Projectors: Don't Project On Transparent Areas? (Projecting on Cutouts) *Please help*

Unity Engine
1

Hello, everyone.

I am trying to get projectors to work with alpha test/cutout shader materials. Setting the Ignore Projectors tag to “false” enables this, but of course the projector then causes the transparent/invisible parts of the rendered object to become visible. Is there a way to make it work properly (not projecting on the transparent parts of the cutout)?

What little I’ve been able to find on the subject suggests that it is impossible … but I’m finding that somewhat difficult to believe.

I noticed that the standard multiply projector uses “AlphaTest Greater 0”. Shouldn’t that automatically cause the projector to only project onto areas that have an alpha value greater than 0 (0 being fully transparent)? Based on the fact that I’m having to ask about this, the answer seems to be “no, it shouldn’t”. But then what exactly is that line’s purpose?

I tried using various blend modes, but none seemed to create the desired effect.

Thank you in advance for any assistance.

2

I’d really love some help with this.
Am I failing to explain the issue correctly?

3

Is it that I’ve posted this in the wrong section?

4

No its the right one just nobody knows the answer, im facing same issue, but im too busy right now to look into it, lets keep thread afload until we dig something.

5

No, it’s a test in the projector’s shader, which doesn’t know about any other shaders already applied.

I know what it does but not why it would be in the shader; my guess is that it at least used to provide a performance benefit on some hardware.

6

For anyone else who might also be trying to figure this out, this conversation is largely taking place in a different thread:

1 Like
7

The discussion seems to have hit a dead-end.
I could still really use help with this.

8

I’m surprised that this doesn’t seem to be very common.
Are projectors generally avoided? Are cutouts generally avoided?

I imagined it was somewhat common to have a situation where, for example, 2D sprites (with transparent borders) would need to be projected upon while still retaining their transparency.