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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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<HTML
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>SDL_JoystickNumBalls</TITLE
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>SDL_JoystickNumBalls</H1
><DIV
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><H2
>Name</H2
>SDL_JoystickNumBalls&nbsp;--&nbsp;Get the number of joystick trackballs</DIV
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>Synopsis</H2
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><P
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_JoystickNumBalls</B
></CODE
>(SDL_Joystick *joystick);</CODE
></P
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><H2
>Description</H2
><P
>Return the number of trackballs available from a previously opened <SPAN
CLASS="STRUCTNAME"
>SDL_Joystick</SPAN
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
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><H2
>Return Value</H2
><P
>Number of trackballs.</P
></DIV
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></A
><H2
>See Also</H2
><P
><A
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><TT
CLASS="FUNCTION"
>SDL_JoystickGetBall</TT
></A
>,
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>SDL_JoystickOpen</TT
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