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te: Thu, 17 Apr 2003 11:25:26 -0700 From: "Jim" Subject: [SDL] Frame buffer patches... Would seem that GCC 3.2.2 promotes all signed values to unsigned if any single vlaue is unsigned in an expression... for instance when calculating an elo touch position....evertyhign is an (int) except for cach_vinfo.xres which is unsigned. THerefore if y ou reverse the SDL_ELO_MIN_X and SDL_ELO_MAX_X values the resulging negative value pegs the expression to it's max. Attached it the accumu lated patch to typecast the unsigned values to (int) - *dx = (cache_vinfo.xres - (cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); + *dx = ((int)cache_vinfo.xres - ((int)cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); and also to provide quite failure to operations which have the screen currently locked... The touch screen I'm using the original values were exactly opposite of any position I touched on the screen - evaluating the math the expr ession SHOULD have handled reversing the min and max values - and after casting the unsigned .xres and .yres to a signed int - worked well. .. Jim
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Jan 2006 06:36:43 +0000
parents 355632dca928
children
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><H1
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>SDL_BuildAudioCVT</H1
><DIV
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><H2
>Name</H2
>SDL_BuildAudioCVT&nbsp;--&nbsp;Initializes a SDL_AudioCVT structure for conversion</DIV
><DIV
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><H2
>Synopsis</H2
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><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_BuildAudioCVT</B
></CODE
>(SDL_AudioCVT *cvt, Uint16 src_format, Uint8 src_channels, int src_rate, Uint16 dst_format, Uint8 dst_channels, int dst_rate);</CODE
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><H2
>Description</H2
><P
>Before an <A
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><SPAN
CLASS="STRUCTNAME"
>SDL_AudioCVT</SPAN
></A
> structure can be used to convert audio data it must be initialized with source and destination information. </P
><P
><TT
CLASS="PARAMETER"
><I
>src_format</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>dst_format</I
></TT
> are the source and destination format of the conversion. (For information on audio formats see <A
HREF="sdlaudiospec.html"
><SPAN
CLASS="STRUCTNAME"
> SDL_AudioSpec</SPAN
></A
>). <TT
CLASS="PARAMETER"
><I
>src_channels</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>dst_channels</I
></TT
> are the number of channels in the source and destination formats. Finally, <TT
CLASS="PARAMETER"
><I
>src_rate</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>dst_rate</I
></TT
> are the frequency or samples-per-second of the source and destination formats. Once again, see <A
HREF="sdlaudiospec.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_AudioSpec</SPAN
></A
>.</P
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><H2
>Return Values</H2
><P
>Returns <SPAN
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>-1</SPAN
> if the filter could not be built or 1 if it could.</P
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><H2
>Examples</H2
><P
>See <A
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><TT
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>SDL_ConvertAudio</TT
></A
>.</P
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><TT
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>SDL_ConvertAudio</TT
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>,
<A
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>SDL_AudioCVT</TT
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