view docs/man3/SDL_GL_GetProcAddress.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_GL_GetProcAddress" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_GL_GetProcAddress\- Get the address of a GL function
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBvoid *\fBSDL_GL_GetProcAddress\fP\fR(\fBconst char* proc\fR);
.SH "DESCRIPTION"
.PP
Returns the address of the GL function \fBproc\fR, or \fBNULL\fR if the function is not found\&. If the GL library is loaded at runtime, with \fI\fBSDL_GL_LoadLibrary\fP\fR, then \fIall\fP GL functions must be retrieved this way\&. Usually this is used to retrieve function pointers to OpenGL extensions\&.
.SH "EXAMPLE"
.PP
.nf
\f(CWtypedef void (*GL_ActiveTextureARB_Func)(unsigned int);
GL_ActiveTextureARB_Func glActiveTextureARB_ptr = 0;
int has_multitexture=1;
\&.
\&.
\&.
/* Get function pointer */
glActiveTextureARB_ptr=(GL_ActiveTextureARB_Func) SDL_GL_GetProcAddress("glActiveTextureARB");

/* Check for a valid function ptr */
if(!glActiveTextureARB_ptr){
  fprintf(stderr, "Multitexture Extensions not present\&.
");
  has_multitexture=0;
}
\&.
\&.
\&.
\&.
if(has_multitexture){
  glActiveTextureARB_ptr(GL_TEXTURE0_ARB);
  \&.
  \&.
}
else{
  \&.
  \&.
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_GL_LoadLibrary\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01