view docs/man3/SDL_Flip.3 @ 1543:98f9b16f565c

From: "Alex Volkov" Date: Thu, 10 Nov 2005 21:53:40 -0500 Subject: [SDL] BUG[?]: 32bpp RGBA->RGB colorkey blit, no SDL_SRCALPHA It seems there is either a documentation vs. reality mismatch or a real bug in SDL_blit_N.c:BlitNtoNKey(). The exact blit in question is a 32bpp RGBA->RGB, where RGBA has SDL_COLORKEY and *no* SDL_SRCALPHA flags. The doc in SDL_video.h states: * RGBA->RGB: * SDL_SRCALPHA not set: * copy RGB. * if SDL_SRCCOLORKEY set, only copy the pixels matching the * RGB values of the source colour key, ignoring alpha in the * comparison. BlitNtoNKey(), however, forgets to "ignore alpha in the comparison". The documentation makes perfect sense, so I think it is the code that is faulty. The attached patch corrects the code.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:43:15 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_Flip" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_Flip\- Swaps screen buffers
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_Flip\fP\fR(\fBSDL_Surface *screen\fR);
.SH "DESCRIPTION"
.PP
On hardware that supports double-buffering, this function sets up a flip and returns\&. The hardware will wait for vertical retrace, and then swap video buffers before the next video surface blit or lock will return\&. On hardware that doesn\&'t support double-buffering, this is equivalent to calling \fISDL_UpdateRect\fR\fB(screen, 0, 0, 0, 0)\fR
.PP
The \fBSDL_DOUBLEBUF\fP flag must have been passed to \fISDL_SetVideoMode\fR, when setting the video mode for this function to perform hardware flipping\&.
.SH "RETURN VALUE"
.PP
This function returns \fB0\fR if successful, or \fB-1\fR if there was an error\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_SetVideoMode\fP\fR, \fI\fBSDL_UpdateRect\fP\fR, \fI\fBSDL_Surface\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01