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view docs/man3/SDL_SemValue.3 @ 688:c0522010bb6d
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 |
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.TH "SDL_SemValue" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_SemValue\- Return the current value of a semaphore\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" #include "SDL/SDL_thread\&.h" .sp \fBUint32 \fBSDL_SemValue\fP\fR(\fBSDL_sem *sem\fR); .SH "DESCRIPTION" .PP \fBSDL_SemValue()\fP returns the current semaphore value from the semaphore pointed to by \fBsem\fR\&. .SH "RETURN VALUE" .PP Returns current value of the semaphore\&. .SH "EXAMPLES" .PP .PP .nf \f(CW sem_value = SDL_SemValue(my_sem);\fR .fi .PP .SH "SEE ALSO" .PP \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_SemPost\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00