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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_Overlay" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_Overlay\- YUV video overlay
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint32 format;
  int w, h;
  int planes;
  Uint16 *pitches;
  Uint8 **pixels;
  Uint32 hw_overlay:1;
} SDL_Overlay;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBformat\fR
Overlay format (see below)
.TP 20
\fBw, h\fR
Width and height of overlay
.TP 20
\fBplanes\fR
Number of planes in the overlay\&. Usually either 1 or 3
.TP 20
\fBpitches\fR
An array of pitches, one for each plane\&. Pitch is the length of a row in bytes\&.
.TP 20
\fBpixels\fR
An array of pointers to teh data of each plane\&. The overlay should be locked before these pointers are used\&.
.TP 20
\fBhw_overlay\fR
This will be set to 1 if the overlay is hardware accelerated\&.
.SH "DESCRIPTION"
.PP
A \fBSDL_Overlay\fR is similar to a \fI\fBSDL_Surface\fR\fR except it stores a YUV overlay\&. All the fields are read only, except for \fBpixels\fR which should be \fIlocked\fR before use\&. The \fBformat\fR field stores the format of the overlay which is one of the following: 
.PP
.nf
\f(CW#define SDL_YV12_OVERLAY  0x32315659  /* Planar mode: Y + V + U */
#define SDL_IYUV_OVERLAY  0x56555949  /* Planar mode: Y + U + V */
#define SDL_YUY2_OVERLAY  0x32595559  /* Packed mode: Y0+U0+Y1+V0 */
#define SDL_UYVY_OVERLAY  0x59565955  /* Packed mode: U0+Y0+V0+Y1 */
#define SDL_YVYU_OVERLAY  0x55595659  /* Packed mode: Y0+V0+Y1+U0 */\fR
.fi
.PP
 More information on YUV formats can be found at \fIhttp://www\&.webartz\&.com/fourcc/indexyuv\&.htm (link to URL http://www.webartz.com/fourcc/indexyuv.htm) \fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_CreateYUVOverlay\fP\fR, \fI\fBSDL_LockYUVOverlay\fP\fR, \fI\fBSDL_UnlockYUVOverlay\fP\fR, \fI\fBSDL_FreeYUVOverlay\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01