I have a scene in which several planes (stacked almost on top of each other) have textures that use the alpha channel for transparancy. I also have the pro standard asset’s glow image effect on the camera but I don’t want the planes to glow at all.
I tried having two cameras, one main and the other for drawing only the things that were supposed to glow. Now I’m stuck with how to use this setup. Am I supposed to render the second camera to a render texture and “apply” that to the first camera? How would I do this? I didn’t get very satisfying effects when just applying the texture to a plane that I put in front of the camera. I guess the technique to show the render texture perfectly in match with the main camera is what I’m looking for. Or a technique that just chooses what objects should glow based on the layer or tag of it could work?
I’ve never touched shader programming so it’s all quite daunting
Any suggestions?
The glow effect is based on the amount of alpha in the frame buffer. The default Transparent shaders that come with Unity use color masking to make sure the alpha is not written into the buffer. The way to make sure this is working properly is to change the drawing mode of the Scene View to “Alpha”. Then you can see where the alpha is being drawn.

Thanks for your reply.
Not sure if I understand this but this would mean that everything that’s supposed to glow would glow when the scene’s in alpha mode, right?
The textures with active alpha channel don’t glow but when something that glows passes over them they seem to strengthen the glow effect. So much that it just isn’t cool. I’ll attach two pictures that show what I mean.
How would I solve this? I can’t modify the alpha-channel on the picture since I’m dependent on it for the overall scene. Is it possible to selectively choose what should glow and what shouldn’t glow buy somehow modifying the shader? Like make it look at a tag or maybe the object name? This would be a really neat way if it’s not too hard.
Any suggestions?


Sorry for resurrecting this one but I just can’t figure it out. The situation is pretty much the same as my last post… I tried to dabble with the shader but didn’t get far. Any suggestions as to what I could try?
Ok, so it looks like the ship “forcefield” glow is a bit much. What shader are you using for that? Try turning the Opacity down in the Material you’re using for it.
Be more specific about the problem you’re having as I’m just guessing a bit at what you’re having issues with.
Sorry for not being clear enough. I’ll try my best to explain this better.
The problem isn’t only about the shader. The force field glows like it should all the time, except when the ship is over the galaxy, like in the picture. I believe the cause of this is that the texture of the galaxy uses the alpha channel for transparency so the glow effect “adds up” (force field + galaxy) and gets too high. This is my problem. I need a way to constrain the glow effect.
What I’m trying to do is to either draw the galaxy or the force field in another camera and then somehow overlay the other camera on the main one, or (and this would probably be a lot harder?) change or rewrite the glow image effect so that it only draws over specific objects that I specify and thus only draws glow on the force field and not the galaxy.
I hope I was clear enough… it’s hard to be clear when I don’t really know what you need to figure out the answer. Thanks for helping out!