. At least how to achieve this.

Rohit

[andrey-kozlov]

Hello Rohit,

Auxilary Pass happens during rendering opaque objects. Alpha blending usually order dependent and it's available during rendering transparent objects (which are sorted from the farthest to the nearest). There's no support for such a thing right now.
In theory you could create your own "auxilary" buffer and render your objects with custom forward pass materials there. This is not simple though. And there could be performance issues.

[rohit.gonsalves_]

Thank you. I have checked it by putting a small red coloured box and it never understood the depth and transparency 

  

Left one is real scene and right is one auxiliary pass. Please suggest how we can do it for our use.

Rohit

[andrey-kozlov]

I'm afraid there's no way to achieve transparency in auxiliary pass. Maybe you could apply some simplifications in your case and still get appropriate results. You could try to get edges smoother in screen space by blurring texture. Or you could write your alpha information in auxiliary texture not with blending but with overwriting (in color channel). If not, as I already mentioned in my previous post, you have to emulate auxiliary pass for transparency objects manually

[rohit.gonsalves_]

Hi  andrey-kozlov,

May  you specify how to emulate the auxiliary pass for transparency objects Manually?

At least simple workflow for this.

Rohit

[andrey-kozlov]

Hello Rohit,

This can be a way:

• Create 2nd viewport
• Clone objects which you are interested of
• Mask them to render only in the 2nd viewport
• Bind your custom forward pass material to them
• Render 2nd viewport, grab color texture and use it as an auxiliary texture later

GBufferRead sample may be a good start point, it contains creating and rendering 2nd viewport and grabing textures