Transparent background in Unity 2019 HDRP

Questions & Answers
1

165963-mycapture.pngI want a RenderTexture image with transparent background.

I set the Background Type to “Color” and alpha value of the Background Color to zero in Camera property.

It was OK with the Unity 2018 HDRP.

But it does not become transparency with Unity 2019 HDRP. (2019.1.0f2, HDRP:5.13.0)

Even if it is Unity 2019, it is possible if not use the HDRP.

Is it impossible with Unity 2019 HDRP?

6

Same here, tried to fiddle around FinalPass.shader but nothing good out came out of it.
This is a huge stepback when using Render Textures ! We’re using them all the time along with Spout in digital art and live show projects, but this is a blocker…

8

This is outrageous!! Alpha is needed for MANY purposes.
Does Unity at least propose any other way of blending cameras if not through RenderTexture!?

2

FYI, one reason this is impossible in the current version of HDRP is that that in HDRP’s FinalPass.shader, you’ve got this line:

 return float4(outColor, 1.0);

I’m not sure why HDRP is setup to always throw away the alpha value…

3

Hello kelloh. Thank you for answering.

In other words, it is difficult with the current HDRP specifications.

I tried to rewrite the FinalPass.shader you taught me but it did not resolve.

By the time the HDRP is officially released, I will wait for the issue to be resolved…

Thank you. :slight_smile:

4

I observe the same in the LWRP - a workaround for me was disabling multisampling / antialiasing in the render texture, does that work for you as well @Satsukawa ?

5

I think that this has not been resolved yet, right?
Any workaround to show a transparent background using hdrp?

7

I’ve seen them say that they simply don’t support alpha… that the alpha channel is being reserved for some future feature.

Which is ridiculous. Alpha already has a purpose… ALPHA!

This decision needs to be reversed. It’s one thing when you have an annoying bug… this is apparently by some ill-advised design. It’s killing my (and many other’s) ability to move forward with Universal or HDRP.

9

So am I right to assume that this is still not resolved?
Is it really impossible right now, to get a transparent background in my rendertexture?

(Why would someone make such a strange decision o.O)

10

If you are talking about stacking cameras: Camera Stacking | Universal RP | 7.2.1

11

Unity 2019.4.5f1 with HDRP V7.3.1. Render Texture, transparent background, not working. Note tried changing the Render Texture > Color Format to ‘R16G16B16A16’. Is there a fix not requiring custom shaders or engine code that can resolve this problem?

12

I’m also blocked by this issue. Does anyone have a solution for a transparent spout render texture in HDRP?