Mercurial > sdl-ios-xcode
annotate 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 |
| rev | line source |
|---|---|
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_GL_GetProcAddress" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
| 0 | 2 .SH "NAME" |
| 3 SDL_GL_GetProcAddress\- Get the address of a GL function | |
| 4 .SH "SYNOPSIS" | |
| 5 .PP | |
| 6 \fB#include "SDL\&.h" | |
| 7 .sp | |
| 8 \fBvoid *\fBSDL_GL_GetProcAddress\fP\fR(\fBconst char* proc\fR); | |
| 9 .SH "DESCRIPTION" | |
| 10 .PP | |
| 11 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\&. | |
| 12 .SH "EXAMPLE" | |
| 13 .PP | |
| 14 .nf | |
| 15 \f(CWtypedef void (*GL_ActiveTextureARB_Func)(unsigned int); | |
| 16 GL_ActiveTextureARB_Func glActiveTextureARB_ptr = 0; | |
| 17 int has_multitexture=1; | |
| 18 \&. | |
| 19 \&. | |
| 20 \&. | |
| 21 /* Get function pointer */ | |
| 22 glActiveTextureARB_ptr=(GL_ActiveTextureARB_Func) SDL_GL_GetProcAddress("glActiveTextureARB"); | |
| 23 | |
| 24 /* Check for a valid function ptr */ | |
| 25 if(!glActiveTextureARB_ptr){ | |
| 26 fprintf(stderr, "Multitexture Extensions not present\&. | |
| 27 "); | |
| 28 has_multitexture=0; | |
| 29 } | |
| 30 \&. | |
| 31 \&. | |
| 32 \&. | |
| 33 \&. | |
| 34 if(has_multitexture){ | |
| 35 glActiveTextureARB_ptr(GL_TEXTURE0_ARB); | |
| 36 \&. | |
| 37 \&. | |
| 38 } | |
| 39 else{ | |
| 40 \&. | |
| 41 \&. | |
| 42 }\fR | |
| 43 .fi | |
| 44 .PP | |
| 45 .SH "SEE ALSO" | |
| 46 .PP | |
| 47 \fI\fBSDL_GL_LoadLibrary\fP\fR | |
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
48 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |