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Bug 893 - SDL_SetGamma ignores small gamma values
Summary: SDL_SetGamma ignores small gamma values
Status: RESOLVED WONTFIX
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: 1.2.14
Hardware: All Windows (All)
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-11-26 07:18 UTC by R.Lamprecht
Modified: 2011-02-16 04:41 UTC (History)
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Description R.Lamprecht 2009-11-26 07:18:37 UTC 
float gamma = 0.2271;
int result = SDL_SetGamma(gamma, gamma, gamma);

does apply gamma to the screen, but just for gamma values greater equal 0.2271. Any value of 0.227 or less does not change the screen. This may be a feature of Windows or a bug.

Of course I checked the return code, too. It seems to be totally independent of the gamma value. Even on success it is always "-1" on the first call. Just if the same gamma value is set twice, the second SDL_SetGamma call returns "0". This is obviously a bug in the Windows SDL implementation.

The return code on Linux seems to be o.k..
Comment 1 Sam Lantinga 2011-02-16 04:41:14 UTC 
The gamma API has been removed in SDL 1.3, due to lack of support on many platforms.