Fixed bug #15 SDL_blit_A.mmx-speed.patch.txt -- Speed improvements and a bugfix for the current GCC inline mmx asm code: - Changed some ops and removed some resulting useless ones. - Added some instruction parallelism (some gain) The resulting speed on my Xeon improved upto 35% depending on the function (measured in fps). - Fixed a bug where BlitRGBtoRGBSurfaceAlphaMMX() was setting the alpha component on the destination surfaces (to opaque-alpha) even when the surface had none. SDL_blit_A.mmx-msvc.patch.txt -- MSVC mmx intrinsics version of the same GCC asm code. MSVC compiler tries to parallelize the code and to avoid register stalls, but does not always do a very good job. Per-surface blending MSVC functions run quite a bit faster than their pure-asm counterparts (upto 55% faster for 16bit ones), but the per-pixel blending runs somewhat slower than asm. - BlitRGBtoRGBSurfaceAlphaMMX and BlitRGBtoRGBPixelAlphaMMX (and all variants) can now also handle formats other than (A)RGB8888. Formats like RGBA8888 and some quite exotic ones are allowed -- like RAGB8888, or actually anything having channels aligned on 8bit boundary and full 8bit alpha (for per-pixel alpha blending). The performance cost of this change is virtually 0 for per-surface alpha blending (no extra ops inside the loop) and a single non-MMX op inside the loop for per-pixel blending. In testing, the per-pixel alpha blending takes a ~2% performance hit, but it still runs much faster than the current code in CVS. If necessary, a separate function with this functionality can be made. This code requires Processor Pack for VC6.

.TH "SDL_GL_SetAttribute" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_GL_SetAttribute\- Set a special SDL/OpenGL attribute
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_GL_SetAttribute\fP\fR(\fBSDL_GLattr attr, int value\fR);
.SH "DESCRIPTION"
.PP
Sets the OpenGL \fIattribute\fR \fBattr\fR to \fBvalue\fR\&. The attributes you set don\&'t take effect until after a call to \fI\fBSDL_SetVideoMode\fP\fR\&. You should use \fI\fBSDL_GL_GetAttribute\fP\fR to check the values after a \fBSDL_SetVideoMode\fP call\&.
.SH "RETURN VALUE"
.PP
Returns \fB0\fR on success, or \fB-1\fR on error\&.
.SH "EXAMPLE"
.PP
.nf
\f(CWSDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
if ( (screen=SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL )) == NULL ) {
  fprintf(stderr, "Couldn\&'t set GL mode: %s
", SDL_GetError());
  SDL_Quit();
  return;
}\fR
.fi
.PP
.PP
.RS
\fBNote:  
.PP
The \fBSDL_DOUBLEBUF\fP flag is not required to enable double buffering when setting an OpenGL video mode\&. Double buffering is enabled or disabled using the SDL_GL_DOUBLEBUFFER attribute\&.
.RE
.SH "SEE ALSO"
.PP
\fI\fBSDL_GL_GetAttribute\fP\fR, \fIGL Attributes\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01