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Date: Tue, 12 Aug 2003 14:26:19 +0200 (MEST) From: "Mattias Engdeg?rd" Subject: bug in SDL_GetRGB/GetRGBA There's an embarrassing bug in GetRGB/GetRGBA which apparently has been there for years. It incorrectly converts colours with < 8 bits/channel. It came to my attention today in #sdl. What it does now is (for each channel): rv = (pixel & fmt->Rmask) >> fmt->Rshift; *r = (rv << fmt->Rloss) + (rv >> (8 - fmt->Rloss)); which is wrong; the last line should be *r = (rv << fmt->Rloss) + (rv >> (8 - (fmt->Rloss << 1)));
author Sam Lantinga <slouken@libsdl.org>
date Tue, 12 Aug 2003 15:17:20 +0000
parents e5bc29de3f0a
children 546f7c1eb755
rev   line source
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e5bc29de3f0a Updated from the SDL Documentation Project
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1 .TH "SDL_SemPost" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_SemPost\- Unlock a semaphore\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 #include "SDL_thread\&.h"
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8 .sp
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9 \fBint \fBSDL_SemPost\fP\fR(\fBSDL_sem *sem\fR);
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10 .SH "DESCRIPTION"
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11 .PP
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12 \fBSDL_SemPost\fP unlocks the semaphore pointed to by \fBsem\fR and atomically increments the semaphores value\&. Threads that were blocking on the semaphore may be scheduled after this call succeeds\&.
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13 .PP
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14 \fBSDL_SemPost\fP should be called after a semaphore is locked by a successful call to \fISDL_SemWait\fR, \fISDL_SemTryWait\fR or \fISDL_SemWaitTimeout\fR\&.
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15 .SH "RETURN VALUE"
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16 .PP
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17 Returns \fB0\fR if successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&.
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18 .SH "EXAMPLES"
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19 .PP
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20 .PP
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21 .nf
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22 \f(CWSDL_SemPost(my_sem);\fR
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23 .fi
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24 .PP
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25 .SH "SEE ALSO"
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26 .PP
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27 \fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemWait\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemValue\fP\fR
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28 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00