Mercurial > sdl-ios-xcode

view docs/html/sdlsetgamma.html @ 3880:74e828c64315 SDL-1.2

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Fixed bug #292 I might be on crack here. It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and right channels of a stereo stream together, and clamps the new mono channel if it would overflow. Shouldn't it be dividing by 2 to average the two sample points instead of clamping? Otherwise the mono sample point's volume doubles in the conversion. This would also make the conversion faster, as it replaces two branches per sample frame with a bitwise shift. --ryan.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 24 Sep 2006 15:45:37 +0000
parents 355632dca928
children
line wrap: on
line source

<HTML
><HEAD
><TITLE
>SDL_SetGamma</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
"><LINK
REL="HOME"
TITLE="SDL Library Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Video"
HREF="video.html"><LINK
REL="PREVIOUS"
TITLE="SDL_SetPalette"
HREF="sdlsetpalette.html"><LINK
REL="NEXT"
TITLE="SDL_GetGammaRamp"
HREF="sdlgetgammaramp.html"></HEAD
><BODY
CLASS="REFENTRY"
BGCOLOR="#FFF8DC"
TEXT="#000000"
LINK="#0000ee"
VLINK="#551a8b"
ALINK="#ff0000"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>SDL Library Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="sdlsetpalette.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlgetgammaramp.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLSETGAMMA"
></A
>SDL_SetGamma</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1569"
></A
><H2
>Name</H2
>SDL_SetGamma&nbsp;--&nbsp;Sets the color gamma function for the display</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1572"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1573"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SetGamma</B
></CODE
>(float redgamma, float greengamma, float bluegamma);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1579"
></A
><H2
>Description</H2
><P
>Sets the "gamma function" for the display of each color component.  Gamma
controls the brightness/contrast of colors displayed on the screen.
A gamma value of <TT
CLASS="CONSTANT"
>1.0</TT
> is identity (i.e., no adjustment
is made).</P
><P
>This function adjusts the gamma based on the "gamma function" parameter,
you can directly specify lookup tables for gamma adjustment with
<A
HREF="sdlsetgammaramp.html"
>SDL_SetGammaRamp</A
>.</P
><P
>Not all display hardware is able to change gamma.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1586"
></A
><H2
>Return Value</H2
><P
>Returns -1 on error (or if gamma adjustment is not supported).</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1589"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlgetgammaramp.html"
>SDL_GetGammaRamp</A
>
<A
HREF="sdlsetgammaramp.html"
>SDL_SetGammaRamp</A
></P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="sdlsetpalette.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="sdlgetgammaramp.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_SetPalette</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="video.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>SDL_GetGammaRamp</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>