view docs/man3/SDL_JoystickOpen.3 @ 1542:a8bf1aa21020

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.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:39:29 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_JoystickOpen" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_JoystickOpen\- Opens a joystick for use\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_Joystick *\fBSDL_JoystickOpen\fP\fR(\fBint index\fR);
.SH "DESCRIPTION"
.PP
Opens a joystick for use within SDL\&. The \fBindex\fR refers to the N\&'th joystick in the system\&. A joystick must be opened before it game be used\&.
.SH "RETURN VALUE"
.PP
Returns a \fBSDL_Joystick\fR structure on success\&. \fBNULL\fR on failure\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWSDL_Joystick *joy;
// Check for joystick
if(SDL_NumJoysticks()>0){
  // Open joystick
  joy=SDL_JoystickOpen(0);
  
  if(joy)
  {
    printf("Opened Joystick 0
");
    printf("Name: %s
", SDL_JoystickName(0));
    printf("Number of Axes: %d
", SDL_JoystickNumAxes(joy));
    printf("Number of Buttons: %d
", SDL_JoystickNumButtons(joy));
    printf("Number of Balls: %d
", SDL_JoystickNumBalls(joy));
  }
  else
    printf("Couldn\&'t open Joystick 0
");
  
  // Close if opened
  if(SDL_JoystickOpened(0))
    SDL_JoystickClose(joy);
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_JoystickClose\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00