view docs/html/sdljoystickgetaxis.html @ 2042:3908e1f808e1

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 15:56:36 +0000
parents 355632dca928
children
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>SDL_JoystickGetAxis</H1
><DIV
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><A
NAME="AEN6320"
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><H2
>Name</H2
>SDL_JoystickGetAxis&nbsp;--&nbsp;Get the current state of an axis</DIV
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CLASS="REFSYNOPSISDIV"
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>Synopsis</H2
><DIV
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><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>Sint16 <B
CLASS="FSFUNC"
>SDL_JoystickGetAxis</B
></CODE
>(SDL_Joystick *joystick, int axis);</CODE
></P
><P
></P
></DIV
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><DIV
CLASS="REFSECT1"
><A
NAME="AEN6330"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_JoystickGetAxis</TT
> returns the current state of the given <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
> on the given <TT
CLASS="PARAMETER"
><I
>joystick</I
></TT
>.</P
><P
>On most modern joysticks the X axis is usually represented by <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
> 0 and the Y axis by <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
> 1. The value returned by <TT
CLASS="FUNCTION"
>SDL_JoystickGetAxis</TT
> is a signed integer (-32768 to 32768) representing the current position of the <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
>, it maybe necessary to impose certain tolerances on these values to account for jitter. It is worth noting that some joysticks use axes 2 and 3 for extra buttons.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6341"
></A
><H2
>Return Value</H2
><P
>Returns a 16-bit signed integer representing the current position of the <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
>.</P
></DIV
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CLASS="REFSECT1"
><A
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><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>Sint16 x_move, y_move;
SDL_Joystick *joy1;
.
.
x_move=SDL_JoystickGetAxis(joy1, 0);
y_move=SDL_JoystickGetAxis(joy1, 1);</PRE
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><H2
>See Also</H2
><P
><A
HREF="sdljoysticknumaxes.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickNumAxes</TT
></A
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