2d filters and alpha cause blue tint on screen

Game Engine Game Engine Support and Discussion
1

As the title describes, when I look at anything with alpha for transparency on it and have a 2d filter on, the screen gets a blue tint to it. Is there any solution to this?

I’m trying to use Martinsh’s Advanced filter’s for my game and this problem just makes them unusable. Also, this happens with any filter, not just the custom ones.

Pics below, the yellow box has been set up with alpha to make the arrows transparent(original black)

Thanks

Attachments

2.jpg1024×640 74.9 KB

1.jpg1024×640 65.7 KB

2

Weird - Try a basic 2D screen filter that just passes the original colors out. If there’s still a blue tint, it’s your graphics card that has problems with 2D screen filters.

3

Thanks for the reply.
No I don’t think it is graphics card related. This happens on my main (NV GTX260), and also on my laptop (ATI 4550).

Now, with much fiddling in my texture settings of various objects I think I have found the problem. I thought it strange that the text objects did not cause this by themselves so I decided to check the UV Textureface settings of the Text objects. The problem seems to lie in the Add Alpha option and sort of in clip. If I have clip alpha on, the text is fine with the filters, but if I look at another object clip with alpha, the blue tint appears. If I change it to add alpha its blue straight away. However if I change the Text’s settings to just Alpha, it doesn’t happen even when looking at the other objects with Clip or Add on! :slight_smile: ? :S ?

I’ll post again with more findings if I run into any further problems but this looks like a decent solution.

4

The blue tint is because the screen is first cleared with the world color, so any alpha means you can see through to the world color which is set to blue.

Do gl_FragColor.a = 1.0; at the end of the shader to set alpha to 1.

5

Ah, well it looks like the HDR shader is using that to function:

gl_FragColor = (value/contrast)-brightness;

When I your line to the end, it stops working.

But everything is working fine now anyway since I changed my text from clip alpha to alpha.
Also, I changed the settings back and set the world colour to black and the problem was also gone :smiley:

6

What version of Blender are you using? This sounds like a bug that was fixed somewhat recently, but I think the fix should be in 2.55.

7

I’m using Blender 2.49b. I think I’ll wait until they have a non-beta build of 2.5 with everything complete (e.g.export to exe :slight_smile: ) before I use it.