PNG problem

BlitzPlus Forums/BlitzPlus Programming/PNG problem

Billamu(Posted 2003) [#1]
I find that all my PNGs look a little on the dark side. I've heard that PNGs contain gamma information so it's meant to look the same on any monitor(?).

Still, it's coming out dark. I use a Radeon 7200. Would that attribute to this problem at all?

My immediate solution is to 'turn the brightness up', but I'm thinking there might be another way...


Beaker(Posted 2003) [#2]
Blitz ignores gamma information in PNGs so don't bother setting any. Best solution is to a) make sure your monitor is calibrated correctly or b) make the PNGs brighter.

Blitz has built in gamma commands that might help the overall look of your game.


sswift(Posted 2003) [#3]
There is in fact a problem with PNG's. Blitz may ignore the gamma info, but it's not making use of the data correctly either.

I have noticed this in the past when I made a game logo, and only a couple days ago when I created a mouse pointer.

Use targa if possible instead of PNG for now. I have reported this bug already to Mark but it wouldn't hurt to post it again. But when I mentioned it to Mark last time he said he was using the reference PNG code I think. However, there may have been bugfixes for that or something because I have seen this issue in a few other programs when loading PNG. Photoshop for example used to have issues loading it, and occasionally I have an issue with another viewer I use called Ifranview.

Weird thing though is even with TGA, and a fullbright sprite, my mouse pointer still seems less bright than it ought to be. The text in my game is just fine though. I wonder if perhaps my card has a funny gamma ramp or something where white is white, but colors below that are much darker than they ought to be.

I don't seem to have issues with my other textures though. Maybe it is something which affects alpha mapped textures only. Hm. But I had a mouse cursor in another demo that was red and it looked just fine.

Strange.


Billamu(Posted 2003) [#4]
I've found if you save the files as PNGs in Gimp, you can tell it to contain gamma information, then Blitz loads them in fine.