compositors and hardware gamma

Discussion area about developing or extending OGRE, adding plugins for it or building applications on it. No newbie questions please, use the Help forum for that.
Post Reply
User avatar
sparkprime
Ogre Magi
Posts: 1137
Joined: Mon May 07, 2007 3:43 am
Location: Ossining, New York
x 13
Contact:

compositors and hardware gamma

Post by sparkprime »

http://www.ogre3d.org/docs/manual/manual_30.html#SEC150

says:

gamma
If present, this directive means that sRGB gamma correction will be enabled on writes to this texture. You should remember to include the opposite sRGB conversion when you read this texture back in another material, such as a quad. This option will automatically enabled if you use a render_scene pass on this texture and the viewport on which the compositor is based has sRGB write support enabled.

What does it mean that the viewport has sRGB write support enabled? I can't find anything in Ogre::Viewport for selecting this. I actually want the texture to not be gamma corrected -- it's a deferred shading pipeline and it's gamma correcting my depth values. However the ultimate target (post lighting) does have hardware gamma enabled because it's a framebuffer of visible colours.
User avatar
dark_sylinc
OGRE Team Member
OGRE Team Member
Posts: 5296
Joined: Sat Jul 21, 2007 4:55 pm
Location: Buenos Aires, Argentina
x 1278
Contact:

Re: compositors and hardware gamma

Post by dark_sylinc »

Ummm, good question. Gamma is an RT option, not viewport's
User avatar
sparkprime
Ogre Magi
Posts: 1137
Joined: Mon May 07, 2007 3:43 am
Location: Ossining, New York
x 13
Contact:

Re: compositors and hardware gamma

Post by sparkprime »

It should not automatically turn on gamma for intermediate textures, and especially not on the basis that the final output target has gamma. I'm going to delete the code that does this in my local fork.
User avatar
dark_sylinc
OGRE Team Member
OGRE Team Member
Posts: 5296
Joined: Sat Jul 21, 2007 4:55 pm
Location: Buenos Aires, Argentina
x 1278
Contact:

Re: compositors and hardware gamma

Post by dark_sylinc »

I couldn't agree more.
This is an issue I haven't looked myself too much, but definitely needs attention. Keep us informed how it works for you! :)

Upload the patches if you want so I can give them a try too
cyrfer
Orc
Posts: 424
Joined: Wed Aug 01, 2007 8:13 pm
Location: Venice, CA, USA
x 7

Re: compositors and hardware gamma

Post by cyrfer »

I realize this is old, but I'm using OGRE 1.7.3. I am wondering if I am subject to this problem. What version removed this problem?

Can I avoid it by choosing a pixel format? I read somewhere that OGRE only tries to use sRGB for 8 byte formats. If my target format is different, maybe Float16, would that avoid the problem?
Post Reply