Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_BlitSurface.3 @ 1120:8e1fde455471
Patch by me to fix crash described below.
--ryan.
To: sdl@libsdl.org
From: Rainer Deyke <rainerd@eldwood.com>
Date: Tue, 16 Aug 2005 01:08:18 -0600
Subject: [SDL] Bug report: SDL_CreateRGBSurface with SDL_HWSURFACE crashes
If SDL is in full-screen mode with a hardware video surface on OS X,
SDL_CreateRGBSurface with SDL_HWSURFACE crashes. The crash occurs on
line 109 of SDL_Surface.c. This was tested on OS X 10.3.9 with both SDL
1.2.8 and the latest CVS. Here is a small C++ program that demonstrates
the problem:
#include "SDL.h"
#include <stdio.h>
namespace {
void wait_for_key()
{
SDL_Event e;
printf("%d\n", SDL_GetAppState());
while (SDL_WaitEvent(&e)) {
if (e.type == SDL_KEYDOWN || e.type == SDL_QUIT) return;
}
}
}
int main(int, char *[])
{
SDL_Init(SDL_INIT_VIDEO);
SDL_Surface *screen
= SDL_SetVideoMode(640, 480, 32, SDL_FULLSCREEN | SDL_HWSURFACE);
SDL_Surface *s = SDL_CreateRGBSurface(SDL_HWSURFACE, 640, 480, 32,
screen->format->Rmask, screen->format->Gmask,
screen->format->Bmask, screen->format->Amask);
wait_for_key();
if (s) SDL_FreeSurface(s);
SDL_Quit();
printf("Success!\n");
return 0;
}
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Thu, 18 Aug 2005 06:46:32 +0000 |
parents | e5bc29de3f0a |
children | 546f7c1eb755 |
rev | line source |
---|---|
181
e5bc29de3f0a
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1 .TH "SDL_BlitSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_BlitSurface\- This performs a fast blit from the source surface to the destination surface\&. | |
4 .SH "SYNOPSIS" | |
5 .PP | |
6 \fB#include "SDL\&.h" | |
7 .sp | |
8 \fBint \fBSDL_BlitSurface\fP\fR(\fBSDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect\fR); | |
9 .SH "DESCRIPTION" | |
10 .PP | |
11 This performs a fast blit from the source surface to the destination surface\&. | |
12 .PP | |
13 Only the position is used in the \fBdstrect\fR (the width and height are ignored)\&. | |
14 .PP | |
15 If either \fBsrcrect\fR or \fBdstrect\fR are \fBNULL\fP, the entire surface (\fBsrc\fR or \fBdst\fR) is copied\&. | |
16 .PP | |
17 The final blit rectangle is saved in \fBdstrect\fR after all clipping is performed (\fBsrcrect\fR is not modified)\&. | |
18 .PP | |
19 The blit function should not be called on a locked surface\&. | |
20 .PP | |
55
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21 The results of blitting operations vary greatly depending on whether \fBSDL_SRCAPLHA\fP is set or not\&. See \fISDL_SetAlpha\fR for an explaination of how this affects your results\&. Colorkeying and alpha attributes also interact with surface blitting, as the following pseudo-code should hopefully explain\&. |
0 | 22 .PP |
55
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23 .nf |
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24 \f(CWif (source surface has SDL_SRCALPHA set) { |
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25 if (source surface has alpha channel (that is, format->Amask != 0)) |
55f1f1b3e27d
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26 blit using per-pixel alpha, ignoring any colour key |
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27 else { |
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28 if (source surface has SDL_SRCCOLORKEY set) |
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29 blit using the colour key AND the per-surface alpha value |
55f1f1b3e27d
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30 else |
55f1f1b3e27d
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Sam Lantinga <slouken@lokigames.com>
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31 blit using the per-surface alpha value |
55f1f1b3e27d
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32 } |
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33 } else { |
55f1f1b3e27d
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34 if (source surface has SDL_SRCCOLORKEY set) |
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35 blit using the colour key |
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36 else |
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37 ordinary opaque rectangular blit |
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38 }\fR |
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39 .fi |
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40 .PP |
0 | 41 .SH "RETURN VALUE" |
42 .PP | |
43 If the blit is successful, it returns \fB0\fR, otherwise it returns \fB-1\fR\&. | |
44 .PP | |
45 If either of the surfaces were in video memory, and the blit returns \fB-2\fR, the video memory was lost, so it should be reloaded with artwork and re-blitted: | |
46 .PP | |
47 .nf | |
48 \f(CW while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) { | |
49 while ( SDL_LockSurface(image)) < 0 ) | |
50 Sleep(10); | |
51 -- Write image pixels to image->pixels -- | |
52 SDL_UnlockSurface(image); | |
53 }\fR | |
54 .fi | |
55 .PP | |
56 This happens under DirectX 5\&.0 when the system switches away from your fullscreen application\&. Locking the surface will also fail until you have access to the video memory again\&. | |
57 .SH "SEE ALSO" | |
58 .PP | |
59 \fI\fBSDL_LockSurface\fP\fR, \fI\fBSDL_FillRect\fP\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_Rect\fR\fR | |
181
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parents:
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diff
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60 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |