Post processing effect to a 'depth only' camera.

Unity Engine
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1

Hi,

I want to apply a post processing effect to a Camera with a culling mask set as Depth only.
My configuration is :

  • Camera 1: renders the game, depth set to 0, culling mask set to SolidColor
  • Camera 2: renders the UI, depth set to 1, culling mask sef to Depth Only

I’d like to apply a simple “Grayscale mode” shader (renders everything in grayscale) to the content of Camera 2 because I want this effect applied only to the UI.
But as the Camera 2 is rendered after the Camera 1, the post-processing effect is also applied to Camera 1’ content.

How could I do something as simple as this?

Thanks in advance for your help.

2

Are you rendering second camera to a render texture ? or just applying effect to the screen ?

3

The second camera is directly used as a camera… I’m not using a render texture… Should I?

4

I just did a test with my post fx asset and I had to make the overlay ( gui ) clear solid with alpha as zero then use a transparent blend mode in post fx shader to overlay gui properly ( so only overlay is grey )

I guess u could render a depth texture and pass that to the post fx shader too ( might be slower than above method )

If there is a better way id really like to know myself

5

And yes for an overlay to have a different effect then main cam … that camera would have to render to a rendertexture otherwise the gui and game scene are already rendered in the screen buffer

6

Ok so you suggest that Camera2 renders to a Render Texture.
This texture will be used with a material using my grayscale shader.
But what should I do after that? How to apply this material to see my overlay displayed above Camera1?

Sorry I’m very new to post-processing effects :frowning:

7

It would basically be a transparent shader that adds greyscale… taking the rendertexture and drawing it to screen ( so you have to clear the camera 2 solid black with alpha 0 )

8

Ive actually done all this work already and there is nothing faster

Post FX Studio

Can make just about any effect

9

Ho that’s nice!

About what you suggested earlier (solid black + alpha 0)… what about semi-transparent pixels? In my overlay I use semi transparent sprites, and setting solid color + black + alpha 0 on camera overlay make these semi-transparent pixels not visible :frowning:

10

r u setting a transparent blend mode in the shader ? can u pastebin your shader ?

and the gui elements are using a shader that writes to alpha channel as well ?

11

Another option would be make it additive then u wont have to worry about alpha channel

12

This is my post-processing shader : http://pastie.org/private/kiwufaizaii1fcyj6f47a
And my GUI elements use the default sprite shader.

13

here try this … i changed a few things to make it faster as well in frag part

http://pastebin.com/wQUpVxZa

This is untested … but it should work

14

Thanks a lot for your help… but… there is a problem here.

As you can see, there is a clear problem on game view :slight_smile:
Any idea?
I just render the camera overlay in a render texture and then I use Graphics.DrawTexture on repaint event on Camera1.
Is it the right thing to do ?

Thanks again.

15

I use Graphics.DrawMeshNow ( i think DrawTexture is basically same thing just uses its own quad )

mymaterial.SetPass(0);
Graphics.DrawMeshNow ( _mesh, icamtrans.position, icamtrans.rotation );

is the problem those extra lines ?

are you clearing the bottom camera as well to solid black ?

16

If you PM me a link to a simple project that shows all this … i can take a look real quick