Mercurial > sdl-ios-xcode
view docs/man3/SDL_keysym.3 @ 997:3bf4103b2b89
Date: Sat, 27 Nov 2004 13:35:43 +0100
From: "Martin Bickel"
Subject: [SDL] Patch: fixing uninitilized palette
while running Valgrind over my application I found the following
problem in SDL:
The function MapNto1 allocates SDL_Color colors[256] but does not
initialize it.
SDL_DitherColors is then called which initialized the r, g and b
component, but not the 'unused' component of each color.
When Map1to1 is called from MapNto1, it runs a memcmp on the colors,
which also evaluates the unused component and therefor returns
differences much more often than necessary.
So the 'unused' component of SDL_Color should be initialized. This
patch does this by calling memset for the whole array in MapNto1 .
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Tue, 30 Nov 2004 14:28:20 +0000 |
parents | e5bc29de3f0a |
children | 546f7c1eb755 |
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.TH "SDL_keysym" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_keysym\- Keysym structure .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct{ Uint8 scancode; SDLKey sym; SDLMod mod; Uint16 unicode; } SDL_keysym;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBscancode\fR Hardware specific scancode .TP 20 \fBsym\fR SDL virtual keysym .TP 20 \fBmod\fR Current key modifiers .TP 20 \fBunicode\fR Translated character .SH "DESCRIPTION" .PP The \fBSDL_keysym\fR structure is used by reporting key presses and releases since it is a part of the \fI\fBSDL_KeyboardEvent\fR\fR\&. .PP The \fBscancode\fR field should generally be left alone, it is the hardware dependent scancode returned by the keyboard\&. The \fBsym\fR field is extremely useful\&. It is the SDL-defined value of the key (see \fISDL Key Syms\fR\&. This field is very useful when you are checking for certain key presses, like so: .PP .nf \f(CW\&. \&. while(SDL_PollEvent(&event)){ switch(event\&.type){ case SDL_KEYDOWN: if(event\&.key\&.keysym\&.sym==SDLK_LEFT) move_left(); break; \&. \&. \&. } } \&. \&.\fR .fi .PP \fBmod\fR stores the current state of the keyboard modifiers as explained in \fI\fBSDL_GetModState\fP\fR\&. The \fBunicode\fR is only used when UNICODE translation is enabled with \fI\fBSDL_EnableUNICODE\fP\fR\&. If \fBunicode\fR is non-zero then this a the UNICODE character corresponding to the keypress\&. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character: .PP .nf \f(CWchar ch; if ( (keysym\&.unicode & 0xFF80) == 0 ) { ch = keysym\&.unicode & 0x7F; } else { printf("An International Character\&. "); }\fR .fi .PP UNICODE translation does have a slight overhead so don\&'t enable it unless its needed\&. .SH "SEE ALSO" .PP \fI\fBSDLKey\fR\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00